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1 6"8 45 FO2 ; a 9MC*IAtZKID 109,2 N

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3 SCOTTk AI35 62~ lilt. FL4i4 FILE COM ask n) 0 r)0q5 _ F kafl J ,- APBr zr.p"4l U OPERATING LOCATION - A USAFETAC Air Weather Service (MAC) NOV 1987 REVISUED UNIFCMI UUWAY OF1 SRFACE NEATHER OSERVATIONS BND FORKS AF ND NUC N 47 SS N ELEY 911 FT KRDR PARTS A - F HOIUM OUIHARIZED LOT PERIOD OF weckorda HOURLY ONNERVATIONSa ALM 77 - JUL 37 UMMV OF DAY DATA* JUN 59 - JUL 37 NW so Ion Sfe public relee3 FEDERAL BUILDING DE-ECTE etrihati n Ulieud.- AHVLE, N.C W. --. *., - *v bz 1D

4 URCET DOOIU&TIU FAC Ua. Impsort Security Classificat ion: UMSSIviN 3. DIstrIbutiem/Amilabilit, of lesert!: Approved for public release; Distribution unlimit-ed. 4. Ferftga 2gemutiest Resort Numer: UShIKTACIDS-87/ Maitorim orsomizatiem Desert Number: USAFTACDS-87/073. Ga. 6b. Nam of Tierming Ormsizat ion: UShJITAC/OL-A Office Symbol: 6c. Airsew: Federal Building, Asheville, NC Title: (RUSSWO) Grand Forks APB ND. 12 Pereonal Author(s): 13 Tp of Desert: Data Summary 16 Supplementary notation: 17 COS8M odes: Field-04, Group SobJect Term: *climatology; *eather; meteorological conditions; winds; precipitation; temperature; visibility; barometric pressure; relative humidity; sky cover; psychrometric data; ceiling; Revised Uniform Summary of Surface Weather Observations (RUSSIIO); Grand Forks APB ND; North Dakota; USND mospheri hmena; A Rl lt, ofreptraton SAe as rort. s AR D eiig n 21 Abtract SecurIty Claseificatim: UNCLASSIFIED. 226 amo a2w " siiel Marianne L. Cavanaugh 22b ZZ 22aof t USAPSTAC/LD ID FM 1473 UUCLASSIFU

5 * PIREUU ssssss SsssSS MU W U.0000 om v s~s MM no OR uu UU SSS SSS SIs sss WM M 0: an OR UU UU. SS SS SS SS vm MM RONRRSS SI MM MW mmwnm &ls S MM v mm 0 ER AR 1 UU UU sis us ss Ss SS uu MUM um SS~sSSS SSSSSS UK u vv m UUssSS ssssss WNW MUM 0000 STATION NAME GRtAND FORKS arm NO a For STATION WNINK?TSTS CALL 10t KROR PERIOD OF RECOD 14OURS SUN"ARIZES: LSI~ 0 * 4 o3 POURLY OUSERVATIONSS LUG 17 - JUL 47at1n.. su~nat of0*, Aas JUN 59 - JUL 67,at covcsult tou: *HI Dletribuilon/ oatcpaoucco ~ *~ 13? vailablllty Co4.a D vaut an/or D st ioec ~-- - N

6 OL-SIUSAFETACIACAVS REVISED UNIran SUmARY Or SURFACE WEATHER OBSERVATIONS ASHEVILLE MC HOURLY OBSERVATIONS: ALL RECORO OR RECORD SPECIAL OBSERVATIONS RECOROtO ON TH" ims FORMS 10110A AT SCHEDULED HOL'UL INTERVALS. SUMARY OF DAY DATA IDALY OBSERVATIONS): OAT& COMPILED FROM ALL AVAILABLE OBSERVATIONS WHICH INCLUOS H4OURLY OBSERVATIONS AND DAILY DATA RECOROED IN COLUMNS 66-?3 AIS FORMS 1o11A. DESCRIPTION Or SUMMARIES: PRECEEDING EACH PART OF THE RUSSVO IS A BRIEF DISCUSSION OF THE SUMMARY INCLLOING THE ANNMER OF PRESENTATION. STANDARD 3-HOUR TINE GROUPS: IN ALL SUMMARIES SHOVING DIURNAL VARIATIONS. WE SUMMARIZE DATA USING THE FOLLOkING EIGHT 3-HOUR TIME PERIODS IN LOCAL STANDARO TINE OSOO, , 09OC-I l400, 1S00-T100, , LST. FOR A D[TAILEO 0ESCRIPTION OF EACH SUMMARY WITH EXAMPLES AND EXERCISES Oi ITS USAGE, SEE UsAFETaCiTN-O3-OOI, 'AN AID FOR USING THE REVISEO VNIFORM SUONMARY OF SURFACE WEATHER OSERVATIONS" 1iUSSVGO. TABLE OF CONTENTS STATION HISTORY PART A: PART So PART to PART Ds WEATOER CONDITIONS AND ATMOSPHERIC PHENOPENA SUMMARIES PRECIPITATION@ SNOWFALL, AND S.NO DEPT" SUMMARIES SURFACE NINO SUMMARIES CEILING VERSUS VISIBILITY AND SKY COVER SUMMARIES PART to TEMPER4TURE AND RELATIVE HUMIDITY SUMMARIES PART V: PRESSURE SUMMARIES AWSMSC NUMER: 11 IS VUPK* IS THE AIR WEAIHER SERVICE MASTER STATION CATALOG NURDER. THIS NURSER IS COPPRISEO OF THE WHO NUMBER WITH SHE AODTTION OF A SUFFIX 40 THROUiS0 'P, IN CASES VHER TH[EE IS *0 SESIONATED Wme NURDER, a S-DIGIT NUMBER IS CREATEO IN AGREEMENT wilp UND RULES PLUS a SINP DIGIT. IHSE N0UMERS AE ALSO 1RFiEE TO AS AITSAV OR USAPE1AC NUMBERS WHICH UNIQUELY IDENTIFY MORE THA ISwOOO REPORTING STATIONS WORLD VICE. i '

7 a pnm D Y t- ; N 7 4m_, v F r "!o o A n o mtt c m, 4 7 g 5 8 l u, 9 7 M STATION LOCATION AND INSTRUMENTATION HISTORY OFI "ci LATTN LINTO m qm meo IsJU m "MTN AlmOR_ u I Grand Forks APB ND AFB Sep 59 Mhz 62 N W ansans A 62 Doe 70 N w Sams Sa 24 3 Same Sas Jan 71 rob 78 N Same Same Sans t Baims Mar 78 Jul 87 N Sane save save 24 urs ws mhuli FI l I IT U W TTVK IT AMl! VERS. AS9flUSAL UPI!?.U MEAI TOO CUm I 2 Sep 59 Apr 60 Located on top of Contzol lbwet A N 1 N/A located 1540 ft N and 950 ft 8 of N/MNV L no-2a 80 ft 15 ft 3 Apr 61 and of zny 35. Located 1560 ft N of 8 end of rnvy Si Sis ssam and 950 ft 2 of oenterlje. 4 Apr located 1560 ft N of 8 end of Sano Sam Barns rnwy 950 ft 3 of centerline ro"i Located 1000 ft S of V end of ( rnwy and 50 ft 3 of centerlne so" Sai Sam rnvy 17. s Noy no dong. Sans W-36 Sums 9APITA "mq 0-I I OLA I a

8 WMAKmm Weu lemma..... Uff-SP I UIdg$11 gl lll IF a WARM 1191 w NTASMw KHUL AfThSSUL IUIMI 0 KMU MS GUI 6 J=71 1. Loted 2800 ft N of the Send UGNQ11 RO ft of RAW and 900 ft Z of centerliae of hruy lodated 2200 ft S of the N end Sam Same of ravy and 400 ft a of the centr. line of Rnwy feb Sam Same Same Sam 2. Same Sam Sam Jul Sem Sam Sam Same 2. Sim -_7!*. P US

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10 WEATHER CONOITIONS AND ATMOSPHERIC PHENOMENA SUMMARIES WEATHER CONDITIONS SUMMARY 1. A PERCENTAGE FREQUENCY OCCURRENCE SUMMARY OF VARIOUS ATMOSPHERIC PHENOMENA AND OBSTRUCTIONS TO VISION. 2. DATA BASED ON HOURLY OBSERVATIONS. 3. SUMMARIZED BY TIE STANDARD 3-HOUR TIME GROUPS BY MONTH, MONTHLY AND ANNUALLY IALL YEARS COMBINtDI. ATMOSPHERIC PHENOMENA SUMMARY 1. A PERCENTAGE FREQUENCY OF DAYS SUMMARY OF VARIOUS ATMOSPHERIC PHENOMENA AND OBSTRUCTIONS TO VISION. 2. DATA BASED ON SUMMARY OF DAY DATA. 3. SUMMARIZED BY NONTH WITH ALL HOURS AND ALL YEARS COMBINED. OEFTNI TIONS: THUNOERSTORMS: ALL REPORTED THUNDERSTORMS, TORNADOES AND WATERSPOUTS. RAIN AND/OR DRIZZLE: ALL REPORTED RAIN AND OR DRIZZLE FALLING TO THE GROUND BUT NOT FREEZING. FREEZING RAIN ANO/OR FREEZING DRIZZLE IGLAZEI: ALL REPORTED FREEZING RAIN OR FREEZING DRIZZLE. SNOW AND/OR SLEET. SNOW INCLUDING SNOW PELLETS AND GRAINS, ICE CRYSTALS AND PELLETS. ANDIOR SLEET lice PELLETS1. PAIL: ALL REPORTED HAIL. A ALL PRECIPITATION: THIS CATEGORY INCLUOS ALL OBSERVATIONS REPORTING PRECIPITATION. BECAUSE MORE THAN ONE TYPE Of PRECIPITATION MAY APPEAR IN A SINGLE OBSERVATION, THE SUN OF THE PERCENTAGES IN THE INODVICUAL COLUMNS MAY EXCEED THE PERCENTAGES IN THIS COLUMN. FOG: ALL REPORTED FOG. ICE FOG AND GROUND FOG. SNORE AND/OR H4AZE: ALL REPORTED SNROPE HAZE AND ANY COMBINATION THEREOF. BLOWING SNOW: ALL REPORTED BLOWING SNOWS INCLUDING DRIFTING whrf REPORTED. OLST AND/OR SAND: ALL REPORTED DUST, SAND, BLOWING OUST, BLOWING SAND AND ANY COMBINATION THEREOF. THE ATMOSPHERIC PHENOMENA SUMMARY (OATS WITHI INCLUDES ONLY THOSE REPORTS bfen THE PHENOMENA VISIBILITY LESS THAN S/4 MILES METERS1. ALL OBSTRUCTIONS TO VISION: INCLUDES ALL REPORTS OF OPSTRUCTIONS TO VISION IFOG THRU OUST/SANDI "NO A LOWING SPRAY. BECAUSE MORE THAN ONE PHENOMENA PER OBSERVATION MAY OCCUR, THE SUN OF IN INDIVIDUAL COLUMNS MAy EXCEED THIS COLUMN.

11 NOTES. I. A VALUE IN THE TABLES Of ".0" INDICATES LESS THAN.054 OCCURRENCE WHICH IS USUALLY ONLY ONE OCCURRENCE 2. EVAR STATIONS ESEGINNENG IN JAN 1961 AND SYNOPTIC REPORTING STATIONS RECORDED ON THE AiS FORMS AND TRANSMITTED LONGLINE ONLY THE HIGHEST ORDER OF ATHOSPHERIC PHENOMENA OBSERVED. BEGINNING IN JAN 1970, "ETAR STATIONS RECORDED ALL OISERVED PHENOMENA BUT CONTINUED TO'TRANSMIT ONLY THE HIGPEST ORDER. FOR EXAMPLE, If THE OBSERVATION CONTAINED RAIN, FOG AND SHONE, ALL TFREE WILL APPEAR ON THE AUS FORMS O OA. BUI ONLY THE RAIN AS TRANSMITTED LONGLINE. THEREFORE ONLY THE RAIN APPEARS IN OLR DATA BASE FOR HOURLY SUMMARIZATION. TIqS PRACTICE EFFECTS THE PERCENTAGES IN THE TABLES. 1 I.., 17 L, 4,.

12 GLOBAL CLIMAIOLOGV BRANCH USAF ET AC PERCENTAGE FREQUENCY OF OCCURRENCE Of WEATHER FROM 'DVRNLV OBSERVATIONS CONDITIONS AT* WEATHER SERVICEIMAC r STATION NUMBER: STATION NAME& GRAND FORKS AFS BIC PERIOD OF RECORDs 76-4? MSPIN: JAN IRAIN FRZIN6 SNOW I **s SPOKE OU1ST I BSs HOURS I SIMS &/OR RAIN &too SAIL WITH FOG 100 SLOWING &/OR NICEST TOTAL ILSISI DRIZZLE 9IAR SLEET PrCIP HAZE SNOW SAND 10 es IDRIZZLE VISION oo0 2 I S." C3-OS I l A C9-11 I b I.? IS S I I.2.3 2S TOTALS I STATION NUMBERS STATION NAME: GRANO FORKS AF@ ND PERIOD Of RECORO: MONTH: FES I RAIN FRZING SNOW I 035 SMONE OUST I 085 FOURS I STMS 61CR RAIN &IOR FAIL WITP FOG 91OR SLOWING 91OR WICBST TOTAL ILSTI IDRIZZLE 61OR SLEET PRECIP 14AZE SNOW SAND 10 CBS IDRIZZLE VISION C3-05 I %64, 06-D6I i09-i S S I?.6 i S Z I $ I1.? s k.

13 GLOBAL CLIMATOLOGY RACH PERCENTAE FREOUENCV Of OCCUPRiNCE Of ElACII CONDITIONS USot A C FROM HOURLY OBSERVAIONS SSTAION NLPE ENy STATION NAMES GRAND FORKS AF8 NO PERIOD OF RECORD: 18-B?. ROIVT0: PAR S N1AIN FIZING SNOW % ass SPOKE DUST 2 OBS IOURS TSIKS L/OR RAIN Cl0n PAIL 1111 FOG C/IO SLOWIN G 1On 1OST TOTAL ILSI DRIZZLE &/OR SLEET PSECIP HAZE SNOW SAND 10 OSs DRIZZLE VISION O Ii. e.g C is.; C t S S I" $ ": I ? I TOTALS ?.2 1S.S STATION NUMBERS 727STS STATION NAMES BRAND FORKS Are No PERIOD OF RECORO: I MONTHS APR I lain FIZING SHOW It OS SPOKE Dust I CBS P HOURS g ISTIS & O RAIN IO1 MAIL MITH FOG /Of BLOWING 1/OR Ufc8SI TOTAL (LOT} DRIZZLE L/OR SLEET PRECIP PA2E Show SAND TO OS DRIZZLE VISION S S Is.7.1 lo.4 7.S I % SIS-1T ? l TOTALS ?20L eeo

14 GLOBAL CLIMAIOLOGY BRANCH L SAFETAC AIR WEATHER SERvICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF WEATHER CONDITIONS FROM sourly OBSERVAIIONS STATION NUM (R 727STS STATION NAME: GRAND FORKS AFB ND PEPIOD OF RECOROD MONTH: MAY... #A... ;;-;.;..... I RAIN FMZING SNOW I DBS SMODUT POUcRS I ISImS &/On RAIN 1 OR FAIL WITH FOG CIOR BLOWIN G C/OR M1QS TOTAL SLST I DRIZZLE 5/OR SLEET PRECIP HAZE SNOW SAND 10 OS I DRIZZLE VISION... LO-2, "* ;'; ;; OS o C6-06I. 9.7.S IZ S.1 S L IS Z 930 TOTALS % STATION NUMBER: 72757S STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONTHS JUN... RAIN FRZING SNOW I OeS SMOKE OUST I OS POURS I TSTHS ctor RAIN c/or PAIL WITH FOG C/OR SLOWING &/OR u/oust TOTAL ILSTI ORIZZLL LIOR SLEET PRECIP HAZE SNOW SAND 10 OBS I DRIZZLE VISION D00-0O OS S TO o IS-]? oo OO q0 j!o:als 1: ?200 *** 0,.... * l * * * *eeee* ***... * *** :5o... * Rel*** 0** *~e

15 )I~~~ GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY Of OCCURRENCE or WEATMER CONDITIONS 'S,eTAC FO" HOURLY OBSERVATIONS AIR WEAT14ER SERVICE/NAC iii; SATAO 6LoDAL NUBR Dl, STATION NAME: clogio06 [RIN GRAND FORKS clogic AFS No MAI. Ni,(l" OG o PERIO~ I LOWIG ~;:o RECORD 78- IO losetoa SPINNEe,.,,, ~LE,T00,*OO PA, SNOW., SANDOsnN CBS, I 3.O RAI0 DRIZZLEN a.7 VISIO I S OS S $.? : S.: 930-1TOTALS I I : STAIO 170 N UMBER: STATION NAME- GRAND FORKS AFS 140 PERIOD Of RECORD: *.1 MONTHS AUG RAIN FRZING SNOW I CBS SNONE OUST I 035 HOURS I SIRS S/OR RAIN ClOR MAIL WITH FOG I/OR SLOWING 91OR N/CBS TOTAL ILST)I DRIZZLE &/OR SLEET PRECIP HAZE SNOW SAND DRIZZLE VISION '"00-02 I * 03-0S 1 2.S 7.% ? S IS-17 l I %.9 1.S TOTALS 2.1 oco 0 e S.3 eee 6.3 eeeo 9.0 eee o ee eee e e L

16 CLINATLOGY "AC PIEC ENT A Ei F REO U CY Of OCCU RENC E of WEITNHE CON ITIONS USif(ifC P3NN HOURLY OSSNUVAIONS IR weatk[ SERLVICCIPA STATION wmsh t6 721SS STAT00I NAES Gnbe runs Are It P(RIO Of RECORS 7-06 I 03-OS I ote Frzli spew a gas IS*~[ DUST % as FO U o S s l s L O R m i ft & O N V A I L I T H F o s 9 0 L O W N G 9 00 V IC O S T T O T LAf OLS11 DRIZZLE 9104 SLECT PREIF[l P42[ Snow Save To RSs DRIZZLE VISION ? C Ce o.o S.6 1.? :o 9.1 S S-37.0? go ,.,1 goo... ILS S.S 720" NUMIBES -STAION 72TS STATION N9.ES O1R0 f0wns 2.r No PERIO o RECORDS Ili *AIR ro 6 snow I Oss SN0llf DUST I 01S : 2-19OS Islas 6.6p I: c/o* 3N MAIL 114. FOG $LO IN 0 62ST T30L ILSI I L[ I9 LE6.6CIT MAZE SON3.3ND 10 0 enizzl[ VISION 03-0S S.A. S '"!C6-06, S.3 9o O * c v o l l S O ~ 4.0 6h I2 s S.2.1 S So ~ ~ ~ 4vJts.1 9el 3.0 it.? 6.9.T e 1440 eee ee*eee~e* eeee

17 .4. GLOBAL CLINAI1LOGV BRANH PERCENAGE FREOUECV Of OCCURENCE OF ULATPER CONDITIONS USAFCTAC AIR WEATNR SEtVlCuONAC FROM NOU 9 LV OSERVATIONS mumsta, i21515 StatION hntme seams rooms Are No PERIOD Of RECORD: Ti-SO MONTHS NOV S... e RAIN rming SNOW 1 Gas SHONE OUST I 035 HOURS STHS Clan RAIN coo HilL WITN FOG 10N SLOWING 11i$ w/09st TOTAL ILST DOIZZLE glop SLEET PEECIP HAZE SNOW SAND 10 OS J DRIZZLE VISION * I DOS e Is o IS is-1i V Io S T OTALS 2.41 S $ STAIO NUNKt 7273,75 STATIN *NAMS SEAND FORMS AF ND PERIOD Of RECORDS??-96 NONTM: DEC rAIN FIZZ SNOe I 0ss SMOKE DUST I 085. HOURS ISINS &LO Oain o NAIL W11v FOG glo SLOWING 100 I/CAST TOTAL ILSI) DRIZZLE 101 SLEET PECIP HAZE SNOW SAND to OS ORIZZLE VISION I S-OS S O8 I * e I.? 9.7 ** S *9-1? I IS.? I.S I.0.6 Is.% I TOTALS I , , Is.?

18 GLOBAL CLINAIOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF WEATNER CONDITIONS usafeiac FROMN OUNLY OBSERVATIONS AIR WEATHR SERVICEINAC STATION NUHMBR: STATION NANE: GRAND FORKS AF8 NO PERIOD OF RECORtD: NONTHS ALL HOURS I RAIN TSTHS, lon razin RAIN SNm &OR HAIL % OBS WITH FOG SNOaE.9000 BLOWIN G OUST LION % OS3 WIOBST TOTAL ILST I DRIZZLE /O SLEET PRECIP 04AZE SNOW SAND 10 OS DRIZZLE VISION J,., FEB h A, ? *0 AP MAT o D os S JUN S JUL 2.0 S AUG SS i r % S e S?2 0 0 ~1 OC T.1 9.S ?.a -.EC o0 l..s 1s o 1s.T 74oo_4'".1. TOTAYLLS IT74 1. I..o.i..o...o..o...e...o...o...o...o...oo...o...O...eoe...

19 .OBAL CLIMATOLOGY BRANCH PERCENIAG Of OaYS WITH VARIOUS ATMOSPHERIC PHENOMENA.AFE1AC FROM DAILY OBSERVATIONS IN wealter SERVICLIMAC fajion NUMBER: 72157S S IAI04 kame: GRAND FORKS A's No PEPIOD OF RECORD: ;... " "' I ' '... ; NG... N B "... MONT-: K ALL ' U, ' I RAIN FAZING snow % 06 S MOEOUT A I 1SIMb LIOR RAIN LIOR HAIL WITH FOG OR BLOWING LJOR WILUSI TOTAL MOAN I LRIZlLL LIOR SLEET PRECIP IAZE SNOW SAND 10 OaS I DRIZZLE VI!IoN JAN I FE 1u b 781 MAR IL 1t b Ob APR u c.1 ;6.3 b4l "AY ;1.s 86b JUN 22.3 S..L G 640 JUL 31.2 'b *d AUG l , SEP I i0. 82t OCT i2.6 b6b NOV 5d So b4o DEC % b TCTALS 8.9 3J.U g.5 s

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21 i PERCENTAGE FRQEC FVAIU AL AMONT Of PRECIPIT:ATI N DISNF ND b DETH) SUMMARIES: GVE AMU. DISPLAYED ARE: PERCENT OF DAYS WITH MEASURABLE AMOUNTS. APECNOfDY T OAMUSRCS9GVNNURS MEANS, GREATEST - AMOUNTS AND.. LEAST AMOUNTS ITA'E STATISTICAL VALUES ARE NOT INCLUDED IN THE SNow I.. DEPTH SUMMARY BECAUSE OF THEIR DOUBTFUL A06D LIMITED VALUE 3. ALSO PROVIDED ARE TPE UISERVATION COUNTS. A VALUE OF ".0" IN THESE TABLES INDICATES LESS THAN.OS% WHICH USUALLY INDICATES ONLY ONE OCCURRENCE. EXTREME DAILY AMOUNTS OF PRECIPITATION ISMOUFALL AltD SHOW DEPTHS SUMMARIES DATA DERIVED FROM SUMMARY OF OAT DATA PRESENTED ARE THE EXTREME DAILY ANMNS OF PRECIPITATION, SNOWFALL AND SNOW DEPTH OY INDIVIDUAL MOh AND YEAR. ALSO PRESENTED ARE THE MEANS, S14ANDARD DE VIATIONS AND TOTAL OBSERVATIONS COUNTS. AN ASTERISR '$" PRINTED IN THE TABLES INOICATES THAI T$HE EXTREME VALUE FOR TH-AT YEAR AND MONTH DERIVES FROM ANi INCOMPLETE MONTH IAT LEAST ONE DAY Of TPF MONTH IS MISSINGI. VI-Ef A MONTH O-AS VALID OSSERVATIONS REPORTED ELY NO0 OCCURRENCES, ZEROS ARE DISPLAYED IN THE TABLES: EXTREME DAILY PRECIPITATIONS ".00" EQUALS NONE FOR THE MONTH ifundre THS 4EXTREME DAILY SNOWFALL: N." EQUALS HONE FOP~ TH'E MONTH ITENINS1 EXTREME DAILY SON DEPTH: "0" EQUALS NONE FOR TH1E MONTH' IWHDLE INC1S-ES TOTAL MONTHLY APOUNIS Of PRCIPITATION AND SNOWFALL SUPPARIES DATA DERIVED FROM SUMMARY Of DAY 0ATA. DATA PRESENI1O FjRN BT YEAR AL RCPTTO$ AND MONTH. nonf~asnn O N O; IUOETS ALSO PRESENTED ARE THE KANS, STANDARD DE VIATIONS AND TOTAL OBSERVATION COUNTS. AN #STERiLU -F 1N THE TABLES INDICATES THAT ONE OR MORE DAYS WERE NISSIN FOR S THE MotHl. SDno OCCURRENCES FeR THE ONT" APE INDICATED ST EOS. IF THE ASTU IS A 10RACE, THEN TRACE- IS PRINTED IN THE TABLES. STATISTICAL VALUES DO NOT INCLUDE MEASUREMENTS OROP INCOMPLETE A LMENS. I [ INP[ A L SOO~iL m Om OUAS NNF FP. E ONTMqTET-S

22 GL:,OA. CLIN.TOLOG. B.MOCH PERCENTAGE FRa.UEWc, or OCCUmECE Of PRECIPITATION US AFElc FROM SUM"ARY OF OAT OA1. AIR WETAINt SCEWICEINAC STATION NUPK 121STS ST1101 MANts GRANO FOmNS A Nr mm ANOVNIS IN INCHES PR100 OF RCONO: S9-0? S I. 2oI $ OVER I 5 DAys1 IOTALI PONTPLY ANOUNTS I I 09 To To I TO I I 10 I T0 I I WIT1 I I "nri I mone ITACEI.Cl I S I.S0 I S01 S.00 I PEIS I OS I 1 I i I I I I f B I I anisi R " S RE TEST LEAST B B B I Bi II I I B BB I JAN. I 33.S S S.81 4, $ I I I I I I I B I I I I III IB F S o ? ST 3.21 *07 I I I I B BI I I I I I IIB B Nl I 1S.? S I P I35.2 I 39.S9 2.1 I S.21 3.& I I I 2S IRACE I B I I I I I I I I I I I I y I s$, Of JLON Is T S JL S I SS I 1 o I 9 9I I I I 9 I I IBI 9 AUG I S S S S.SI I S.S0.3S B I I I ~I I I I I I I III I SEP $7.B I I S KT , I S S S.71.i NOV 1 Oe O $.02 KC 1IS,q 1 4.0l loll S ,S S.11 ANN $ 3.S S I I l C.00.VA II j C

23 GLOBAL CLIMATOLOGY BAN CH EXTENN VALUES OF PRECIPITATION US FETAC IFROM GAILv O&SEEVATIONSI AIR WEATHER SERVRC[Ac STION NUMBER: f2tss STION NAMEg GRAND FORKS AF NO PERIOD OF AECORD: 59-8?... 24O0L0 &"OUN?$ IN N PIS *N*O*N-T-H-S- ALL. A J im W & APR "AV JUN JUL AUG SEP OCT NOV CCC MONTHS s % I.C So.51.2S S S % S S % 2.2S S6 22S *70 1.2S I.S & o so S % 1.13.S6.OS *so S ? *.1f S.0s S : So ST S ? S?.6.2%.09 2.S7 To,12.1i :6 1:09.72 :13 so I.%S.9.32 S i 76,? 6 I..o , 55.7.I S.1, S 9 :t , 7 3, *i *I S %S % I Sq oi TRACE,3S soa cl al ss S0.9g.9s S *0 1S S% I.GS.3S.36 I*.s s S S 69.* S.72.s Is S sa I %1.,91.%S.IS I1S T7 I5,so S AN I : * S4.262 Was S.0. I.@.12.29S S3S S92 TOTAL OlI M0I NOTE 9 IASO ON LESS THAN FULL MONTHSI.L

24 ... "+" SAFTAC I FO 0831 OOSERVATIONS 1AIR E8Y SERVICEI/DC TOTAL MONTHLY PRECIPITATION IN INCHES IR-O.N-T-J"-S" ALL YEAR JAN r O MAN APR MA T JUN JUL AUG SEP OCT NOV LEC "ONT7#S S o0 60 S a.s S ?2 1, % S q0Cq 62 o OS.4% S 1.05 * s S8 seos l.10 S i S , l.07.3s 1o T fi 6%8 013 Is9 S SoSq T0 023.C *6S S * I o % C9 70 I 39 os S I % * o o I S0 i , s B% S TRACE t $ C? , lo o s Z : s T.?1 19o46 85 * ? S.o " cos T9 T ?? S % al.t :140 6: EAN S oSS 1.S S *TS S Se oS TOTAL OS I go NOTE 0 I8SE ON LESS THAN FULL NOWINSI I L*

25 GLOBAL CLIPATOLO6 BRANCH PERCENTAGE FREQUENCY OF OCCuRRENCE Of SNOWFALL USAFETAC FROM SUMMARY OF DAY DATA AIR WEATHER SERVICEIMAC STATION NUMKR: 727S75 STATION NAME: GRAND FORKS AFS NO... PERIOD OF RECORD: S AMOUNTS IN INC'ES 14ONT I I 1 I 0.1 I 0.5I 1li 2.5 I S I 6.S I 1o.s I 1S.s I 2s.s I OVER I OAYSI TOTALI PONtILY AMOUNTS I I TO To 01 TO TO o I TOI TO TO WITH I NONE I1RACEI 0.4 I I S.9 I SO.% I so.9 I meas I oes I I I I I I I I I I I I I I I I I I I I I IANTSI I s I MEAN GREATEST I~ 6~TS LEAST (S ;. o....o... JAN Si ?.S FES I S PAR 1 S I 9.l TRACE AP S 14.5 TRACE PAY o JUN II JUL AUG 1o III0 SEP I I I I II I I OCT S NovI I.ol 1.9 I.S *So S B 1 C I I I I I I i1 ANN [C I I Il.a I.2 l6l.1 3, 1I.0 I I I I ID.? I ,.

26 GLOBAL CLIMATOLOGY BRANCH usafetac AIR WEATHER SERVICEIMAC EXTREME VALUES OF SNOuFILL IFROP DAILY OBSERVATIONSI STATION NUMBER: STATION NAME: GUANO FORMS AFI NO PERIOD OF RECORD: S9-0? 24 OURN AMOUNTS IN ]NCPE S I -N-O-N-T-H-S- ALL TEAR JAN FESn MAn APR "AY JUN JUL AUG.... SEP... OCT o0 o.. NOV.. CCC.. MONTHS ee oe e *.a.0 *.0 TRACE o ,1 TnCE TRACE TRACE TRACE TRACE S. 2.2 S TRACE TRACE TRACE 4.3 S S s TRACE TRACE TRACE I* TRACE, : TRACE *Iot I.S TRACE *0 TRACE S S TRACE S TRACE ?3.6.9., 0, ?s 3.1,.*S TRACE TRACE is *S. O TRACE % TRACE TRACE S.S s TRACE I S.S I 1.S 67 TRACE 0 :O :0 : , to 1, RC[1:0 RC o O,0, 2.0, I*s *0.0 TRACE S il es S TRACE TRACE O.0 TRACE ?87 I TRACE MEAN S # S.2S t ;149 TOTAL 08S I a NOTE 6 ISASEO ON LESS THAN FULL MONTHS)

27 GLOAL CLIMATOLOGY BRANCH PONTILT SNOWFALL USAFETAC #FRO" DAILY OBSERVATIONSI AIR WEATHER SERVICEIMAC STATIO NUNKE?277S STATION NAME: GRANO FORKS Aif No PERIOD OF RECOROs S9-81 TOTAL NONTYLV SNOWFALL IN INC;ES 'B -N.-O-NoT4oS- ALL YEAR I JAN FEB PAR ApR nat JUN JUL AUG SEP OCT NOv DEC MONTHS s9 *.o TRACE * TRACE 2.S S TRACE TRACE TRACE S O * TRACE ? TNaCE a TRACE TRACE S S S.0 *0.0 TRACE I TRACE TRACE ST.% S %.3 S.S !. 2.6 TRACE s TRACE *et S TRACE TRACE 3.0 1C TRACE S.i OS 9.1 TRACE S S * G.S S TRACE TRACE S S S 6s 079 T S TR1C S I 19 TRACE TR0 ACE S 2 6.S S 1.0, T S i , TRAC C ? I o so TACE 80S TRACE TACE ,0.0 *0 TA 0 1E S.7 2oS S TRACE S.0 I. 3S. as C A N *3SS 6.OO * * S.T IS.21 TOtAL Tl i60 60 i $ NOTE 0 1MASED ON LESS THAN FULL MOWTHSI

28 ID GLOBAL CLIMATOLOGY BRANCH ScSAFETAC AIR UATHER SERVICE/MAC PERCENTAGE FREQUENCY or OCCURRENCE OF SNOW DEPTH FROM SUMMARY OF OAY OATA STATION NUMBER: T2717S STATION NAHE: GRAND FORKS AF9 NO PERIOD Of RECORD: AMOUNTS IN INCH4ES t~7 JA I T 1 7 To 1 I 13 To 2S TO ITo 37 1N9 To ' 1 OVER NAYS I TH TOTALI MONTHLY AMOUNTS MONTH I NONE ITRACE1I I 12D I MEAS I OBSI II I I I I I I I I ANTS I I EAN GREATEST LEAST... o e o... JAN 1, I FEN I I I I I 5,6 I S.81 I I 11q.81 I 2-11 I I I I I I no, MA R 17.2 I S,?1 SS I I I I I II I APR 73.S I S I I 1. I llel I 8.0 RA ,S, Il I JUN I J U L o I I I, oi I AUG IICO.O I I II I I 8621 S SEP OC T 1 5,0 2-S! I -9 1.,e l , NOV IS1.1! ,Sl ,4OI IIII III DEC S O.OI e 8bel... ANNII 5.71 I I

29 GLOBAL CLIMATOLOGY BRANCH USAFEIAC AiR NEATHER SEEVICCINCO EXTREME VALUES OF SNOm DEPTH IFROl DAILY OBSERVAIIONSI STATION NUMBER: 7127STS STATION NAME: GR:AO FOuKS Fo N0 PERIOD Of E0O: RECORDS -7N.S DAILY SHOM DEPTH4 IN INC14ES -M-0o- N- I -S - I'LL ' YEA JAN FEB MAN APR "AT JN JUL AUG SEP OCT Nov DEC... INS S 9 so 0O *0 0 3 T 2.: TRACE 4 a S 61 O 5 1 TRACE TRACE $ a TRACE S 4 is z I TRACE q # is O to a a a a a S O S a a *1 0 a 2a S I 0 a S V 4 g ? a I 18 1V 6 TRACE 0 TRACE V 6 is : 3 9?b TRACE TRACE V is a a is a sa TRACE 3 2 It al a a a is is 83 V 2 2 TRACE a V off 6 6 V TRACE 0 0 a 0 1 TRACE 2 V 6 a s a 0 7 V 1? A? S 6 13 TRACE S.a. I *a ,Vi6 V V5?.%IS TOTAL OOS I I6B OqO I4O 67 B40 $ *s... NOTE 16OASEO ON LESS THAN FULL HONTHSI j 4

30 *Mae"cccccc pp Ip A a 0 11mei cc cc cc as cc as mm mni cc c P: at asugmiic mmm A :::c' TV timp~h a: IN sot -3 S ac

31 ii 1ETRNrE VALUES OF PEAR WINDS SURFACE WIND SUMMARIES DATA DERIVED FROM SUNAY OF DAV 01T. VALLES PRESENTED BY INDIVIDUAL MONTH AND YEAR WITH ALL YEARS COMBINED. SPEEDS PRESENTED Iu KNOTS. DIRECTIONS PRESENTED IN 16 compass POINTS FROM BEGINNING OF PERIOD OF RECORD THROUGH JUNE COMMENCING JULY 1968 DIRECTIONS PRESENTED IN TENS OF DEGREES. AN ASTERJSU "e0 IN?HE TABLES INDICATES THAT THE VALUE IS BASED ON AN INCOMPLETE MONTH OF THREE OR MORE MISSIN G DAYS. MEONS AND STANOARO DEVIATIONS PRESENTED DO NOT INCLUDE INCOMPLETE MONTHS. FOUR OR MORE MONTPS ARE NEEDED TO COMPUTE THESE STATISTICS AND INCOMPLETE MONTHS ARE NOT INCLUDEO. TABLES ALSO INCLUDE TPE OBSERVATION COUNTS. BIVAITIF PERCENTAGE FREQUENCV TABULATIONS OF SURFACE WINDS DATA DERIVED FROM POURLY DATA. PRESENTED ARE THE PERCENTAGE FREQUENCY OF MIND DIRECTION TO 16 COMPASS POINTS, CALM AND VARIABLE VERSUS WIND SPEED IN KNOTS IN INCREMNTS OF BEAUFORT CLASSIFICATIONS. PERCENTABES A1E SHOWN BY of1t DIRECTIONS ANO SPEED, AND IN ADDITION TPE MEAN WINO SPEED IN GIVEN FOR EACH DIRECTION. DATA PRESENTED BY THE STANDARD 3-HOUR TIME GROUPS BY MONTH, MoNThLY AND ANNUALLY (ALL YEARS COMBINEDO.. A SEPARATE ANNUAL TABLE PRESENTS THE SAME BIVARIATE DISTRIBUTIONS WITH IMPOSED CEILING/VISIBILIIY L KITATIIoSs HEN VIS 9I LXTIS EQUAL TO OR GREATER T1AN 1-12 MILES, THE CEILINGS ARE 200 TO I400 FEET AINDOR WHEN?ME CEILING IS EQUAL TO OR GREATER TPAN 200 FEET, THE VISIBILITIES ARE 112 THROUGH MILES. A PERCENTAGE VALUE OF "O.0 IN T-ESE TABLES INDICATES ONE OR MORE OCCURRENCES AMOUNTING TO LESS ThaT GUS1. LIIAIgS HN3SBLTSEULT RBETR HN12MLS H ELNSAE20T NDFE

32 GLOBAL CLIMATOLOGY IRANCH EXTRME E VALUES OF SUIFACE WINDS us IF lac IN"DIYC9EVTOS AIR 1EAIHER SERFICEIMACIIOM DAILy OgSEIVaTIONSI STATION NURVER: 72757S STATION NiNE: GRAND FORKS AFS ND PERIOD OF RECORD: 60-ST DAILY PEAK GUSTS IN KNOTS -M-O-N-T-04-S- ALL YEAR J JANI FE[I MARP APRI MATI JUN I JULO AUg I SEPI OCT NOV DeCI MONTPS "'... 6D 1 5 *Sol finll 391 SSE 361 SSU*411 N 401 SSW 361 N 3al MUM 361 NNW 615 WUOSSI 61 NNV 561 V NM 3g NNM 391 S 375 N 331 VNW 621 S 321 WSW 421 WW 391 WNW 361 SSE 321 MNM SSW 355 NNM 661 NN 335 S 311 S o65 SE 331 N $311 M *431 S *381 NwM*361 WNW 31 NNW SIS NNM WI.M 71 N 37 WNW W. M. SI *37 SE 365 N 331 NM 35 SM 615 SSC 325 MW i 395 NN465N IASI 1 NNW 621 ESE 681 NM 4615 NNM %SO NW 415 S95 66 o U 3W ISS 3NS5 WN: 6 S NNW 401 MNW 571 NNW 6I NUM 635 WNW 1SI M #611 N 371 C 331 WSW 361 NM 631 WNU 42 WN 361 MNW S? 66 5 n 21 M 371 NN 631 NM %31 SW SI SSE 25 MNW 531 M 365 :M 395 M :?I MN 3,01 SS*39 NNM NN 51 N SM 615 NM M N q7 36 MV %If NW MNM N 391 NNW SI 66 SSC SDl M 4SI RN 665 N 431 NNM / / / 51 27/ / S0 3/ S / / Ill 35 ill / 51 To I al 371 3I/ $SI 19/ / / / / 6S5 32/ / 6S 27/ SS / / %o IS/ S0l 2S/ / S sl l6/ 311 1/ so M S1 29/ 311 3%/.65 33/ / / / / SI / 335 1I/ / * / 3SI 28/ 3S 3S/ / S / / / / S 27/ 65 20/ / S/ / 6 7S 321 Sol 33/ / 32 S l6/ 625 2S I 01 32/ / / 361 3/ / S l : l16/ / / / SSI / SS 77 3/ 65 3/ / / 3SI / / Sol q2 33/ SS 35/ l Sol 341 off 32/ Sl / IS/ 15 31/ ql 0/ S /ll 361 SO -O 19 5 I 24/ 31/ 295 qal SS 31/ 605 3*l 3S/ 32/ / 36/ / SS 30/ 26/ / 23/ /01 31/ / 29/ / 30/ / / 32/ S/ 6s / 3 3S/ / / /1 1 10/ / / / / 05 31/ / / / 38 29/ S0l 16/ 61 1S 65 32/ / / / / S SI / 321 3SI / 31 1/ / 4SI 3/ / %81 17/ 3S / 37"5 231 S9 T ota SI 361 4S / 3 1/ / / / / 4S : S s i s/l~ 3ll JO/ 16 J 71.$l St/ l / / SO# 36t So all/ 421 1/ 4101 got / % 16/ i/ $SI / / l MS 34/ ! % "*.lis.0. 6.:91 S.qSSI l I S STI S SI q.966 is TO ArVL 0il 831?l IS 59 8b 82SI esel 8211 T91i 8321 $l NOTES 0 18A$(0 ON LESS THAN FULL. PONTHS1 IIASIO ONe LES$ THAN FULL MINIMHS ANDO 0100 U;NITS)

33 ~ IGLOBAL CLIRaTOLOGY BRANCH PERCENTAGE FREOUENCT Or OCCURRENCE Of SURFACE WIND DIRECTION VERSUS WIND SPEED USAFETAC FEO" HOURLV OBSEEVATIONS STATION NUPBER: T2?STS STATION MAHE: GEAND FORKS AFB NO PERIOD OF RECORD: TB-IT MONTH: JAN HOUNSILSYI: 0000!!0200 I WIND SPEED IN KNOTS DIRECTION B-S5 BE S6 TCTAL MEAk foegrees) I IND Nk "NE 1 ~.4 * EWE.2I. E I 1..3 * ESE I SE I.3.9 * ?.C SSE I.9.9 *B S 7.8 S I. 2.S IO.S SSW S SM I S.1 WSWIM.9.8 f s 8.1 MNM NNW ? '... TOTALS I 9.C S TOTAL NUMBER OF OBSERVATIONS: 930

34 GLOBAL CLINATOLOT BRANCH USAFETAC AIR WEATHER SENVICE/NAC PERCENTAGE FRQUENCV OF OCrURXENCE OF SURFACE MIND OIIECTION VERSUS WIND SPEED FRON NOURLT OBSERVATIONS STATION NLBSRE[ 727S7S STATION NAMEs BRAND FORKS AFB No PERIOD Of RECORO 8-0T NONTMt JAN MOUSILSII: 0300-OSOO I WINO SPEED IN KNOtS DIRECTION I ? l qs-ss BE 56 TOTAL lean REES I 9 WIND. N I ,T NNE I.S N C (NE S6. E IS[.2.s SE I SSC S ts.? 9.S SSW $ S I S.? WSW S % ? 709 NNW I TOTALS 4 NW.2 1* *0.S 6.9 NNW S *S I 7.S S.S Ir TOTAL MLRAEN OF OBSERVATIONSZ 910

35 SLOIhL CLXNAIOLOGV BRANCH PERCENTAGE FEOUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS 1NO SFEED USAFETAC FROM HOURLY OBSERVATIONS AiR WEATE R SERVZCE1NAC STAIION NUMBER: STATION NIN$E GRAND FORKS AFS No PERIOD OF RECORD:?6-Si NONT14: JAN 4OUSILSTI: I 3iINO SPEED IN KNOTS OlECION I T GC 56 TOTAL "EAN IOGREESI MIND... 1o. i IS.S 13.2 WhE e N S.7 EWE I ,.6 I ISE S SE.I.S S.8 SSE.3 1.$ 2.4 1: 6.1 S S, ,2 It SSW.4 los I.S To S I.S WSW %.S" J %?.9 b N I i S W S N l. OL.6 TOTLS R3 V1 T.3 2T.0 2USE 4.F 2.S 1A0.0 "] TOTAL %UNOER OF obscroatlions8 0 30

36 GLOBAL CLINAlOLO6V OR ACH USAFEAC. All M[TI-EN SEEWICEIN*C PERCENTAGE FREQUENCV Of OCCURRENCE OF SURFACE WINO DIECTION VERSUS NIND SFEED FRON HOURLV OBSERVATIONS I J I STATION NUNKE:?27575 STATION NANE: GANO FORKS ire No PERIOD OF RECORDt 738-I NONTH: JAN HOURSILSIIS I I MINO SPEED IN KNOTS DIRECTION I 1-3 V T V8-SS GE S6 TOTAL MAN IDEGRESI J N MIND N 1.9 l S 14.C NNE NE EkE E (S[ S.4 SE SSV I I.S.2 V.S 9.9 S Ssb SM S.7 MSW.V A.V M 1.0 %.1 3.V S O.s MMW I *2 *? MM I V Io.. NNW I *V TOTALS? S.1 2A.2.? SIAL NURSER L mi IIII L. lom ~~i S3SZEO *59VATISNSS 3

37 GLOBAL CLI HIOLOSY SIEAIC PERCENTIGE FREQUENCY OF OCCURRENCE OF SURFACE WINO DIRELTION VERSUS WINO SPEED us c El A C FROM HOURLY OBSsRVATIONS SAIR MEATH[R [VC IA STAION KCPBEs2TSS STATION NAMEs GRAND FORKS AFB:No PERIO OF RECORD:?6_81 OOllTp JAN 1OUS3LST)l SPED IN KNOTS DIRECTION , T-10 11o IN F41o4T *a-$s 6E S6 TCTAL MEAN N T NNE.4.s c I( ENE S E s t.5 ESE S.9 SE ,1 1.9 T.s CSSE i , L tas.s SSW c :* " Sm WSW S 70 W JO*T 7 WNW q C MW 2 1o , &.. NNW S VARIASLE CALM o otj/i/l /Ioo too too to ot //Ii t oiii/i I/I t ili too i 11/ 11 /ti oit Ar/ it i////,# to i. T lillil/ TOTALS! S.S $ , VL au,[ us ,(,V W A,

38 JI- GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY or OCCURRENCE OF SURFACE WINO DIRECTION VERSUS WIND SPEED Us 4rrTE C FROM 1#OIULY OBSERVATIONS AIRl WlEATP'ER $(RVICEIPAC STATION NUMBER:?2':7S STATION NAME: GRAND FORKS AF N: PER1OD OF RECORD: 7"67 Kosovo's JAN HOURSILSTI: ISO i NN SlN tps' 1.2~.NOT 2.S- EGEE ME I ENE C ESE." SE I SSE I S I SSW S WN : WNW a Nw SS 16 21,,3,1q*7,?.L NNk S CALM 4.3 /fill/ TOTALS I.C TOTAL N1uPER Of OBSERVATIONS t 93C

39 GLOBAL CLIMATOLOGV BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MINID DIRECTION VERSUS MIND $FEED USAFEIAC FROM HOURLY 09SERVATIONS AIR WEAT14ER SERVICEIMAC STATION NUMBER: 12?SS STATION NAME., GRAND FORKS AFB NO PERIOD Of RECORD: MONTH: JAN SOURSILSY3: I WIND SPEED IN KNOTS DiRECIION D ? %8-55 GE 56 TOTAL MEAN IDEGREES) I MIND N I S* S NNE NE I ENE I S. 3 E I ESE I SE I S 6.C SSE I i0.s S I SSW b.9 Su I ?.S v.w b.6 W I S WNW I S D 0. 9W TOTAL NUMBER Of OBSERVATIONS 1 930

40 GLOBAL CLIMATOLOGY BRANCH LsAFETaC AIR WEATIER SERVICEINAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND STEED FROM HOURLY OBSERVATIONS STAT1ON NUMBER: 727S7S STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 70-S7 MONTH: JAN NOURSILSTI: D.... e e o o e o SMIND DIRECTION I SPEED IN KNOTS f? c S6 ICTAL MEAN IDEGREESI a MIND ;.... N ? NNE NE S.0 ENE E b.? (SE.1.6 *1.9 S.C SE SSL.3., Ia.? S J SSW SW WSW S 5.8 W I.C WNW S m NIM NNW C VARIABLEI CALM I /// ///1 1/ / 1//III/ IPt /II I f I/ I1//1.'' TOTALS I S ? TOTAL NUMBER OF OUSERVATIONS$ 930

41 GLOBAL CLIMAIOLOGY BRAN USAFEAC AIR MEATHER SEEVICEINAC PERCENTAGE FREQUENCy OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED FROM HOURLY OBSERVATIONS STATION NUMER1 7277STS STATION NAME: GRAND FORKS AFS NO PERIOD or RECORDS NONTH: JAN HOURSILSTIt ALL I WIND SPEED IN KNOTS DIRECTION ? ? SS Ge $6 TOTAL MEAN IOEGREESI I I MIND... N oi S 13.0 NNE I.3.s ME (NE * E.2.S (SE I j i SE * * 2.% 6.6 SSE S S S S % 10.3 SSW, ?. Sb.5 1.S WSW ? N ,a.1.0 1o. GO. MNW N.5 1.S NN.6 1.S VARIABLE 1OTAL MUMER* O OBSERVATIONS 1460 TOTALS?? 21.S S ilII.i --mi i =ii L m

42 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR WEAT (ER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SEED FROM HOURLY OBSERVATIONS STATION NUMBER: 72757S STATION NAME: GRAND FORKS AFB ND PERIOD OF RECORD: MONTH: FEB POURSILST1: SWIND SPEED IN KNOTS DIRECTION I %1:-47 %-S5 GE 56 TCYAL MEAN I DEGREES I & MINo N NNE I S S NE I C ENE L ESE.1 1.S.7 a.6 SE.A SSE S S oi SSW S WSM I WNI t N.,S NNd VARIABLE TOTALS 9.9 2S S K. TOTAL NUMBER OF OBSERVATIONS: 66

43 GLOBAL CLIMAIOLOBY BRANCH L SAFE I C AIR WEATI4ER SERVICEIMAC PERCENTAGE FREQIENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SFEED FROM HOuRLV OBSERVATIONS STATION NUMBER: 727STS STATION NAME: GRAND FORKS AF NO PERIOD OF RECORDS MONTH: FES HOURSILSTI: , 1 i ii iind SPEED IN KNOTS DIRECTo, I ? q7 46-ss Gc 6 TOTAL "Eal IDEGREES),or(, ; " 1 9 KIND '.;... s....: N 3 S NNE I :: S -9.: NE ,., ENE S.9 E C ESE( ?.S SE C SSE.* e 1.7 * S SSW S.? SN WSW.6 I ,. S1.2 3., , WNW.6 3.S NN N NNN ,s ,.1 CALM j I.? IIIIIIf I IOTALS G... TOTAL NUMBER OF OBSERVATIONS a 86

44 SLWA 1 CL i Ie*Y DCW U PmCEIINiE FP01IEC of occoim"cc OF SURFACE UlMi DI(CTION VERSS vii SPile AIR WEATHER S[RVIC[1INK STATION NMNRs 7271,19 STiTIO MANE: 6iM FiRS F9 U0 PcalU Of ai'os: NiTii? Vim NbU"*LS13 w.s.9 2.? ISS 5.9 IS $ o? M uo.s j iii[ , 7., WE tot ? I Es 2 S SE IS SSE *% Z.0 * i IS SSW b Ski.9 ten IS e bsw S 1.0 " qe 2.6 1,.I 9.3 GoS W W ?.?.2 7.? 9.3 Nib z 9.S... I... I j TOiT&S 9.$ ? I TlOTL UNDE O ISERVATIS$ 91 L

45 GLfOOL CLISI4OLOY -RACH pgeclala46l FREhSAUCV OF OCCUIRINCE OF SURFACE MIM DIECTION VERSUS M1ND SPEED USafEuiC FROM "OUlLV OBSllVATIO1S SiAlll RUNNEbR 72iSS STalTION Nh sran reams AF MD PERIOD OF RECODi 70-i ONTH: FES HOURSOLSTI * M PEE Sft IUOs *lncile 1-S i-il o %I-ss GE S61 TOTAL NE, 40COMCS3 I INI D ao7 9.7r 1.3.9P I 1 S ME I , S2. in [ It I SSE S I.2.? S b n s ~ I.,2 2 1l,*.4,Vm S?r.9 i ", IIS T5 + "+.,S.1., r.: + + $ 1.9 3I l.6 6.7!.I ?..o 20..r.1 '9., 'j. J CAgLKf 6. t TOTALS a?.s 2S C T OTAL MhUMER OF OSIN(UISMIUSS 96 L

46 G LOBAL CLIMATOLO6T BRANCH PERCENTAGE FREGIJENCY Of OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MINDO PE USAFEIAC FROM S'OUQLV BEVAIN AIR WEATNER EVCIA STATION NUMUER: STATION NAME- GRAND FORMIS ars NO PERIOD OF RECORD: 70-8? MONTH: rern HO4IRMESTJ: WIND SPEED IN AINOIS DRCIN 1-3 r GE 56 TOTAL MEAN S IW:; NUHE I NE I ENE I.2.6 *1.I%. ES.1.2.6q. SE :, 1:: S ? SW S 1 jv NN I * VARIABLE... TOAL S TOTAL NUMDER OF OBSERVATIONS: 86 LN

47 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED USAFETAC FROM HOURLY OBSERVAIONS V AIR MEATSER SERVICEIMAC STATION NUMBER: STATION NAME: GRAND FORKS AFI NO PERIOD OF RECORD: NONTH: FEB HOURSILSTI: 1S0O I MIND SPEED IN KNOTS DIRECTION I SS GE 56 WTAL MEAN IDEGREESI I MIND... IENE I E Ek , SE *.6 "SS[, N ,6,6 TI'S. 10,3 WS W.2 * W.2 1.S "CAL,,7 lt, S.422 II I/// WNW I I TOASt? S 9. 0 ;... TTLNUMBE Of OBSERVATIONS&.046 "

48 GLOBAL CLIHATOLOGT BRANCH PERCENTAGE FACtI NCY Or OCCCRRENCC OF SURFACE NIND OIRECTION VERSUS WINO SFEED us 'FIETA C FROM 14UNO ~SsERVATIONS * AIt WEATHER SERVICEI"AC STATION NWUSERt 7271 STATION NAME: GRAND FORKS AFBj NO PERIOD Of RECORD:?$-IT MONTH: FED HOUNSELSII: I UNIO SPEED IN KNOtS DIRECTION ? SS GE S6 TOTAL MEAN ISEREESI I WI NO N NNE NE S.C ENE 1.1 S S E.7,4 I,1 3.1 ISE SE SSE S 9.2 I, S S.0 Z.4 *r SSW.S Sm S.2 WSW ?.C W NWM S NM NNM S S VARIABLE CAL?.,/1 TOTALS I.C 2S , TOTAL NUMBER OF OSEROSV 0NAZSS 636!I

49 GLOBAL CLi"AIKotos BRIOSCN PECENTAGE6 Fh(UtNCY or OCCURNCE Cof SURFACE vivo DIRECTION VERSUS vivo SPEED ~ ~ I WEt ATHER SERVICUPmiC. STATION iclo. NUMBERS?2?SYS - STATION MAKES GRANO FORMS AF% Me PERIOD of RECORDS 70-8? " 4ONTP: Fe.OU3S.LST C D iret -Ss.- I 1 *2 1Ela 1IS S Mi.9.2.S 9.9 f [m( 2,S,i , 2.3 o 1. q..o. 1 Sc S.O SSE I IS s SS B SIM Sm.7 t S.1 WSW S.O S l.s NNW pol,s '.O 3,1 1.2 ' *1 6.9 I.1 *km "'low i.2 6.i 1o5.. J ] 4I A *~oco oee**oce l * * * * * TOTALS G.s s o 10.0 ;*6fUROER f OBSVTONS 699 LAI - _

50 GOAL*1. CLIKAVSLOSV ORMACN MS*FEI*C AIR KMERN SERVICEIN&C PERCENTASE FErEUENCV Of occurrence OF SURFcE WIWe DImEcTIoN VERSUS MINO SPEED FROM FnOUOLY OBSERVATIONS STAiTON mufhis 727STS STATION NMN[s GRAND FRANS AFm md PERIOD OF RECORD IN-67 _ NHOWT14 FEB HOURSILSTI: ill S6IND SPEED IN MNOTS DIOCEION 1-3 4" ' $-e0 6# SS GE S6 TOTAL MEAN IKGR[ESI I S WIND.... N o v Mo.e ?. NE.2.*.S I L 1 [ll S 1.* (SE.2,S SE.s..4 * ?.1 SSE S I.7 2.g SSW ?.6 I SM WSW S " H ?.c MNM mn Nmm TOTALS I S ,6 TOTAL. MNMER OF OUSEUV*U@S:S * cooe*oe*e ee* ec o ee e e * eco e e **e e e e e ee*e o e ee eeee eeee.. vva.u av f,,o e~mvvxo, ". I - "

51 GLOBAL CLIMATOLOGY RAMNCH PERCENTAGE FREE UENCV OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED USAFE IAC FRO" HOURLY OBSERVATIONS AIR WEATHER SERVICEIMAC STATION NUMBER 727STS STATION AH; GRAND FORKS IFS NO PERIOD OF RICORD: 7R8?8 EONTHI PAR HOUSILSTS : :. : DIRETION %8.SS GE S6 TOTAL 2.3 "EA 0-0 SE e NNE I E~WN. 1.3.KNOTS 2.S.1.2 SPE IN 3.S.96.?,2 lo r7.ia1in 6.7 EWE.S HE EI I 1S SSE SE. S.6 1.S *s S.1.S S : S SW S 1.41 SE ? T : s W. 9 I,S S S.*S 8.1" 1,k Sn 1.i I S , , Nkm A VARIABLE I CALM # H #e #/# #/ 13.3 iff//i.;.... ii TOVALS I j.8 22.@ A.? TAL NUMBER Of OBSERVATIONSa 930 J

52 .LOq t. M OLOGV BRANH PERCENTAGE FREQUENC Of OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WINO SPEED USAFETAC FROM HOURLY OSSERVATIONS AIR WEATNER SERVICEINAC STATION NUNBERS 72TS S STATION NAME: GRAND FORKS AFB No PERIOD OF RECORD: 78-@I MONTH: MAR HOURSILStI: WIND SPEED IN KNOTS DIRECTION 1 3 N O 1-7 #8-ss GE S6 TOTAL MEAN loebreesi % M WIND... N 1.0 N ? NNE I , P HE ENE I N E *6 1.0.S ESE.6 * N 6.3 -: SE SSE C s SSW Sw S s.6 t WSW S S. " S I WNW I j NW S NNW VAROL IABL TOAL NMI OF OUEVIIOMS il/ 930/ Ii /# o. I I/ fi / Iit1/.1 //o to t.014i S2III TOTALS I TOTAL NUMBER Or OGSRVATION$: 930 '1 A. L 4N

53 ".l GLOBAL CLIMATOLOGY BRANCH USAFEIAC AIR WEAT14ER $[rrv CEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED FROM "OURL OBSERVATIONS : A jdirection STATION NUBERS 727S A STATION NAME: GRAND FORKS AFB NO PERIOD MONTH: OF MAR RECORD: HOURSILSI.- 788? I MINDSPEED IN KNOTS $ I GE 56 TOTAL MEAN DEGREES I 8 MIND... N NNE t ME I b 61 [E.1,S " E ISE SE SSE.i S, a. SSW.9 1.2,S S.C S I.3 * ISW.3.S S.1 82 WNW * ? N-.6 2.S 2.S p 8.6. NNW VARIABLE I CALK ) 13 I.1 11/111 g< TOTALS I ?.S TOTAL NUMBER OF OBSERVATIONS: 930L

54 GLOBAL CLIMAIOLOGY BRANCH USAFETAC AIR WEATHER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WINO SFEED FROM HOURLY OS[RVATIONS STATION NUMBER: 72757S STArION NAKE: GRAND FORKS AFB NO PERIOD OF RECORD: MONTH: MAR HOURSILSII: WINO SPEED TN KNOTS DRECTION 1-3 N N-N0 NI-7 4B-SS GE 56 TOTAL MEAN CDEGN[ESI 2 ino " E ,C1. SE.I E SE SE, ENE N NSE W ? S.6 II7 1,. i,o 1oi J/ ssl.s ,1,1 I i.2 1,. a,. : i 'NW WSW "3.2,S * : " q %,S 8.9, -,.,...", ~....V, S VARIABLE TOTALS S O.C TOTAL NUMBER OF OBSERVATIONSs 930-4:

55 GLOBAL CLIMIATOLOGY BRANCH PERCENTAGE FREQUENCY Of OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED USAFETAC FRO"q HOURLY OBSERVATION4S 4. ; f A AIR MEAlT.ER SERVICEIPAC STATION NUP[R: STATION NAME: GRAND FORMS AF NO PRIOD O r RECORD: MONTH: PAR HOURSILSTI: IOD WIND SPEED IN KNOTS DIRECTION D il-ss GE 56 TOTAL MEAN... N T 13.I NNE NE S ENE I E , ESE S E S * SSE,B ? 12.C S.t SSW I is I WSWI I I.? 6.6 I ,S ba I S5.1 S Nw I S , NNW I , TOTALS S Z7.0 3C c... TOTAL NUMBER OF OBSERVATIONS: 930 OYAL.

56 GLOBAL CLIMATOLOGY BRANCH usafetac AIR WEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED FROM HOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 7-87 MONTH: MAR HOURSILSTI: IS I WIND SPEED IN KNOTS DIRECTION I o S GE 56 TOTAL MEAN (DEGREESI % MIND N NNE NE ENE.9, E G ESE.2.S SE SSE, l.5 S * SSW SM MSM b 9~ MNM No 03 o NNW,/ VARIABLE TOTALS o TOTAL NUMBER OF OBSERVATIONS: 930 t" Ji

57 GLOBAL CLIMATOLOGT BRANCH PERCENTAGE FR(OUECY O, OCCURRENCE if SIRFAC i 13(CTIIS VERSUS vine W 10 USAFETAC FROM POWELV OSERVATIONS AIR WEATHER SERVICIMAC STATION NUMBER: 72751S STATIP W n: GRAND FORKS AIf NO PtalOs OF RECIMPI: t6-91 +' 65gm: mar 65U5IL$11: mmeascool goo-40 I ailwn SPEED It snots DIRECTION I I $%_%a %1:l i6-ss 6 5 Vl6 Iall IO(GRESI I illsm '....."... N S.% II. N.( NE E[E Z S %.I ISE 12 I.s SE.9 2.? ?. 1.I SSSE,2' fs 10.0 S, 2.6,9 3.3 S SSW I 3 * SN I NSh,a I S *I, WNW , q.? NW I I. NNW io....- VARIABoLE I+ TOTALS I 6.% TOTAL NSJMBC[R OF 061CR VATIONSs 930

58 GLOBAL CLINSIOL06T SRACN PECENC~TAGE FREQGUENCY or occurrecec OF SURFACE MIND DIRECTION VERSUS WIND SPEED W56F1?6CFROM 4OURLY OBSERVATIONS At* u(ainin SINICEIRAC SIATION 0J000911: 1277SS STATION NAME: GRANO FORKS ifs NO PERIOD OF RECONOt MONTH: MAR HOURSILSTI: "i 1WND SPEEDo In KNOTS. s atcliell SS GE SE6 TOAL MEAN mi stc lot.3* [ME * S I.E st e6.163* :: Ssb sc I SN i.0 o[,q 13 08,3 q0 8I :2. i.iis( ) !.?L Nis" io.s % CALM TOTALS S o o... TOTALs 014elOI F 0SSLRV6tIONSa 930

59 i ' - GLOBAL CLIN*16OSS gmimtat PIC[NSI F SLiNCY OF OCCURRENCE OF SURFACE MIND DIOECTION VERSUS VIVO SPEED us CI AC "a" FROM SURL OBSERVATIONS S NURKINt T27STS STAION Ri[s GRAND0 FORKS AFG NO PERIOD OF OECONO:?@-of. ~ ~ ~ ~ O1t HAD ma URSILSTIS ALL - * o o,;. * ; , DIRElCTION 1-3 %-* o ! D-40 a41.41 ql6-ss at st TOT1AL MEAIN mimgciiom I I I-3~l 1 mmii '2 3.1 S.:? e I.S o 1e %.S p.s rot,s a?.1 it S.6 IS S[ s*t I jo. S SSW.5.9,9,6 * S i ' ' ' W SW 4 a ? 60? V: * , 9. r u ? 1.4.S S.S 10.0 'lo,e* I 6.1 foes mm. I.6 1., i VAOIABLE I a, CAL*.,./ I IoIo /I I,f iii tii i i t I ii, I Im I Io III It. p m J TOTALS I G S :... :......

60 6LOUAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCUPENCE OF SURFACE WIND DIREC!ION VERSUS MIND SFEED USaF c C.In WEST N SERVICEIRAC FROI 'OURLY OSRVATIONS STATION NUN: R 72?SS STATION NAME: GBRAND FORKS AFB NO PERIOD Of RECORD: 7-67 MONTH: APR HOURSOLSTS: i DIRECTION F48oSS 6E S6 TOTAL MEAN : EH I " E. 1.9RES a8 2.6 WIN ESt S.3._.5 St , : S z.1 3.@ SSW ,1 S.2 S.6 S I S.0 WSW, I ,. 6.5 NNW %.3 6.S "m ?.C NN6 i.c VAR IASLE CAL" 11/11111 IIIJII///jII j/t I h//t 11.9 IIill TOTALS ' TOIAL NUMBER OF OISLRVTIONSs

61 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED. USAFEAC FROM HOURLY OBSERVATIONS AIR WEATHER SERVICEINAC STATION NUNDER: 727S7S STATION NAME: GRAND FORKS AFB RI PERIOD OF RECORD: MONTH: ~A HOURSILSTI: Soo i ' I MIND SPEED IN KNOTS DIRECTION I * SS GE 56 TOTAL MEAN IDEGREES1 I " WIND NNE O 10.6 NE EKE E c (SE SE.6 1.* SSE I S S : SSW S. Im WSW S C. VNM Nmw ?.3 NNW S... VARIABLE I 1... TOTAL NRMDER OF OBSERWATISNS: quo TOTALS I T.C

62 GLOBAL CLINAOLOGY BRMNCN PERCENIAGE FREQUENCY OF OCCURRENCE Of SURFACE MIND DIRECTION VERSUS WIND SF-EO USAFEi / ffrom HOURLY OBSERVATIONS *2* UC[INENI SERI]CEIN*C' STATION NL!PSCR:?ZTS S S110N NANE GRAND FOUNS AF@ No PERIOD OF RECORD: T-A?. NOWTW: APR HOURSILSII: I N IW SPEED IN KNOTS OIRECTION - A-& iA R-33 3-N a n I*N7 46-SS GE S6 ITAL WEAN IOESOES!I W AIND M I ? 11.5 E. WRE I *9 *I.1 N.N.C. NE..9.8 *l (he S.A E * ISE.. : *:. 1.? 7.9 SE s., 6.- S U.N SSW * SW WSW 1.* WN'. 1.0.? RW I* S.9 7.S " b TOTALS 11- ti 2.4, ,.? S , 1 TOTL PNDROf OMSVAI TNS$ 900 Ii m ~ e mm mm

63 '108LO8 CL1PAOLOS MRCH US Ae AC AIn WEITH SERVICEIRAC PERCENTAGE FREGUENCV OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND SPEED FROM P0LNLV OBSERVATIONS STATION NUNBRE: STATIO MANE: GRAND FORKS AF8 Ng PERIOD OF RECORD: MOUTH: APR HOURSILST 09o I MIND SPEED IN MOTS DIRECION I o 1-I S$ 6c S6 TOTAL MEANt... 4K... Got... C I I s... WIND N *7 IZ S.0 S.u %.C NNE 'E I? ERE S* ' E ISE.., ,.5 SE SSE I S SS II.S SM.I SMM WNW :,O 13.0 ft I II*' NNW , CAL I II II~ i IlilolilIi it-ii Illil tl / I o fliillli Iff IIIII il i I taotls I TOTAL NUngE of OlSINVATIONS 900 6i

64 SIONAL CLINAIOLOGY GRAMMcI USAPF T AC AT*B WEAVtO[E S[ERVICEIRAC PtCNTAGC FffEOUENCV OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WIND SFEE0 FIom MoUwLI OsFIIATIOSS STATION MUN s STATIONI NAs GRANID FrORKS Aft NO PERIOD OF RECORDS MONTH: APR HOURS(LSTIt Ii IND SPED IN KNOTS DIRECTION ?-to o1 48-SS GE 56 TOTAL "EAN " " ;.:... I KGEES! I a WIND N * * 9 la 3.0e * * NME I S N, ,O 1.3 I : ". EI, I S1 [S[ SE SSE.2,l 1.2 S g.. S SSN Sd WIN W.1., ? " WNW Wb I ROMb n I TOTALS I ?.? 13.3 S :0T1 sme s or OF *URIAT1ONS2 900 L 4

65 p GLOBAL CLIMA1OLOGY BRANCH USAFE7AC AIR WEAT ER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED FRO" HOURLY OBSERVATIONS STATION NURSER, 2TS7S STATION NAME: GRAND FORKS Aeg NI M OfTN0 AR MOLRS0I "ONTH% APR HOURSILSTI: ISO : NINO SPEED IN KNOTS DIRECTION I SS GE S6 TOTAL MEAN (0EGREESI NN j, N ? 1ot NiNE I ? NE (NE,* q E [SE b SE I SSE C S SSW SW W SW.I S.3 I. i I NNV.2 * ? 13.2 NU NNW TOTALS 4.1 1S ;T... TOTALL Of 10, 3 3, 00,NSS"

66 GLOBAL CLIPAIOLOGV BRANCH PERCENTAGE FREQUENCY Of OCCURRENCE OF SURFACE MINO DIRECTION VERSUS MIND SPEED usafetac FROM VOURLV OBSERWATIONS AIR WEATNER SERVICEIPAC STATION NUMBLR: STATION NAME: GRAND FORKS AFI NO PERIOD OF RECORD: MONIN: APR 4OURSILSTI: I MIND SPEED IN KNOTS OIRECIION I GE 6 ICTAL ME AN IDEGREESI I S MIND N NNE, ,S NE ENE S E (SE SE.9 2* SSE ,s ' S SSW '" Sw ? 6.S WSW.2 * C WNV NW NNW VARIABLE I CALM 6.6 oil/if TOTALS I ?.S TOTAL NUMBER Of OBSERVATIONS: 699

67 GLOBAL CLIMATOLOGY 8RANC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WINO DIRECTION VERSUS W1ND SPEED usafetac FROM OL'RLY OBSERVATIONS AIR WEATI4ER SERVICEIMAC STATION NUMBER: STATION NAE: GRAND FORKS AFO NO PERIOD OF RECONDs MONTH: APR HOURSELSTI$ I MIND SPEED IN KNOTS DIRECTION I T o10 41"T 148-SS GE 56 TOTAL EANE (DEGREESI a MIND N I S EN S NC ENE '.6 E ESE C I SSE I S 1.1 % SW SR WSW.2 1.z W % WNW f N T.3 NNW , $.S VARI::EE I CALM $ / /l// / /// //.#11.141/# /ip1 1/ 1 //l il 11 / li1l1 TOTALS I T T TOTAL NUMBER OF OBSERVATIONS& 900 6~.

68 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE INO OIIRECTION VERSUS WIND SPEED USAFETAC FRO HOURLY OBSERVATIONS VF1, AIR WEATHER SERVICEINAC STATION NUMBER S S7AYION NAME: GRAND FORKS APR NO PERIOD OF RECORD:?$-AT MONTH: APR HOURSILSTI: ALL WIND SPEED IN KNOTS DIRECIIO oil-%? 96-SS GE 6 TOTAL "CAN ""' O[R[SII MIND toesreesis :: :: 3$ ':,.n 20:9 12:.D NNE.4O a4 * ; NE os S.? ENE S.-, E C (SE C SE I.S * S 8.s SSE,S C S O.0 SSM 1.. 3, isw,s ?.2 MS W S S WNW loa at.1.0 S NNW *S ? 9.% TOTALS 9, S.1 2S O l~l~nnl;h( O OISERvATIONS&;?9 101 T19 L WV

69 GLOBAL CLIMATOLOGY BRANCH LSAFTIAC AIR WEATINR SERVICEJmAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED FROM HOURLY OBSEaVATIONS STATION NUPSER: 727S7S STATION NAME: GRANO FORMS ArS NO PERIOD Of RECORD: 78-S7 MONTH: "Ay HOURSILSTI: ShWIND SPEED TN KNOTS DIRECTION I ZZ SS GE 56 TOTAL MEAN SOEGRESI I MIND N g, NNE NE ENE,S S E ESE * S.G SE S S SSE 1.S ? S.D I SM S S 9.??.0 SSW I A.C WSM,S S.3 S.7 ' WNW 1.S 1e S.6 NM I S NNM j VARIABLE * Ie! ** * 1 * * * * * ** e *** ** * TOTALS I TOTAL NUMBER Of 0StRVATIONSt 930 j.

70 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND SPEED S'IFEl C AIR WEATHER SERVICEIMAC FROM HOURLY OBSERVATIONS STATION NUMBER: 727S?S STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORD: TB-8 MONTH: MAY HOURSILSTI: 0300-OSO o... I WIND SPEED IN KNOTS : DIRECTION O I fg 9l SS GE 56 TOTAL MEAN IDEGREES I M IND N.... I-c P NNE % NE..S (NE.2.8 * " E ESE.4 S SE.i SSE S S I.S SSW S ?.1 Sw T.C N I ? 5,2 W s WNW MW MNW o " " o..'"..... VARIABLEI CALM Is.) /// %/j/,i#//////////j/i//jj 19.2 IIi TOTALS I IS.S ,S TOTAL 14VBER OF OBSERVATIONS: 930 L

71 ius,,etc GL OBAL CLI"AT OLOGV BR ANCH PERCENTAGEFREQUENCY Of CURRENCE OFSURFACEWND DIRECTION VERSUS 0100SFEED,ROM 1OU LY OBSERVATIONS I, WE T SE*Ve.3.6. MONTH: MAY lounsilstiz 0600-OGoC 0 PECTION. 1 1" 4-* WO SPEED IN 28- KNO 33 S sS GE S6 TOTAL MEANu NNE ME ,b o1 ENE O G.c. L.6 * *7 7.3 (SE S. SE SSE ?.1 S 1.2 Z ? % SSW S.6 8.T SW.5.S WSb S U MI 6.8 * s 9.2 S S.4?.I lips* , 7S. 1.6 WARIASDL( I totals I % S ? TIAL %LOE* OF OBSERVITIONS: 930 L.

72 01149M clinsieoet PEOCCm?*S( FmlSSW iv O CCUUUCU Of 1~fCf * IN 1 gi IOc IM M I mimesd1 MCU N@ as Ugand s"uca0em SNOW SIUCCGINO Iae STAT 130 f$ 011 ORMS -2 a0-3 of w OF-1 C I? L A V DRCN RE * 4.e4 GE S W an. II icit S.t , 11. bsi S. ESE SSE z ? &*.a S.2l ofii[ INS I1..5 S.3 soft Soo 2~ SSW I.s CALM 0 i's $ till I 0" "1 f i IIIIIlifmIIIIIopIIIfIIII ril IIItIIItI I smo l.t &@.a WIN U 5 [C now z 0.? g.@ ISAL #I. 906f WSJ. 4 6 Ole LO

73 BLOMAL CLINAIOLOT CMRK PECtuIIE[ FKaiNCV OF OCCURRENIC Of SURFACE WINO D1KCIIIN VERSUS WING SF1D Us$I TAC fee" "mluit OBSRVAIONS AIR WMATSi-I $ENVIC0INOC ; STATION "lupiips,?24,s SI,,IN4 MES BOAR fags$ Are no PERIOD of REC80;?48? t". ITAIS (I 723 S,e: " N, 'OUNSILSt : I MIND SPEEO IN KOTS eiatcli eft 1 1* * '2-2? 2-33 I%*%o SS 6E 6 TOIL HE:: + 16(6i0SI I s MIND 1 I.2 l.s Z.?,s N I $.2 9.C hi * 6.6 t.c, I.1.2 S S %.S 1.6 [bi I.2.6.O ? 9. SE *6 I SSE S S.s $.9 SIM So S bsw S 12.1 b S.2 12.S Nb. I MW.I.3 I.S ? NOW * l I.S ,..o..... o * : Awl tc I fotals I.3 36.I s IBMAL NuNSU Of.*316 ee BOB$ 6 I L

74 SLODAL CLInAVOLoT DRANCH PERCENTASE FREmgUNCV OF OCCURRENCE or SURFACE WINO DIRECTION VERSUS MINo SPEED I' USAFEIAC FROM 1ouMLV OSSERVATZqOS I. STATION. NUnBER?27SS STATION NANE: GRAND FORKS NO PERIOD OF RECORD: Is-$? NORTH. "AV 04OURSILSTIZ ISDO-1700 MIND SPEED IN KNOTS DIEnCIION I GE S6 TOTAL MEAN W&RE[S) WIND u.: : S Nkt.4 IF e4.2 S %(.4 *S 1.9 1h ENE #o s " " L IS[ I..S Z SE I S SS S 12.1 s.3 los : S io. 1,9.6.$ 5.3 1%,C So *I e WSW los, o ,S $ 3+ b.2 o3 e S.1 1%*S N.W2 IS ,9 U S TOTALS I % TOTAL %WURL OF 9699OIATIONSt 930

75 GLOBAL CLINATOLOGV BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND OIRECTION VERSUS MIND SPEED us AFErIA C FROM MaINLY OBSERVATIONS AIR MEAT14ER SERWICEIMAC * STATION NUMBERs 727TS7 STATION ANAES GRAND FORKS AFS ND PERIOD OF RECORD:?$-a? NTH: "T AHOURSILSTIs 1I00-00 I WIND SPEED IN KNOTS DPIREClION I Z J o-SS GE SA TOIAL MEAN IO[GREESI X b INo li I ? NME ke ME E S.7 0 ' (SE 1.e SE SSE I S W ? S I,? 7.0 WSW W NNW *! Nu.2. I N S 9.6 TOTALS ? I.C... o TOTAL NURGER Of OGSSERATIONS 930 eg,oeseooeeeeeeeeeeeoe~e* eo**eoe 0 oee eoc oeeoee 0 L L *-

76 GLOBAL CLI"AlOLOGY BRAhCH USAFETiC AIR WEAlTER S[VICEIN&C PERCENTAGE FREQUENCY Of OCCURECE Of SURACE WImD DIRECION VERSUS MIND SFEEo FROM NOUL? OBSERVATI0S STATION NUMBS8 TZ IT STATION NAME: 60NO FORKS if9 NO PERIOD nohnu12 of ma N COffOr NOURSILSIS: WIN SPEED TN KNOTS DIRECTION I o-40 I gogosg$ I o SS $E S6 ICAL "[AN a MIKO... ;:......, N o *1 S.2.9 at * 4.c 1..9 l.2?7. [ S L ii S c ESE S ,8 s[ 1-1 3,1 ZS 1.2,I 0.0?,3 SSE , 1-7,S O.S 2.4 S 1.$ i 10.0?S Ism *4.2, $y 1-2 1, &,S WSW m ec Smlm.q.* fm Now.S 1*4 1.I.4 *i 4.6?.q AL " ******* *..1** '0,01 iteeoo1 i*********** * OF#**************,il 00 im i oil ee i *l*tei 1e gilMS I I.* I * OTAL SUKI Of SSV9ISUI:I~ *10 L

77 go.al CLIAViOLiT MAiCH PtICthlag[ FKI6SfCT OF occuioct Op SufeCot WIND *3ICWIOO,g6.S1 WIND UM(10 asafli Films.,.6 IllsrillitreS 841 WIATH 1[UVIIC[I STATION NMWKIs M117S STAT140 MAC& SUI&N Pill IFi 60 :of collii IS;-S1 WWI", Hit ~Sl$ILS!II A LL wife. too66 0if1t 16-6? oi.1.9 l.ot * ~.1 t ? 6.6 Est11 g i. It, SSE 2.0 Z.?.9. z 6.3 a.s 1.c 2.? ? 1.a a SSW IN WSW * i.2 I*a.? a?.0 I ao io5 o.6.9 g.? 1. os.1.. O.. is ".0.o.7 3.a i..i 30.3 VA IA1. I! 0 9 * ll i I.6 to 3? 1.? 1.6 o6.1 0~ O.. Y. 0.O.. o. fitsm w o l vlet * a *,s e oo4t fhists I ? 6.6. *... o, 1 0 o

78 6K6OM CLIPNIKLSSV IC PERCENTAGE FUUENCV Of OCCU*NrKcE OF iuofauc MINDo miiaccto LIENEI4 ItvCINI TOON "OUILV SOSENV*IONS VERSUS uinud SPEED STATION a 12216T Stall" GRANO FORNS are No PERIOD Of RECORDS 16-8? MOW: JUN 0000-O2oo eisiction I IC ? N0 NI-N? 44-SS of 66 TOTAL MEAN $01Mts$ N~~ INO bu.n ? KI ~E I *N.3 6.? N E. I a S.6 S E E 6.1 Stu *2 4. S *.3 3.) ad.? VON *V.L S6 No

79 .-- +l " OLOBA CLIUNTOLOSY uhohc PENCCOT*SC FREQUEIkC of OCCUIRNCE OF SURFACE MINO DIRECTION VERSUS WIND SPEED US&PIT&/l FRO" NOUNLY ONS[NVAIO N5 STATION NUNERs TZ7TS STATION NINE: GRAND FORMS AF NO PERIOD OF RECORD: 7T-67 MONTH: JUN HOURsILSTIs 0300-OSOO S MIND SPEEDC Ift KNOTS DIP[CTIOm O - 06-SS GE 56 TOTAL NEO: 10SGNES I I x WIND ME ZZ 6.7 at ' [NE l.0 S.3 I * C tse S5.o2 1.?.9.. *.0 S.6 SSE j.0, $ I SSW S.2 S.s SW 1. $.1.?.3.l S. S.0 MSW 1.C S.4 K boo.9 2.? ? 7.0 ku a.2T.6 o1 N : : YARIASL( IO6LS i 56.? S.3 o o o... o TOTAL 01N6 Of OS1gRIA11gN l '00 J

80 14~ '1 MIVNO SGLOAL CLINATOLOGI BRANCH SAFETAC AIR WEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS UIND SPEED FROM HOURLY OBSERVATIONS STATION NUMBER:?2?SS STATION NAME: GRAND FORKS AFa NO PERIOD OF RECORD: 78-B7 MONTN: JUN HOURSILSTI: SPEED IN KNOTS! DIRECTION I ss GE S6 TOTAL MEAN IOEGREESI I V MIND N NNE C NE ENE s E.3.9 * ESE S? NME S SS o1 303?? Sm.? ,S WSW ? m O.1 8.1?.a WNM Nu NNW ! 1 9.3?,9 VARIABLEI TOTALS S TOTAL NUMBER OF OSIER VATIO"St 900 j..l

81 . G LOBAL CLIMATOLOGV BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND SFEED VSAFEIAC FROM HOLRLY OBSERVATIONS AIR MEATPER SERVICEINAC STATION NUMBER: 7277S5 STATION MANE: GRANO FORKS AFB NO PERIOD OF RECORD: T NONTH: JUN HOURSILSTI: WINO SPEED IN KNOTS DIRECTION I 1-3 4' SS GE S6 TOTAL MEAN IDEGREESI I WINO NE. 1.: S.0 i0.9 A( I ,2 ENE E..8.6.b ISE SE ? SSE S I SSW * S I ? WSW.0.3 o.o W.8 l, T W tn N N1 *! VARIABLE *CALP 1.1 // I // /lji// 111/./ ili III/ Ii ,1//1 TOTALS I S.? TOTAL NUMBER OF OBSEAVAT2ONS: 900 L.

82 GLOBAL CLIMAIOLOGY BRANCH USAFETAC S1R WEAT(4R SERVICEINAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND SPEED FRO" HOURLY OBSERVATIONS STATION NUMBER: 727STS STATION NAME: GRAND FORKS afs ND PERIOD OF RECORD: 78-ST MONTH: JUN NOURS(LSI1: I MINO SPEED IN KNOTS DIRECTION I ZZ SS 6E 56 TOTAL "LAN IDE[IREES I % MIND... N * S NNE * ke * Z.T 7.7 ENE ,1 E I ESE ? SE I *86 bo.c SSE S * * SSW I S WSW ' WNW ,? NW NNW I I CALM 1.1 lili TOTALS I fl 10.2 *... J L. TOTAL NUNDER OF OBSERVATIONS$ 900

83 GLOBAL CLINAOLOGY BRANCH PUCENTAGE FREQUENCV OF OCCURRENCE OF SURFACE vmo DIRECTIOh VERSUS MIN0 SS(EO IS IF I C FROP MOU 1 LV OBSRVATIaNS AIN EAWTER SIIV C(IH*C STAIION NUNKN 7275TS STATION Napt( GRAND FORKS IFl NO P(I0O OF RCOgRO: To-@? NONWY, JUN HOURSILSIS: Q I MINO SPEED IN KNOTS DIRECTION : l 'V t SA TOTAL ": k 40EME(S I 2 WIND u S.4 S S.2 1. NNE S WE,* ? 6. [HE. 1o E u 6. (SE *g SE,2 * I 3.9 a. SSE s Z I2,.2b * e " &V i WSW , I WW i. NW O.1 N.M I ? VARIABLE CAL" oii 0,1//fIo III I // I I #/ I, I/0 IIF # o/ III1, 10 p 1. 1i11LS I ? c lo.c TOTIL NUMIR O OBSIEITIONS: 900

84 GLOBAL CLIMATOLQGV BRANCH USAFEVAC AIR WEATPER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WIND SFEED FROM HOURLY OBSERVATIONS STATION NUMBER: 727SS STATION NAME: GRAND FORKS AFB No PERIOD OF RECORD: 76-ST. ee.. e e... e e l e e e e e e.. e. e..; MONTH:.... JUN... HOURSILSTI: I MIND SPEED IN KNOTS DIRECIION GE 56 TOTAL MEAN foegreesl 8 WIND Z, c NNE I N [ie L ESE SE SSE S ISV ?.8.2 %.a 8.3 I I SW S WNW ; hit N.1! VARiAOLE I?OVALS I TOTAL NDRLU Of OUSOIVAV2OW. 90O - m mmmmmmmlm mmm ~

85 IML"'f SNMIC PERCENTAGE FREQUENCY Of OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED UswIllac FROM HOURLY OBSERVATIONS *36 d*im6~ $II [ICEIN* sl38336 MM* 71,7S STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORD: MONTH: JUN HOURSILSTI: I WIND SPEEO IN KNOTS J 1IIISU I T ? SS GE 56 ToYAL MEAN oeness 1 WINO M S ** 7.j S ? t.v I I l.8 O bv I ISO 1 j.1 2.? , C. I t ?.0 S.2 *. I,6 2.8 * * i.* * "Go. t C ft. mt G * I i as590v1i i0,,kmmn.l I'DO+L I e41ll~lllll!

86 GLOBAL CLINAIOLOSI $NHu PERCENTAGE F(OUkCY Of OCCURENCE OF SURFACE MINO DIRECIION VEOSUS MINO SFE[0 USAF[IAC FROM NOuLv 08SC3mATiONS A18 I [AE R SERVIC[INAC STATION VV'PI s SiTAION A,&ME[ GRAND FORNS AFg NO PERIOD OF R[COOt "OUT JUN l0ues4sil ALL r WINO SPEED IN %MOTS OIRECTION I al 22? 20-3j *-51 SE S& TOTAL PMAN I DEGRISl I % WIND i HUE ,0 4.2 Goc ME O,0 2o1 6.9 [ME.? E J.2 S.? ESE.7 1,3.0.S S toy 5.9 SSE *2.0 T S SSW %.3 D.c S I.6 1.? * % ISM O W WNW NW *l NNW ?.9 9.c **o...*... * o o... oe CALM Is1iJii//iiii///i/II~I~iJI/iiIJI/I/II/iii/IIdi.8 /ilt/il TOTALS I e..o... TOTAL NUMULR Of OBSENVATIONSI 7200 L

87 ilo&al CLlISO14LOOY suman" PCI[puI*SG4 FIgWAbCV Of OCCUOSEUCI Of SUOF&C WMND DIRECTION VEIISUS NINO SFEtD USufEiAC *3I d11ag1 SElI9IO~fINKk Fie p6unl5 msvossis 9111S360la b3dlkls S 11*1106 6*6(1 eases ruls org go 9(5IO0 *F *icoim, il-sl "N: JUL. OURSILSTI: istciolu I I *.O.OK 27-2o so-%a 4l-47 O-SS s6 TTAL oeeeee.l eeeoe..e,oo*... *.,*, o... l3ll[ I9 3.I O G 33. ft?l. I S *a 2 t I 3., , ~ a A 9.9 I I k *I SSW I 2.9,-.9. S.3 S S. S , SS 55 I W I 1-2.I..S S.) Num O. S.1 S. lis 1, I,.4l 6*.6 S.6 "Nollll 1.L 10FALS t~tl. US( * * I 930e* * S O. ~ TOTA~lL bivwi Of OSUVIM4O9 ISO

88 K.*ShL CLINAIOLSGV gaftcw KCENIAS FIRL0UECV OF OCCUIRECE OF SUIFACE WIUD OlfCTCIOW VERSUS WING S1[O 4 US FET C FRON 4OUINLY OS[IVAIONS Al I a l~l[ E 14t VIC[E"AC STAION NUsERa: 727SS STAIO M 66 s GRAN r D FORAS LF fib0 PERIOD OF CCOROt Is-at #0#14: JUL NOUSitLSII: I WIDSEDI *T DIRECTION I6-ss 6E 56 IOTAL ataft l ifo llll[s I a INGII ti s N6E.S I t lot f. S, I.C C %.1 SI.8 3.S S.9 SSE 2.C S I ? * 12.?.C SSW 1, o S I %.I Z w s IS.$ II I S.3 km g b.0 $.I loft W b Cat II., SL. I S TOTAL NUBE OF 6SCRVAW6?1S6: 9s0 III Ii IIIii I iiiii IIII II i III+I iiiii i II ii II ii I I I I iii II IIII iiil

89 b0.41m CLIMN*IOUS4IRAMiO,i.CLIOG*I FKUEACW Of OCCVN1UCC Of S~ff~t VM *3RECl3SO IFIIIg WINO $010 OSAF91C URLV son SESII S "1 IflA *C ia 311ggM 185 I*C~ * It *,E11.9 bgo see#%.1 I Iowa I *g fin.6 I SLt I SSE I 3.9 a s 1.4 MUM I I 1 A3la so 1.a S.1 S.1 us5 V 3.9~ ~..6. *... I. TOTAL NUi0SL OF *,SKINAsVIOaS 036

90 t:j& IIfIIII CLI*AIetOGV911611". II PROCgefae IIIII F11,9119 liiii 1 OF MO ulll OCgu,0MwgA qgiigle of O!i Ige91I wime IIIIIIIII810.II 9~ll ulottis" Itesus 1101 I'VII) lto u*aio SIIUs 131oei m 86 0 f9llllll AK11 "OllILl0l O o eg1110 S MO P ,P:3 its ISOl OF-s lk&99 i to c & &?.# 1 1.l4S % IIIII $K I l I s.o ? 5.1 J.?,1 I10 S I. 1w 99 I S. 1.9 l % l I, 9.. o... S., lot *.. s*9.* l.o 0.6.,9 l.g I, *9w I t iil $9 h. I.9 too I, Io I 6.9?,...,... loa, owam II 9*I9l,I o95,8, ~, b, ~ III I I o,,, L -i lllll 0,I hl l~l,i -, II

91 *,Q~IsaftfC "At* CL3IMAOL10 "mw,iluc i,6 l PageIKUO v of O CVv00gfl room P"tlLV iof "W69*1 4IcO vlllle$ vius ssiaco Ui0 S6011 ~~~~~~~~~~90 WSMOS 1159, $961104~ #?%I $C(, 141% ot 0&9 rs% osopol$ofot0?*o filll. IeI( site ;.... ;; ;... i ' in Go I I3, 1ee.. 1 I?-#I1. tif o0 #,, S I ~~.a 2.S a. 553t l.o,2 9.1 e.e a *o a..s i.0.. ;,* *, sb a * 11i I I l i1.0 i.9 $ O 3.0b I..3 2l. e. g V~ I *6 1et *g. b5a,i il.c... ti5l5 2.. I ,]... Sl.OC 35l LS I It3.2 Il J eseeeoeoeeoeee o **. * * e heat ftnit of 930 *stlyolas L

92 M Cl 44M 416O01 961amll P691i9418 PselIgele o 414CUeavUil Of NoIPI Viso fiicilei vsislls gaul %Ott0 SeM 1101 glp POmSI, S ole1 103 $ stflflos N plll?mt 'lmr i l llo *W ILi oa es II fso posts* of otcoil to-of I~ ~ ~ ~ * ~ - ~ -i ~ Io6II*Il-rIl) ~ ~ il~l ~ ~ II-!i*t ~~W Ib ovstil IIl I Spot*s toroots 1sam g 1i- l o?-to $11i 6 i li i 2-1i 8- Is o-o f s 55 at S4 1 oat l 04 11% 6 a lu 4.4 1*3 *l i.6 6.l et I i ea i.1 3.O 6.9 S. * It I J.C * I,S ? S.3. Si. 9.3 t I.% a.o i. s % a ** *.1 9.c ss I...* , 6. t. 1s S e~g I.9 a.. $ to.% us s LI I 1~.2 a.. 2.u a C o I * I1 P.10 9)o I l I59 I I Iol $#A I~ W ls... i IO... I.. *$ L...

93 GbLOO L Ilai. PRCl81ai0( F?6ECY O CCURRNCE OF SURFACE WIND DIRECTION vesus IlNO ksati SFEu ac FRM wn o OUNL 09sERVATIoNs agofus WCA1,111 OgS(RV*IIOWS fiflion WUMS, STAI ON MAKEI GRAN0 FOols ir 0 P(ROD or I(COI, '1ONTk: JUL HOU*SILSTI D0... I WIN SPEED 1t0 NOT lloctist I li-6 IT-il 2Z oss Sf f FOAL IAN *6(6l i S B I WIND... i.l I.8I II C.8 I.0 Z.0 1I sat I s g IM S Il,l.8 isi.4ot. S-2 t I.$ S 5.6 S.4 IS St e SE S $ 3d S S I S. WS I ?.1 W % 1.9.S Willi I W I.S ' b I TOTAL% I S s TOTAL *UG gil '.,..,+ J,,,,,,.,,..,,,,,,,.,.,,,.,..,,,,,,,..,I,,,L

94 %I GLOAL CLINTVOLOSY BRANCH V S4FIA C AIR WCATWER SlavICEINAC PCRC~bTAOC FREQUNCY OF OCCURRENCE OF SURFACE MIND DIRCIiON VERSUS MINO SIED FROM VOLILV OBSERVATIONS STATION!UNBRS 72ThS STATIOMN AMAE land FORKS &?1 #0 PEIOD of RCORIe I7-a, NONH: JUL OUOSLSIIS Kc1iow ? S Q? o %-1 SE 1 TOTAL MEAN l oesicso s MIND * N I , NNE o1 S.Z G.C NC.S S.S [NME.9 1.s.3 2.? 9.2 C I S.9 ESE SS SE SSE NT 2.0.? ,6, SSSW S $2Io S.2 WSW $ i WNN S.1.9 I I (AILP f i/, l 100. l1.101*111$li &%.I 11111I * TOTALS I 36' 3.i 20.3 S.S I! TOVIL I %UNDLI OF OIKClWI910MSs III 6.

95 MOslaL CLINAIGLOSY MANIC" PECECNIAGE FNEWOI~Ct OF OCCURRECEC OF SURFACE WINO DIECION VERSUS WIND SfECO us I C FRO" NOURLI ORSCIWATIS AIl WATPEN StOWICEIWC STAft M, nug siation NAME& SlAM0 FOAMS AF8 NO PERIOD OF ICCONDt MNTH: JUL MOURSILSIIS ALL MINDs SPEED IN KNOIS OIIECIROM ?23l S se-4a 41-4? 93e-5 6E S6 TIOL PEAN "at ? 6.9 If I ? 5.s I35lot s s S.1 I1 st b.c SE *3.0 %.S?.1 55 I at I.S, S %.2 3.) SSW ~.1 So C Wsb * I 1.9 Z.4 I., who S.? 7.3 lob ~ ? bwl fp weffas %.2, s C Gf 653l30116Mts?%I%

96 GLOSAt. CLIMATOLOGY USIUCH Us "rela c AIR WEAT04LO SEAVXCECJNAc PECCkIASE FRE QUE CY OF OCCURRENCE OF SURFACE WIND DIRECTION. VERSUS WIND SfEOC FiOt HOULY OSINVA115S STATION UVISCU?27575 STATION NME: 61*60 FORKS Afe No0 PERIOD of RECORDS 77-6 MONT"% &US HOUg~fLSU3: I WIND0 SPEED IN KNOTS DIRECTION sii% 48-SS GE S6 I&IAL MEAN Ii I Z* C t.5 S.1 kc S.1 ISE I.2.# S5S..9 SSE 1-2~ 2.S S I 1.9 % SSW C sm WSW S.5 d I 3.6 % S5 7. S # a ?.S ' 6.1 Nk I 2.C c TOTALS I TOTAL. %tude Of 66118uV110U1: 930

97 GLOBAL CunMATO*Lee BANK" ot*tklasi FUISMAfCV Of *CCU*RSIWCL OF SURFACE IND Dimat1303 ot*sus Wjmg j.fiio LSAF( lac Fee" wejmkv esselralleu$ STATION IZfl?1 STATION Gw6( o"s are NO Ptauog OF NaCgas tM bus ~%bgokst): 0100.OSDO I WIND SPEED INg %6091 D*ICTION a? * Z0-93 3m6-4o %1-4? 04-SS BE S4 3(9*.. "I&% NNE 3. ~..2.0 s. lot S. S5.3 i let I..2.3.S s*. ($1 I ~L I1b c $$ S1.2.1 V.6 b.1 i SSW %1 Ia I %.. WSW I S * m #,.S b.6 too I S.2 %too I VeAI 3601 * 1 Ewa360 CAM flll 11iljl 114 it tllitiil.j111/ldlpp.111ii L.

98 LOSKI Ca IP~lIS.S SLUICH PECENTaaAGE FREQUENCY Of OCCURRENCE OF SURFACE WIND DIRECTIONd VERSUS WIND SPEED US Lil [Ic FRO" 140OV OSSERVATIONS S1*1I04 kwoksi: MS?%3 STATION NAME: 60ANO FORKS IFS 040 PERIOD OF RECORD: MONTHN: AUG HOURSILSII: DIfICTION 1 I WINO SPEED IN RNOTS b? '8.-5 GE 56 ICIAL MEAN 4CE&R1fSi M IND 4 J * I NEi t s Ie SI si.6, Is SE Sb I ? S I S I. b~ b4. 4.4? p b.7 bb ' K Z VARIABLE I CALM Iol/#t/imill..iIJJ1011il //JI /14.6 j~i'//ijj#t/i/ji//~jjjji//i/i/ 111jii TOTALS I j.c S.7... TO1AL NUMBER Of OBSLERVATIONS: 900

99 -A Fop DANTO I CUIIAIt 7I /2 v L.

100 ILI I~~Ii8 W-ROCOPY RESCUTIcM TEST CHAR MTWI KOIM OF STNMW 93-A

101 GLOALs CLINATOLOSV BRANCH PERCENTAGE FREQUENCY OF OCCVRRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED u "sfta FROM WOURLI OBSERVATIONS i!... AIR WEATNER SERVICEIMAC STATION NUMBER 727S7S STATION NAME& GRAND FORKS AFG NO PERIOD OF RECORDs TT-6 MONTH: AUG HOURSILSTI: WIND SPEED IN DIRECTION T-10 I SS GE S6 TOTAL "El SOEGREESI t WI0 N I NNE NE.6.,S [NE E.6 1.S ESE SE %.S I SSE s S SSNW.3 *s 2.? SM WSN , W WNW.3. 1.S Nw G NN I.6 1.? T TOTVARIUBLE O TOTAL NURSER OF G TOAS I ,

102 .... ~ ~ Il GLOBAL CLIMATOLOGY BRANCH USAFrETaC.WE-A.',Tt4E SRV CEIMAC PERCENTIA6E FREOUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WIND SPEED FRO" "OULY OBSERVATIONS STATION NUMBER: STATION NinE: GRAND FORKS AFS NO PERIOD OF RECORD: NONMd AUG HOURSILSTI: I WIND SPEED IN KNOTS DIRECTION i Z ~t7! %1-S5 SE S6 TOTAL. MEAN.65N 2.9 4ob S NNE I NE S. ERE , E I ESE SE * SSE S.6 2.S 4.9 S SSW S,& io.0 SI S a.' USk.3 lot N *1 S.S a., UN I.s S bb m.i NNW ,. 9.' ; VAI ABLE I TOTALS TOTAL NURSER O r OBSIERVATIONSI 930

103 GLOBAL CLIMATOLOGY $RANCH PERCENTAGE FREQUENCY OF OCCURRE1NCE OF SURFACE NINO oirecvon VERSUS MIND SF(EO USAFETAC FROM 04OUNLY OBSERVATIONS AIR WCATI'ER SERVICEIMAC STATION NUMUBER 12?STS STATION NAME: GRANO FORKS AFS No PERIOD OF ACCORO: ONTNZ AUG HOURsILSTIt I WIND SPEED IN KNOTS DIRECTION I Il ? %a655 GE S6 TOTAL. KEAN.... ""o I0E[ORES I ;: ".. I 0"... WINE) N I NNE 1.0 1:: S*1 6. NE I." S..'.6.1[,A S E., LESE S S s. SC * SSCE S A, S S.? i: 55w I q.1 I0. SN WSWIh :?,.6., 1.1.J 4.9 S., WNW TOA,OF NUMBE OBEVTOS TOTALS I S

104 GLOBAL CLIMATOLOGG BRANCH PERCENTAGE FREOUCNC OF OCCURRENCE OF SURFACE MIND OIRECTION VERSUS MINO SPEED AIR WEAT4ER SERVICEINAC STATION NUMBER:t 2TSTS STATION NAME: GRANO FORKS AFO ND PERI O *OF RECORDs "*.MONTH: AUG MNOURSILSTIt 1O00-2O00... I WIND SPEED IN KNOTS DIRECTION I a VI-VT 46-SS E S6 TOTAL MEAN 10EGAEESI... ;;.... :;... 1;... ;:...:;... WI ND NNE ?.2.1 S ENE ,S *3 V.? V.9 E I.0 2.V ISE.V SE.V ? 2.V SSL S 9.6 $.5 S SSW * SM I S 6.2 WSM.9 :8 :3, " 1" I 1.~q 6 6, S 4 2 S.4 MjNMW V.2?.2 NVs.3 i i NNW os ? S VARIABLE i CALM 4F.411 /m* / 1 Imill miltl m TOTALS I IS.? S.... TOTAL NUMBER OF OISERVATIONS 930 -a

105 GLOBAL CLINATOLOST mig0nc USAFETAC A1 IAIMER SEAVICEI Ac PERCENTAGE FREuNkCV OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MINO SFEED FROM HOURLY OBSERVATIONS STATION NUMBER& STATION NAME: GRAND FORKS AFB ND PERIOD OF RECORD: MONTH: AUG HOURSILSI1: SWIND SPEED IN KNOTS DIRECTION N8-SS GE SG fetal NEAN IDGOREES3 I % WIND N I $.1 0.S N.E ? S.3 ME Ij ? ENE E 1? S.C ESE S SE I SSE S 1*S 2.S ,2 SSW j.c I;:! SN ,S WSW N.j w i NNWN. 1.I S.3 NW 1, S 6.8 NNW S VARIABLE 4 TOTALS S.1... TOTAL NUMBER OF OBSENVAIONS: 930

106 GLOBAL CLINATOLOGY BRANCH SAfETAC AI watit.[r SgnMVCEINAC PERCENTAGE FREUIENCY OF OCCURRENCE OF SURFACE HIND DIRECTION VERSUS WIND SPEED FROM HOURLV OOSERVA71010S STATION NUNERS 727SS STATIOi ANME GAND FONS AFe NO PERIOD OF RECORO MONTH: AUG HOUSELSI: ALL I WND SPEED IN KNOT$ DIRECIION I z S5 SE 56 1tAL KaN IUEGWt ES I a WIND... N, S % NNE a WE.T S. FN * C (SE.S ?.2 SE, * t S SSE S S S. 12.S 9.C SSW S.C s" I WSW S.0 3.S 6.3 H I I.S S 6.6 HUN i.0 S.S 8.2 N IS NUN Jos s T o... VARIABLE I TOTALS I S T I o*1oeooeeeoeooo eoo*o*o~ooooeeeoooe ee eoee e**~* *, '! OtAL NUIA OF 0OSs vaions: 7330

107 GLOBAL CLINATOLOGT BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WINO DIRECTION VERSUS MIND SPEED - USAIFETAC r OURLY OBSERVATIONS.i ** AIR WEATHER SERVICEINAC STATION NUMKER: 727S7S STATION NAMEs GRAND FORKS AFm NO PERIOD OF RECORO: T7-86 MONTN: SEP HOURSILSTI: I MIND SPIED IN KNOTS DIRECTION SS BE S& TOTAL MEAN foireesi I WIND....* $ 8. 3 NNE S 7.3 NE ENE *1 2.? 5.9 S SESE ?.C SE S S SSE SW I s T.e ski SC WSW oS S.S W SoS W MNW NM I *NNW S.6 6.c TOTALS I *LJ 0 4 TOTAL 01UMUER Of OBlER VATIONSt 900

108 GLOBAL CLINATOLOG? BRANCH PERCENTAGE FREOENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND SFEED to AFrTA FROM HOURLY OBSERVATIONS / "; AIR WEAIIEA SERVICEI"AC STATION NUMBERS?27$?S STATION NAHE: GRAND FORKS AFO N I PERIOD Of RECORD? 7-86 I MIND SPEED IN KNOTS MONTH: SEp 94OURSOLSTO: 0300-OSOU OIRECTION I : S GE S6 TOTAL MEAN IOEGREESI I % MIND... N A NNE M NE ENE * ESE ? 7.0 SE I S ISSE S SI ~ SM S.3 WSM S.S b'i MNM.7 2.g * Ni M :1 -J.4 CIiti "1 1 lli, TOTALS I j.9 3% TOTAL NUBRO 3C II : 900

109 GLOBAL CLIMATOLOGY BRANCH4 PERCENTAGE FREQUENCY OF OCCURERENCE Of SURFACE WIND DIRECTION VERSUS WIND SPEED us "rrlr C FROM "OURLY OB~SERVATrIONS SAIR E THER S[RVC[/MAC STATION NUMBER: TZTSTS STATION NAME: GRAND FORKS AFB Nd PERIOD OF RECORO: MONTHS SEp MOURSSLSTI: INO SPEED IN KNOTS DIRECTION I %1-4? 48-sS G S6 TOTAL MEAN IDEGEEI s MIND ft I ?.9 NNE o3.? 7. NE * ENE E * ?.7 ESE SE SSE I Z * S r 1.! ? SSW SM S.4 WSW S.9 I s *I.! I WNW NW I q NNWM I 1.? o... VARIABLEI CALF 111/11/f/l t ll I/i/fil I lm/m I/ll TOTALS I I Iq

110 J GLOBAL CLIMATOLOGI BRANCH PERCENTAGE FREQUENCY or OCCURRENCe OF SURFACE MIND DIRECTION VERSUS MIND SPEED USAFETAC "* AIR WEATHER SERVICEINAC FRO" POURLY OBSERVATIONS STATION NUMBERs STATION NAME: BRAND FORKS AFB NO PERIOD Or RECORD: 71-S6 "ONTHS SEP HOURSILSTI: I... NIND SPEED IN KNOTS DIRECTION I ? O %I-4T 98-SS GE 56 TOTAL MEAN IDEGREESI I WIND N S NNE NE C IkE I E ESE *1 2.8?.C SI ? E S SSW SM :: S* 1.6, Wi.3, , 11.6!WNW Nv ' Z O.9 NNh VARIABLE I CALM TOTALS I TOTAL NUMBER Or OBSERVATINONS 900

111 *GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED USAFETAC FROM HOURLY OBSERVATIONS AIR WEATHER SERVICE/NAC STATION NUMBER: 727S7S STATION NANE: GRAND FORKS AFB No PERIOD OF RECORD: MONTH: SEP HOURSILSTI: o... MIND SPEED IN KNOTS DIRECTION I :-I7 %B-SS GE 56 ICTAL MEAN IDEGREES) I W MIND N NNE * NE ENE E * ESE SE.. 3., S SSE I S So SSW SS.2.? I?] WSW S M I.A ? 9.2 ll.c WNW NM NNM CALM I i /iii iiiij#iiiiiii/i/ii/i h /,t,,i //,,I //II/ui //uiiii TOTALS I TOTAL NUMBER OF OBSERVATIONSt 900 j..

112 GLOBAL CLIHAIOLOGY BRANCH PERCENTAGE FREOIUNCV OF OCCURRENCE OF SURFACE WINO OIRECTION VERSUS MIND SFLED USArETAC FROM NOULV OBSERVATIONS UIR WEATHER SERVICEINAC STATION NUPBER: 727STS STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORD: 77-6b NONTI SEP HOURSLSTI: 1SO-1700 WINO SPEED IN KNOTS T DIRECTION I A55 GE S6 cial MEAN IDEGREES) s WIND.... o... ; ; o N NNE I NE ENE ,4 L ESE.s3.4 1.& SE SSE S SSW S" WSW S NNW ?. IO.S N., NNW o CALM 3.9 l/ill TOTALS ? TOTAL NUMBER OF OSERWATIONSs 9U0 4

113 GLOBAL CLINAIOLOT BRINCN USFrIC "1R WEAT64ER SERVtCEInAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECIION VERSUS WIND SFEED FRON IOURLY OBSERVATIONS STATION NUMBER: 72?S7S STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORD: HONTHS SEP NOURSILSTI: I MIND SPEED IN KNOTS DIRECTION i 1-3 f4 1-ID 1-lb ,33 S SS GE S6 TOTAL HEAN IDEGRES) a MIND V.k NE NE EE E E *6 * ESE.3 1.? SE SSE a. S SSW S. SM WSW.4 2.? S. W T. WNW Nw S.9 9. Ni N W , ,. II ITOTAL NUMBER Of OBSERVATIONS: 9.9

114 GLOBAL CLIMAIOLOGV BUANC64 usafeta PERCENTAGE FREQVtNCV OF OCCURRECEc OF SURFACE WIND DIRECTION VERSU~S FROM YOURLV OBSERVA71OUS WIND SPEED AIR WEATNER SERVICcINAC STA71ON NUNDERt 72757S STATION NAmli GRANO ORKS Are No PERIOD OF RECORO: "ONTN: SEP NOUSMLSI$s 2100-o2500 WINO IN DIRECTION I to SS SE S& TOTAL MEAN (DEGREES1 MIND N oi 9,3 8. NNE I ? a. NE I ENE S ESE SE SSE l $ SSW S. Sm f*t. 4. SWSW I*C ee 6. b WNW ,3 S,4 Nu NNW VARIABLE -CALM Ii-fl /I IiliIIIIIII f I m l l i TOTALS I I G. d... TOTAL NUMBER OF OISEIVATIONSs 900

115 GLOBAL CLINATOLOGV BRANCH US AFE I ac '4 AIR WEITHER SERVICEIMAC PERCENTAGE FEOUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED FROM HOUALT OBSERVATIONS STATION NUNSENs STATION AMEZ GRAND FORKS ifo NO PERIOD OF RECORD: 7?1-8 MONTH: SEP HOURSILSTI: ALL I MIND SPEED IN KNOTS DIRECTION i IT-Z ? 98-SS GE 56 TOTAL MEAN IDEGREES1 I MIND N"I ! NNE IS NE (NE I ? 7.3 E I ISE SE.S 1.S ?7 SSL *S.1? S.6 2.S ID.0 SSM SM C WSM S MNW kb ? 9.0 N inw " V R AOL[ ;... LIj TOTALS I ?.1... TOTAL NUMBER OF OBSERVATIONSt 7200

116 GLOBAL CLIMAITOLOG BRANCN PERCENTAGE FREQUJENCY OF OCCURRENCE OF SURFACE MINO DIRECTION VERSUS WIND SPEED USAFETAC FROM FOURLV OBSERVATIONS AIR WEAINER SERVICEI/AC STA1O NU4SER: 7277S STATION NAMEs GRAND FORKS AF NO PERIOD OF RECORO: MONTH: OCT NOURSILSTI: SWINO SPEED IN KNOTS DIRECTION I ss GE 56 TOTAL MEAN DEGREES) s WIND A :S ;.. NNE NE $ ENE E ESE S S.1 SE SSE @ %.7 9.S SSW SW c Wsm ? *9 *S.2 4.4?.C ' , 3- $ 1 1.6,1 10.2?.q WNW 1* ?.? N I ? 1.S ',4 NNW I VARIABLE o *I ~~ ~L" 11/l/i/i oil/ m 1 1/11 //m Imilmillil ii mil TOTALS I ?.S 6j TOTAL NUMSER OF OBSERVATIONSs 930

117 ' GLOBAL CLIMATOL06T BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE or SURFACE WIND DIRECTION VERSUS WIND SPEED us Art TA FROM POURLY OBSERVATIONS AIR WEATP[R SERVICEOMAC STATION NUMBER: 727S75 STATION WAKE: GRAND FORKS AF9 No PERIOD Of RECORD: SMONTH: OCT HOURSILSTI: 0300-OSOO, VARIABLE I Sm WIND SPEED IN KNOTS DIRECTION I ? %I-SS G S6 TOTAL EAN IGOGREfS % NIND N NNE NE S. [NE.1.S E S ISE.$ SE SSE S,S S 9. SSW S MS I WSW " * W MNW NW NN * TOTALS I TOTAL NUMBER OF OSStIVATIONS: 930 i

118 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SFEED I USAFETAC FROP POSJRLY OBSERVATIONS AIR EATNER S[RVICEIMAC fri... STATION NUMBER: 727S7S STATION NAME: GRAND FORKS AFB No PERIOD OF RECORD: MONTh: OCT HOURSILSTI: o.. eo..... o.o... * o o.. o... ee e..... o... " WIND SPEED IN KNOTS DIRECTION ? 0-SS GE S6 TOTAL MEAN 0IEGREESI I MIND N NNE l. 7.6 NE ENE S.4 E I.0 o3 *A C ESE.6 * SE.S 3.3.S SSE h S o SSV S Sm ft 8.S 6.8 WMSW.S W I 2.5 % l.b C MNMW m I i NNW I i.3 i i.? I I 1.9 I ii I.1 I I i I I I 8.1 i l 10.1 l o..... o... o... o... VARIABLE I CAL I III I/III/ III I /iliii/i / I/I II // IIIII III UIIIiIl tf1/ If 11114F 11/ /11 W TOTALS L * TOTAL NUMBER Of OBSERVATIONS: 930 j3

119 GLOBAL CLINATOLOGY BRANCH US'F[ TA C. AIR WEATHER S[NMIC[INAC PERCENTAGE FREQUENCY OF OCCURNENCE OF SURFACE MIND DIRECTION VERSUS MIND SFEED FROM HOURLY OBSERVATIONS STATION NUMBE:?R: 2757 STATION NAME: GRAND FORKS AFS No :7-T6 PERIOD Of RECORDs M ONTH: OCT MOURSILSTI: WIND SPEED IN KNOTS*** ****..... DIRECTION ? ? :-4? 48-SS BE S6 TOTAL MEAN IDE6REES1 I WIND... ; ; ;: N e * NE WE S.9 ENE.6 S ? 5.4 E.4 *6 1.2, S ISE * SE, S?S SSE.3 1.c 1.S 3 1 1,S.3 a.? 12.0 S I. 1.0 S SSW.2 i SM WSW.4 S 1., c I ? WNW ? 10.2 "W h WNW VARIABLEI TOTALS I?*. S*S TOTAL NUMBL OF OBSE[YATIONSt 930 6

120 - GLOSAL CLINATOLOGT EiMwCI PERC[NTAG FOfUENCT OF OCCURRNCE OF SURFACE IN11 DIRECTION VERSUS MIN0 SFEED I USAFI[AC FROM NOURLV OBSERVATIONS AIR33 MIATHEN SEillCIIII*C STATION NUMNSS: 721S7S STATION NME: GRAND FORMS AFI NO.PERIOO OF RECORD: NONTHZ OCT HOURSILSTli I WIND SPEED IN KNMTS DIRECTION i l-ss 6E S6 TOTAL MLAN IOGR[ IS1 I % WIND * NlE I NE S (ME E.S S 7.0 (SE S 7. SE I ? 9.1 SSE.1 '9 l.s S S S C SSM S ' S, I S k, WSWI II I.2 *S O.8 WNW ? NW,3 S S ,S NW " VARIAtBLE I '1 TOTALS S.S J TOTAL NUMBE 6J R Of OBS(RVATIONSs 930

121 GLOIL CLIMATOLOGY BRANCH SA AIR WST:ATIOR S:RVIC:/:AC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WIND SPEED FROM VoURLV OBSERVATIONS STATIONNUBR 2SS TA1NMH:GAOFRSF8NPEIDOREOD??6 MONTH: OCT HOURSILST 1: 150O-170O J WIND SPEED IN KNOTS DIRECTION I z O %$-SS GE S6 TOTAL MEAN IGOEREESI % MIND... N NNE 'NE [ E.3.8,S q Z ISE SE I1.l j SSE S ssw'i li SW m.. * q I S Vo1 I.MW. I.C *S Nw NNW IS VARIABLE I CSLff IIIUIIlllIlll /ll/ll/lilili/iilljl/iilol/i//iil TOTALS I I

122 GLOBAL CLIMAIOLOG? BRANCH USAFETAC.3 AIR WEATHER SERVICEIMAC PERCENTAGE FRRLENCY Or OCCURRENCE or SURFACE WINO DIRECTION VERSUS WIND SPEEo FROM 'OURLY OBSERVATIONS STATION NUMBER& STATION NAME. GRAND FORKS Are No PERIOD or RECORD: 77-Bb MONUTH: OCT NOURSCLSTI: I WINO SPEED IN KNOTS DIRECION T D SS GE 56 TOTAL MEAN IDEGR(ESI t * WINO N I ? NNE NE,3.9.S ENE I E S 5.1 ESE I.1 *B SE I SSE.9 2.g S.S s 3.5 t ? 9.1 SSW. 2.2,S b.c SW I S.4 W"S N.s WN Nw S Nw S... I" TOTALS I 12.C ? TOTAL NUMBER OF OBSER VATIONS1 930

123 GLCOL CLIMATOLOGY BRANCN USAFETAC AIR WEATHER SCRVICEIMNC PERCENTAGE FPCOUNCY OF OCCURRENCE OF SURFACE MINO DIRECTION VERSUS WINO SPEED FROM HOURLY OBSERVATIONS STAION NVNBSRt 727S7S STATION NANHs GRAND FORKS AFB NO PERIOD Or RZCORO: NIONIP: OCT NOURSILSl: MIND SPEED IN KNOTS DIRECIION i z o5-$5 GC 56 TCTAL NEAN I D GRES % WIND N NNE WE I ENE SE 1 1 S 1.7 S.6.E SE SE,S SSE b s S c SSW S5 71 Sw S WSW 1, C " N1 % S 6.7 WNW q,1 S NW 1.3 1,4 2.? SNNW , CALM wim i ///.'/I I ip // it /111 /1111.* 1/11 li 1/ /1 / I/I1 Ilitt TOTALS I TOTAL NUMBER EVATIONSt 930

124 *' GLOGAL CLIMATOLOGY BRANCH AIR ISAFtIAC EATPER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SFEEO FROM HOURLY OBSERVATIONS STATION NMUER: 7277 STATION NAME: GRAND rorks Arm ND PERIOD Or RECORD: 7T-6 * MONTH: OCT HOURS4LST): ALL MNO SPEED TN KNOTS... DIRECTION I S ? 1 8-SS GE S6 TTAL MEAN DEGREES) I t WIND " N I NNE o 9.s ME.3 * ENE S.8 E C ESE SE S SSE S %.S SSW Sb S WNSW S I N Wi NW S.1, i F Nw " NNW.s p VARIABLE I ' CALM S. 56 Illf TOTALS S " TOTAL NUMBER OF OSSERVATIONS: 7010O.j

125 GLOBAL CLIMAIOLOGV BRANCH PERCENTAGE Or OCCURRENCE Or SURFACE MING DIRECTION VERSUS WIND SPEED UsAre T Ac FRO" NOUpELY OBSERVATIONS AIR WEATHER SERVICEIHAC STATION NUPUERS STATION NAME: GRANO FORKS ArB NO PERIOD Of RECORD: MONTOI: NOV NOURSILSTI: i.';... [... ;.. ; I WIND SPEED IN KNOIS DIRECTION ? AD Vt-A? 4 6-SS GE S6 TOTAL MEAN IDEGREES I IND... N.? ? o NNE.2.9 l C NE.* SS ENE *A.3.A.2 1. S.9 I *V ESE.3 * SE S.2 SSE S. 7.8 S.6 V SSW S Sw I V WSW V.A 7.5 W ?.6 7.A NNW A s N V * NNW.6 1.A ALM /it 11/11 ~eoellooelte III/// ee III i~le II /I/ l. it I///.* it/ oit Iififi 01 ml TO27LS S.i *... A.TOTAL NUMBR Of OBSERVATI0NS$ 900

126 GLOBAL CLIHAIOLOGT BRANCH US FETAC AIR WEATPER SERVICE/MAC PERCENTAGE FREQUENCy OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED FROM NOURLY OBSERVATIONS STATION NUMBER: STATION NANE GRAND FORMS AFB NO PERIOD OF RECORD; 7?-86 MONTH: NOV HOURS(LSTI: I MIND SPEED IN KNOTS DIRECTION I i-s S4-NO SS GE S6 ITAL MEAN A (DEGREESI 2 WING N NNE.2 * N E3 *N.3 1.1?.S ENE,N E I ESE I *N c SE * SSE *.C S S * ? 9.0 SSW * SW WSW I ?.S WNW NW NNw VARIABLE I TOTALS I C I 7 TOTAL NUMBER OF OBSERVATIONS: 900 L

127 GLOBAS CLIPATOLOGY BRANCHG PERCENTAGE FREQUENCV OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND SPEED US AF ETAC FROM POURLv OBSERVATIONS AIR MEATHER SERVICEInAC... STATION NURSER: 72757S STAtION N&E: GRAND FORS safb ND PERIOD OP RECORD: NOR NH O HOURSLS '! IMIND SPEED IN KNOTS DIRECTION I : ? 6iSS Gf Sb TOTAL PEAN 4DEGREES) i I WIND -. N NNE * T NE.. 1 * EME.6.4 *1 1.1 f.c E.3..1 *1 1.0 S.7 ESE.2.4.? 6.3 SE., SSE S C SSW S.3.1 Sw * a W SW S N I NW.a ? 9.C NM NNMb ' VARIABLE I, 1 CALP USR OSRA IONS:/ Iit1 TOTALS J..1 TOTAL NUMBER OF OBSERVAT ONSt 900

128 GLOBAL CLINMAOLOGY irawcn PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND OIRECTION VERSUS Wl/O SPEED. Us SA, T C FRO" HOURLY OBSERVATIONS AIR WEATI4ER SERVICEINAC STATION NUMBER: 721SS STATION NAEz GRAND FORKS AF MD PERIOD Of RE OcDt 17-8( MONtN: NOV HOURSILSII: I MIND SPEED IN KNOTS DIRCcTION ?-10 Il ? I 6-SS GE S6 TOTAL MEAN IEGRE E I I NINO k * NNE I ?.a :1E (NE I L I..a FSE ? SE ?.6 SSE I * S I * S ? 10.i. SSit S * SW WSW * ? W, ? WN b kb * NNW I VARIABLE I CAL" / #$ #/ / / / it I Illilifillill Ilill it // / /III loil# iii III TT 1@2LS do T OTAL AluMBLQ OF OBSERVATIONS: 9O0 -J

129 GLOBAL CLIMATOLOGY BRANCH US AFT AC AIR UEATlER SERVICEIMAC PERCENTAGE FREOUEkCV OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED FROM HOURLT OBSERVATIONS STATION NUMBER: 727SS STATION NAME: GRAND FORKS AFB ND PERIOD Of RECORD:??-86 MONTH: NOV HOURSILSTII I WINO SPEED IN KNOTS DIRECTION I 1-3 V l S GE S6 TOTAL MEAN IOEGREES) I 2 MIND N. 1.6 S IS.7 12.S NNE NE c INE *V.1 V E c ESE.6.V.V 1.V V.6 SC SSE.2 2: ,e S SSW Sm ,7 3.4?.4 W: SW W ?.2.2.1? N W , 8.8 1l N I NNW V TOA NMER*.. CAL" 3.7 ItIIII TOTALS V TOTAL NUMBER OF OBSERVATIONS: 900

130 GLOBAL CLIMATOLOGY BRANCH USAFEAC AIR WEATHER SERVICEIMAC PERCENTAGE FE QUENCV OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND SPEED FROM YOURLV OBSERVATIONS STATION NUMBLS: 727SS STATION NAME: GRANO FORKS AFB NO PERIOD OF RECORD: MONTH: NOV NOURSILST: IS S... I MIND SPEED IN KNOTS DIRECTION i SS GE S6 TCTAL "LAN IDEGREES) 2 MIND N NNE S.1 TO. NE * [ME E I ISE I 3.* SE SSE S SSW *1 S SM S WSW I Z. G1 Z so$ WNW * * Ni I NNW I *ji VARIABLE I :jcalm t 10. q6 illlit TOTALS I j S StOTAL TO NUMBER OF OBSERVATIONS: 900 I 4 m m u m i ~ m m m

131 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCT OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED S' CFROM USA HOURLY OBSERVATIONS..:' AIR WEATHER SERVICEIMAC STATION NLBER: 727S7S STATION NAME: GRANO FORKS AFB No PERIOD OF RECORD: TONTH: NOV MOUUSILST): I MIND SPEED IN KNOTS DIRECTION q7 46-SS GE S6 TOTAL MEAN IDEGREES) I W IND N NNE S NE N ENE I E I 1.C (SE SE I SSE S ,2 SSW.7 Z S.? 7.6 SM WSW, S. w ?., WNW NW NNM ? VARIABLE TOTALS I ? T

132 11 GLOBAL CLINiAIOLO6T BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MINO DIRECTION VERSUS WINO SPEED USAFETAC FRO" 4OUULV OBSERVATIONS *.1 AIR WEAIER SERVICEINAC STATION NUNSER$ 7ZT5 STATION NAME: GRAND FORNS AF0 No PERIOD OF RECORD: 17-6 MONTH: NOv MOURSILSTI: I WIND SPEED IN KNOTS DIRECIION I 1-3 N N-40 N1-Ni 40-S5 GE S6 TCTAL MEaN ID1GREESO.... o. - I o o. s... WINO N NNE I S ME I N EWE S-2 " E I I ESE o S.2 SE, Z SSE ? S S ISSW SW I C WSW Z W o C SNNW NH ? : NNW % b.? VARIABLE 1 IOTXL 7TALS S , *C o... o... NUMUIR OF OSEN WATIONSs 900 j

133 GLOBAL CLINAOLO6Y NMIAc PERCENIAGE FREQUENCY OF OCCURRENCE OF SURFACE W1ND OIRECTION VERSUS MIND SFEED us F.vAC FROM HOURLY OBSERVATIONS Am NR WETHE SERVICEIAC STATION NUJMBERS STATION NAME: GRAND FORKS Are No PERIODOor RECORDs SWINO SPEED IN KNOTS MON NO V: H NOURSILSIIS DIRECTION I Z _o0 %1-%y 6-SS Bc S6 TOTAL MEaN IOEGREE S, % WINO o N S l.o S NN WE.2..S of l (NE.S.S IS 6.3 E I.3.S S,? (SE S,. S" I SS S S S ? 9.6 SSW S.? 6.5 ALL SW s WSW.5 1.S S 6.1 V I.C m. MNW.S N , Nb S VARIABLE I TOTALS I G.? TOTAL NUMBER Of OBSERVAIONS: 7290

134 GLOBAL CLIPATOLOGY BRANCH PERCENTAGE FEOUENCV OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS hind SPEED USAFETAC FRON VOUNLV OBSERVATIONS AiR MEaIER SEOVIC(IciC STATION NUPSERs STATION ANME: GRAND FORKS AFE NO PERIOD OF RECORD: TT-6 MONTIH: DEC HOURSOLSTI: ; ; o OI II MIND SPEED IN KNOTS DIRECTION N-A ? O N4-N? 4A-Ss GE 56 TOTAL NEAN IDE6REES1 WINO k I.c S MINE I.3.S PE i T.8 IN[.6.1,I c ESE.1,N.S 7.a SE * N SSE I*S S N SS SM * WSW N.E 6.7 S bnw C u I.6.s 3.N FAR S I i.i q.s TOTALS I 11.S 2% Ie TO se s o e o o oe o oo o

135 fi GLOBAL CLIMATOLOBY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND OIRECTION VERSUS WINO SFEED USAFElAC FROM VOURLY OBSERVATIONS AIR WEAT14R SERVICEIPAC STATION NUMBER: 727S7S STATION NAME: GRAND FORKS AFS ND PERIOD OF RECORD: MONT84t DEC HOURSILSTI: MIND SPEED IN KNOTS DIRECIION I ? % GE 56 TGAL MEAN EOIEF.RES3 I WIND... N , * NNE NE (NE E I (SE.1,S SE. s SSE S SSW SW S WSW ?.I W z WNW NW NNW, ,2... CAL ~ II TOTALS J,.C s TOTAL NUMBER OF OUSCRVATIONSS 930 J4

136 GLOBAL CLIMAIOLOT BRANCH USAFETAC AIR HEATHER SERVICEIMAC PERCENTAGE FREQUENCT OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS WIND SPEED FROM POURLY OBSERVATIONS STATION NUMBER: 72757S STATION NAME: GRAND FORKS AFe No PERIOD OF RECORD: MONTH: DEC HOURSILSTI: I DIRECTION I MIND SPEED IN KNOTS 2S ? 88-SS GE 56 7CJTAL MEAN IOEGREES, a WINO ;... i N NNE.1 *6.8 * NE EE Is E ESE SE SSE.6 1.S S s SSW I S.0 SW S 6.0 WSW ,e W S a WNW.S NW I S NNW.S IS VARIABLE I TOTALS I TS T 4... TOTAL NUMBER OF OBSERVATIONS: 930

137 GLOBAL CLIMATOLOGY BRANCH USAFETAC -,-1 AIR WEATHER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WINO DIRECTION VERSUS WIND SFEED FROM HOURLY OBSERVATIONS STATION NUMBER: 7275 STATION NAME.I GRAND FORKS AFI No PERIOD OF RECORD: T7-BA MONTH: DEC 14OURSOLSTI: SI WINO SPEED IN KNOTS OIRECTION GE 56 TOTAL NEAN rdebreesi WIND ]N I S NNE I.1.8 S C NE I.2.2.2A ENE I 1.2 * E I ESE SE 3 * c SSE S SSW I SW I "W SW,e ? T,.9 Us-o M i.s kW I S O.S NW JWNNW S V*" R*;ABLE I CALM Ii// 7.S 7.5 //I/, III TOTALS I TOTAL NUMBER OF OBSERVATIONSs :

138 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR MEAT14ER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WIND SPEED FRO" HOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AFS No PERIOD OF RECORD: M onp: DEC NOURSILSTI: IZOo-1o0 AN I WIND SPEED IN KNOTS DIRECIION b z O-55 GE Sb,TAL MEAN IOEGREESIt WIND.9.9 3, ", NNE I.2.S S 7.1 NWE I S* ENE.2., E I.S 8.5 ESE I, SL SSE S SSW S S I S WSW I WNM Nb.6 Z ? 11.2 NNM, S 10.6 Ii.S VARIABLEI CALM 111/ ////////i//iiii//iiui//ji/i////iuii/,i,/.9 I/1/11 TOTALS I S T total NUMBER OF OBSERVATIONSs 930

139 UL.088LACLIHaTOLOGY BRANCH PERCENTAGE FREQUENCY Of OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WIND SPEED US AETAC FROM POURLV OBSERVATIONS AIR WEAT3NER SERVICEIMAC STATION NUMOER: 727S75 STATION MNE: GRAND FORKS API NO PERIOD OF RECORD: MOWTH: DEC NOUSILSTI: 1S I WMIND SPEED IN KNOTS5 4DIRECTION I BE S6 TOTAL MEAN IDEGREES) WINO... N I NNE I ME I ENE E I [SE I SE I SSE I S I SSW I q sm WSm W I WNW I Now I NNW I pcalk I~I/ i of/ I I i/hi lhu//i /.#/ 1. /J.41//i0/1If i/ #U tiffl.#/ i.4 / / /I TOTALS I * TOT~~~AL UBRO UEVTO~ 3

140 GLOBAL CLIMATOLOGY BRANCH USAFETaC AIR MEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED FROM IOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRANO FORKS AFB ND PERIOD OF RECORD: JMONTH4: DEC IOURSILSTI: I MIND SPEED IN KNOTS [:. DIRECTION I I8-SS GE 56 TOTAL MEAN 4OEGREES) I W IND NNE NE S.8 ENE E I (SE * SE S SSE 1.S ?.2 S SS ?.9 SM S WSW.S ?.2 W 1.S WNW S NW NN S e VARIABLE CALM // ////////i/ 7.8.///// ///it//i I//I/I TOTALS % L TOTAL NUMBER OF OBSERVATIONS: 930

141 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE MIND DIRECTION VERSUS MIND SPEED US AF ET AC FROM POORLY OBSERVATIONS AIR WEATHER SERVICEIMAC STATION NUMBERt 72757S STATION NAME: GRAND FORKS AFB NO PERIOD UF RECORD: MONTHS DEC IFOURSILSTI: 210O-2300 DIRECTION I I WIND SPEED IN KNOTS NO N-N7 N8-SS GE S6 TOTAL MEAN IDGEGREES) t W MIND. 8 1.N NNE I NE ENE E N,S ESE SS SE I SSE S 1.S 2.6 N SMW S 8.6 SM S MI 1WS M l S ,2 MNMW * NW N.1 N '" NNW I TOTALS I S TOfAL NUMBER OF OBSERVATIONS. 930

142 GLOBAL CLIMATOLOGY BRANCH usafetac PERCENTAGE FREQUENCY Of OCCURRENCE Of SURFACE MW19 DIRECTION VERSUS FROM I'OURLY OBSERVATIONS MIND SFEED AIR ieit1'4e SERVICEIMAC STATION NUMBERI 727S7S STATION NAHE: GRAND FORKS AF No PERIOD Of RECORO: MONI' DEC WOURSILSTI: ALL DIRECTION I ? ss GE S6 IOIAL NEON IDEGREESI I I... o+... NO N,* S *a N"ME -* S 6.0 NE.* * (NE...3.S I $,.6 ESE " SE T,2 SSE.S I.2...+S S 4 O O 1,.% " SSW.6 1et ,g S.2 l8.4 4 WSW W WNW NN I NN.S VARIABLEI "i,:calm+ Ill/l $ /./ 111/1f/111 / fl #1 I/t I f14ili 7.4 t111tl TOTALS TOTAL NUMBER OF OSERNVATIONSI 7990

143 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREOUENCT OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS MIND SFEEO USAFETAC FROM lourlv OBSERVATIONS AIR ueatier SEEVICIMAC STATION NUMBER: 7277S STATION NAME: GRAND FORKS AFI ND PERIOD O RECORD: 77-$? MONTY: ALL HOURS4LSTIl ALL " MINO SPEED IN KNOTS DIRECTION I ' SS GE S6 TOITAL MEAN IOEREESI I I UIND... N ; I[NE NE *D ENE * S 1..D ,I, MSE I SE S * ']SSE *? *S *1 *O? '"S Sssm.6 1ea clq 8.2 JSW o*.1.0 * m o1.0 * mM S ii N I ,S s tnnm JCALM 8.2 o/1l/l TOTALS 10.S I o TOTAL NUMBER OF OISERVATIONSt 57661

144 GLOBAL CLIMATOLOGV BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SURFACE WIND DIRECTION VERSUS WIND SPEED USAFETAC FROM 04OURLY OBSERVATIONS AIE WEATNER SERVICE/MAC STATION %UTBEOs?2757S STATION NAME: GRAND FORKS AFS No PERIOD OF RECORD: 77-e1 MONTH: ALL HOURSILSTI: ALL... CEILINGS 200 TO 1o00 FEET WITH VISIBILTIES 112 MILE OR MORE CEILINS 200FEETNRDMOR CEILINGS 200 FEET OR MORE WITH VISIBILTIES 112 TO 2-1j2 MILES I WINO SPEED IN KNOTS DIRECTION ? o ss GE 56 TOTAL MEAN IOEGREESI 2 WIND N I NNE , NE ENE E ESE I ? SE I SSE ,S S.5 1.? SSW I SW I j WSW I ?. WNW.3.S NW I NNW VA'ALEI TOIALS I o n TOTAL NLMBER OF OBSERVATIONS: 9063

145 Al. II pppppppp A O&a Aw ua e tvuutttr TIT TI TI 0100 oc0 pppppp a&aaa A A 11u ITI 00DOD00 ppppp AAAA*IAAA Ran MR IT 00 co pp AA AA E TV 0O D PP 44 a* R MR IT 0D000DO0S 'I0

146 CEILING VLRSUS VISIBILITY AND SKY COVER SLMMARIES j CEILING VERSUS VISIBILITY SUMMARY THIS SUMMARY IS A BIRVARIATE FREQUENCY DISTRIBUTION BY CLASSES OF CEILING FROM "a" THROUGH EQUAL To OR GREATER THAN 20,o00 FEET AND AS A SEPARATE CLASS "NO CEILING", VERSUS VISIBILITY IN 16 CLASSES FROM ZERO THROUGH EQUAL TO OR GREATER THAN 10 MILES. DATA DERIVED FROM HOURLY OBSERVATIONS. FREQUENCY DISTRIBUTION PRESENTED BY THE STANOARO 3-HOUR TIME GROUPS BY MONTH. MONTHLY AND ANNUALLY CALL YEARS COMBINEDI. NOTES: BEGINNING IN 196B, METAR STATIONS REPORTED VISIBILITIES 10 6 MILES AND GREATER THAN 6 MILES. THEREFORE THE COLUMN FOR VISIBILITIES EQUAL TO OR GREATER THAN 10 MILES APPEAR BLANK. AS A RULE, AIRWAYS STATIONS NORMALLY REPORT VISIBILITIES TO 6 MILES AND I OR GREATER, HOWEVER SOME STATIONS REPORT HIGHER VALUES. THEREFORE. THE 10 MILE VISIBILITY COLUMN SOMETIMES CONTAIN SALL PERCENTAGE VALUES. HOWEVER, THESE VALUES ARE OF LITTLE MEANING AND SHOULD BE DISREGARDEOD. 1 FOR METAR CIVILIAN STATIONS REPORTING "CAVOK", ALL CEILINGS ABOVE 5000 FEET WERE SUPPESSED TO SOCO FEET. THEREFORE, NO PERCENT VALUES APPEAR ABOVE 5000 FEET. SKY COVER SUMMARY PRESENTS PERCENTAGES OF SKY COVER IN EITHER JOTHS OF COVERAGE OR "AIRWAYS CLASSIFICATIONS". DATA SUMMARIZED BY TPE STANDARD 3-HOUR TIME GROUPS BY MONTH, MONTHLY AND ANNUALLY (ALL YEARS COMBIhEDI. ALSO PRESENTED ARE REAN SKY COVERS. FOR AIRWAY STATIONS, THE CONVERSION FROM THE AIRWAYS DESIGNATIONS TO JOTNS FOR PRESENTATION ARE: CLEAR - (110 SCATTERED - 3/10 j 1OCR :OVERCAST - 10/10 OI OBSCURED

147 GLOBAL CLINATOLOG BRANCH USAFETAC AIR WEATHER SERVICERAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROH HOURLY OBSERVATIONS STATION NMBRERs 7275S STATION NAMES GRAND FORKS AF9 NO PErIOo OF RECORD: 78-B? ROUTH: JAN HOURSLSTI: CEILINGVIIIIYISTTT"LE IN ige Gf BE GE GE GE GE GE GE 6E GE GE SE GE GE GE FEET I 1O 6 S I SIB NO CEIL I S.S S%.9 S5.1 S5.9 SS.S S S6.S 56.S S6.5 S GE S7.1 S7.9 S.S $ S9.4 S6.S S6.6 S9.4 S.S S9.S S9.8 S S9.6 GE I$.'o S7. S7.S S 76 So S Sm.? S9.S S S SV.9 GE S S $ S.2 S6.S S S9.S 59.6 S S9.9 S9.9 S9.9 A.GE S S S S 55.6 SB.7 S9.S Sq GE s5.2 ST. ST.7 ST So.? 5.45 $8.9 S GE S1.7 S S GE S S S GE BCOO S8.O 61.S S %.S 6%.S GE 7COOI s S S GE S S GE SCOGI GE so S 70.4 To.S ? GE 9000G S S.3?S. IS.S?6.3 7.s ?6.5 GE S.3?s. 7S.7 7S.6 TS ? T GE 0oOO % G 2SJOI 67.S I.S SE S S S S.9 6S G2 GE S S.l 6S e6.s 66.S GE 1S S : S 69.S GE S a *S s 92.5 GE S S GE GE l.% S % GE S ? S.? S.6 9S. GE S, % q GE SO1 7S.3 P S GE 9100c ?? 97.7 GE S r S *s GE S S , GE S S.1 9S GE 01 7S S TOTAL NUNER OF OBSERVATIONSz 930 I

148 I I I " " GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY UShFE7hC FROM HOURLY OBSERVATIONS AIRt WEATHER SERVICEIMAC STATION NUMBMER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD$ MONT1S JAN HOURS(LSTI: 0300-OS CEILING VISIBILITY IN STATUTE MILES IN IGE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET t o0 6 S N I 1/2 1 1/ 1 3/4 5/6 j12 5/16 1/# NO CEIL I SI.S S S1.l S S4.1 GE ? SSl SS.S $ N s7.% GE ? S S6.7 S GE S S6.7 S $ GE ICOO 51.6 SS SS S ST S G S SS.6 SS.9 S S S S8.3.1 GE Sl.S GE 9Cool S4.4 S S o GE N.2 6N.2 6N.2 6N.2 GE 7' %.2 6N S S GE St N.3 6N N 67.N 67.N GE SDOo s 70.5 GE GE NoCoI N.N 7N.N N GE 3SO be S GE I0.N GE 2C O.S N.2 84N. 81.S *. 67.N E IsuCI N N.3 8% GE " GE %.S GE 1C N.0 9N.2 9N.2 9%.2 GE IS N.3 94.S 9N.6 9N.6 GE l00 73.N 83.2 I N N.N 9N.6 9N.7 9N.7 * GE N N.2 9N.2 9N.9 9S GE 60c 73.8 e N * GE s GE 4O0I 7%.0 #%.C N.6 9% S GE!Oct 7N GE r GE 1oci GE 01 71N.0 It N Ve TOYAL NUMBER OF OBSERVATIONS: 930

149 GLOBAL CLIMATOLOGY BRANCH US'FrTaC AIR WEATNER SERVICEINAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FRJON HOURLY DBSENVAIIOWs STATION~ %U"qER: 127S1S STATION NAMES GRAND FORKS AFS NO PERIOD Of RECORDS?6-07 MONTHS JAN HOURSILSvi: o6o IN G 5::: GE GE;A G G GE GE 6E GE GE GE GE GE GE FEET 10 6 S IS / /41 SIB 112 S/ NO [IL St.? S S2.6 S S3.0 S S S E( ZC0OCI S S3.7 S4.0 S4614.,6 5.8 S%.9 $5.9 S5.1 S5.S S505 SSo GE iacj S0, S3.7 S4.0 S S.. S4.9 SS SSe.SS 5.6 5S.6 5S.6 SS.6 GE Wool S3.7 S Sq.@ S SS.1 SS.S SS.S SS*6.GE S009 SoO S%.5 so SS05 So55 S SS09 S S S 56.S Sf's GE SS.1 ss~q S S6.3 S6.S $7.0 S1.o (0l001 S%.2 57,6 S0,2 SB.S $9,1 59.S $ I so.% 50.9 S GE SG GE EGCOO I S S S.3 6S.1 6,S GS GE GE 50001'60.9 SO S.7 6S.9 66.S 66.? S ? S % S TO S 10.0 b[ %coo 63,s GE 3S ? 7q.7 74.? GE S 78*S GE 2S S GE ? S S.2 8S.2 6S GE : S.1 8S GE ISOO :S : a9.2 GE 1200? a a gos S 90 s G ICO S S GE 900, St.% Be.$ G ? GE ,.1 9%.s GE bo % 6S S S GE S.3 88.g S S GE S ? S s * G S.2 9S GE ? GE S.3 9s.4 9J GE OI B s ?.? TOTAL MUMUER OF OSRVATIONSS 930 j....

150 G LOBAt CLIMATOLOGY BRANCH LSAFE7AC AIR WEA11ER SERVICE/MAC PERCEN7AGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM IOURLV OBSERVAIIONS STATION NUMBER: STATION NAME: GRAND FORKS AFI NO PERIOD OF RECORD: 7a-a7 MONTH: JAN HOURSILSTI: C. CEILING VIS BILIfY IN STATUTE MILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET /2 2 11/2 1 1/ Si8 112 S/16 1/4 0 V... NO CEIL S.S S % q8.s GE 2000C % S $ 51.1 S1.8 SI. 9 S1.9 S2.9 S2.4 S2.4 S2.S S GE S0.8 S S1.9 S2.1 S2, S2.S S GE S 50.2 S S S ? GE S1.1 S S3.3 S3.4 S3.S GE SO S JGE GE S2.! $6.6 S * *S , S S9.8 f, q 60.S GE S GE S GE GE GE SCOOI 59.7 # S * ?a.% ? S *3 GE 9coo S S.5 75.S 7.5 7S GE GE S s GE ZS 70.S S :2 79: S GE 2C00I 6S : S S.1 8S.2 85.% 81.9 GE IGSOCI 6S.S I.S S GE GE S GE ICOGl GE C S S GE : :S 93: GE S GE : S s.1 9S GE s S GE GE S % 97.S s 98.6 GE S g.S GE 10i S ?.6 98.S GE S S s I TOTAL NUMBER OF OBSERVATIONS: 930

151 GLOBAL CLI a4olosv B1*NC0 PERCENTAG( FR[QUENCV OF OCCUIRRNCE OF CEILINlG VERSUS VISIBILIT? USAFEIAC AIR E(ABS[RVI:Ct::ACC FROM 0OUOL OBSERVATIONS 'i STATION NUMBER: TZ7S73 STATION NAME. GRAND FORKS raf NO P[N]OD OF RECORD: " smcont:nf :FOURSOLS7 JAN IN GE S[ 61 G( GE GE GE Gt BE GE BE GE GE GE GE G1 FEET I IV o2 1 I / / a NO C[1L : #$&. 98* GE 200O01 4T S5.3 5S SS S6, S6.S E S2.2 S2.8 S9.1 SS.S S5.6 5S.8 S S6.2 S G SS.S SS S S60I -E S Sq.S S S SW GC 12C S2.9 S3.5 s S6.4 S70 S7.0 S7.3 S7.3 S? FA 5T. GE S S S S 62.S GE 9C S GE S GE 7Coo SS s ::? GC GE S S o0 GC AC 6E /SS G 3500 S Tef GE ' GE D.S o $ GC T G GE b S S % as.% 9s.% S.S GE ISOC $ GE S SS S S 92.6 G ? S.1 9S.2 " GE C %.9 9S.1 9S.4 9SeS GE S G q.? 9S ? GE S G D 6,:??77:2 822~ :0 93:4 9S03 96:S 96 9?:06 ;1:8 9:: GE ; s4 89 9e SS a7, a GE 200I Z S S IO *.2 02.Z #S , o SE G &S.,1 $ SoS o TOrAL NUNBE O0 OBSCVAUIONSt 930

152 GLOBAL CLIMATOLOGY BRANCH '/ " 'AIR USAFTAC WEATHER SERVICEMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM IOURLY OBSERVAIONS NUMBR: 727 STAISTATION STATION NAME: GRAND FORKS AFB No PERIOD OF RECORD: i..e: ;MONTH: JAN HOURStLSTI: IS IBILTCILING INSST EMILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET i ' S/ 1/ l14 a e. e NO CEIL I '3.S '7.6 ' SO.1 SO.2 50.' 50.5 S SI.2 GE 2000D1 ' S7.o S6.0 SR S8.7 G '9.4 S S6.1 S S8.3 s8.' S S8.. GE ' 54.6 SS S7.6 ST.? S S8.3 S9.3 SB.' S GE 11Co S0.1 SS.8 S6.5 S7@.1 $ S9.' at S8.9 S9.1 S9.S 59.6 S GE S ' ' GE 9c00l ' S ' S.S 6S.8 GE S 00 SS '.' GE GE C GE S0O ' % GE S S %.3 74.S 7%.S 7' GE '0001 S S GE S 7S.S ' S 79.6 GE ' GE ' GE ' S s 6S.S GE S S & 87.6 GE '. 89.' , GE GE ' %. GE e0.b ' S.1 GE '. 76: S: S 96.a :. G S as.? S S.S ,': 97.7 GE S a GE S ' GE ' S '. 97.' GE S S ' 97.' GE S S SGE & ' 97.' GE S TOTAL NUMBER Of OBNSRVATIONSS 930

153 GLOBAL CLIMATOLOGY BRANCH UsAFETAC AIR WEATHER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE Of CEILING VERSLS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRANO FORKS AFS NO PERIOD OF RECORD: MONTH: JAN HOURSILSTI: CERLING..... VISIBILITY IN STATUTE MILES IN IGE GE GE GE GE GE BE GE GE GE GE GE GE GE GE GE FEET I /41 SIB 1/Z 5/ NO CE0L 1 86.? , 50.2,.S GE S SS SS E & S GE 16C S4.7 5% S GE SS $ S GE 12r0o S o S S 57.5 S.6 GE SS GE S GE 8COOS 58, : :9 65.l :3 6Se S: G o GE GE so GE 450k ? GE GE O GE s GE GF S GE GE GE GE GE S GE GE B GE s GE SOl l GE ? GE GE c ? GE IA GE OI TOTAL NUMBER OF OBSERVATIONS. 930

154 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE rrequency OF OCCURRENCE Or CEILING VERSUS VISIBILITY usafetac FROM HOURLY OBSERVATIONS AIR WEATIER SERVICE/MAC STATION NL'OER: STATION NANE. GRAND FORKS AFB NO PERIOD or RECORD: 78-B? MONI1: JAN HBURSILSTI: CEILING VISIBILITY IN STATUTE MILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET / / /2 S/ NO CEIL 1 %7.0 50o s109 5Z GE sq '.' ' GE '. 5' S GE 16C Sq.3 5'.' ' S GE 14C S S S5.S 5S GE Sq S s ? 56.8 GE s S GE G ' S C.5 GE S S ' GE ' ' 63.' GE r S GE 5C b be S GE 4CO0I ' ' '. 75.q GE GE ' GE ' GE GE S GE ' G.. GE GE GE S GE o S GE s GE GE OO? 'I GE ' GE I GE ? GE S :9!: JGEI 'I TOTAL NUMBER Of O6SERVATIONS: 930

155 GLOBAL CLI9AIOLOY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFETAC FROM HOURLY OBSERVATIONS AIR WEATHER SERVICE/MAC STATION NSMBER: STATION NAME- GRANO FORKS AFB NO PERIOD OF RECORD: 78-A7 MONT: JAN HOURSILSII: ALL... -W CEILING VISIBILITY IN STATUTE MILES IN GE GE CE GE GE GE GE GE GE GE GE GE GE GE GE GE *'FEET / /16 lit 0 NO CEIL i SO S1.1 SI SI S S2.i GE S1.1 S9.S 5S S S GE S SS SS.9 S S S GE S S GE 14o0oo SO Sq.? S S6.S S GE o.8 5q.6 SS.1 ss.6 S S S7. S ' GE $ O GE 9CO01 S GE Oool GE S.9 6S.0 6S.? a GE S ? GE SCOOl GE GE S GE S '"GE GE 2501C GE S GE OS GE GE GE GE " GE S S S.4 GE S , GE GE GE GE S GE *ii GE OJ " TOTAL NUMBER OF OBSERVATIONS: 7990

156 GLOBAL CLIMAIOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY UsAFETAC FROM 04OURL OBSERVATIONS AIR WEATHER SERVICE/MAC STATION NUNIER: STATION NAME: GRANO FORKS AFB NO PERI00 OF RECORO: NONIT: FEB MOURSILSTI: CEILING VISIBILITY IN STATUTE MILES IN I GE BE GE GE GE GE GE GE GE GE BE GE E GE GE 6E FEET I 10 6 S I ' Sig 112 S116 lif 0 NO CEIL 1 '.2.6 '.'..9 %'.. '5.5 '.6.0 '.6.1 ' s 46.s 4.6.S 46.1 '.6.5 '.6.S 46.S 4.6.S 46.0 GE %.5 '.7.9 '.6.0 '1.. '.6.9 '.9.1 ' '. '9.'. '.9.'. '.9.'. '9.'. '9.' '.9.'. '9.6 GE :..: '79.6. : '.69 f'91 '.9,.3 '.. ".9.' 9'... '9. '.*. 9.. '9'.. GE 1000 j.55 '79 '.6. N6.S '9.' '9.' 9.09.'. '..' 9..' '.9. '..' 9.6 GE '6.3 % '9.3 %9.0 ' S0.2 SO.2 S S0.2 S0.2 S s0.s GE 12evOOl '6.9 '9.3 '9.. '9.9 s0.%.s 10.7 SO. So S SO GE 10COCI '.9.6 S2.4. S2.6 S3.3 S '4.1 5'..3 S 3 S4.3 1' so GE s0.! 53.2 S S4.6 1'.? S.1 SS1 5.1 S1.1 SS.1 SS SS GE M0CI S2.2 1S.1 SS S6.9 S7.0 S7.2 ST.3 S ST GC S S ST Sa62 S.' $6.' S8.4 so.9 $6.'. Sm.% 56.' 16.. S6.6 GE S S8.3 So69 S S9.S S9.S E GE 0SOO0 S GE ' S.S GE 3S ? GE ' '. 71.' ' ' 71.6 GE ' S ' T GE GO.S GE ' , GE S S GE S.S GE 1COO 69.S S S GE S S1.S ? ' ' ' 90.7 GE ' ' ' GE o'.' GE ' s.s G : S %.6 GE ' ' ' ' 91.' GE '.' 9S S S GE Is ' 97.' GE s ' 97.' GE S TOTAL NUMBER OF OSSERVATIONSt 6196

157 GLOBAL CLIMATOLOGY BRANCH USAF[T C /FROM AIR WEATHER SERvICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE Of CEILING VERSUS VISIBILITY HOULYL0BSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PENIOD OF RECORO: 7B-S7 MONTH: FEB HOURSILSTls CEILIN6 VISIBILITY IN STATUTE MILES i IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I V /2 1 11/ 1 3/V 5/8 1/2 S/16 1i 0... NO CEIL V.1 4.V 41S S.s S.S 5.5 S.S *S.S S.s 5S.5 "5.6 GE S.7 S.7 VS.7 V V8.9 8R.9 V8.9 V V9.1 G E I2 C GE 18COl e ? 7e ' GE SO SO. S n.6 S GE * 60.9 SG z S GE S.71 S ? GE 9C ? 72.0 S S.S S4? s ? 90.3 GE S4.6 S V "E 700 GE 1 S0 S SS6 23. :S:: ? lv. 9 0 VS S V V6 98.3? V V6 T58:. GE GE SCOO S: :1 63: :S 63: " GE S SGE 3S00J S ? GE GE6 GE 2S CQOJ 6S.? S S ? ? ? ?8* GE S ? fge IsooJ ?S $1.? * !GE $ , GE ?0.6 ll S 8706 $ GE 900J $ o GE $Di $V * GE 700J S.3 68.S GE $ % s SGE [ oo0 71* : :3 91* 90: : : : :7 99 9S-: : : * 95.9 GE ? , ? S.2 9S b GE * "E G , $4e S f 97, ,0 6[ al S TOTAL NUMU9ER OF 0%SERVATIONSS 89#6

158 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRFENCE OF CEILING VERSUS VISIBILITY USAWFEAC FROM ourlu OBSERVATIONS STAION NUMBER: 727S7S STATION NAME: GRAND FOKS AF: NO PERIOD OF RECORD: M0 N, T. H : F E S,,, I o 6 0 o-lt 60 o EILGISIILITV IN STATU MILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE j FEET I 1 e 6 s ,9 5,6 1, NO CEIL I '7.0 '7.3 7., '17.5 % s. '7.5 q ! GE '16.9 #16.3 ' '9.3 G ' ' ' '9.3 '39.3 '.9.5 ' g9.3 9.s '9.5 f GE GE 16G0oi W 14? o 147.z S % ' , 0 S SO * s S s S S O.0 '9.5 S s S S O,O O * O '9.5 S0, S * G 12C S0.5 So.8 S1.3 S S1,3 51, ,3 S S S1.3 GE IOCOOI S S3.' '.3 S4.3 5' S4.3 5'.3 S S.3 5' GE S4.0 S4.4 $4.8 S.6 5'.6 S S.. 8 S4.8 So Sq.$ Sq., GE S S '. 57.'. $7.' 57.4 S ' S7. S7.' GE 7C S7.6 S S S S6.% GE S S9.7 $ GE S q S ' S 63.S GE '.5001 so G 4coo0 S t 67.S 67.S 67.S GE 3SO 'q.S * GE S GE ' GE ol GE ' ' GE ' , S * GE ' '.. G ' GE g S.? ' 89.. GE g ' GE : 92.9 GE ' '4 93.' GE : : , , 99.6 GE '.OJ ' a S7 9'.8 91.? GE ' , , GE a GE ' ' , '1 GE O.' ' ' S TOTAL NUMBER OF OBSERVATIONS: 096

159 GLOBAL CLIMAIOLOGY BRANCO' PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY usafetac AIR WEAIHER SERVIC:oAC FROM FOURLY OBSERVAIIONS!]STATION NUMBERS STATION NAME: GRAND FORKS AF9 NO PERIOD OF RECORD: M1NIP: FEB HOURSILS11" :: ::: :0 *,, ,,..,.. C I IN IENG t! IN GE SE BE GE GE GE IE GE GE GE GE 6E 6E GE GE GE FEET 1 10 b S / , /8 112 $116 1/ NO CEIL I %% %s.o e S S GE %S: '48.6 ' '6.9 '1* ' GE 1'01%. S '47.9 ' ' ' ' ' GE A60OCI 42.? 4S '9.S 49.s q9.s so. S0.2 GE l ' SO.0 S0.2 S CG0 '4*2 '7.3 '469 S.G SI I S SI.S S.S SI.S S.9 S2.0 S2.0 S2z.2 G OCOO 466 5O.S 52.6 S3.6 S%.7 54.S 55.0 S5.1 S SS.3 SS.3 SS SS.8 S6.0 GE 9Coo S3.3 s5.s 55.6 SS.6 S.7 SS.8 S S6.S S6.S 56.7 GE $C00l 48.6 S3.8 S6.1 S7.3 S.S 58.6 S S9.S GE 700! 492 5'.S S6.9 SS S GE 6cool S ,.S GE SOO S.S 6S GE $2.1 S S S * 66.s GE 'oo $ GE 35CO5 S ? GE GE SS q.S 71.7 GE 2C!00l S ? ,9 7.1 GE S GE S * "3 GE 120I s a%.6 GE S. 8s GE S S GE 600C GE S S S GE S GE SOOl S S.3 9S GE ' GE '4. 9q.? S 90S GE % GE loso ,S I_ GE a6.& S TOTAL NUMBER Of OBSRVATIO14Sz 846

160 GLOBAL CLIMATOLOGY BNANCH USAFETAC 410 WEATHER SERVICEIPAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISI8ILITY FROn HOURLY OBSERVATIONS STAION NUMBERS 727S7S STATION NANE: GRAND FORKS AFB NO PERIOD OF RECORD: NONTHx FEB HOURSILSTI: 1200l1OO CEILING VISIBILITY IN STATUTE "ILES IN GE SE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET IV i / S/ 1/2 5/16 I/% 0 NO CEIL * ' %6.3 A0.6 '19.2 F49.2 '9.2 ' '9.2 GE '.' ' S ' 5.% 5'4.4 5' GE 1iCO8 4. ' S S3.2 S s Sl. 5.' 5.ol. 5.4S.4 GE ' 49.S S S ' 5q. 540 GE S ' S S4.6 S4.6 S GE %S,3 50,7 SI.2 $2.' q.3 S% S S. SS GE10 IOOO S3.8 SS.2 57:2 S S S GE 9000, S S7.9 57, 17.8 S GE 6CO S ' GE 7COOl 48.7 SS S.0 60.S GE 6C00 ' ' S6.S ' GE S7oo1 ' fge ' '.'. 64.a GE ' S S * GE ' GE C GE '.? '1. GE ? S ? GE loil 5S ?6.3? GE ' s GE S S ' $ GE ICOO B' GE ' GE %.? S GE ' ' 91.' 9' GE S.7 6.S S E S GE 'O ' 9' GE 3001 S GE ' " GE S 99.9 G O TOTAL NLRBER OF OBSERVATIONSS 846'

161 GLOBAL CLIMATOLOGY BRANCH USAFE7AC AIR IEA4ER SERVICEIMIAC PERCENTAGE FREQUENCY OF OCCURRENCE Of CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS "" " '.. *. STATION NUNGBN 7271SS STATION NAN(: GRAND FORKS AFB No PERIOD OF RECORD: MONTH: FEB HOURSILSTI: I CEILING VISIBILITY IN STATUTE PILES IN I GE GE GE GE GE BE GE E GE GE GE GE GE GE GE GE FEET I 1O 6 S Al 3 2 1/ / / N0 CEIL fit %S. %S s.5 45.s S.S 4S S.6 6E ZOCOOI s SO.11 SO.5S 51.2 SI S S GE I&CODI S S S1.8 S2.o S S S2.% GE 16COO S.I S I S S GE ICDOl 44.C O.S 51o S S S3.3 S3.3 S GE S.4 SO S S3.8 S S4.8 5S GE ICOODI 46.8 $2.0 S3.9 S11.7 SS.9 O *q 57.% GE N6.8 S2.0 S S S?. 57. S.K* ST.% GE S S S E S S GE 6CO 44.6 s GE z GE %S1001 *&.S s 63.5 GE ODOO 51.3 S GE SI.? S GE o ?? GE ?4.5 7%.S 74. 7%.5 GE 2C S T8.S?B.S E SS GE S S GE B q 8.% GE A S O GE 90cA GE GE 7TOM S GE * GE 500i S GE 400 S S.S GE S S GE 2001 S ? % GE %.0 9S GE DI $ S TOTAL NUMBER OF OBSERVATIONS$ 8%6 L

162 GLOBAL CLIWATOLQGV BRANCH U5SAFETAC AIR.EAIIER SERVICE/AC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISI ILITY FROM gourly OBSERVATIONS STATION MVP6R: 727S7S STATION NANE: GRAND FORKS AFN NO PERIOD OF RECORD: MOH TH: FEe HOURSLSII o O IN GE 6 GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I 10 6 S i /2 1 1/' 1 31/ 5/6 1/2 5/16 1/4 0 NO CEIL I li S 18.5 '.8.5 '18.S 4.S ' s '.8.S GE '.8.9 '9. So.' St.? 51.7 St S GE l '. SI.? S.2 51S 51.7 S7.? t SI.? 511 GE 16DO S F49.1 %9.9 SO.5 S SI.? 51.8 S S S1.8 SI St.8 GE lcoo ' SO.2 So.$ S2.0 S2.1 S S2.1 SZ S2.1 GE lzcool S S S GE '8.7 5S.0 SS.9 56.S S GE 9cool ' S S8.2 S8.2 S GE 'SO.q 57.' BE 1!001 SO S S S 61.5 GE S1.1 S ' 62.' ' 62.' 62.'. 62.' 62.'. 62. GE C ' 63.S ' '.3 6'..3 6t GE S ' S. 6S.S S *S. GE '.COO S.7 62.' 6' GE SOCI SS S 6S ' ? GE ' ,S GE '.? S.5 7S S.9 7S S.9 GE S.S 78S o GE %@eac ' S GE S GE S 7'.9 78S ' I7.7 GE S GE gal S Be.% GE S * ' GE ' ' GE '.98 so.' ' % '..0 GE S 82.7 I S 90.s ' S S.7 GE S o VS GE ' GE ? GE % S GE 0t L TOAL NUISER OF OBSERVATIONS 8'.6

163 GLOBAL CLINATOLOGT BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFETAC FROM HOURLY OBSERVATIONS AIR UATHER SERVICE/MAC STATION NUMBER: 7275?5 STATION NAME: GRAND FORKS AF8 NO PERIOD OF RECORO: 7-87 MONTH: FEB HOURSILSTI: CEILN VISIBILITY IN STATUTE MILES IN GE GE GE GE GE GE GE GE GE GE GE BE GE GE GE GE FEET I / 1 31/ SI NO C6.L 'ss. 'S '665 6S '6.5 '6*5 ' S '6.5 " GE '8s '9.3 '9.3 s9.3 4s' ' s '9.3. GE ''.2 '?.3 s7.9 8se ' 's ' 's GE 16C001 ' 's '9.8 GE S '9.' o.2 SO SD.? 50.2 GE S S1.5 SI.S SI.S SI.S S1.5 S S S GE 10000, 50.6 $'s6 5S S $6.9 $6.9 $ $6.9 S GE SS S S GE GE S $8o $ $9.? sq.? $ $ $ $ GE S%.% GE SC00 S6.S f05 64.S % s 0 GE S s.4 6S.s s.S s GE ' S ? GE ' S 69.S GE 3C GE GE S ,7 GE ) 's ' S GE ?S.S ' '.8 6s a GE %.sS 6' ,9 GE ? UE s GE 80O o CE S ' GE $1.7 8' GE s 's6 94'.s 9' ' t GE 'soq 6.0) : :- 93:6 9s.0 9S GE ) ,8' 's GE ' ? GE $3.S ' 91.' :6 GE ' S ) J L TOTAL NUMBER OF O8SERVATIONSS 86

164 GLOBAL CLIMATOLOGY BRANCH USAFEIAC AIR WEATFER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVAIIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 70-S7 MONTH: FEB NOURS(LSTI: ALL......o... "'" o... CEILING VISIBILITY IN STATUTE MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET S / / /' 5/ /16 1/ NO CEIL % o.6o. '6.' '16.9 '46.9 4b GE o SO. S0.5 SO.S So GE q.s 49.2 S S so.? GE 16CO01 ' %9o So.S SD S D GE 1'.C5 4O.1 49o S S SI.. S1.4 S.S GE ,! 49.7 SO $2.0 S S S S S GE S3.1 SO5 5SS SS. SS S6.1 S6.1 S6.2 S6.2 S GE S3.01 S S S S S6.S B GE S5.1 Si.3 S7.3 S S8. S S GE S s GE S S GE : :G 63:1 63:7 63:7 63:6 63: B9:0 6'.0 ' E 'S50 S' a 'eT 69 6'. a za 6' GE S ' o GE GE '.B '. 72.'4 72.S E ' '.0 7'.3 7'.4 7' GE p GE s01 GE ISOO S GE ' & ' 86.' GE ICOO 6' S. GE SS k GE ' GE ' o5 92.S GE ' 93.' '..1 GE SO S 61. 0' ' GE So S.' GE S j' GE ?.? S ' , GE IS C '.7 91.' ? " GE 0I 6S S f.7 95.' ' TOTAL NUMBER OF OBSERVATIONSs 6768 L

165 4 GLOBAL CLINATOLOGV BRANCH PERCENTAGE FREQUENCY OF OCCURQENCE OF CEILING VERSUS VISIBILITY USAFTAC FROM POURLY OBSERVATIONS AIR WEATVER SERVICE/IAC STATION NUMBER: STATION NAME: GRAND FORKS AFe No PERIOD Of RECORD: 76-AT MONTH: MAR HOURS(LSTI: CEILING VISIBILITY IN STATUTE MILES FEE' i GE GE GE EIN GE GE GE GE GE GE GE 6E GE GE GE GE GE / SIB 1/2 5/16 1/ o.... NO CEIL GE 20CO S 55.5 S4.8 S4.9 S% Ss.1 SS.1 SS E St.$ S.2 5S S SS SS.f ss. 5.5s S SS.3 SS.* SS.5 5S.S SS.5 SS.S 55.5 'E 19O SS.5 SS S5.6 SS SS " GE S4.2 SS SS5. SS.9 S S GE ST S S GE 9C S S 59.5 S GE OCOOD ? GE S S GE 6COc GE 5C00 68* :6 71: t1.s E 50D , GE S GE GE 3C S GE GE GE S.9 i GE GE S ? 90.2 GE ICO0O GE E :2 9 GE 70C % GE e S GE Soo GE 9ool S GE ? GE GE , GE OI TOTAL NUMBER OF OBSERVATIONS: 930.J L

166 GLOBAL CLIMATOLOGV BRANCH USAFE IC AIR beather SERVICEIPAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOUqLY OBSERVATIONS STATION NUMBER: 727ST5 STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 78-8? MONTH: MAR HOURStLSTi: CEILING VISIBILITY IN STATUTE PILES to GE GE ae GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I 1I 6 S # /2 1 1i/ /8 12 S/16 1/8 0 NO CEIL SO $ r. GE SO.S S2.2 S2.% 52.S S S GE $3:3 GE S2.S S3.3 S S SE 1CO 5S S S GE 12Co0 S S.2 S Sq S S GE S S S7.0 S ST.? ST.? GE 9C S7.0 S S S * S GE $ b GE S GE S S.S 65S S GE S GE 8S S , GE 80O GE 3S GE % GE 2SOi S GE P GE GE ISO 78.S 79.S S.5 8S.S 8S.5 GE S i GE lol S 89.s q.? GE S GE GE S S GE S GE So , GE : S.S S GE GE * GE GE % TOTAL NUNER OF OBSERVATIONS: nm nulu m nnnm bmala IIRI~n~ m ml

167 GLOBAL CLIMAIOLOGY BRANCH USAFETAC AIR WEAT4ER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM 11OURLY OBSERVATIONS STATION NUMBER: STATION NMNE: GRAND FORKS AFB NO PERIOD OF RECORD:?6-87 M4ONTH: MAR HOURS(LST3: CE ILIN4GVIiIIYISAuTMLE IN I GE GE SE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I I 3 2 1/ /2 I / 5/B /' 0 NO CEIL 9 P43.6 & e6.3 e ' ' 1e e9.' ' GE SO.8 $ S S S3.8 S GE Z S3.0 S S4..1 5o.1 S.1 I 5'. S. S GE ' $1.1 S E 's S' % '.2 5' GE 12COO '.8.8 S.? S2.2 S2.% 53.7 S S ' oT ? 59.8 OE S S'..S 1.8 5S $7.0 S GE Se S S7.7 GE S S9.2 S ' 60.'. 60.' 60.'. 60.' GE S S GE & ' '.6 GE SOO C BE S GE %oo S ' '. 12.' 72.' 72.' 72.' 72.' 72.5 GE 3S b.S ' GE ' ' S S.3 7s'. GE ' GE S GE ' GE 1500, 67.' GE GE ' 78: ' , GE ' ' GE!00 69.' GE :4 79:6 :1:9 83:1 :6:3 :7:00 88:: :9:5 9S 99 O90 91:2 91:3 91:3 91:3 :1:3 91oe E ito o a 93oa 93o0 93 a 9 1 t GE Soul 6905 S e o2 96 9e.3 G E e e S GE S GE '. 9V S BE ' E o S TOTAL NUMBER OF OSERVAI1ONS: 930 L

168 GLOBAL CLIMAIOLOGT BRANCH USAFEIAC AIR WEA7FER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VFRSUS VISIBILITY FROM HOURLY OBSERVAIIONS STATION NUMBER: STATION NAME: GRAND FORKS AF NO PERIOD OF RECORD: SONIP: 1AR HOURSILSTO: CEILING VISIBILITY IN STATUTE "ILES IN GE GE GE GE GE E GE Gr GE GE GE GE GE GE GE GE FEET 10 6 S /% /2 5/16 S1 0 NO CEIL ,9..6 ' s ' ' GE ' S S4.1 S9.1 S S GE S S S4.2 5' GE 16COol S Sq,3 sq.3 so.3 S., GE ' S4.5 S S S s S4.9 GE 12000, S $ S.? S.7 SS S t GE S.S S S S GE GE S $ GE GE S S GE Scoot GE ' GE 4CO01 S o.S? ? GE 350C S8.S ' GE GE ? S S GE s % GE S QS GE IS S S s Z GE S S GE GE GE s GE 70C 6S S GE S ' GE s01 s5.s 77.S " S.6 GE S , S.6 9S.6 96.S 96.s GE S S Z S , E 100 6S s GE S s TOTAL NUMBER OF 08SE89811@NSt 930

169 I GLOBAL CLINAIOLOG5 BRANCH PERCENTAGE FREQUENCY OF OCCURPENCE OF CEILING VERSUS VISIBILITY USAFETAC FROM HOURLY OBSERVATIONS AIR WEATHER SERVICE/MAC STA71ON NHUMERs STATION NAME: GRAND FORKS AFB NO PERIOD OF RECOROt MONTi: MAR )OURSILS7P: e *..e. CEILING VISIBILITY IN STATUTE MILES IN I GE SE GE GE GE GE GE S GE GE GE GE GE GE GE GE FEET I N 3 2 1/ /2 1 1/4 1 3/ 5/ 1/2 5/16 1/4 0 NO CElL I 0.8 ' '4.6 '49.0 '9.1 '9.1 ' ' ' GE 2Go S4.5 Sq.S S.S % GE 1Jo0O N S.6 s4.6 S S , i GE SN.4 S S4.7 S S GE S.S SS SS 5 SS.6 5S P GE 1200, S ST GE e s GE $ S9.1 S9.0 $9.1 S GE secol 58P ' GE N GE 6CO S GE 5CO S S.9 GE o ' GE o GE q GE N S G ? GE s 0.6 GE 1: :8 76: :: 79.: GE 1500J ' GE AS.? GE 1Cool S GE S GE ) GE % o 9' GE S 94.S GE S S E *act $ GE S N 9S GE 2QO S S GE GE 0t oses '0.? U TOTAL NUMBER OF OBSERVATIONS: 930 J L

170 J Of 1j uiobal CLIHS?0L91? BRANSCH PERCENTAGE FUEQUE1CY Of OCCUIRNoCcE OF CEILING VERSUS VSSIBILITY USAFETAC Fra Nou*LY ossenvaiiems 41E WEATHER SERVICEIRAC STATIONM URBSU: STATION WNE: GRAND FORKS A78 NO PERIOD Of RECORDS MO~RN: Pan HOURSILST5 2 IS1100O IN I E K BE GE GE SE SE KE St SE SE GE SE Sf Sc E FEE to I. 514 :S01 Ste St S St.8 S 's 11.4 GE BE S T 17S.2 ST1 S7. 17S.1S7. 17S C9O01a S7.3 S Be 00 18ol l 9.1 1qS SO? GE W GE ? i! u.,.,... s,,., I~...L st O &: 78.0 :: 755 :o 753 "a BE 2C t T S Isis S.? I2. 8.0? it 1S St 20O t fit S s ~ ~~ & E Go ? GE a9. a GE S To B E s. Ma f Sf ? MI S ? Sf ,.8 cot !GE " ? "9.I 9t " SfE tool V BE S OSTAL NNO OF * SN0981AOOR 935

171 GLOBAL CLIMATOLOGY BRANCH PERC[NTAGE FREQUENCY or OCCURRENCE OF CEILING VERSUS VISIBILITY VSAFE1AC FROM HOUOLY OBSERVAIIONS AIR WEA? (A SINKICEIRAC STATION NUMBER: STATION NAME: GRANO FORKS Ar NO PERIOD OF RECORD: 76-8 M4ONTH: MAR HOURSILSTIt CEILING VISIBILITT IN STATUTE MILES IN 6 GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE. FEET I 10 A S 3 2 1/ /2 1 1/4 1 3/6 SI8 1/2 S/16 1/6 0 NO CEL I 97.0 % s GE S2.5 S2.8 S S S3.S S S3.7 S S3.7 S GE S S3.9 S S fit WoolC 51.2 S300 S$,3 S3.6 S40.0 $ S S4.2 54,2 S4, S.2 540S42 GE 1 W0ol S S4.0 S sq.1 1? S% GE 12o000 S2.3 S.2 56S 54.9 S5.2 SS S.3 $5.3 S5.4 SS.4 5S.6 S5.9 SS. $ GE ID00C t.5 S7.1 S?.S $ S S 58.5.S GE 90o0l SG.S s S S S s S9.5 S9.S 59s 9S5 GE 6CO01 58S % ? GE 7OOl S A * GE 6C S 6S S*S 6SS SS GE SCOoJ ? G b6.% GE %Coal T0.% o '- GE 3Soci GE 3C p GE 2SO Sg GE 2OC S $3.6 GE lcal GE S S S S S * GE S GE 1COO ? GE 90C % SGE $ $6.6 $ s( 70Cl $4.4 86, GE GE S GE l.& S GE S GE % GE G Do TOTAL NUNGER OF OBSERVATIONS: 930 JL

172 GLOBAL CLIMATOLOGY BRANCH UsAFEIAC AIR MEATlER SERVICEINAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS MONTH: MAR HOURSILSTI: CEILING VISIBILITY IN STATUTE PILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEE, I V 3 2 1/ /2 1 1/V 1 3/V 5/6 1/2 S/lb 1/ a NO CEIL S $3.V GE ST S7.5 S7.S GE S u.5s 7.5 S GE 16C005 $ S S7.S S 575. ST.S 7.5 L GE 1V S S GE SS S.S B GE 1OOGJ bo GE GE :V : V : 6:: V.6 68: GE V S GE S GE GE GE S GE GE S GE 2SO GE 2CO GE GE 1500, GE * GE 1COl ? GE t. 66o o # GE co S 93.S S GE S 98.S S GE S GE as.$ GE S GE as.& GE S ? 99.8 GE GE 0I TOTAL NUMBER OF OBSERVATIONS: 930

173 GLOBAL CLIMATOLOGY BRANCH usafetac AIR WEATHER SERvICE/MAC PERCENTAGE FREQUENCY OF OCCVRRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBER: 727S7S STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONTH: MAR HOURSILSTI: ALL IN IGE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I A / /10 1 3/14 5/ /16 1/t% 0 NO CE[L GE s :02 51: < GE SO S311 S :e " GE 16000i SS S S BE SI 'S S9 S S " GE S.S 55.6 SS6 SS SS.8 SS.8 SS.8. SS SS.8 SS.9 GE b B S6.41 S S % 58.5 GE S GE GE GE 6C S GE S GE GE GE GE GE GE GE GE GE GE S " GE GE s00l S GE GE.OOI % s GE S GE GE S.S 96.S :.1 GE GE s.$ SoS S 99.6 GE $ S.S s TOTAL NUMBER OF OBSERVATIONS: 740 J U.

174 .1. GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR WEATHER SERVICEINAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSVS VISIBILITY FROM HOURLY OSS(RYAEIONS STATION NUMBER: STATION NAME: GRAND FORKS AFO NO PERIOD OF RECORD: MONTH: APR HOURSILSTI, 0000:0200 CEILING VISIBILITY IN STATUTE MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEEI I la 6 S : /4 Ste O. N O C I L I b l o c 6 Z " GE S GE T I Ti GE b.6 6S T GE T GE q GE G E Vocal $ 3 G E ? ?%.9 7 % GE S b S S S S T6.9 ' G E S E o b Ge dlo00j J GBa o2 GE S s a GE S q E GE C GE GE GE ? 93.7 GE %.? GE 90o GE ? ? GE 70CI ? GE GE $ GE S GE S GE GE loci o GE Of : C TOTAL NUMBER OF OBSERVATIONS: 900 L

175 -II GLOBAL CLIMAIOLOGY BRANCH4 Us FE7AC PERCENTAGE FREQUENCY Of OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS MONTH: APR NOURsILSTI: CEILING VISIBILITY IN STATUTE MILES IN GE GE GE 6E GE GE GE GE GE GE GE GE GE GE GE GE FEET Ia10 6 S / /4 1 3/4 SiS 1/2 5/16 1/4 0 *.... NO CEIL GE " GE % Ic GE 16C s S S S.1 GE S GE s.4 6S.4 6S.4 6S GE IC GE ? GE GE ?4.9 GE GE S GE L GE GE GE 3c00i S.2 8S S S GE s GE 2GO GE GE IS GE GE GE GE : S: GE GE GE GE : GE GE 20C % % [ GE ool GE S V TOTAL NLMBER OF OSERVATIONS: 900 L

176 GLOBAL USAFEIrC CLINTOLOGY BRANCH AIR WEAYSER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVAIIONS STATION NVMSER: 727S7S STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONT1: APR POURSILSTI: a CEILING VISIBILITY IN SIATUTE MILES IN GE GE GE E GE GE GE GE GE GE GE GE GE GE GE GE FEET I 10 6 S /2 1 1/ /8 1/2 5/16 1/ 0 NO CEIL I S4.3 S S5.6 SS.6 SS SS.8 SS SS.8 S5.9 S5.9 GE S GE IBO GE ,2 9.3 S be 1qOOD a GE B GE S.0 6S GE GE ? GE GE O To.7? GE SO GE 9S * GE GE S GE $ GE 2SOOi B GE S.9 5.? GE 18G a5.? 85.6 BS B B6.6 GE &S ,9 8o GE E, GE 100l GE GE GE S GE GE SOal GE GE s # GE GE too S.1 9S ) GE oi S.1 9S S... TOTAL NURIER Of 08SERATIONSI 900 SL

177 ,'AIR GLOBAL CLIMATOLOGY BRANCH USAFETAC WEATHER SERvICEIMAC PERCENTAGE FREQUENCY or OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUNBERZ 72757S STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 7-87 MONTH: APR HOURSOLST1: CEILING VISIBILITY IN STATUTE MILES IN GE GE E GE GE GE G GE GE GE GE GE GE GE GE GE. FEET ID / /2 1 1,f 1 3/ S/ /16 1,, NO CEIL S S5*. SS. 5S.6 SS S S S6.0 GE ! GE , GE 16C Z 6Z.2 6Z GE GE GE 10% : GE GE 6C GE t G: D GE S3 TS GE , GE GE S GE GE GE s GE : GE Bbe6 a? GE S GE GE GE GE f; GE , GE Gt GE ,0 GE , , IGO, o G f v-... TOTAL NUMBER Or OBSERVATIONS: 900 L A - nm unm n m

178 ~1CEILING GLOBAL CLIMATOLOGY BRANC14 PERCENTAGE FREQUENCY of OCCURRENCE OF CEILING VERSUS VISIBILITY USAFETAC FROM HOURLY OBSERVATIONS AIR WEATI-ER SERWICE/mIC STATION NUMBER STATION NAME: GRAND FORKS AFB NO PERIOD Of RECORD:?8-87 MONT": APR HOURSILSTI: I VISIBILITY IN STATUTE MILES... im GE GE GE GE GE GE GE GE GE GE GE E G E G FEET I / /1. GE GE9 5/6 GE8 GE2 NO CElL S2.6 S S GE s S S GE GE S9.? GE S *1 GE 12C001 S6.@ '21 GE S GE :6 66: : :6 67:6 67:6 67:6 6?.? ? G a O GE?Col 66.7 ' "1GE GE S :2 71: :9 72: G ? GE J S GE GE 3C GE GE % ? a GE GE sq.? GE G ol ~ GE p GE Go0l # GE GE o # *1GE Z ? GE GE OI TOTAL NUMBER OF OBSERVATIONS: 900

179 GLOAL CLIMATOLOGY URANCH SSAFETAC AIR UtEAtEN StRVCEINAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISI8ILITW FROM 9OURLY OS RVAoTIONS STAItON NUMBRs STATION NAME: GRAND FORKS AFU NO PERIOD OF RECORD: MONTH: APR NOURSILSTI: CE ILN 11VISIVILIT? IN STATUTE MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET 10 6 S / /2 1 1/9 1 3/8 5/8 112 S/16 1/ 0 NO CEIL I S S S3.9 S3.9 S3.4 S S5,4 53.% 53.9 SG GE 20000! 56:3 59: G 18C S GE GE * GE GE ? GE CO GE GE GE GE ?.1 GE , GE GE as.8 a S GE : GE GE Re GE GE GE :0 91:3 92: GE GE GE : o GE GE SO0 I o : :0 9,: : GE GE * GE , GE E TOTAL NUMBER Of OBSERVATIONS: 900 J L_

180 GLOBAL CLINATOLOY BRANCH USAFETAC AIR WEATHER SERVICE/NAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM YOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 78-6? MONTH: APR HOURSiLSTI: o...o.... CEILING VISIBILITY IN STATUTE MILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET to / /2 1 1/% 1 3/6 5/A 1/ /6 0 NO CE!L so $ GE ,1 G1 180G01 S GE 16CO01 $ GE GE 12C GE S.D GE 9C O G S0O GE GE S GE SCOO GE GE " s. GE S o GE 3C GE GE , be GE : : S S S G GE IC :3 96: GE GE GE 70C b GE GE sol GE CIE , , , on.c io!do GE : : GE GE TOTAL NUMPER OF OBSERVATIONS: 900 L.

181 GLOBAL CLIMATOLOGY BRANCP USAFETAC AIR ELATHER SERVICEI/AC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM 1 OURLY OBS[RVAIXONS STATION NUMBER: 727S7S STATION NAME: GRANO FORKS AFB NO PERIOD OF RECORD: MONT1: APR OURSILS1: CEILING VII--Y NSAUT ie IN S GE GE GE GE GE GE GE E GE GE GE GE GE GE GE G1 FEET S N /8 112 S NO CCIL I GE % S.0 6S.4 6s.. 6S N 6S." 6e.N 6s S.1 bs GE 1s000i S.0 6S S.4 6S S.4 6S.4 6S.% 6S.4 65.N bs.n 65.9 GE 16C b S s. as. 6S.4 6S.4 6S.4 6S. as.. 6s.. 6S.. GE 1.0OCI 6S.6 b b GE 12C GE GE 9ro N GE 6c000 7N S GE 700 7S GE GE sco0l N N S GE N N N N, GE.000C 92.6 s5.0 6S.2 65.N E N *N GE t 69,N 69,N GE : 'a., GE 2r Z GE GI N GE N3 9N.N ? k? 9. GE N S GE GE N N N GE GE e u 9N: : : , GE so N G 601C S * GE s.2 9t GE S.2 9S GE 1oot $ 9S.2 9S I' GE S.9 97.q q TOTAL NUMBER OF OSSERVATIONSt 900

182 GL0AL CLIMAIOLOGV BRANCH usaferac AIR MEATHER SEVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONTH: APR HOURSILSTI: ALL CEILING VISIBILITY IN STATUTE MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I 10 6 S /16 1/ eo o... o o e..g NO CEIL I SS.3 $ S7.2 S S7.6 S7.S S GE 2QCJOI b1, S 62.S G( 18COGl 6O b J 60.S b C b (.r 12c0o A GE 1OCO , GE S 69.5 b GI o3? GE?roof FOBS GE S S.S (1 SCOD, &I 95,3l 7S SE %=ool U 6( 3SCO 76.% GE ]Cool S S s.7 s r-e GE 2T G( o S UbE C b1 120Q O GE ItOCI 6s G( 90c1 6s r.1 AOol S ( GE COOl 86.S [ toei CA 30c 66.7 ' S S rt S bt IuuI a8. 9a GE ri % TOAIL OLNPtg 8 O9N69ATISvs: 1200

183 GLOBAL USAFETAC CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVAIIONS :. 410 WEAT04ER SERVIC[/MAC STATIC NUMR STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: J' emonthi: PAT MOURSILSfl: 0OQ CEILING VISIBILITY IN STATUTE MILES IN i GE GE GE GE GE GE GE GE GE GE 61 GE GE GE GE G FEET I ' / / 6/ 112 6/ NO CEIL I GE S S 66.S s GE 16r S s 66.S S S 66.S GE 1600i S 66.S 66.S S S 66.S 66.S S 66.S b6.s 66.S GE 16C b1.7 67* GE 12COO 6S , GE GE 9cc G i fi O000C S.3 7S.6 7S.6 7S S S.7 7S.7 7s7 7S S.? 76.1 GE 7e To fe 6i : CA StOci S S S GE 65OJ * S.9 6S S GE %COCI B e GE S COO GE 2OCI E ZCOCi , GE IO0cI 67.S o GE , O 88.S " 1CO S.2 qs S.7 9S.7 9S.7 9S S A 906i S GE go 69.S S b 7001 i S.2 9s bt 69C S %9 scg o*.2 9S be oci 91.2 S S 99.S s q9.s 99.S 99.S feel 9OZ 9S S (A S S oci 90.z 9S S ai 91.' 9S l7t ftipe of *16M.VATiON~s 930

184 Al6 ~masea a~ p9iaa186 RIrnENc' Stccummcint OF fcilina wrsus WiSISLilT STATIN uwpotm, i2stis STATION kaut 646a6o rooms its Ise P99100 of *icepot t6.61 cct. INGotss pt[ pa? Is0,0u 330 CElL I S S9. 1 %.a 9aSo& ISa. S46 se.a %6.1 Sm*? So.? 14*.1 So.? So.? 5. ut as.7 as.s at.. as., al 1. a.. as as.9 at.. as., at., a1. It a1.? 63.2 at.. as.1 at.m 63.8 at.e as.. 6b.4 as.9 at.. as.. a1.9 as v 6.U as.? as.2 at.. as as.4 a3.s a.a at al.9 at.0 as.. 6S.9 6t.0 6-b.0 61 iftcoul 62...S a.? a4., as. as.1 aq.1 ass1 as.1 ass 0.2 as.2 as.? 6%., %. 6.z a S S.6 6%.6 6S %. F m%., 6S.1 *.4 i GE scoas?i.& I0.? 'a.' to b %.4 1*.% 95.? 95.? It.% f%8.6 CIt?'Cl 70.9 P ?A o ?*.a Y6.0 V to.% 6C120 s?*l. 92.S s.% 93..% 9.S %. #1.? be ol Go $4.2 4Q.a to* $ Co.) $4.? 9*.1 Go.f $4.1 so. q *.. s GE 9005a 1?.9 9S.% $ Sa 46.S ? 40.% go.& * belmoos % go.? tis $9.. be 2-0 All.* 93.1, S9.9 sa.* t.0 GE CCs Im.4, $1.: 0a.: 9a.: 0a.3 91al a.3 9a.0 GEIfC 905 o a.a ? ?.'. $1.? of v0=1 ma OZ.? mg Z a gn (A 96.' to.% ql.a to.% 96.1 q6.% 96.,. 96. atirc t i 40.0 C a4 91j C A C6.1 rif 205 $ a o.% 99.% ToaL s.mansc 4w 94sSwrggmONst 910

185 "o"clinsiftky some" PC*CtI&Ot FIt9SMOCY Of OCCU6IOCE OF CCIL 300 9fQSU9 VIS36ILlIV &to utlles so6ictmat 1614% 9UWK& fts"i : RNsmas moare 4 Ptois@ 6, RECORDS to-$? voil3u:.11t 06GUR3L ,100 K a a& 1oo 9as 1 am at3m at of at 6(696 Fit I I lo 6 1, 0 1 : P:t 2 I log I too I I r So 116 to 13 li% a of el Iu St.? SS." So.# S6.1, r I $ S4.6 $0.6 $0.9 %1.) (A S1.0 Sq.% * e 0.6 " 'q b $ , b1 %$ % A 63.% 61.1, l be &3.F G Ua.0 6P z.0 b of.* of.% of., bf : t Z be Afteeg 61.1 bo.a f So o of.: be be 61C6Cl 06.0 No.$ ts.p M3. pg.% I3.$ 19.0, 73.9?I.% 73.S leg6l 19.9 F P No. 4, bf bego3 t vs fo.g *.@ lq.uj mok"i A9. *9 at. I. a1. I2. a a of %.8 s0*3 *%.I W, as-* 9.6 es.6 Os & %.? level M $ , 61.? at., of3.1 6f.? of.% 0 Mae6 N &'.1 ON #* No.% 06f to0o$ be016.0 so~ 6.$ o ka IS&Ll go.? to " to. 004V.I g.% W I 06.* f., so., of.,? l~ I 9 I.E 14Co oz.* , 91.0 $1% '.4 P q.0 9: ut $loeg ON.? o.% 93. 1, 3*.0, % 93.% W4 *ati to.@ ) Ui rod G *1.119.* 9.9 to. T4.o go., foci of * ,1.1 9s.$ 9%.I it.% 99.4 " " * of.$ of.* 93.* 93.$ 91.% bf ".a "O , or o , t6.% & O $ I.1 '3.0 " OR g9., o O0f t to " S of J 1~ ?.1 of.* 96.?. 90. to to.@ , fos om#*a Wotlpe e

186 GLOOAt CLIMATOLOGY ORANCS4 PERCENIA6E FREQUENCY OF OCCURRENCE OF CEILING VERSUS VIS19ILITV US "IETAC FROM HOURLY O6SERV6IIONS In mea"if SINV3CEIP6C 11IN STTO NUMBERg STATION NINEs GRAND FORNS AF8 Nol PERIOD Of RECORD: 76-ST MONTH: MAY HOURSILSTI: IL~VS VSIBILITY IN STATUTE MILES GE S at E GE GE GE 6 E GE GE GE GE GE GE 'E FEET I 10 6 S V 3 2 1,# WIV 1 3/V Sig 112 5/1* 1/9 0 NO CElL SG.2 S S7.0 S7.0 S7.o S T.a S7.0 St 2O001o * *3.0 * * * *3.0 * *3.0 GE 14!10I $ * * * *1.3 * b f 1*0001 S9.$6 2.6 *2.9 *2.9 *3.3 * * *3.3 * b3.3 *3.3 6E W~ool * S * V.9 *V * Woo 2.0 6V *S13 *S.7 *5.? *5.7 *5.7 *5.7 *5.? *5.7 *S.7 *5.7 *5.7 *5.7 * I001~ IS. 6.:S :::I "6. : :2 *9:2 69: *9:2 69:2 69:2 *9.2 * * *95 9. *9 5 *9.1 *9. *9. *9. *9. *9. *9. *9. *9.G5s IF MalO ?2.V GE legal V.3 7V.? 7V S ?S.3 1S Is.3 15 fif * IS.V 75.9?*.0 76.s P* *.s 1*.s *.s 76.S 16.S?*.s *.5 61I SCOGl * R.* 76.* 76.6? (.L 9' o fa.s ~s &.% * ~210 If :2 62:6 62: z2* 6. 6* Idl1. 32,:4 6. V$ s~~ : : ? ' &t *: fI co $016.# it.@ It 120CO * Is S.3 &C V I Y G * *, s 1 6c " GpI s % % (AI *Goo % *,o * 4It IS 6.6 9S.$ % s , 99.s S GE 500l 6% * 99.* 99.* * t * It f.## t eg, Ad td.* 99.? S... TOTAL "W"019 6W 6661VAI I L

187 GLOBAL CLIAI10OGY SRANCH PERCENTIAGE FROUENCY OF OCCURENCE OF CEILING VERSUS VISIBILITY L resa C FROM HOURLY OBSERVAIONS his W(ATI (R S( a C[I STATION NUNK: 727?S STAI0N NANE: BANO FOAKS AFI NO PERISO OF ECO0O 7i-i? "OktHt NmAV M@URS(LSIt 1z29 Go CEILING SIIIYIStttMIL IN I E GE S[ GE S GE 0E EE St GE of at G E GE GE 1.E FEET 10 6 I /9 1 It% SIG 12 S/ 6 1j, 0 tno CEIL S2.3 S2.3 S2.1 S2.7 S2.1 S2.1 S2.7 Sz,1 S2.7 S7.7 $2,1 S $2.7 $2.1 4 SE S S G E S 766, : o0 : 2 : 6, 0 : Z O : 1' ol : 2 : 0 : 1' 1.0 2,0' 6 2 ItG 12C00, 5S7.S &?.a [ 1%0001 S~OS 62* $ * SGE S * 6% * 6(100 local, ,1 61*$ 67.s 611 S 61. 5, 6I$ 61.9, 61.S 61.S 6T. 61.S 61,$ 6~S 1.% Gt61 16, 61.i 64.& 64.s i $ 44.s 6*.$ S 6ies ViG $ ie.% be.% 6[ :C001 66:* ? ?O O G, fit?cool 660??t S?Z S S 12.S 12.s?Z*s 17.S?2.S lz*s?2.s I17s?2.s (. 6[ 00, J, 13.3?].& 73o ?3, ?$.a Sco TS,5 7S , !GE fiscalo,?0. S.l?S, T ?6*3 16.1? I.1 61 ft coad $ $ (Al 1S00I 14.1 IO % a,% Stk llos $I.% GI S l,s $I.% a&.% GItS 41oS $I.% $I S Gt local 10.7 I4.9 OS*S l l6.1 $6.1 $6.1 l GE S ll,1 84. eq.% 1 l 9.4 4l 19 4q*5 I9$ 09.s 199S Gq.S , eq.$ 09.6 II*$S GE I i06 91, Slt 91.1 *11,? 9i. of loclo0 1, 90. I ? ol 9l.l l ,8 01.l 91.4 (.[ I! ] ,j GE as.? Is~f 95.? 9S.7 9S.8 9s.9 as S.909 9S.9 9S.9 9S.9 I'SeO 9S.9 &E l[ ocajl,. 941*J 9S S 91. S a?.? ( $.% * i I'( loc0 61 IS.?91* ? go.? Va.? c $?.$ , G1 tool $ $ 9G.$ , $ t o.% GC fecal q9$,% " * * OQ,0 G4 loci I?.o 96, ,? 99,1. Oo c I GO I? ,1 91,I 99, AT loci C , I1, Vic of $ c 97.I 91, "e? 99.I 100, TOTAL NUmeIIN of GISINV~tlfftsi *so

188 CLIPSOLD4SY BOANCH PENCSIO1061 Fh(OUENCT Of OCCUMOPENC V CCILIN3 VfN8US WISISILIVY us: 114C to* POIJLT a 630?HERI~ StC 1/H*C S11 apeo WUPKPb02?% 7181 IO 164"t0 Ct: rooms &to me Pt.,.. of micepl?*-at "901"1 PAT 96u83Lsip 333:18W-300 :W3 of S fit 7 69t I at Sq Gt &I 81 St 63 #63 61 ua *a173li i 4 3? 83 i lt, I jo K A 3I... BIO CE3L I %% fte.i l $ S9., 89.6 S9.6 S9.6 S S9.0 S9.4 %9.6 S9.* 89.6 * St Israel ss0 89.7v S9.9 %9.9 S9.9 %9.9 S * (A 1&ooO S S % S ' I.9 5 w lbrocl S '., b!' bf J $ * t ICcol S ? 0&.j 06.p j 66.? 60.j SC oc00l of t To ' "4.6 It,. oif?cool 60.% V1.9 St acod F3.9 ' F sro0i % IT.S 70.3?@.1 I TV.8 Is.% T of *%De ? & I9.% 9.8, i9.-, $A %cool $ I.S to.? 63.6 * * 03S.9 61 SSO %.1 V8.& 08.? $ of.) v8.) P68.3 Stf Scol I Go.% % St o * ? 9. G too 0r ,,2 93.1l :93: :s :,:o : :0 : Str lo0al me., i %$ Wt ls t.. " g.? ( to.& 98. 9S ?* % 0.% t % to.$ ut go0l it.$ of.$ 93.0 of.& Gt f0u S t0.) F.t IS S t % go.& 906 9* (It S % to.% bt S o & S le0.@ ( ? loc Go 03 6.? l " COt11Of t

189 *i6 qulgs $11193(WK $ wfe C3J PSYS %falls 'lfsf $ease Pto% alo We UU~ N it esfg,%a ol t?*-a $ wl, tl IO1 $lall1m Nim aoil IB 90 P elfo 0(ra Icie 5 390SL?, 0"1. Raw 13 U K at at of 6 6 K 6O at GC %I a S( rill I to S ~ toi I, 1 l0% a its %j Is II t s.11 a Of Fi- oofaeis ; moo Clt 1 %2.4 %$.1 S41.0 So.% '%c~ So.# So.% Sss.a a,.s %*. a %%.b asa % ~.6 of I00623 S@ $ $1 Is 61.e &J.% b1.-i a1.% 3.41 a1.% IA jc0 g03 ao~e Nail 0t. 09.tl a'.g a% as.i as.? a'..? a'..j a'..? as*i a'l. as, U 04l No..0 N.9 a. $ a. * 1*" a.s6s $'S age l 6 as, a3.% :6.1 g.' a::,1 at Igregg 09.I i3.g i9.+ ic.a in.a Paa (A 0001.l. al. 61.i ieg of.$ il.a a1.8 lea s9.6 lb.a Pa., P+.. i pb.. *0.9 'e.i *1.* ic.p +e~l i1.* 61 gorel Sq.? ? P1. is.? 09.1?a ? s lt.) 1.9 4a.1 IF.0 to. be 411,00 69.% pi Fa o.6 0a.'. la.a t.??%.i I%.? to.a to.a sa.a be tpf's l 1 I. 15$ l~11.1 P 8 IS$.9 lb**k sol., 10.4** lib,+, 16 S.1 Pa ,6? a i01.6?* i I.* IS., 1, F t9.p bt %loci 16.l 6.6 Si., Of.t et.9 I1t s*- 4g.o l g.O 1l.0 41.o %. f es05 11.? *5 *e 0e. 04.a 66.0 go IS.. g.l ".1 " i.1 4 l0ocl 10.$ $. 11. so ,0 49. l 0i9. SiB **.1 'I 10g01 so.? $1.@ l1.g , %0015 *% OlS 93f.$ I.0 Ofr Ina2I It.?, 0t.09 0,.9 ".% c.i,c to., ace8 4.0 IS.* a4.. s".4 So.$ 99.0 be l si l 9.. at.i a l 1*.* t s 9.9 at 1001 s.1 9l.,9.c 9oS41 9S.? e 1* 9? 90. " %. 1S. F a.l 9e 0.F.? be Itoo a0. 9*.0 96.j S.1, : ? at Reo #a.? P.G 9?.l i Vt.) Ir. at.' 91.% ai.0 9I.a 9i OF.0 (A Dgel S.2 96o VO. 9loS IF.$ of.% St.% ?.* It o.? 9S P i.6 1l I s.? 99.1 Ol.l lo S.1 96.i i. ala a to. a. 96.1a l.g 9 W4 a S. 1 I 91. So.$ to.? ai. g. 61 ' VI G.J 99.0 "9.1 go.? "c.99s.* 09.a ** a~ e 40CI FA 0. " o.* I ov loci 0, A o.% I0.* Joel s V So.% aoo.u to.0~ S l.0 9i o.i g1O* O , l ) O".g I1nc Mlot N " * 149 leftau 93r. el m el

190 sis,. CstuINSIOes "emi. Pt.Ctmt&GS 'ICOWClmi' Of t01u9101 Of i Mam. of*$,% 1M111,1 Stalls's 40114, S 41 tllm ftiil, 8604mg1996 room 90' Pgoj Of oo -61 polef"g 041 NOUOIILIPP, J M1.S '1 Ill slavult "ILLs I3V 1 64 a of 6( 60 Q! at OF Uc of at of &I at 61 of a* (S L I so., 61.% 6S lo( z % op.t &1.1, P P 64.S 6,47.s s 41.% &I 36( P BPS P.6 BP P.6 6P ?. C4 mbttif s P * P "I t9or0i , see BO.O * airngo ? P P PC.) I 6.0,?1.) , P2.6 71, l Z.4 7w.4 U. 'oiol ? t 0003t, 73* 1. PP It ?? T. 71.3??.1? ?"Do# to.?7 Po.j 16.% 111.1, 141.% P.4 0.4?10.$ F11.11 It.% Is.% P.4 I0.% 74.%?a.% 704A ?I.% $1.% Ga.c ? #:.o W. $('out of.? A " #1.* 67.0 P Uo %tool $ e9.? P 09.7 (.11 GLI 6% g.,I go.4l 9fl.4 g0.% n.%4 9.4 t 1 3K0el o OZ.$ Z.3 V,001go , !.% v3.% Eifool a 9% %.? S.1 9S.1 94.?, o level S $$ S 3 9S. 1S. 9S.3 I'( 3-col so S s.% 9S a.% 9S.41 9s.% % 11S c rt we 001 's.c 9S I7.j * A BO1S S W1 700l 90.: % o7.% V7* s Bot o ?.a "a %Get~u S 97.S S " of ? 96.S 91.S ra & O ost 930.jL

191 US L;: IFi * C "CLiz 0LOG laacw PENCENTAGE FREQUENCY ROM Of OCCURRENCE HOURLT OGSERVIIOM0S Of CEILI NG VERSUS VISIOILITI &IN wi8t 8 S[RvICEIRAC STATION NVNIERS WS757 SIMON, NME GRAND FORKS 8FS 100 PERIOD OF RECORD: MOT' MAT7 PO URSILSTI: ALL , CE ILING G G VISIBILITY IN STATUTE MILES Its BE [ GE GE GE GE GE GE GE GE GE GE GE GE FEET S / I 11ft I14 0 NO CEIL I S3.6 $ S6.1 S6.6 S $ ? be ? S S S GE 6c S S S 63.S 63.6 GE 19ft G *S1I 6S S GE S S G, ? GE ? ?3. GE? S.6 7S.7 7S ?1.7 7S @ 71.6 I GE ? ( $ ? GE S S A GE %C0a &s S s s.9 s., GE 310i S A be (E g GE I.S S 92.S GE IS00I S * be S GE ICool S S E 002 6? S GE l S o G( GE S K GE GE 002$ 7.9 9S S 99.s GE S ? :0 GE E ? TOIAL NUMBER Of 06SERV8T80N$: 7990

192 GLOBAL CLIMATOLOGY BRANCH PERCENT4GE VEEOUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAVIFAC FROM HOURLY OSSERVITIONS AIR wbiner SERVICEINC STATION kupbirt STATION NAME: GRAND FORKS IF1 NO PERIOD OF RECORD: MONT s JUN 14OURSILSTI: ; ; CfILIhG VISIBILITY IN STATUTE MILES l id Ge GE it GE GE GE GE GE G GE GE G[ GE GE GE GE FEET I t0 6 S /1 1 3/9 S/ /9 0 NO CEIL G Z GE GE ? G G, % % " GE re GE?Cool GE Be.& 69 6S.0 &S.0 0S.0 6S S GE Slool GE 0! GE %C GE GE 3oot GE Z S. 9.% 9S S be S GE S '6.3 GE g * GE ? ? E ICOO v GE &. 6ool GE GE U[ SOl l GE fge ? 99.? GE I f GE tol ,I G J TOTAL NUNIER OF GOSE991301# L

193 i i nl "1 ll mm mm i ul GLOBAL CLINATOLOGV BRANCH USAFETAC AIR 2EAIER SERVICEI"6C PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMSERs 727S7 STATION NAKE: GRAND FORKS AF8 NO PERIOD OF RECORD: MONTI: JUN HOURSILSTI: S00 CEILING VISIBILITY IN STATUTE MILES IN I GE GE GE 6 GE GE GE GE GE GE GE GE GE GE GE GE FEET I / % 1 3/6 1/8 1/2 5/16 1/6 0 NO CEIL I S6.9 S5.7 SS.9 S ,0 S S S GE % G 18c % GE 16C' b ? E 19% % G S.8 6S GE T GE 9roo ? GE coal GE ' E 6COO GE Sool S B? G S S C001 as.? z E 3% UE GE 2! G( 2CO ? S S GE S.0 9S.0 9S S S *c 1G00E S.6 9S GE S E Irol S GE S ? ( 80O S ?. 9 7.g r , GE S E SOot GE s BE! , GE S @ GE G.? GE S IOTAL NUMBER Of 01UIRVATIONSt *oo 0 o ee c4 J L.

194 GLOBAL CLIMITOLOGY BRANCH LSAFETAC AIR WEATI.ER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CtILINtG VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBERz STATION NAME: GRAND FORKS AF NO PERIO OF RECORD: 76-8? 4 MONTH: JUN MOUOSILSTI: 0600-O6go CEILING VISIp3L1Y1 IN STATUTE MILES IN I GE GE GE GE GE GE GE G GE GE GE GE GE GE GE GE FEET I 10 6 S !2 1 / S f6 1 5,16 1/ NO CEIL I S S S SS S5.3 GE ? 61.8 GE 1SCOO GE ? ? 61.? ? GE Z b GE b6.2 fge GE ? T2.l 12.2 be goodl 7.1?S : ?.1 GE 10GO: , TO.3?.% GE ic GE SOOO $ ? 3.8 : GE 0s a N.0 5, GE z 66.3 m6.9 GE IS GE ?.q 8B b s6.? 56.6 GE GE 200 :.A '2.7 '2.6 GE & ? 92.? ? Z.? G ?.c GE S S S S.1 GE 1o S S S GE 900 s S S S.1 9S.6 9S GE GE e be S sool % GE %a GE $ol I % ? ? GE loci P ? st I TOTAL NUMBER OF SBIKRVAIONS$ 9.0 Li

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196 IL t C.E P(..C2Ift61, 6(BLLtCOF OCCLUREPI1 OF ceilitib VFRSLS VISIBILITY t~c 1Ic 4 6w10,0 P2'% II~ 61 4* lat 83640r 'IS UFS ft PEPIOC Of RECORD: 76-B? MONTI-.: JUNO 0OuRS(LSTI: UO.f It afsvisipil 11 V IV STATUTE PILLES A 44I 66 be 6 61 bi s 64l 64 1 GE E GE GE GE GE GE. i9' sill S/ /16 1.1% 0.9sl '..~.c 15.C S S3.0 S3.0 S t~~~~~~ ' I~7 26, 6. 2,.~ t l8cg O b : : ~.4~ 2?62.1 e. 2. b ? ~.434 *. 1? *3? 4. T ? a.'3 3' S 5, *%L a4 6s aci*. 03 ' TO '.I %.4. fs.: '-S T%... vs. Z 7S5?S 7.2.2? 75.2?S '. 9. 7, T' ? I~ ?~ 64?a4'. 1.% *.I :Z'.: :Z. 6Z. 1: 62:2 :2:2 622 : : ~~~~ ?~ P ? , ~,* as.. *%.a 85.6 o.v 1S ' b ':It*.* $ ~ ~~~ - 0? * , , ' : I 6. *9.6* % (0 9S.0 9S os. 4.* 46. a4~ V b ".0 *1.. '14 41? ' **. 4.I 46.2 o6.2 9o.? * ?.* to #8.a 'I 66* to.* 9".I v4.z Z V.' ' I 44.7 * ~~I' ~ I : ', 44.4 to.: l ) ;.0 l cl 41.. *.9 1?.& d , ~134.- it ji1* t * #VIA 0LftvOko f eflloalf~l

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199 GLOBAL CLIMATOLOGY BRANCH us UsIaEC AIR WEATHER SERVICEIMIC PERCENTAGE FREQUENCY OF OCCUROENCE OF CEILING VERSUS VISIBILITY F RON HOURLY OISERV TIONS STATION NU14KR: 12757S STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORD: 78-8? MONTH: JUN HOURS4LSTI: CEILING.VISIBILITY IN STATUTE MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE BE GE I FEET I 10 6 S / S116 1I NO CEIL I S1.1 S S6. SO. S6. SO S S S1 GE GE : : Gc &a GE E GE S GE GE M GE GE : OE SCO E GE %C GE 3S GE E s GE GE 1: : : , c ? ' GE * GE GE : G GE GE ' GE GE SE E " l04 GE aj TOTAL NU SER OF OBSERVATIONS: 900

200 I GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISISILITY USAFCAC FROM HOURLY OBSERVATIONS AIR IiEATPER SERvICEMAC STATION NUPSER: 727S7S STATION NAMES GRAND FORKS AF8 NO PERIOD OF RECORD: MONTH0: JUN OUeSLSTlo CEILING VISIBILITY IN STATUTE MILES IN I GE GE GE GE GE GE GE 6E GE GE GE GE BE GE GE GE FEET i 10 6 S lift 1 3/9 sl8 112 S " NO CEIL I S SO.6 S8.6 S S so.? ? S6. GE GE GE GE 1COO GE E 10COO ? GE GE GE A S S.0 8S S S S.1 6S GE GE 5COOl ". GE GE #SO ' G GE S S S.0 9S GE 2SO S.9 9S.8 9S S S S GE GE , GE ISOO ,I GE GE G GE GE ? G GE , 99. GE GE GE GE ? GE TOTAL NUMBER Of OBSERVATIONSS 900

201 orr +,, AIR heatheo serv c[imac GLOBAL CLIMATOLOGY BRANCH4 PERCENTAGE FREGUENCY OF OCCURRENCE Of CEILING VERSUS VISIBILITY US AFE a C FEOM HOURLY OBSERVATIONS iii1r + - S7ATION NURER: STATION NAME: GRAND PORKS IFS NO PERIOO U RECORD: USLT:1O2OF 78-a? se se 00ONTH:! JUNi YOURseeLS7I e100230o *CEILING VISIBITY IN SYA1UTE MILES IN I IE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET i O / 1 3/N 518 1/2 S/16 1/1... NO CEIL I GE ? GE s E 16OOi e. GE 14OO o GE GE IS GE e * GE 60OJ $1. * E COOl GE & O S GE S GE , GE GE 35oo GE GE zsoo S.q S. 9S.7 9S S.7 9S.? 9S. GE S q GE S '6E ISOO S GE :1 GE ? GE GE 0 )a 93.C E T * GE z GE loc. GE GE GE O ,, TOTAL NURSER OF OBSERVATIONS: 900

202 GLOBAL CLIMATOLOY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFET Iac FROM POURLY OBSERVATIONS AIR WEATHER SERVICEIAC STATION NUNK*: 727STS STATION WANE: GRAND FORKS AFB ND PERIOD OF RCCORD: ONTH: JUN HOURSILSTI: ALL CEILING VISIBILITY IN STATUTE MILES In I GE SE SE E GE GE GE GE GE GE GE GE SE GE GE GE FEET I to I 1l 1 3/4 5S S116 1/4 0 NO CEIL S7.6 S.7 S7.6 S S7.9 S7.9 S ST S7.9 S7.9 S7.9 GE s.2 61S. 6S.4 GS,6 6S.6 6S S.7 6S.7 6S.? 6S.7 6S.7 6S.1 6S. 6S.6 K[ S.3 6S.4 6S3S 5, 6S.? 6S S.7 bs,8 6S.8 6S.8 6S.0 6S.8 6S S.4- GE S.4 6S S.8 6S.9 6S S.9 6S.9 6S.9 6S.9 6S GE ? S GE S GE Y ? GE GE MO00 7S.9?7.1 7$ S TS T8.S 78.1 T7.S S GE GE GE scoo S.3 6S.7 6S GE, e GE GE S G S GE 2So GE GE S.1 9S.1 9S.1 9S GE S.1 9S.S 9S.9 9S GE S T GE GE GE i j GE? S GE G S GE o.Z o G S i i GE GE o GE S ,I TOTAL NUMBER Of 6OSERVATIONSS 7200

203 GLOBAL CLIMATOLOGY BRANCH USFT sar ac AIR NEAITER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBERS 727S7S STATION NAME: GRAND FORKS AFI NO PERIOD OF RECORD: 70-s? MONTH: JUL NOURSILSTI: i:ceil INGVIIIIYISTTTMLE IN I BE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FELT S I/Z* lit I I/% SIB 1/2 S/16 1/4 NO CEIL I o GE S ? ? GE w? GE G E ) G S I GE S ' zt. GE S 82.S B GE S.7 6S.7 6S.& 65.8 &S S.6 8S GE S E S GE 50:: : :2 93: GE a GE S5. 9S S.7 9S S GE % S S S GE S GE GE S S l GE S GE GE GE S G S GE GE G E S o 99.5 GE 00S S 99.S 99.s GE 90r S S GE 3Ogi G E S S GE s GE s TOTAL NUMBER OF OB RVATIONS: J

204 GLOBAL CLIMATOLOGY BRANCH USAFETAC A1R VEATHI SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE Of CEILING VERSUS VISIBILITV FROM MOURLY OBSERVATIONS 1 STATION NUMBERS TS75 STATION NAES GRAND FORKS AFB NO PERIOD OF RECORO: MONTHS JUL NOURSILSTIP { EILING VISISILITT IN STATUTE MILES.R I BE,E BE 6E GE GE GE GE GE GE GE GE 6E GE GE GE FEET I IC 6 S Sle t/ '... NO CEIL S.1 6S.2 6S.3 6S S.3 6S.4 r, a...,,.u.. u Ia.9 1.z 7.T ? G GE ?2.5 GE ? S 72.S? ??2.g GE S ? ? GE S S 79.S GE GE S 62.S 62.6 GE %.5 6q.S 89.6 GE S as.% 6S GE S o GE GE S %.1 G S S 94.s 99.S GE S S.9 9S S S S.9 9S GE S S.9 9S "GE GE $ S 9S.2 9S S ? ? ? GE ISO GE S.S S GE S GE ? E gal 57.S ? GE S S GE S? ? C GE sol GE 9001 m7. 9S S 99.7 BE S ? GE S S G GE S ? TOTAL NUMBER OF OBSERVATIONS: 930.

205 SLOSaL CLIMRIOLOSI BRANCH PE[CEMIASE fpesuvect or OCCURRNCE Of CEILING VERSUS VISISILITY u afet c FROM HOURLY OBSERVATIONS STATON ENuRKP 127SES STATION NAME: GRANo re,*s ares : PERIOD Of RECORo 7o-a7 IINL I ST., "_IN G ( GE GE GE GE GE GE GE GE GE 6E GE GE GE GE FEET i , /6 1 1/2 5/16 1// 1,, %/6 0 NO CEIL I S.9 S SS.5 SeS. SS.6 SS SS*7 SS6 S5.6 S59 S5.9 GE GE I6COO o3 64e. 6S01 6S S., 6S.S 6s S.8 6s.7 as as.9 6S.8 as,9 65.e 6S.9 6S as a.1 66.o E e S S. 6S. 6S., as.9 a GE S ? G8. GE i * GE TS S a GE S.4 6.1? ??.a E S S s.s 81.5 GE $ * E AS.? S.9 sa.0 9a a a SGE GE SOO a GE a S O00 h S S 69.S GE $a.$ hES GE GE 2OO S S GE GE 150 4: GE GE S.2 GE S.2 9S.2 9S $ S 9S s S 9S. 9S.S s S GE S S.6 9S.6 9S a.6 GE S a 9a a.e GE S S.S S GE Sool s s Va. GE S a * G GE S S S 99.S GE 1001 $ s s 99.S SE S S S TOTAL NUMBER OF OBSEVATIONS: 930

206 GLOBAL CLIPATOLOGV BRANCH USAFEiAC AIR REATHER SERVICEINAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISlBILITV FRON POURLY OBSERVITIONS STATION NUMBER: 72757S STATION NANE: GRAND FORKS AFI NO PERIOD Of RECORD: MONTH: JUL OOURSILSTS: CEILING VI5ISILi77 IN SVIUTE RILES ; IN J GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEEt i Z S/8 112 S NO CEIL ; ST S9.1 S S S GE EG S :3 68: : GE f : GE S : GE 1ecoCl S S GE e :1 GE 9Cool ? GE , % GE GE s GE SC GE GE 900a8l ? GE 3S e o.7 8e.? 88.7 GE 30OOi GE 25s0o 66.9 E1 2C00J :: : S S , 93S S S S S GE S GE 1 SO GE S S 96.S 96.S S 96.S 96.S S 96.5 I GE S S s 97.S S S GE 900, GE % GE S GE S GE S GlE GE SE GE : GE Of *o TOTALNU[SER OF OSSEEVATIONS8 930

207 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR WEATHER SERVICEINAC PERCENTAGE FREQUENCY Of OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION HNUMER: 727S75 STATION NAKE: GRAND FORNS AFS NO PERIOD OF RECORD: MONTH: JUL HOURSILSTI: CEILING VISIBILITY IN STATUTE MILES 6 IN GE BE GE GE GE GE GE GE GE 6E GE E GE GE GE GE FEET 10 6 S / 1 3/4 5/8 1/ /4 a NO CEIL I GE O O.S S GE GE Ti GE ? ? ? ?.S 7q.S 7.5?%.s?1.5 7q.s 7qS 71.S 71.S 74.S GE IGE 9C GE , : GE S.9 8s s S GE GE SOO S S O.S 66.S S 8.S 88.5 GE GE %, GE GE GE S.4 9S S s S.9 9S S S.9 6B GE Z S S S S GE GE BE , GE GE GE GE ? ? ? V BE SO t BE S GE S GE t ,5 99,S , , cc+ al Se 99.ee 7o ee 10e0.oe100.0e eee , TOTAL NUMBER Of OS@NtVTIONSI 930

208 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR WEATHER SERVICE/NAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBER: 727S75 STATON NAMEs GRAND FORKS AFB NO PERIOD OF RECORD: MONTHS JUL HOURSILSTI: IING GE GE GE GE GEE E GE GE GE GE GE GE BE GE GE GE FEET 1o 6 9 % 3 2 1/ /8 1/2 S/16 1/ a... NO CEIL E GE " GE GE q GE S S S S 76.5 GE GE S S GE *S GE & GE BE S S 92.S S S S S GE soo GE GE 3S q GE l GE E S GE GE S GE GE S GE GE GE S GE GE GE * GE GE IOG O GE Iool ' S.? TOTAL NUMBER OF OBSERVATIONS& 930

209 GLOBAL CLIMATOLOGY BRANCH usaretac 4 AIR ETATHER SERVICEINAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVAIONS V STATION NLPSER: STATION NAME: GRAND FORKS AFB No PERI00 OF RECORD: MONTP: JUL I4OURS(LSTI: CEILING VISIBILITY IN STATUTE MILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE 6 FEET I 10 6 S / /2 1 1/ 1 3/4 5/8 1/2 S/ NO CElL Gr GE 11& GEt 16C GE 18o S.3 7S.3 7So S GE GE GE 9C :9 83: : GE 8C GE 700e GE S S 91.s 91.S 9l.S 91.S GE SO Z GE 110Ci o GE 4c00l S 95.S S S GE S S GE 3CO GE s B GE 2CO c GE GE o S 9 9.s G 1200i 94o GE a o GE GE :.8 98.: GE , GE GE 500i GE GE GE so GE n* GE TO.AL N...E..O ,.TOTAL NUMBER Or O9SERVATIONSt 927

210 w GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFETAC FROM HOURLY OBSERVATIONS AIR iea1her SERVICE/MAC STATION NUMBER: STATION NAME: GRAND FORKS AFR ND PERIOD OF RECORD: MONTH: JUL POURSILSTI: CEILING VISIBILITY IN STATUTE MILES IN i GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I IC / /' S/16 I/4 0 NO CEIL 1 70.' GE GE ' ' GE GE S GE GE A1o : : A GE 9C0GI ' GE SC001 S GE 7C GE GE SCO ' 95.' 95.' 95.' 95.' 95.' 95. GE ' S S.6 9S b ,6 GE %COG: :1 96:'. 96.' :6 96: : GE 3SOoI GE 3C GE GE 2SO , ? GE ' e GE ISO be GE ICOO GE GE BOl ' GE ' : GE ' GE o' GE ' * GE ,00 GE , GE S i GE lci TOTAL NUMBER OF 0OSERVATIONSS 927

211 .j... GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY o OCCURRENCE OF CEILING VERSUS VISIBILITY USAIF ElC FRO" HOURLY OBSERVATIONS AIR WEATHER SERVICEIMAC STATION NUNKR:~ STATION NAME: GRAND FORKS AF9 NO PEROTH JUL RE OR 78-L I MONTH: JUL HOURSILSTI: ALL CEILING VISIBILITY IN STATUTE MILES IN I G GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I 10 6 S q /4 1 3/4 S/8 1/2 5/16 1/4... o NO CEIL GE 20COO GE GE S S 72. GE ? S GE S.0?S.1 7S S.1 7S.2 7S.2 7S.2 7S GE S S GE , St. GE S GE 70C S.S S 66.S 86.S 86. GE 6C a o. GE ,7 90: : : : : GE % , ,I 91. GE GE 3S G S S.3 9S.3 9s.4 9S GE S GE 2CO S S GE 1MC0I S.S GE 15o S 97.S S 97. GE GE 1I : GE !GE GE , GE GE S S S 99, GE ? , G GE GE S , GE S TOTAL HUNKER OF OBSERVATIONS: 7434

212 I GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFE[AC FRO4 0-OUPLY OBSERVATIONS AIR WEATI1ER SEsVICE/NAC STATION NUMBER: 727S75 STATION NAME: GRAND FORKS AF8 ND PERIOD OF RECORD: MONTH: AUG NOURS4LSYI: CEILING VISIBILITY IN STATUTE MILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I 10 6 S / /2 1 1/ /8 1/2 S/I16 1/ c... NO CEIL GE S.4 7S ? ?6.7? T T T6.1 GE ISCOI S.9 7S ? ? GE S GE 1CO GE S.S S A GE 10COGO 60.0 A A3.2 e3.2 a GE A GE S A GE S ] ' GE 6C001 AS A GE SO GE Sool , GE 9L S.9 9S S.4 9S.4 9S.9 9S9. 9S.9 9S.9 9S.4 9S. GE S S S.6 9S.6 9S.6 9S.6 9S.6 9S.6 9S. GE S.1 9S.9 96.S 96.S 96.S 96.S 96.S 96.S 96.S 96.S 96.S S 96.5 S5 zsooi GE 2COOl S C GE So S S 98.S S 98.S 98.S 96.S 98s 90.s 98.S 96.5 GE S GE GE OG GE GE ool G GE S s s 99.S 99.5 GE S S GE GE GE TOTAL NUMBER OF ISERVATIONS: 9S0 U

213 * GLOBAL CLIMATOLOGY BRANCI PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFEIAC FROM FOURLY OBSERVATIONS AIR 6TM:R $ERVIC IMAC STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 77-B6 MONTH: AUG HOURSCLSTS: CEILING VISIBILITY IN STATUTE MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I 10 6 S / /A 5/8 1/2 1/16 1/A 0 NO CEIL I A S S S GE ? ? 69.? GE IMOO! S GE A? A GE lsooj $ GE S GE lorol B GE B.A A GE $ R GE GE $ S S * GE s GE o be %coo GE GE 3r GE 2SO * GE GE *6 G 1! i GE s GE S GE S : : GE GE S S.S GE GE G GE S 97.5 GE * GE GE GE TOTAL NUMBER OF OBS(RVATIONSS 930

214 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFETAC FROM OURLY OBSERVATIONS AIR WEATHER SERVICE,AC STATION NUMBERS STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORD: MONTH: AUG HOURSILSTI: CEILING IIIIYISAUTMLE IN AGE E GE GE GE GE GE Gt GE GE GE GE GE GE GE GE FEET I IC / / % 5/8 1/2 5/16 1/4 0 j NO CE:L I S.: ? ? GE ZOCODi ? GE GE GE GE 12000o , GE ? ? GE GE S GE GE 6C g S GE SCOl s GE s S 84.5 GE 4COO :0 63: S: : GE GE 3COO GE GE GE GE GE S GE GE 9CO S GE S S 95.5 GE S.6 G s S S S GE Soo S.1 9S S 96.S GE GE S S * G GE * GE al TOTAL NVMBER f OBSERVATIONS: 930

215 GLOBAL CLIMATOLOGY BRANCH us AFfE AC AIR WEATHER SERVICE/MAC PERCENTAGE FREQUENCY Or OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS - -STATION NUMBER: STATION IdAME: GRAND FORKS AFB NO PERIOD Of RECORD: "ONIHI AUG FOURSILSTI: CEIL ING... VISIBILITY IN STATUTE MILES IN I GE GE GE 6E GE GE GE GE GE GE GE GE GE GE GE GE FEET I 10 6 S / i/... /2 S/16 1o a NO CEIL I S.2 SS.6 SS S S S S6.3. GE GE s.9 6S S S.1 6S. GE ISCDO : : :, GE 16000I S GE 19COO b GE 12C Icoo0 6S GE GE GE cool B Gr C.3 GE SCOO $ GE SZ.T S o GE COO 7S g GE e GE 3CO S S GE S S 90.5 GE 2c GE % 92-S 92.S S GE GE ? GE GE S.1 9SS S S S S GE S S GE S GE q GE : S.3 96: _J ,0 9 2G GE S B GE S B" G S TOTAL NUMBER OF OBSERVAIONS: 930

216 " GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FRO M OUR &SERVATIONS SI1R li8tiver SERVICE/MAC STATION NUMBER: 727S75 STATION NAME: GRAND FORKS AFR No PERIOD OF RECORD: MONTH: AUG HOURSILSTI: CEILING VISIBILITY IN STATUTE MILES IN i GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE 1FEET 10I / /12 1 1/94 1 3/91 S/B 112 5/16 1j NO CEIL I SS* SS.8 SS SS * a GE ? S s 63.S S 63.S S 63.5 G Is0oDI GE S8.A GE A GE GE OCOl G q GE &ool S S 77.5 GE 7Coo GE S GE Seoul S S S 83.5 GE SOO s GE ? % GE E a go.? 6.? 86.7 B6.? a.7 o.? GE SG GE a 9S S S GE GE ? ' * GE GE ] GE GE e s 99.S GE ? GE mj GE sou GE foo GE S s GE C GE S J GE 'I TOTAL NUROER OF OSCRVATIONSt 930

217 _GLOBAL CLIMAOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY LsAFETAC FROM HOURLY O6SERVATIONS AIR i[eatir SERVICE/MAC STATION NUMBER: 727S78 STATION NAME: GRANO FORKS AF8 NO PERIOD OF RECORD: MNTH: AUG HOUBSILSTI, 'I CEILING VISIBILITY IN STATUTE MILES IN 1 GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I V 3 2 1/2 2 11/2 11/1 1 3/V 5B 112 s/16 lie 0 NO CEIL I S S S7.3 S S S GE 20C ?.7 67.? ?.? 67.? 6?.? ?.? 67.? 67.7 GE 10cool GE e B GE 14LV E V E GE GE S jj GE 7C GE b sq.s 62.3 OqeS %eS qeS %.S $2.3 O%.S IeS eS %oS 92.J 8%eS S S GE S0001 7@ S GE V $ GE VOOI :5 91: GE I 3S :V 92:4 9 2:V 92: :9 92:V : 920V 92.9 GE V S GE S S S S GE 2001 e7.v S 98.S 96.S 98.S S 96.S 96.S 96.S SGE S S GE 10so V 99.V 99.V 99.4 GE GE ICODO :: : GE GE S * GE GE I 98.S S GE Sou 8$ GE 4ocI GE GE 1oi S S ' GE S TOTAL NUMBER OF OBSERVATIONS8 930

218 4 SLOSAL CLIMATOLOGV BRANCH PERCENTAGE FRCQUENCY OF OCCURRENCE Of CEILING VERSUS VIISILITY *1 ISSI IAC FROM 1OUOLY OSERVIlIOUS AIR WEATPER SERvICEIN8C * STTION NUNOERI 727STS STATION NANE: GRANO FORKS AF8 NO PERIOD OF RECORD: MONTH: AUG HOURSILSTI: CEIIN VISISILI??V IN SAPITE MI1LES IN B E BE SE GE BE BE SE SE GE GE GE 6t BE GE GE SC FEET /2 1 1/4 1 3/11 1S 112 S/16 1/ NO CuB I % S 71.5 ee BE S 72.3? SE 16COCI Z SE S S : T2.S : BE~~~~0 SO fc A is FE Z BE SC &COOI GE GE scooi ST.? E 1: SE %00 e V SE 6C BE, GE 3S GE ? BE 2C r GE isoog o SE & BC 10OI S BE ? G ? SE SC SE S of * BE S ? m l SE S ? SE [ , , , ? , , SE CI S 99.S TOAL NUMBER Of 9SERVATIOSs: 930

219 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIILITY US AFET AC FO ORYOSRAIN AIR WEATHER SERVICE.OMAC FO ORY0SR~jN STATION NdUMBER STATION MARC: BRAND rorms AF9 No PERIOD OF RECORD: 77-a6 MONTH: AUG VOURSILSII:21030 CE ILING V ISIBILITY IN STATUTE MILES IN IGE GE GE GE GE GE GE GE GE GE GE GE GE GE GE G FEET Ic / /2 1 1/4 1 3/4 SIG 112 5/16 It%... NO ii CEIL ? GE 20C b S GE IioCai To.# GE 161DO A L ?9.0 i9.l ? i j ?. GE s % % A % GE 000 a *1GE GE 6CO , GE S Z ) GE GE S S 9S GE * GE : $ GE : , DOGI a GE GE S S GE 10001i S 99.S GE GE S GE s GE 6T S GE S.2 9S G GE 20C GE E GE 600o 90.1 : 97. ;7J 9.3 9:2 9:)9:6, S *... TOTAL NUMBER Of OBSERVATIONS: 930l

220 GLOBAL CLIMAIOLOgW BRANCH ','! AIlR,VUSAFCAC WEATHER SEflViCEIMit PERCENTAGE FREOUENCY OF OCCURRENCE OF CEILING VERSUS VISIILITV FROM b4ourly OBSERVATIONS ST110N NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONTH: AUG HOURS(LSTI: ALL CEILING VISIBIL1TY IN STATUTEMILES I o GE SE 6E GE BE GE GE GE GL GE GE GE GE GE GE GE FEET I 1 6 S if / S/8 1/2 S/16 1/f 0 NO CEIL GE 20C000 GE , : : GE 16C GE s S TO.T T GE ? GE S * GE GE oo : : GE E o % GE SOO % S 87.S GE GE GE S GE 3C GE S.0 9S.1 9S s.2 9S.2 9S GE 2c S GE GE S (, s E S GE GE S GE , , GE S q ,6 GE fit SOO S.6 Vs.? , S 96.S S :EE GE :7: $ : : _1 BE S o *

221 -. 1!....~ GLOBAL CLIMATOLOGY BRANCH usaretac AIR WEATHER SERVICEIMAC PERCENTAGE FREQUENCY Of OCCURRENCE OF CEILING VERSUS VISIOILITV FROM HOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRANO FORKS 6F8 No PERIOD OF RECORO:U77*a6- M O NT : SEP OU RLSI0 T CEILING VISIBILITY IN STATUTE MILES " IN 9 GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEEl I 10 6 S I /2 I / SIG 112 S116 1/' 0 j... NO CElL I ' be GE l8coo GE GE GE 10COC GE 9CGG : GE 80 o GE?Cool GE 6C GE GE S 00I : : : o GE 110co s Jj GE s.6 96S GE GE ? GE 2^ GE c GE GE GE Ic00l GE : S GE S GE GE S ? GE 600l GE GE , GE GE * GE CI TOTAL NVIBLR OF OSERVATIONSt 900

222 GLOBAL CLINATOLOY BRANCH U SAfETAC AIR EA1 ER SERVICEJhAC PERCENTIAGE FREQUENCY Of OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS o STAION tvpb[r: STATION NAME: GRANG FORKS AF9 NO PERIOD OF RECORD: PMkW:V SEP 14OLRSILSTS: CEJLING VISIBILITY IN STATUTE MILES 1N GE( E GE GE GE GE GE E G G GE GE GE GE GE GE FEET 10 6 S / /2 1 G/9 1 I /9 S 1/2 5/16 1/9 a NO CEIlL Sq GE0 ZOOM GE : :3 61: j- GE GE Wool Z Of,1 GE %.3 6% E GE 9coo % GE 81GO A :3 71: :4 71:7 71.: : 71: GE s GE 60CO , GE , GE o.z GE GE GE S GE Z GE : :3 86: : GE , , GE IS0i z GE GE GE : : GE SG l , GE G : : GE G GE S.0 9S G S G Ul S TOTAL NUMBER OF OSSERVATIONSt 900

223 11- GLOBAL CLIMATOLOST BRANCH USAFETAC AIR WEATHER SERVICEAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM IOURLY OOSERVATIONS STATION NUMBER: 727S75 STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORDt 77-6 MONTH: SEP HOURSILSIS: CEILINGVISIBILITY IN STATUTE MILES IN i GE GE GE GE GE GE SE GE GE GE GE SE GE GE GE GE FEET J / S/B 112 S/16 1/9 0 NO CEIL SO.% S $ GE S4.7 SS.1 SS.2 S S.9 SS S G SS S.9 S GE so.$ 55.7 S5.1 SS.2 SS SS.8 SS.9 S5.9 S GE S $ S7.O S S7.6 GE S3.7 S i.2 SO S GE S , GE 90001S GE b GE?Cool GE S GE SCOO GE 9SGOI ? ?4.7?4.4?4.9? GE GE T.0 T GE ? GE GE 2COO S.O As 'p G AT ?. 8704?70??.5 GE GE a GE GE GE Z, GE S.1 9S S S GE tool ? S G GE GE ? GE ? 99.0 GE tool j GE ? TOTAL NUM5IR or ORSERVATIONSs 900

224 GLOBAL CLIMATOLOGY BRANCH USAFETAC EAIR OTER SERVICE PAC PERCENTAGE FREQUENCY OF OCCURQENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONTH: SEP HOUPSILSTI: CEILINdG VISIBILITY IN STATUTE MILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET / / 5/8 1/2 S/16 1/9 0 NO CE1L q GE S S s GE GE GE e GE SS SS GE IOCOOI GE : GE GE CO GE 60VO GE 5COO GE c o GE GE o GE 3CO E 2S GE 2COC GE GE GE 12GUI GE :7 92: :6 93:6 93:6 93:6 93:6 93:6 93:6 93: GE , GE S GE : 70c :0 96:2 96: GE , , GE GE GE GE GE GE TOTAL NUMBER OF OBSERVATIONS: 9G0

225 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY A LSAFETAC FROM HOURLY OBSERVATIONS AIR VEAT6ER SERVICE/MAC STATION NUMBER: STATION NAME: GRAND FORKS AFB No PERIOD OF RECORD: MONTH: SEP HOURSILSTI: O CEILING VISIBILITY IN STATUTE MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE BE FEET I # / /2 1 1/' 1 i. 5/ If2 5/ NO CE1L '6.1 '6.1 '.6.1 ' '6.1 '6.1 '6.1 '6.1 '6.1 '6.1 GE ' 52.' ' 52.' S2. 52.'. 52' 52' 52' : GE 18ool S GE 16r S S S S GE 10coo S '. 53.' '# S '. 53.' 53.' GE SS SS.? GE 1DO00I GE S7.: * GE 80oo GE '.8 6'.9 6' GE 6cO S GE 500 6S GE '0s0oI 65.' L b GE GE ' '. 7'.' 7'. 7'.'. 7'.?'.% 7.' 7'.% 7o.% 7'. 7'. 7. GE GE 21u ' ! :1 86:1 86:! :1 GE a r GE GE GE '. 93.'. 93.'. 93.'. 3' ' 9.. 3' 3w. '3' GE '. 9'.' 9'.' 9'.' 9.' 9'.' 9'. 9.' 94.' 9. GE * GE Pool 88.' 9' GE ' GE 6uO ' ,0 GE GE ' ' 99.'0 99.'. 99.' ' GE ' GE GE 1o ' GE ' O TOTAL NUMBER OF OBSERVATIONS: 900 L

226 GLOBAL CLINATOLOGY BRANCH USAFETAC s AIR WEATHER SERVICEIMAC SCILING PERCENTAGE rrequency Of OCCURRENCE OF CEILING VERSUS VISIBILITY FROM 8OURLV OBSERVATIONS STATION NUMBER: STAION NAME: GRAND FORKS AF8 NO PERIOD Of RCCORD: MONTH4: SEP HOURSILSTI: VISIBILITY IN STATUTE HULES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET / I / 5/ /16 1/ NO CEIL i % GE S3.0 S3.0 S GE GE S0.6 SO S2.s 52.8 S2.6 $3.o 53.0 S S S S3.0 S3.0 S s GE S S S S $ S S341 GE S s S4.9 S S $ GE S S $9, S S9.1 GE 90 A S S9.6 S s GE OCOI '1 GE S : GE GE GE ? ? TO, GE 4n0o o ? % q 77.4 GE GE S5.2 &5.2 1S.2 &S as S.2 BS.2 GE 'a GE GE OE ' GE S S S S * GE ICOOI GE S GE eo001 67: : C.E GE GE : :3 " GE GE S GE GE s.c i Gt O S TOTAL NUMBER OF OBSERVATIONS: 900

227 GLOBAL CLIMAIOLOGY BRANCP usafeiac AIR WEATHER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM POURLY OBSERVaTIONS STATION NUMBER: 7217S STATION NAME: GRANO FORKS AFG NO PERIOD OF RECORD: MONTH, SEP HOURSILSTI: 1AOO-2000 CEILING VISIBILITY IN STATUTE "ILES IN i GE GE E GE GE GE GE GE GE GE GE BE GE GE GE GE FEET I ,02 S/16 z/4 a... NO CEIL S2.1% S S : sq.: 54.1 s GE S ST.8 S7.B ST.8 s GE S s5,0 S.G S s GE S S6.1 S $ GE S S S S6.@ GE S9.9 S SO GE GE GE g GE 7COOI " GE ? GE S0G n * GE 450C GE ? 6S S GE 3SUOI ? GE GE GE s GE GE l 9q GE S GE 1I S T 96.? IbE 90C S ? GE g , GE GE e.? sa ' " GE GE GE GE and j GE of TOTAL NLMBES OF OBSERVAtIONSs 900

228 GLOBAL CLIMATOLOGY BRANCH USAFIAC s ' AIR WEATHER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NU1g9ER: 727S75 STATION NANE: GRAND FORKS AFO NO PERIOD OF RECORD: MONTH: SEp HOURSILSTI: IN ''GE GE GE 6E GE GE GE GE GE GE GE GE GE GE GE GE FEET E 10 S / /2 1 1/ S IA 112 5/16 I/ 0 NO CEIL GE S GE 18Coci GE 16c GE 190c 6S GE 12G ? GE I06C GE ? GE GE S.4 7S.9 7s.4 7S.4?S. 7S.4 7S S.7 T75. GE 6C001 7S ?? GE SCOO GE GE 4COO S.2 8S G 3S : : : : Z 87:9 67:9 GE GE " i GE 2r GE IOG GE 1500i GE GE IoDi GE 9GLI S S.8 GE ,3 96: : GE S , ?? 97.7 G GE 5ee GE 1 GE S * GE S , I GE loc GE S TOTAL N NER OF OSSERVATIONS: 910

229 GLOBAL CLIMAIOLOGY BRINCH UsAFETAC Ar NEATPER SERVICE/MAC PERCENTOGE FREQUENCY Or OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NVMBER: 727S75 STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONT14:... SEP VOURSILSTI: ALL CEILINGVISIBILITY IN STATUTE MILES IN IGE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET /2 1 1/## /6 1/2 S16 1/ NO CEIL S $ S##.2 S4.Z S S4.3 Sq. 5%6S 54.5 GE S8.2 S % S o.7 S8.6 GE $9.1 S Se8 58. /ii GE SS, S6.5 S6.S S S" s8o GE Ificcol S6.S GE IZca S GE S " GE 9C S S.4 6SK.4 6S S. 6SeS GE GE oi G 6COO S 72.6 GE $ GE GE 16C00l OS GE GE S GE 2KO GE 2C S GE GE 1 O j.5 9I.S 91.6, GE GE GE IC S S GE S 96.6 GE , GE GE SUOS S GE GE GE GE I GE CI 98.v TOTAL NUMBER OF OBSERVtIONS: 7200

230 4 GE.4" GE GLOBAL CLIMAIOLOGY BRANCH PERCENTAGE FREQUENCY of OCCURRENCE OF CEILING VERSUS VISISILITY USAFETAC FROM POURLY OBSERVATIONS AIR WEATHER SERVICE/MAC STATION NU"flR$ STATION NAME: GRAND FORKS AF ND PERIOD or RECORD: MONTH: OCT HOURSILSTI: CEILING V ISIBILITY IN STATUTE "ILES IN GE 6E GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET S 3 2 1/ /2 1 1/4 1 3/9 S/ 1/2 5/16 1/ NO CEIL $ S S S GE 20C00I SS SS SS.4 55% 55.4 SS.S SS.8 GE ISCOCI S.1 5S.1 5S.1 5S.% SS.% SS.1 SS ss. SS.4 S.'t SS SS.S 55.8 GE SS S5.2 SS5. SS.S SS.S S.5S SS.1 SS.S SS.S 5S.S SS.S SS GE 14COU S9.6 SS.9 SS S S6.2 S S S6.7 GE SS ,2 $ S S GE S GE S GE S.4 6S.11 6S.S S S ?Cool S 67.6 GE ?0.6 GE SCOD % S? GE GE 90o S G GE GE 2C o S 55.6 GE o o.7 o.7 n e GE ISO GE : 93.9 GE ICOOl GE CE S S S S GE S S GE S GE GE GE S S S GE S :2 99.: GE S GE al S... TOTAL NUMBER OF OBSERVATIONS: 93C

231 GLOAL CLIMAICLOGY BRANCH USAElAC AIR WEATHER SERVICEIMAC PERCENTAGE FREQUENCY Of OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMSERs STATION NAME. GRAND FORMS AFB ND PERIOD Of RECORD: MONTH: 0CI HOURSILSTI: CEILING VISIBILITY IN STATUTE MILES IN GE SE [ GE GE GE GE E GE GE GE GE GE GE GE GE FEET I /# 5/ / NO CEIL I SZ.S , 52.5 S2.S GE 2COO ? S S6.0 S GE 1Oo S S GE 16000i 5.6 SS $ S GE 16oo S S S S7.0 GE ST S S SS S6.5 GE GE l0ol %6. GE Tco S 66.S GEt o GE 5ool GE G :: : : 76:$I? I?: I?: GE i e GE 3oo GE Zs0ol i GE fg GE $ GE GE coi GE 90Cl GE POOl ' GE?003 & ? S GE SOD E GE! : * GE * 99.% GE 100l I BE TOTAL NUM6Lf OF Oat' O$ AT6ONS 930

232 ~ ~ ~ I ME GLOBAL CLIHIOLOGY BiRANCO PECENTIAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFETAC 1nV[T [ SERvICEINAC FROM IOURLY OBSERVATIONS STATION NMBE: 7:: 7S: STATION ei(e: BRAND FORXS AFS NO PERIOD OF RECORO:?7-86,iM ORTHt OCT HOURSILSTI: CEILING VISIBILITYISTUEMLS IN GE GE 6E GE GE GE GE GE GE GE GE GE 6E FEET I 10 6 S / /9 5I 1/2 S/16 1/4 a NO CEIL I o & GE S 53.S 53.7 S3.7 s3-7 S S GE S S3.3 S3.S S S*.0 S.1 S9.1 S S.S S9S. GE 16COC SI S S S3.S S S3.7 S.O S9.1 S.1 S S4.S S%9S GE 1COt S2.2 S S S3. S3.4 S S4.3 S.3 Sq. 59.S 59.7 GE 12C S3.5 5q.5 S.1 53 SS.3 SS.9 S5.4 S.9 SS SS.6 5S GE S S S 60O5 60.S G $ ol GE OCI 56S S GE 7OI S. 6S.9 6S.S 'i1 GE 6c S ol GSE : ? : GE GE S b.6 GE S.6 &E GE :3 62:3 62.S :6 GE o1 0 a S S. 6S S.1 &S.1 *5.S S.S Is.$ S S 66.5 GE l :9 67: : : eq GE ICO S.q o 69.9 l00s S GE GE GE S S S.4 9S.S 9S.? 9S. 6E S GE l GE S.S % to G E S s S S GE S. 96.I 97.S GE Of S S TOA16 UNIS of oe n5: 930

233 GLOBAL CLIMATOLOG BRANCU PERCENTAGE FREQUENCY OF OCCURPENCE OF CEILING VERSUS VISIBILITY USAFETAC FRO" 1-OUqLY OBSERVAIIONS AIR WEATHER SERVICE/NAC STATION NU14DER: 127ST5 STATION NfME: GRANO0 FORKS Ar6 NO PERIOD OF RECORDS NONIP'. Oct 14CURSILSTII * CEILING VISIBILITY IN SIATUTE PILES IN GE GE Gc GE GE GE GE GE GE GE GE GE GE GE GE GE FEET /% 1 31% sis 112 S/16 it% 0 NO CEIL I % % GE SO S S0.1 S GE % $ol S , SO.3 GE S.q 50.0 SO.S S so.6 GE % $1.0 St.$ S S $1.9 S S GE 12CO I., s GE 1C ".9 57., ,?.? S7.8 S7.. ST.$ S.I ST.:n GE 6C #coa S So6.% s6.% ,0 61,8 GE 7000) Ssj S 63.S S 63* GE 6CO S S S.6 GE SCOOB a GE GE 0O Z GE GE 3C S GE 2SO0 71.S GE GE 100l GE Z 8S0.2 4S.3 S I5 6 GE a GE C GE S z.S 92.S 92.5 : GE sou %.0 GE GE so.@ S S GE S.3 95S z GE S.0 9S GE S GE I 1005 c 770C I. GE c % TOTAL NUfBER Of 05RVAI ONSI 930

234 GLOBAL CLIMIOL06 BRANC USAFEIAC 8 AIR WATHER S[SVICE/"AC PERCENTAGE FREQUENCY OF OCCURRENCE Of CEILING VERS S VISIBILITY FROM VOUQLY OBSERVAION5S STATION NUKR: STATION NAME: GRANO FORKS AFB NO PERIOD Or RCCORD: f MONTH: OCT HOURSILSTI: CE.. ILING VISIBILITY IN SIATUTE MILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I 20 6 S /2 1 1/9 1 3/4 S/8 1/2 5/16 1/9 0 NO CEIL 1 ' ' '2.9 '#2.9 '2.9 $12.9 % ' '2.9 GE ' S SD S0.3 S S GE 161, So.6 S.6 SO.6 s so GE 26G S0 9 5C.6 S $ , B E 119c00i ' S.S S GC o S S S3.9 1[ 1 ool s $ $ S GE 9c00B S4.4 S S6.4 5.S S 56.s GE ,% bo ' GE lgal GE 6COD % GE S S S GE '150O S S 66.S 66.5 E %ca000 6'.' E :B S S B 3C S?6.S GE GE GE q.s S 89.S 8.S 6q.S 6.S %5 GE $ S GE c GE IC GE GE S S GE GE GE GE S GE GE , GE to GE , * TOTAL NUMBER OF OBSERVATIONS: 930

235 GLOBAL CLIMATOLOGY BRANC14 PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY USAFE7AC FROM HOURLY OBSERVATIONS AIR WEATHER SERVICEIMAC SIA71ON NUMBE STATION NAME: GRAND FRKS 6FS ND PERIOD Or RECORD:?7-66 MONTH: OCT HOURSSLSTI; I VISIBILITY IN STATUTE MILES o IN IGE GE BE GE GE GE SE GE GE GE GE GE GE GE GE GE FEET I t0 6 5 Is 3 2 1/ /2 1 1/% 1 3/6 5/ /16 1/ NO CEIL GE Z00C ,D 9.0D 69.0 :9: :0 49: : GE 1CO E 16000: : SO So.1 5o,1 GE 1t GE 12to01 S S1.7 S $ S Sli, S41.$ 51.7 S# of $ S S S S S9.1 GE GE scoot S o GE?Cool $ b b GE S S ! G scool %E GE 4C b ? GE : :0 76: GE GE GE ol GE : GE GE b 6E GE GE 600l % GE GE GE s00t S S GE oo S E fgi S GE BE 0! S TOTAL NUMBER OF 0 SE0VAIIONS: 930

236 GLOBAL CLIMAIOLOGY BRANCH USAF AIR EAC W(AT14P $EBvICE/MAC.. PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBER% STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 77-S6 MONTH: OCT FOURSILSTI: CEILING VISIBiLITY IN SIATUTE MiLE5 IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET 10 6 $ /16 1/ N0 CEL Z fj :::: ::: :6.6 6 B.i GE 20COD1 S S S3.5 S S S S3.5 i GE 18L S3.2 S o5 S S S S i]ge 16C00J 51.2 S3.2 S3.3 S3.4 S S S S3.7 o.ge 1qO00 S2.6 S4.7 Sfj.8 S4.9 S S551 55, S.2 55, GE S7.6' GE 10C003 S GE GE S.8 6S S GE 70O ? 68.2 GE GE 5COO GE GE %C GE I ? GE 3CO0 7S I GE S1S GE ZCOI S GE GE : , q GE GE 1C S GE GE S 96.S GE S 9S GE GE GE S GE S GE GE GE al TOTAL NUMBER Of OBSERVATIONS: 930 J L

237 J GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURREtNCE OF CEILING VERSUS VISIBILITY USAFTAC FROM HOURLY OBSERVATIONS AIR WEATNER SERVICE/MAC STATION NUMBER: STATION NANE: GRAND FORKS AFS ND PERIOD OF RECOROD MONTH: OCT 14OURSILSTI: ILNG VISIBILIY IN STATUTE ILES IN GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I /2 1 1/ S/ / a NO CE L GE 2GO S S11.6 S S s4.9 sq G 18CO S.46 S4.e S S S GE S0.6 S1.8 S.6 Sq0.8 S48 S S SS.3 GE S SS S5.S 55.5 SS.S SS.S SS SS S GE 12oo SS S ST.? GE S S GE 9c GE GE O ? GE 6C GE SOCI GE S GE S % GE GE GE GE GE 15GOJ ,' GE GE S 93.S #0.2 GE S GE GE S S GE GE GE 500 0: e o GE S S s S 99.6 GE IF GE Go S *... TOTAL NUMBER OF OBSERVATIONS: 930 I L

238 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR NEAT*ER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM I-OURLY ObSERVATIONS STATION NUMBER: 7Z7575 STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONT.p: OCT POURSILSTI: ALL CE IL I.G VISIBILITY IN STATUTE MILES IN IGE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET IC Z 1/ ,2 1 1/ '/I 5.8 1/2 5/16 1/ 0 NO CEIL I ' ' '8.1 '8.1 '8.1 ' GE S GE S3, E I 6Coo S GE I 40ol , S4., Y.Z , GE 12CO0I S GE 10COCI S GE 9LOI GE 600o S GE S.S GE 60U GE C.7 GE GE 4'D GE be 3CU GE 2SO GE 2OCJ SGE : : , GE S * GE GE 1COC S GE 9 0 El S %.7 GE pool % S GE : : : :4 96.S GE S GE 6 ' qo GE , GE 20CI GE 1(1O Ij GE TOTAL NUMBER OF OBSERVATIONS: 7440

239 GLOBAL CLIMATOLOGY BRANCH U IAET a C AIR NEATVER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS A STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONTH: NOV HOURSILSTI: CE ILING VISIBILITY IN STATUTE MILES... IN IGE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FE1ET.. I /8 1/2 S/16 1/4 0 NO CEL 43.1 ' '6.2 '6.7 '6.? N N6.0 N6.8 ' '6.8 '16.6 N GE o.0 '18.3 ' % '9.3 '9.3 '9.3 % '9.3 GE ' ' ' '9.3 ' o3 ' '9.3 GE '5.3 '1.0 '8.3 8:08 '9.2 ' '9.3 '9.3 ' '9.3 GE SiloOG 4S6 '8.2 '8.6 '9.0 9t 9.I ' '9.6 ' ' '96 GE 12CO01 0T.3 SO B S GE 10COO : :9 S6 9 56:9 56: GE 9Co N S5S G S : : ' GE ' ,' ,9 G ? '. 63.' GE ' GE ' GE 'C ' o ue l ' GE l '.2 7'.2 7' ' '.2 7'..2 GE ?4.8 7s.% ' 77.' GE GE GE '.2 79.' S GE ? GE 10coo GE 90C 7% ' '. 8g ' :9 90:9 GE as.' ' GE ' ' GE S ' '.40 9'.' 9'.7 9'.. GE S00t ' GE ' ' '1.1 9S GE '.' ' ' ' ' GE ' ' 9'.6 95.' ' GE o ' ' ' TOTAL NUMBER OF 09SERVATIONS: 900

240 * 5LOBAL CLINitOLOG7 BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY "SAFTAC S AIR WE*ITER SENVICEINAC FRON POURLY OBSERVATIONS STATION NUMBER: TAT0N NAME: GRAND FORKS AFS NO PERIOD OF RECOROt MONTH: NOV HOURSILSTI: C. IL.NG.' VISI T INSA E LS... IN GL GE GE GE 61 GE GE GE GE GE GE GE GE GE GE GE FEET I o 6 S /2 1 1/ S/6 1/2 5/16 1/1 0 NO CClL * GIE ZOOO S S Si St.& $1. S16 GE eo.8 GE % S0.6 SO S1.0 SI.3 $1.3 S S1.% $8.6 S S1. St.@ 51.6 S1.8 S S11..J GE ICO GE S0.9 S0.6 S2.4 Si $1.2 S S3.2 St.$ $ S2.2 S4.0 S2.2 S4.0 S2.2 S.O SZ.2 S S S2.2 S4.0 GE 10g:01 S@.1 ;S.9 S6.6 S6.6 S6.6 S y GE 9c00J S6.6 S6.6 $6.6 S S S S7*6 5?.6 S GE $Col Sq.% GE? GE 0001 S7.% GE S S S S GE 9500i W S " GE %Coo % GE 3SO , S GE 3COOl GE GE C W ?S S GE GE S S *GE GE W.? % GE 9Go GE S.e GE "*1 GE GE W S.2 6E W00l GE S G W GE IS-. 6o GE ai S.... TOTAL NUMBER OF OSSERVATIONSS 9uo J

241 GLOBAL CLIPAtOLOGY BRANCH u ASFETAC AIR IEATNER SERVICE/NAC PERCENTAGE FREGENCY OF OCCURPENCE OF CEILING VERSUS VISIBILITT FROM HOURLY OBSERVATIONS STATION NUMSER: STATION NAME: GRAND FORKS Ara NO PERIOD OF RECORD: MONTH: NOV HOURS(LSTI: CEILING VISIBILIYI IN STATUTE MILES *1IN IGE GE GE GE GE GE GE 6E GE GE BE BE GE GE GE GE FEET /4 1 3i9 5S 1/ NO CEL ' '.7 '1.2 1S.2 1S.4 '5.1 ' ,. 5.8 ' ' GE S. ' ' '9.9 '9.9 ' ' '9.9 GE 1SOM 4S.6 '.7.9 '8. '8.9 '9. 49.% ' O SO.0 GE 16C000 %5.6 '7.9 'S '9.9 '9.9 SO.0 SO So GE ' SC.2 SO.' S GE 12C00l S GE SO S.4 $o.% S.7 S GE 9CO S S S S S S6.0 GE aool S9.2 S S9.6 S GE 7VO S.$ S ' GE 6C S ' GE S5ool ' ' ' GE SO S GE S.3 62.' S. 6S GE 3500i S GE 3C GE Z Z E 2CO ' ?S GE 15C ?9.9 fie ' GE o GE s o G ? z GE 8oal S GE a ' GE 600, ' * * GE S0l ' GE 5001l j 96.' 96. GE 3C 70.' ' GE ' GE loaf 70.' GE Of 70.' ' SIOTAL NUMBER OF OBSERVATIONS: 900

242 GLOBAL CLIMATOLOGY BRANCH USAEIAC AIR UEATNER SERVICEINAC PERCENTAGE FREQUENCY or OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBER: STATION NAME. GRAND FORKS AFB NO PERIOD OF RECORD:?7-86 MONTH: NoV HOURSILSTI: CEILING VISIBILITY IN STATUTE IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET i 1C / / 1 3/6 5/8 1/2 5/16 1/ 0 NO CEIL i ' GE ZO S GE IsCoCi % * B GE 16CO GE 16c SO.? SC8 GE * S GE loccoj S.3. 5S.3 SS.7 SS.8 S be 90coc S.0 SS S6.7 Si.7 S GE S S GE S ? GE 6CC $ b GE S001 $ GE % GE 600O S GE S GE 300GJ G 2SU00 60:2 66: : GE ,9 75,7 IS.? GE 160C S GE GE ? S S GE S S GE 90CI GE S GE C GE GE SOi GE GE , * GE 2ul S GE $ GE TOTAL NUMBER Of OBSERVATIONSt 900

243 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR WEATHER SERVICEI/AC PERCENTAGE FREQUENCY Of OCCURRENCE OF CEILING VERSUS VISS6ILITY FROM HOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORO: HONTH- NOV HOURSILSTI: ~ ~~CEILINGVIIIIIISTUEMIE IN i GE GE GE 6E GE GE GE GE GE GE GE GE GE GE GE GE FEET 10 6 S / /2 1 1/ 1 3/4 5/6 1/2 5/16 1/ NO CEIL GE ZOCOOI GE 0coo S0.3 S S0.3 5o.% SO GE SO.0 50.' So GE 16v S S S GE S S.O S.2 S6.2 GE S S?.O S $ GE 9CGOI S7.0 S , GE 0C00l GE 7COOl GE 6CO GE SCOCI GE S S GE GE GE GE S S GE l GE GE s GE s GE 1C E GE 80o GE GE ,0 9S.2 9S.3 GE SU r. GE $ ? 97.6 & fge GE GE loci $ GE o TOTAL NUMBER OF 08SERVATIONS 900 kl

244 GLOSAL CLIMATOLOGY BRANCH USAFEIAC AIR WIEATHER SERVICE/MAC PERCLNTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM IOURLY OBSERVAIIONS STATION NUMBER: 72757S STATION NAME" GRAND FORKS AFB NO PERIOD Of RECORO:?7-66 MONTH: NOV HOURSILSTI: CEILING VISIBILITY IN STATUTE MILES IN I GE Gc BE GE GE GE GE GE GE 6 GE GE GE GE GE GE FEET I /2 1 1/4 1 3/8 5/ /8 0 NO CEIL I GE 20C00J GE GE GE vir00j S ? $ s GE 12V S S S GE S6.9 S GE S b7.2 S S S.? GE &Cool 5S GE?Cool GE GE S S GE $ S S S S GE 8C ?, E 3S GE GE S GE 2oo GE GE % GE GE ICO J GE 90CJ GE GE * GE GE S GE qo GE as q GE 20c s GE 100J GE s.@ TOTAL NUMBER Of OBSERVATIONS: 'Do

245 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR WElTER SE[VICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISISILITT FROM HOURLY OASERVAIIONS STATION NUM8(RC STATION NAME: GRAND FORNS AF9 NO PERIOD Of RECORD: MIIONTH: NOV HOUNSILSTis 1800-ZOO0 CEILING ViSISILITY IN STATUTE MILES IN I6E 6 E GE 6L GE :E GE GE GE GE G( GE GE GE GE FEET I t0 6 5 I I/. 1 3/I. Sg 1/ lf 0 NO C9L % GE S b GE Wool S.? b ' ' GE ? GE * ' '. 43.'3 8.3 GE '.3 s7. S.$ S S1.1 S S1.1 GE S7.o SS '7 SS. S.7 SS.? SS? SS03 SS SS8 S SS.6 GE SS. SS S $ S * GE 1c00 SS s.* 69.6 S S9*. S9.6 $9. 8' $9.9 S GE ' GE o0o G 7 MC ' : S S S. 6S.4 6S GE a ' GE '.0o G : ? G , ? ft CC M01G S T ?7, ,.1 T~ 77.17,. " GE 2C001 7n * 9 TB. $ $0.3 so.% 00.& 00.6 so.& 800&6 60,6 4.6 k. GE le ?7Te e ' $ G *.4 $ S at# $ ' fit as 0 85., $ BG9 $7.3 $ &?.3 :?.3 ;'" CCG S e T GE o $ O GE a , GE?Got TT.0 GS $$.a GE 6boot T.0 as.% $6.9 Be.% $ S.2 IS.2 9S GE Soal 7? ##.o S o GE 4100a S o ?.1 GE Is.$ S % GE 20C 17.3 a.$ S.6 9T.D S GE S GE s.$ '.0 9S.? TOTAL NUMBER Of OBSERVATIONS: 900 j L

246 GLOBAL CLIMATOLOGY SMANC14 VSAFETC AIR A WETU SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING, VERSUS VISWBLITV FROM HOURLY OBSERVATIONS STATION UHMR 727S75 STATION NAME: GRANO FORMS IFS NO PERIOD OF RECORO: ,.. *: : ::... :... ::: :: : : : :... MONTH: NOV HOURSILSTI: CEILING VISIBILITY IN9 STATUTE MILES IN GE GE GE GE BE 6E GE GE GE GE GE GE GE GE GE GE FEET I / /2 I 1/ S116 I/% 0... NO CEIL E 20C GE S Il. q? GE 16c00J ? ? ? E " E SO SO.9 SC S1.0 S1.0 S GE S ? 55.7 SS. 5S SS.8 S$ S S56 SS E 9CO SS. S S S6.3 S ,3 563 E S9.0 S BEc GE a GE S0001 $ S.? ,8 6S S S GE %SCO S W. %COOo GE ? 69.7 GE 3CO ? GE S ? GE GE Z.0 T GE % BE GE CD as.7 GE ? GE R %.2 8S* GE S BEt tool GE so S % G[ tool S J a[ S $ n GE GE S , ?, ? BE S TOTAL NUMOL OF O 8ER 0ATIONS: 900 L.

247 GLOBAL CLIPAIOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE Of CEILING VERSUS VISIBILITY USAFETAC FRO" -OUNLY OBSERVATIONS AIR WEAETHR SERVICEl"AC STATION NUMBER: 727SS STAIION kame: GRAND FORKS AFS No PERIOD OF RECORD: NONTN: 40V NOURSILSTI: ALL F CEILING VISIBILITY IN STATUTE MILES IN GE G B SE GE GE GE GE GE GE GE GE 6E GE GE GE GE f FEET /21 1/0 1 3/9 / 6/16 Ila 3/9 o... NO CElL ' GE , GE 1$ ? % ,92 GE GE S0.9 SO S0.S 5G.5 GE s1.4 $ S2.2 S S2.4 S? S S2.4 GE S1.4 S.9 S5.1 SS. S6.1 S6.1 S6.3 $ S6.4 S S 56.S S GE SS.3 SS.8 S S6.S 56.6 S $ GE 300 Sit S (it ? S GE S 62.S :0 GE SA.S S GE S.S S S SE S ?.? * GE GE 3,O0I 63.S S ? GE S.S S GE Zvool S ? S GE ?S , 'ag o GE : :9.3 1S ,.t GE S S GE S GE t GE S GE S 6f.$ S ? GE q.? GE S S GE s GE Ni 0I OS ? ? GE G CO S G E c ? TOTAL NUMBER OF OBSERVATIONS: 7200

248 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITV 4 USAFETAC FROM hourlv OBSERVAI!ONS Ai wrather SERVICE/MAC STATION NUMBER: STATION NAME: GRAND FORKS AF8 NO PERIOD OF RECORD: MONTH: DEC HOURSLSTI: CEILING VISIBILITY IN STATUTE MILES -- 1 FEET IN I GE t0 GE 6 BE 5 GE 4 GE 3 2 GE 1/2 GE 2 1 GE 1/2 1 GE 1/4 GE 1 GE 3141 GE SIB GE 112 5v16 GE GE 114 GE NO CElL ? 69.6 GE SI.3 51.S SI.S GE 0000e S S51.5. s S t.? GE S1.S S EGE 11' S0.9 S1.3 SI.3 S S1.8 S S2.0 S2.0 S G1 GE 12ool S S3.0 S3.1 1 GE IOCOJ S S S. 57,?.% T 57.S 57.6 GE S $ ST.? S6.1 S GE S UE ? GE S.2 6S S.4 65.S GE SOODJ 62-!S GE GE GE lie T7.q 77.S * GE S 79.S GE S G GE S a S.2 GE $ SGE 6001 GE [COO GE S GE S S 92.S 92.S GE : : E S GE , S S S.6 9S GE S GE S S E S S S E I S FOUAL NUMBER Of OfSEYAVIOMSj 930 eoee L

249 -It- GLO*AL CLI.ATOLO6Y BRANCH PERCENTAGE FREQUENCY Or OCCURRENCE O CEILING VERSUS VISIBILITY s AC T FROM HOURLY OBSERVATIONS AIR WEATHER SERVICEINAC STAIION NUMBER: STATION NAME: GRAND FORKS AFB ND PERIOD OF RECORD: MONTH: DEC HOURS(LSTI r CCIL1NG VISIBILITY IN SIATUTE MILES IN I GE BE GE GE GE GE GE GE GE GE seg GE. FEE LI 1,114 1 /4S 5i8 112 /16 1,t a NO CElL So G.e 50. S SO SO.9 GE 20COG! S S S Z 1E S S3.2 S3.Z 53.2 GE 6lroCl S S GE S Z GE S S GE S R.8 8.e 58.8 sa GE 9CI S S % S GE G000a GE GE S S GE 5OG B GE 4so Z % GE D GE ! o GE 3COG S , ? GE s00 70a B1.S ? BS GE 180i B GE S 84.0 as GE B Be.? GE GE 90u GE : GE 700 7S.7 89, , % GE S GEt SaO GE S ' GE S ? s BE 0l ? V.. GE ci ; TOTAL NUMBER OF OBSRVATIONS$ 930 am*l

250 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR WEAI R SERVICEIHAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NLIPBER: 72757S STATION NAME: GRAND FORKS AF ND PERIOD OF RECORD: MONTH: DEC HOURSOLSTI: IN I GE GE SE SE CE GE GE E G GE GE GE GE GE GE FEET I ' 3 2 1/ / ,6 SIB il, 0 NO CEIL i '8.1 48,7 '18.1 ' '08.9 t GE ' ' S 51.S GE 18CO SO.0 S0.5 $ S GE 16COl ' S.S GE IlCOOI GE 12C001 ' S ' A GE S S S : GE 9ool S : ' 57.' S7.' S fge 8rOCI S59 SOO : CE?CODA GE 6C ' ' '.' 6'.0 6' GE SCO I GE ' " ? GE %0OOI ' 70.' S GE ' GE 3C00J 65.' '.7 7' TS.' 75.' 75.' 7S S.S GE 250CI ' GE 2OOCI 69.S '. 80.' '. 81.S GE GE 1O ' oq.s ' ' GE B.1 ' ' 8?.' 87.'. GE ICOOI ' GE ' ' ' 90.' 90.' GE o.o () 92.0 GE '.' ' GE ' S '.2 9'.' 9'1.' 9'. GE G IG 8S : : : :5 93*1 9J :S ' : : ' 4 96.S GE N ' ' a GE SS ' 9' ' 98.' GE IGI '.2 94.? ' GE Cl S '.2 9..? ' TOTAL NUMBER OF OBSERVATIONS: 930 LL

251 GLOBAL CLINIOLOGY BRANCH UsAFETAC AIR WEATHER SERVICEIMAC PENCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM 1-OURLY OBSERVATIONS STATION NUMBER: STATION NINE: GRAND FORKS AFS NO PERIOD OF RECORD: 77;86 MONT: DEC NOURS LSIP: CE IL ING VISIBIL1TY IN STAIUTE MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE 4 FEET I 10 6 S / / / /16 1/4 0 - NO CEIL # a I GE 2000C1 ' S S GE SO GE 16C GE 1W GE I : Sa GE b GE 9roo GE 8c S GE GE 6COO GE : :9 71: GE GE 41OCI l GE GE 3EOOl GE GE 2CO P4.3 GE q.9 GiE 1501C P GE S GE IC OI GE GE eool ~ GE , GE be GE G E , s GE GE IGG "9 GE Di @ TOTAL NUMBER OF OBSERVATIONS: 930

252 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR AEATI-ER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY FROM HOURLY OBSERVATIONS STATION NUMBER: 72757S STATION NAME: GRAND FORKS AFB ND PRION or RECORD: MONTH : DEC HOURSILS I : U0... CEILINGVISIBILITY IN STATUTV MILES IN I GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET I 10 6 S / S 112 5/ I GE GE 16C , 6 GE 14oo S S S S SAO S S4.1 S S 55. S.S S S.14 S.5 SS S1.7 SS f.7 S5.6 NO CEIL S.3 4S : 47.: : r S S S3., S3." S GE S1.8 $ S S S S.3 $ S GE S S GE $ GE $8.5S : :9 60: GE S , S GE 7cool S GE 6CO G GE :3 65:3 66.S 67: :0 71:1 71:1 71: GE o , GE! :S : : 75.: : GE c 150o 58: is GE S 77.S T GE : e GE GE I8o I GE 15O GE GE lrooi S GE S BS GE 8o GE S GE ? j 91. GE S S GE 10OO S S GE % GE S S GE S.S GE O $ I TOTAL NUMBER OF OBSERVATIONS: 90

253 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY Or OCCURPENCE Or CILING VERSUS VISIBILITY S SAFETC. FROM'r IOURLY OBSERVATIONS AIR NEATFER SERVICE/MAC STATION NUMBER: 72757S STATION NAME: GRAND FORKS AFS ND PERIOD Of RECORD: 77-B6 MONTH: DEC HOURS(LSTI: 1S CEILING VISIBILITY IN STATU'TE MILES IN IGE GE BE GE GE GE GE GE GE GE GE GE GE GE GE GE FEET 1 1C) 6 5 N 3 2 1/ /2 1 1/4 1 3/4 5/ /8 0 NO CElL '18.9 N19.6 % S GE 20C S S S. 55.N S GE S S S GE S3.01 S N % GE I147T.S S11.3 SN4.7 Sq.& S S GE I2couI S6.1 S6.2 5?.? S S &.3 GE GE GE 'COOl ? N a5.? S GE N a GE GE S GE GE ?S GE 3S GE S GE GE 2C # GE $ GE GE s ) GE 1V GE s GE GE GE 6001 E GE sixic S.? GE S GE GE S GE lool 65.S GE 0l , 92.b TOTAL NUMBER Of OBSERVATIONS: 930

254 GLOBAL CLIMATOLOGY BRANCH USAFEIAC AIR WEATHER SERVICEIMAC PERCENTAGL FREQUENCY OF OCCURRENCE OF CEILING VERSUS 6ISIBILITY FROM POURLY OBSERVATIONS STATION NUMBER: 721?S5 STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: 77-o6 MONTH: DEC HOURSILS11: t CEILING VISIBILITS IN SAILIE MILES IN GE GE GE GE GE GE GE GE GE GE GE 61 GE GE GE GE FEET /2 I /8 1/2 S/16 1t a :1 NO CEIL T GE S S2.7 GE S1.6 $ $ S2.9 S S2.9 S2.9 GE S S S2.9 GE S4.0 S1.0 S%.D S4.0 S % GE S s6.6 S6.9 SS S $5.6 $5.6 SS, GE 10COD S o GE 9C0O S E :.6 66.? :b 65: GE a700 ST b GE 600U5 So.? GE S0OS GE T GE GE GE 3C TS T ? b 78.0 GE GE CI off * GE S GE GE GE 1GOO S o2 GE S GE lo0c i $ GE S S GE S o GE o * Gg S GE a? E S GE 100D GE oT o _JA TOTAL NUMBER OF O$StRVATIONS:

255 GLOBAL CLIMAIOLOGV BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISIBILITY ' 4 USAFETAC AIR WEATHER SERVICEIMAC FROM HOURLY OBSERVAIIONS S7STATION NUMBfRY 727S75 STATION NAME: GRAND FORKS AFm ND PERIOD OF RECORD: 77-6 MONTM: DEC POURSILSII: CILIVISIBILIT IN STATUTE MILES IN I GE GE GE GE GE GE GE GE BE GE GE GE GE GE GE GE. FEET I 10 6 S /2 1 1/0 1 3/0 S / NO CEIL I S GE O SO SO.3 SO.3 SO.S 5 So. 0O So.6 GE : S0.3 50: S s S GE :9.8 09:y S SoN SOS s0.6 S0.6 GE l400ot O8.2 s.0 SO $ S S S GE ? S GE IOOD O S S6.S S.5 5S.S 56.6 S.8$ 5B.8 S8.9 S GE S7.6 S S9.0 s S B S9.6 GE &col S S GE GE GE 5coo Z GE O.S GE GE 350Ci S S 70.5 GE ScOOl GE 2! $ GE 2COOl GE S GE IOGI GE ss.s * GE I00I ? I G S.S B9.9 9OS GE 60C % GE % GE S 93.s 93.5 * GE Seal S GE S S S GE S S GE B S G loaf S ? E 01 OI S.3 87.S OO.g... TOTAL NUMBER OF O8SERVATIONSa 930

256 GLOBAL CLIMATOLOGY BRANC4 Us'FEIAC AIR WEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF CEILING VERSUS VISISILITY FRO" HOURLY OBSERVATIONS STATION NUMBER: 727S7S STATION NAME: GRAND FORKS AF9 ND PERIOD OF RECORD: MONTH: DEC HOURS(LSTI: ALL IN AGE GE GE GE GE GE GE GE GE GE GE 6 GE GE GE GE FEET 10 6 S / / / /I6 1/ 0 S NO CEIL i # GE 20CO S0.9 S1.' S3.0 GE 1600C 67.5 S1.0 SI.S S3.0 S GE 16Co S 5Z.6 S S GE $1,9 52.' SE 12Coo S SS SS GE S3.3 S S S S9.7 S GE $3.7 S q S GE 8000! 56: E 73oo! S S.0 6SO GE q 67.6 GE SCo S GE 4SOc o.3 70.S GE GE 3500! S q.S S ? GE 3000! GE 2500! S O.S eo.s GE GE 1800! GE S 83.S S.S S GE 1200! s GE 1COol S GE 900! S J. 91.S 91.6 GE 800! S GE Tool S GE S GE '.a 95.3 Go GE 3E l GE GE 200! GE 0! ?OTAL NMBER Of OBSERVATIONS% 7660 U.

257 GLOBAL CLIMATOLOGY BRANCH USAF[TAC AIR yeaiver SIRVICE/MAC PERCENTAGE FREQUENCY FROM OF OCCURRENCE HOURLY OBSERVATIONS or CEILING VERSUS VISIBILITY STATION NUMBER: STATION NAME: GRANO FORKS AF NO PERIOD OF RECORD: MONIF: ALL FOURSKLSTI: ALL CILVISIBILITY IN STATUTE MILES IN I GE GE GE 6E GE GE GE GE GE GE GE GE GE GE GE GE FEET I / /4 1 31/ 5/ / NO CEIL S S3.4 S3.S 53.S S GE S GE 18000, SS S $ S GE S S GE GE 12C0C f 0 *O.? S ( GE 1C , S S GE GE ' GE 7CO0l D GE 6col GE 5C ?S GE GE %C GE GE 3COO GE S S GE : GE ss $6.8 GE S S GE GE GE %.s 9% GE BUGS GE GE S GE! R S GE S GE S GE s S 99.7 GE Ci s TOTAL NUMBER OF OUSERVATIONS: J

258 GLOBAL CLIKATOLOGY BRANCH USAFLIAC AIR WEATHER SERVICEIMAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SKY COVER FROM HOURLY OBSERVAIIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB No PERIOD OF RECORD: 70-8 MONTP: JAN PERCENTAGE FREGULNCY OF TENTHS OF TOTAL SKY COVER HOURS TOTAL ILSTI ? MEAN 06S " ; ; OS 33.6 Il SS OS I S.? N l1l % TOTALS S STATION NUMBER% 72715S STATION NIME: GRAND FORKS AF9 NO PERIOD OF(RECORO: PERCENTAGE FREQUENCY Of TENTHS OF TOTAL SKY COVER I-OURS I TOTA L ILSTI N S 6 1 a 9 10 MEAN 08s S % % l S.6 1S.9 % C @.? S 9l ? S is 6...TOTALS

259 GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR neati-er SERVICE/MAC PERCENTAGE FREQUENCY OF OCCURRENCE OF SKY COVER FROM HOURLY OBSERVATIONS STATION NUMBER: 72757S STATION NAME: GRAND FORKS AFB NO PERIOD or RECORD: MONTH: MAR PERCENTAGE FREQUENCY OF TENTHS Or TOTAL SKY COVER FOURS TOTAL ILSI I S MEAN COS CO-? I S ? S S TOTALS I1S s STATION NUMBER: STATION NAME: GRAND FORKS Are No PERIOD Of RECORD: 70-O? MONTH: APR PfRCENTAGE FRfQUENCV Of TENTHS Of TOTAL SKY COVER HOURS 101:1 ILSTI a S 6 7 a 9 10 MEAN 0S * ? 0-SO S S I $ ? s-IT is S TOTALS I :1... L

260 1USAFETAC GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY Of OCCU'RRENCE Of SKY COVER FROM HOURLY OBSERVATIONS AIR WEATHER SERVICE/MAC STATION NUMBER: 727SIS STATION NAME: GRAND FORNS AF9 NO PERIOD OF RECORD: MONTH: PAY PrRCENTAGE FREQUENCY or TENTHS Or TOTAL SKY COVER IHOURS I TOTAL ILSII S 6 7 a 9 1a MEAN OBS O-2I 29. IS S ~ I 2::: 31.6 to.a 30:.2 : ,... *I S A? ? I ? ? I ? I q ITOTALS I ? STATION NUMBER: STATION NAME, 6GRAND FORKS AFS ND PERIOD of RECORD: 786? MONTH: JUN PERCENTAGE FREQUENCY OF TENTHS OF TOTAL SKY COVER HOURS i TOTAL ILSTII a s 6? a 9 10 MEAN CBS... o I S *03-OS S7.? S I C9-1l * R-20 I I S.6 69? j S

261 GLOBAL CLIMATOLOGY BRANCH PERCENTAGE FREQUENCY OF OCCURRENCE OF SKY COVER USF TAC FROn HOURLY OBSERVATIONS AIR NEATHER SRVIClIMIC STATION NUMBER: 121STS STATION NAHL: GRAND FORKS AFN ND PERIOD OF RECORD: MONTH: JUL 76-ST PERCENTAGE FREQELNCY OF TENTHS Of TOTAL SKY COVER HOURS i TOTAL ILSTI I * 6 7 a 9 10 MEAN OS 00*02 31*$ 34.8 J6.4 J , 03-aS 19.0 $9.S i. Cq* I o IS-IT 2.S S.S I S ? TOTALS i $.S STATION NUMBER: 727S1S STATION NAME: GRAND FORKS AFB NO PERIOD MONTH: OF AUG RECORD: t" PERCENTAGE FREQUENCY OF TENTHS Of TOTAL SKY COVER AOURS i IA ILSTI S 6 7 a 9 10 MEAN OS... o... o... D-02 i S I a!-os 2S Cb-OR ,, ? S15-17 I S l6.t S S 16.6 SI.S ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ee TOTALS

262 GLOBAL CLIMATOLOGY BRANC14 LSAFETAC AIR WEATHER SERVICEIMC PERCENTAGE FREQUENCY OF OCCURRENCE OF SKY COVER FROM HOURLY OBSERVATIONS STATION NUMBER: 727S7S STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: NONTH: SEP... b-ours PERCENTAGE FREQUENCY OF TENTHS OF TOTAL SKY COVER TA TOTAL ILSTI I a 9 10 MEAN CBS O-02 3S S.S S , C "-1? S.9 S TOTALS S STATION NUMBERt 721S7S STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONTH: OCT... PERCENTAGE FREQUENCY OF TENTHS OF TOTAL SKY COVER HOURS T OTA L ILSTI MEAN OS I SS 925 C6-O S S S S TOTALS

263 - l GLOBAL CLIMATOLOGY BRANCH USAFETAC AIR WEATHER SERVICE/MAC PERCENTAGE FREQUENCY Of OCCURRENCE Of SKY COWER FROM HOURLY OBSERVaTIONS STATION NUPBER: 727S75 STATION NAME: GRAND FORKS IFS NO PERIOD OF RECORD: MONTW: NOV... PERCENTAGE FREQUENCY Or TENTHS OF TOTAL SKY COVER $OURS I TOYAL ILSI B 9 10 MEAN CBS p S cS S B S S TOTALS I ,? F STATION NUMBER: STATION NAME: GRAND FORKS AF9 ND PERIOD OF RECORD: MONTH: DEC PERCENTAGE FREQUENCY OF TENTHS OF TOTAL SKY COVER #OURS I TOTAL ILSIJ I B 9 IC MEAN OS o..... F Cl-OS los 2S I , qs2 6.S 92S > TOTALS L

264 GLOB4L CLIMATOLOGY BRANCH LSAFEIAC AIR hiati-er SERVICE/1AC PERCENIAGE FREQUENCY Or OCCURRENCE or Sli COVER FROM HOURLY OBSERVATIONS STATION NUMBER: 727S75 SIATION NAME: GRAND FORKS AF9 NO PERIOD Of RECORO: MONTH: ALL... ".""."."" ""..."."''...C...'... ';(... '.. ' "."''''".... "''' PERCENTAGE FREQLENCY OF TENTHS OF TOTAL SKY COVER IOURS I TOTAL ILSTJI a S 6 7 a 9 10 MEAN 0BS JN LL FEB MiAR 1S ts APR Ti1 "AY O JUN k JUL ? %19 AUG %.S 19.2 s.% 7362 SEP 16.s ?6 OCT S NOV T DEC %06 TOTALS O L

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266 TEMPERATURE AND RELATIVE 14UMIDITY SUMMARIES CUMULATIVE PERCENTAGE FREQUENCY Of OCCURRENCE Of DAILY MAXIMUM (MjNIMUM AND MEAN) TEMPERATURES DATA DERIVED FROM SUMMARY OF DAY DATA. PERCENTAGE TABULATIONS PRESENTED BY 5-DEGREE FAHIRENHEIT INCREMENTS PLUS THE MEAN. STANDARD 0EV- IATIONS AND TOTAL OBSERVATION COUNT. THE MINIMUM TABLE ALSO INCLUDES A 33 FAHRENHEIT DEGREE INCREMENT. SINCE MANY STATIONS/SITES 00 NOT HAVE MAXIMUM/MINIMUM THERMOMETERS, THESE TEMPERATURES WERE SELECTED BY SCANNING I" IOLRLY OBSERVATIONS FOR THE HIGHEST AND LOWEST VALUES. STAT1STICS DO NOT INCLUDE INCOMPLETE MONTHS ITFOSE CONTAINING ASTERISKS). FOUR OR MORE COMPLETE MONTHS ARE REQUIRED FOR COMPUTATION AND DISPLAY OF STATISTICAL VALUES. EXTREME MAXIMUM AND MINIMUM VALUES DATA DERIVED FROM SUMMARY OF DAY DATA. PRESENTED ARE TH4E HIGPEST ILOwESTI TEMPERATURE FOR THE MONTH FOR EACH YEAR. ALSO PRESENTED ARE STATISTICAL VALUES WITH THE SAME LIMITATIONS MENTIONED ABOVE. AN ASTERIST INDICATES AN INCOMPLETE MONTH. MEANS AND STANDARD DEVIATIONS FOR DRY BULB IWET BULB AND DEW POINT$ TEMPERATURES DATA DERIVED FROM HOURLY OBSERVATIONS. DATA PRESENTED BY THlE STANDARD 3-H-OUR TIME GROUPS BT MONTH, MRONTI-LY AND ANNUALLY CALL TEARS COMBINID). PRESENTED ARE MEANS. STANDARD DtVIATION AND OBSERVATION COUNTS. CUMULATIVE PERCENTAGE FREQUENCY Of OCCURRENCE OF RELATIVE HUMIDITY DATA DERIVED FROM HOURLY OBSERVATIONS. SUMMARIZED BY THC STANDARD 3-HOUR TIPE GROUPS BY MONTH, 14ONTHLY AND ANNUALLY IALL YEARS COMBINfDI. PERCENTAGE VALUES PRESENTED IN 10 DEGREE INCREMENTS Of RELATIVE tiity11. ALSO PRESENTED ARE T14E MEAN VALUES AND OBSERVATION COU-0TS. L

267 -. BRANCH GLOBAL CLIMATOLOGY CUMULATIVE PERCENTAGE Of OCCURRENCE OF MAXIMUM TEMPERATURES USAFETAC FROM SUMMARY OF DAY DATA AIR WEATHER SERVICE/MAC STATION NUMBER:?27575 STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORD: $9-67 TE.P4FIJ JAN FEB MAR APR MAy JUN... JUL AUG SEP OCT No v DEC ANNUAL GE C GE GE S GE GE K E S GE ' * GE 6S.8 IS S GE GE SS S GE S 7.G GE Q? GE GE 33l ; GE 2S GE GE C GE G 5 S A *1 GE _01 76: : " GE -si ". GE S GE -15l GE G -251 Ia0,0 100.D 10.C.. MEAN I SD I SS Z9 II.6z TOTAL ors I I L.

268 GLOBAL CLI"AIOLOSI BRANCH CUMULAIIVE PERCENTAGE OF OCCURRENCE OF INIIU" IEMPERATURES USAFEcAC FROM SUMMARv OF DA DOTA AIR WEATHER SENVICEIMAC STATION NUIlqEM: 727S75 STION NAME: GND FORMS AF9 NO PERIOD Of RACTOs S9-87 I["P IJ JAR FEB N MR APO "AV JUN JUL AUG SEP OCT NOV DEC "a" VAL GE 7SJ.1 01 C G[ GE 6S. S ?.3 I0S 2.2 GE ? %.S o3 7.0 GE GE soi *S S3.0? IS. Z4.3 GE *51 4.S 42.6 $ "S GE S : V q0.1 GE 3S1.1 t# 09% 3% ? ,7.4 6E 331 " SO. GE SS.6 GE GE , S C GE SS GE S GE S s?.3 4S.? E S S.1 1S.S 6[ ' g1.s E , GE " GE -2SI GE :301 G-35J E 9S a a0 99S Icao0 V :0 99 a GE -qfj I.. W s S I S OTAL CBS o ii.

269 GLOBAL CLIMATOLOGY $RANCH CUMULAIIVE PERCENTAGE OF OCCURRENCE O' MEAN remperatures SAFETAC ERO" SUMMARY OF DAY DATA IN WEATHER SERvICE,.IMAC~ STA1IOk NUMBER: 727SIS. STATION NAME: GRAND FORKS AFI NO PERIOD OP RECORD: S9-6? TEMPIFl, JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL GE GE 8ol.S GE 7S GE S 10.6 GE S GE 63l S S GE S S Is.?.6 3S.3 GE Sol S GE S C BE ? GE * S9.? 8 E S.7 62.S 7.S 6S.6 G. zsi SO GE GE IS S GE S GE S G E S GE -SI S S C GE -10J S 9% GE -1S GE -Zol GE ICO GE MEAN i S SD S 12.66S $ TOTAL OS I J ema 0 ooeee e e oeeteeeeeeseeee L

270 GLOBAL CLIMATOLOGY BRANCH EXTREME VALUES OF MAXIMUM TEMPERATURE E USAFE7AC IFROM OAILY OBSERVATIONS) R- AIR WEATHER SERVICE/MAC STATION NUMBER: 727S7S STATION NAME: GRAND FORKS AFN NO PERIOD OF RECORD: WHOLE DEGREES FAHRENHEIT I -MN-O1NM*S- ALL YEAR I JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV CEC MONTHS ?a S 95 AS ? 1 as a as 8 S so AS al Ao S So As G S ? I3 59 7S SS SS ? s ICl s is S2 so 9". s IC S D * so ICS I SS & o S S PEAN I S % S6.9 9L S.D. I S.531 S S TOTAL OBS I Go NOTES * 4BASED ON LESS THAN FULL MONT S, 3 4AT LEAST ONE DAy LESS THAN L

271 " 611 GLOBAL CLIMAIOLOGY BRANCH EXTREME VALUES OF MININUM TEMPERATURE USAFETAC IFRON DAILY OBSERVATIONSI AIR WEATHER SERVICEINMAC STATION NUMBER: 72757S STATION NINE: GRAND FORKS AF9 NO PERIOD OF RECORD: V HOLE DEGREES FAHRENHEIT N- 7.1N.S - ALL YEAR g JAN reb MAR APR MAY JU1N JUL AUG SEP OCT NOV DEC "ONTI S $" ~~~~~~~. " "... "'... " " "." """ "... '" "5;: " "... i *51zS Is ts IT it T s 33 2T TI T TT is S T0 %I S S -23-3S T S T a T S I I S 32 T3 TI T S TO 414 T lt T2 II Z? TI T IS T1 %S T Is TI 2% %T S TO I TI T T Ti 1S ! $1, T?16 1I t a 27 3s $ T0 so I T1q T T S S T T S e Tf T8 NAtql I ITi TO.? S.D. I % TOTAL b alo $T A... NOTES * 8IASED ON LESS THAN FULL NONTHSI I IA T LEAST ONE DAY LESS THAN 24 OBS).t L

272 GLOBAL CLIMATOLOGY BRANCH DRT-BULB ITEPERATURES D(6 F FROM MEANS ANO STANDARD DEVIATIONS USAFETAC AIR WEATHER SERVICEIMAC HOURLY OBSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AF8 NO PERIOD Of RECORD: I I EA 6. I SO I ? 'OT OBSI I MEAN I S ST.% OSI so I S ".OOS *;; MN * S SO ITOT OSI S6, ~~...;...;; ;:..., ;; ;... 0 S % OT OBS g LD I n SO ITOT OBSI S6 MEAN I ;:;...; 1:;. 7, s S ?7.097 h1ot 08S MIAN I GI SD I TOT OS 930 S C I MEAN U So I S33.1OT OBSI S3 "'*"... ;' ; '"... :;' "'' :;"...; :... :... :... : ;... I MAN I ALL I SO I 5I.o7.SS S c LOURSITOT OBSI % I o 0 00o000o e~e 00eeo e

273 GLOBAL CLIMATOLOGV BRANCH USAFETAC wel-bulb ITEPERATURES DEG F FROM HOURLY OBSERVATIONS MEAMS AND STANDARD DEVIATIONS AIR beatoer SERVICE/MAC STATION NUMBER: 72?575 STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: "... ;;'i " ;... : go-021 SO I 19.S? S S TOT ORSI D 930 9o SI MEAN "3-051 SO ? S c0 ITO ? D SI MEAN I S _I6-08 SO TO OS !!... I MEAN I C SO I $ O110 OBSI I EN I SO I S ?110100s O I MEAN I * IS-171 SO I S.ss ITO? OPSI 93C I ME AN o~ej I 7.9 e e~e eeoee o SO zs S ? 110 cr S"LAN I SO I OS S ITOT OBSI U 9oU I "LAN I s ALL 1 S ?2 4IJOURSITOT ORSI 793g % De 0 eooo~eooeeeooeeee oee se e eeeeeeeeoeeoeoe eeee ee Lee

274 GLOBAL CLIMATOLOGY BRANCH DEw-POINT TEMPERATURES 016 F rrom MEANS AND STANDARD OEVIATIONS USAFETAC HOURLY OBSERVATIONS AIR WEATHER SERVXCE/PAC STATION NUMBER: ATION NAME: GRAND rorks AFS N0 PERIOD OF RECORD: IOURSI STATS I JAN FED MAR APR MAT JUN JUL AUG SEP OCT NOV DEC ANN LSY..... I MEAN S S So I G ITOT OBSI TI MEAN I o1 SD I 17.90C ITOT OSI S I MEAN S7.1 S G6_081 So I SS OT OBSi I MEAN I SS S, So I ,662 9,916 10, S1 92S CC I MEAN S S SO V $ OBSI I MLAN I S-171 so TO1 Dell I [a 4 J.3 80 S S0 I I0.SO T ?9 ITOT OPS D S1.... I MEAN I $ so I 17.59S S [TOT o8si S2... MEAN I : ; " ; iall I So I 17.S Ou0SIOT OS ? ]...L...

275 GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY OF OCCURRENCE RELATIVE HUMIDITY USAFETAC AIR WEATI-ER SERvICE/MAC FROM HOURLY OBSERVAT IONS STATION NUMBER: 72T75 STATION NAME: GRAND FORKS AF3 NO PERIOD OF RECORO 761 "" " 1 0O 114: JAN....ONTHI HOURS I PERCENTAGE FRECUENCY OF RELATIVE HUNIDITY GREATER THAN MEAN I TOTAL I *LsTI I IRELATIVCI NUP I I lo Sol D 901 IHUNIDITYI 03e I. JAN I GO-C? I loo OD D 71.9 S E C L Z" I loo t I I I I ITOTALS " ~e l i e g i ) 181e og o 1, elooogoo, 11 Ll

276 GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCV OF OCCURRENCE RELATIVE PUMIDITY USAFETAC FROM HOURLY OBSERVAT IONS AIR WtATIIER SERVICEINAC STATION NUMBER: 72?S7S STATION NAME: GRAND FORMS AFB NO PERIOD OF RECORD: MONTH: FEB NONIHI HOURS I PERCENTAGE FREQUENCY OF RELATIVE HUHIDITY GREATER THAN I MEAN I TOT#L I IILSYI... IRELATIVECI NUP Jos Sol 60% M 90% IHUMIDITYI OBs I FEB o f, C$-0S S S 84k C Is >1 C t I I 12-1.C Do >1 I I I ' s 1 O I I I IOO.c GO S :4 ITOTALS Ie,4 e ec, e ot 0 A I - e, eo, ~ L0 '

277 P GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY OF OCCURRENCE RELATIVE HUMIDITY LSAVEYAC F#OM HOURLY OBSERVATIONS AIR WEA11ER SERVICEIMAC STATION NUMBER: 727S75 STATION NAME: GRAND FORKS AF8 ND PERIOD OF RECORD: T8-A7." MONTH: MAR... MONH OLR IPERCENTAGE FREQUENCY OF RELATIVE HUMIDITY GREATER THAN I MEAN ITOTAL ILS "... "':: '... RELATIVE I N" % % 60% To 80% 902 IHUMIODITI OR$ I MAR C ? E 03-0S * L I %S.i 20.5 T8.0 93L I' ( 12-1 I 100.* ? 93C D 26.1 T C I c " L * ITOTALS s ( I' L

278 :1I 4LSIf GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCV Of OCCURRENCE RELATIVE 14UMITY US 'IFTAC AIR WEATHER SERVICEIHAC FROM HOURLT OBSERVATIONS STATION NUMBER: STATION NAME: GRAND FORKS AFB No PEQIOD Or RECORD: PONTH: APR MONTHI HOURS I PECNAEFEUNYO EAIEHMDT RAE HNI MEAN TOTAL I'" I... IRELATIVEI PJUV I I l 20: 362 4C: so t IHUMIOITYI OBS I APR I Oo.C S.3 4O S.1 90C 03-CS o.o $ T.O 90C 06*of IS.4 9at SS L S S3.1 90E oo.c b SO.3 90L I1O S L ITOTALS I ' S S 6S.1 719s... ] L,

279 GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY Of OCCURRENCE RELATIVE HUMIDITY USAFETAC FROM HOURLY OBSERVATIONS AIR NEAT ER SERVICEIMAC STATION NUMBER: 727S75 STATION NAKE GRAND FORKS AFI ND PERIOD OF RECORO: MONTH: "AY T.~...E MOT IPRETG OR REUENC orrlativ uiiygetrta I MEAN i TOTAL I (LST) IRELATIVE NUW I I I 10s ADS 5s 60T?oS got 90% HUNHDITVI 065 I... I I MAT S L S I ? C I I I ( I I S1.8 92% I I 12-1 I0O.C %S S C IS-1T S C I S c S S6.9 93( ITOTALS... I h.7 $ J L.

280 GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY OF OCCURRENCE RELATIVE IUMIDIT. USAFETAC FROM HOURLY OBSERVATIONS AIR WEATHER SERVICE/MAC STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: MONTH: jun MONHI HOURS I PERCENTAGE FREGUENCY Or RELATIVE HUMIDITY GREATER THAN I MEAN I TOTAL I ILST)... RELATIVEi NU1 I 0t '0% % IHUMIOITTI o8 I JUN C B' ' L C L I ' " I c S0.8 90! ' '7.5 90[ ' ! c ' ' t. IJOTALS I 2oc ' SS.6 30.' E. L-

281 GLOBAL CLIMATOLOGY BRANCH CUMULAhIVE PERCENIAGE FPEOUENCV OF OCCURRENCE RELATIVE HUMDITY USAFETAC FROM HOURLV OBSERVATIONS AIR WEAT0ER SERVICE/MAC lstion NUMBER STATION NAME: GRAND rorrs ArS NO PERIO OF RECORD: 78-8i MONTH: JUL......; o... o;;... o... :e HOVRS OONT L PERCENTAGE FREUENC V OF RELATIVE HUMIDITY GREATER INAN MEAN I TOTAL ILSI) I... IRELATIVEI NUP I J lowif] so 20X 3&s% '0' Sol 6s 70 gout 90: : IHu:I:TVI : o o JUL C0-02 I 100.c OOo S ' E C3"0S OOoo O.0 97eS 46.1 S7,3 IS L I I ' E "" ' ' ' C loo.c 99:9 94o S:eS 26:5 12.S E IS O E I I100.0 lo0o '.? Is.' 6.o I IO0C $ ITOTALS "F.7 2S I.

282 I GLOBAL CLIMAIOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY OF OCCURRENCE RELATIVE PUMIDITY USAFETAC FROM HOURLY OBSERVAT IONS AIR ldeatier SERVICE/MAC STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: PONTHI: AV'G '... i ;'... ; ' ;.... " MONTHI HOURS I PERCENTAGE FREQUENCY OF RELATIVE HUMIDITY GREATER THAN MEAN I TOTAL I LST) i irelativei NUP I AUG I S I 03-C L loo. loo O lo0o 99.S S E I s IOO* C S I I S ( I IO0.C C I Io0.c 10.O ( ITOIALS S J

283 GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FROUENCY OF OCCURRENCE RELATIVE HUMIDITY I EIS&IAC FRO" HOURLY OBSERVA71ONS AIR rat.fer SERVICE/MAC STATION NUMBER: STATION NAME: GRANO FORKS AFB No PERIOD OF RECORO: MONTHN: SE P NONTIKI FO'RS I PERCENTAGE FRECUENC Ofr RELATIVE HUMIDITY GREATER THAN I MEAN I TOTAL I I 7 LST)... RELATIVEI NUP I S : IHUMIDITTI 0s SEP C GC I ? ' E * S.S O.C S I I S2.1 90C I c " E ITOTALS C U.

284 GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY OF OCCURRENCE RELATIVE PUM1OITY USAFETAC FRO" HOURLY OBSERVATIONS AIR WEATHER SERVICE/MAC STATION NUMBER: 727SS STATION NAME: GRAND FORKS AFB NJ PERIOD OF RECORD: PONTH: OCT IS.. o... o... o... REL VE NU I I Jo 202 3U2 40% T IHUMIOITY1 CBS 1 I I OCT C C I I E I I S * L I o S L I 12-1I 10O.C S E I15-17 I OO.C E I S." E %O.C S 81.5 S9.S S?2.9 93E ITOTALS I E e e Q e e I TL

285 .4k GLOBAL CLIMAIOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY OF OCCURRENCE RELATIVE HUMIDITY LSAFETAC FROM HOURLY OBSERVATIONS AIR WEA7-ER SERVICEMAC STATION NUMBER: 72?71 STATION NAME: GRAND FORKS AFI No PERIOD OF RECORD: 7?-86 I MONTH: NOV ;II11 I...IRELA71VE. NP lot % 402 5O% ol 902 IHUMIOITYI 081 NOV ID00C IO E 03-0S ( I ( C I I c E, ol S j I18-z0 100.C C C,TOTALS 1000c (. *1 IL

286 .I GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY OF OCCURRENCE RELATIVE vumioiy USAFETAC FROM HOURLY OBSERVATIONS AIR NEATHER SERVICE/MAC STATION NUMBER: STATION NAME: GRAND FORKS AFS NO PERIOD OF RECORD: MONTH: DEC -4MOTHHUR IPRCNTGEFE~ENYOF RELATV HMDYGRAETANBMAN TOTAL IILSTI I... IRELATIVE I Nup I I i Y 20 3UX sox 90% IHUMIOITYI 0BS I DEC E 03-C L I ( * I.IS-17 Iloo.C S D 929 ' I o.c $ 71.9 So.% L I I IOO.c S ITOTALS SO I L"

287 GLOBAL CLIMATOLOGY BRANCH CUMULATIVE PERCENTAGE FREQUENCY Of OCCURRENCE RELAIlVE HUMIDITY LSAFETAC FROM HOURLY OBSERVATIONS AIR WEAIVER SERVICEIMAC STATION NUMBER: 727S7S SIATION NAME: GRAND FORKS AF6 No PERIOD OF RECORDS 77-ST MONTH: ALL... MONTICI I -O.aS PERCENTAGE FREQUENCY OF RELAIIVE HUMIDITY GREATER I ILSTI I... THAN I MEAN I TOT#LI IRELATIVEI 14UV I I lot 202 3U2 40 so% t INUMIOITMI JAN ALL I100.C E FEB MAR S S.2 794% APR S NA I S JUN , C JUL I " S.3 S AUG %C SEP C.0 79.S 6S C OCT c NOV 100C s C DEC S O t ITOTOLS I 100.0C L. 4o e o

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289 PRESSURE SUMNARIES V STATION POSSURE SUNARIES DATA DERIVED FRO" HOUIILY OBSERVATIONS. SUMMARIZED BY THE STANDARD S-HOUR TIME GROUPS BY MONTN, NON PLV AND ANNUALLY IALL YEARS CONOINEO). * SA. PRESENTED ARE THE PEAKS, STANDARD DEVIATIONS AND OBSERVAT ION COLUENTS.NINDI SEA LEVEL PRESSURE SUMMAIES DATA DERIVED FRNOM HOURILY OBISERVATIONS.* SU MA RZ ED BY THE S AN AR D $*hour TI ME GROUPS BY ONTH, ON HLY ANo ANNUALLY ALL TARS ON IN O P,, *1j PRESENTED Aft THE NEANS9 STANDARlD DEVIATIONS AN n OBSErRVATION COUNTS. J ~ *-:-

290 GLOBAL CLIMATOLOGY BRANCH STATION PRESSURE IN INChES 4G FROM MEANS AND STANDARD DEVIATIONS t SAFETAC HOURLY OBSERVATIONS AIR WEATNER SERVICE/MAC STATION NUMBER: STATION NAIE.: GRIND FORKS AF9 NO PERIOD OF RECORO: FEB MAR APR MAY JUN JUL AUG SEP OCT NOV ENN LST I... I MEAN S Z I SD TOT SD t % ITOT OBSI I MEAN I S S C SO I T Os MEAN , C so I U OT os MELAN I S I SD I * ITOT OBSI I MEAN s o I S I I OsSI I MEAN I S I SO., hiot OSI I SO I IOl o0ss S1... I MEAN ? S ALL I SO I OURSITOT OBSI q S... t ete e e o e o o e o o o e e l o e e t o 0 eo e o. l t l oi le t oo l o l o o. l oe I l J Lo

291 GLOBAL CLIMATOLOGY BRANCH SEA LEVEL PRESSURE IN MBS FROM MEANS AND STANDARD DEVIATIONS USAFETAC HOURLY OBSERVATIONS AIR WEATFER SERVICE/MAC STATION NUMBER: STATION NAME: GRAND FORKS AFB NO PERIOD OF RECORD: SORISTATS I JAN FEB MA AP A U U UG SEP OCT NOV EEC AN&.... LSI I. I MEAN S S 00 1 So B.868 ITOT OBS I MEAN SO B, B h OT OBSI I MEAN I SO S IOT OBSI ii MEAN I BS I I So S "TO OBSI 310 2B Ito 31D '1 [ MEAN I SO iot OBSI ";... ;;T';; 300 ; ;:;;:;";;;:"; ;:; 299 ;;10" 310 ;;:"; 300 ;: :... I NAR Do;; i 1s I So I S, S ITOT OBSI o I MEAN IS S OT O8SI I MEAN Z O 1 D S.371 7,9SI S S D 6.,Ii I MEAN ,5 ALL SD q I-OURS TOT OBSI L... 4(

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293