CLIMATE DIAGNOSTIC BULLETIN FOR AFRICA N 02 FEBRUARY, 2019 OCEAN-ATMOSPHERE MONITORING & PREDICTION 1
SUMMARY FEBRUARY 2019 The precipitation for the month of February, 2019 was above to well above average over northern Libya, southern Ghana, Togo, Benin, south-western Nigeria, south-easternmost of Cameroon, northern Congo, northern and central DRC, southern Tanzania, northernmost and southernmost of Mozambique, northern Malawi, eastern Zambia, north-western Angola, south-eastern Botswana and central South Africa. Below to well below average precipitation was observed over northern Morocco, north-westernmost of Algeria, southern Gabon, south-western Congo, south-westernmost of DRC, central Ethiopia, western Kenya, central Mozambique, northern Zimbabwe, southern Zambia, Angola, much of Namibia and The precipitation in percentage of average for December 2018-Janaury-February 2019 season was above to well above average over north-eastern Libya, northern Egypt, south-eastern Ghana, southern Togo, Benin Nigeria, south-eastern Cameroon and CAR, southern South Sudan, much of Congo, DRC, Uganda, Rwanda, Burundi, Tanzania and Malawi, eastern Zambia, northern and southern Mozambique and northern Below to well below average precipitation was observed over northern Morocco, Algeria and Tunisia, western Gabon, eastern Ethiopia, western Somalia, south-eastern Zambia, southern Angola, much of Namibia, Botswana northern Zimbabwe and eastern South Africa. Positive temperature anomalies greater than or equal to 2 C were observed in February 2019 over Côte d Ivoire, Ghana, Togo, Benin, Nigeria, much of Namibia, Botswana southern Zimbabwe, northern and western South Africa and central Seasonal temperature anomalies greater than or equal to 2 C were observed in December 2018- Janaury-February 2019 over Senegal, Guinea, Sudan, Somalia, Namibia, southern Botswana and Zimbabwe, northern South Africa and western During March to June 2019, below average precipitation is very likely over north Morocco, extreme north-western Algeria, much of Guinea, Sierra Leone, Liberia, Gabon, south-easternmost of DRC, eastern Zambia, northernmost of Malawi, central and southern Tanzania, south-eastern Kenya and southwesternmost of Somalia. Near to below average precipitation from March to May 2019 is expected over south-western Angola and north-western Namibia and central Over southernmost Côte d Ivoire, Benin, south-western and Nigeria, south-western and south-eastern Cameroon, much of Lesotho and south-eastern South Africa, normal to above average precipitation is very likely during March to May 2019. From March to May 2019 above average precipitation is very likely over most parts of Congo, northern and south-western DRC, southern CAR, South Sudan, northern and western Uganda, and south-western South Sudan. Near to above average temperature is very likely over most parts of Northern Africa region, northern and central parts of Sahel region and much of Southern Africa region during March to May 2019. From March to May 2019, above average temperature is very likely over southern Algeria, Libya, southwestern Egypt, south-western Angola, eastern Namibia, south-western Botswana and northeasternmost South Africa. 2
1. SYNOPTIC SITUATION FOR FEBRUARY 2019 This section shows the intensity of pressure centres, the circulation and its anomalies at 850 hpa, the wind direction and speed in the middle and higher levels, relative humidity at 850hPa and 700 hpa, Sea Surface Temperature (SST) and the El Nino/Southern Oscillation (ENSO). 1.1 Pressure Centres: Figure 1 below shows the locations and status of the surface pressure systems: The Azores high of 1022hPa was weakened by 5hPa compared to the previous month, and strengthened by 9hPa the climatological mean (1981-2010). The centre was located at 49 N, 28 W, which is south-west of its climatological position over northern Atlantic Ocean. St. Helena high of 1019hPa was weakened by 1hPa compared to the previous month and it was stable in relation to the climatological means (1981-2010). The centre was located at 31 S, 1 E, it stable of its climatological position over South Atlantic Ocean. Mascarene high of 1021hPa weakened by 2hPa compared to the previous month and strengthened by 4hPa with respect to the climatological mean (1981-2010). The centre was located at 35 S, 98 E, which is south-east of climatological position over South Indian Ocean. The Thermal Low of 1007hPa deepened by 1hPa compared to the previous month and by 2hPa with respect to the climatological means (1981-2010). The centre was located at 7 N, 30 E, it was stable with climatological position over central South Sudan. Figure 1. Observed Mean Sea Level Pressure (Contour) and anomaly (shaded) for February, 2019(Source NOAA/NCEP). 1.2 Wind Anomalies (m/s) at 850hPa Figure 2 shows wind anomalies at 850 hpa. North-easterly to easterly wind anomalies with speed greater or equal to ( 6m/s) were observed over Morocco, Algeria, Tunisia, Libya, Egypt, the same wind anomalies from western sector was observed over Mauritania, Senegal, Gambia, Guinea Bissau, Guinea, Mali, Burkina Faso, Ghana, Togo, Benin, Nigeria, Niger, Chad, Sudan, However over Uganda, northernmost Tanzania, western Angola the easterlies wind were observed, while the western Angola the easterly anomalies wind with speed greater or equal to ( 4m/s)was observed. Figure 2: Wind anomalies (m/s) at 850 hpa for February 2019 (Source: NOAA/NCEP) 3
1.3 Relative Humidity (RH) at 850 hpa High RH 60% at 850 hpa (Figure 4a), was observed during the month of February 2019 over eastern Tunisia, northern Libya, south-westernmost of the Western Africa, southern part of Central Africa and Eastern Africa countries, northern and eastern of Southern Africa region, much of Madagascar, Comoros, Mauritius and Reunion Island. Negative anomaly RH values were less than the mean (2002-2011) over Morocco, northern Algeria, Tunisia, south-eastern of Western Africa region, eastern of Sudan, southern South Sudan, much of Uganda, Tanzania, southern Kenya, eastern part of Somalia, and most part of Southern Africa region. (Figure 4b). Figure 3. Relative humidity (%) at 850hPa (contour) and anomaly (shaded) for February 2019.(SOURCE: NOAA/NCEP) 1.4 Relative Humidity at 700 hpa High RH values 60% (Figure 5a), were observed over southern Central Africa, south-western and central of Eastern Africa and northern and central Southern Africa region. Elsewhere over the continent, the RH values where less than 50%. The regions with RH 60% were favorable for deep convection that generated heavy precipitation with high impacts. The RH values were positive with respect to the mean (2002-2011) over Libya, Egypt, the Sahel region, central part of Central Africa, much of Ethiopia, Somalia, western and southern Angola and the eastern part of South Africa. The rest of the Continent where dominated by negative anomalies (Figure 5b). Figure 4. Relative humidity (%) at 700hPa (contour) and anomaly (shaded) for February, 2019(SOURCE: NOAA/NCEP) 1.5 Sea Surface Temperature (SST) and El Nino/Southern Oscillation (ENSO) 4
Near to above average SSTs were observed over most part of the equatorial Pacific. Neutral to warm conditions were noted over North Atlantic, in Equatorial Guinea Gulf and South Atlantic Ocean, over Mediterranean Sea, neutral to warm SSTs were observed, over Indian Ocean, warm conditions over northern and southern part of this Ocean. Figure 5: Sea surface temperature for February 2019 (source: IRI) 2. CLIMATOLOGICAL SITUATION AND IMPACTS DURING FEBRUARY 2019 This section provides the general climatological situation and its impact, covering two major parameters; temperature and precipitation. 2.1 Precipitation 2.1.1 Monthly Precipitation The precipitation for the month of February, 2019 was above to well above average over northern Libya, southern Ghana, Togo, Benin, south-western Nigeria, south-easternmost of Cameroon, northern Congo, northern and central DRC, southern Tanzania, northernmost and southernmost of Mozambique, northern Malawi, eastern Zambia, north-western Angola, south-eastern Botswana and central South Africa. Below to well below average precipitation was observed over northern Morocco, north-westernmost of Algeria, southern Gabon, south-western Congo, south-westernmost of DRC, central Ethiopia, western Kenya, central Mozambique, northern Zimbabwe, southern Zambia, Angola, much of Namibia and 2.1.2 Seasonal Precipitation The precipitation in percentage of average for December 2018-Janaury-February 2019 season was above to well above average over north-eastern Libya, northern Egypt, south-eastern Ghana, southern Togo, Benin Nigeria, south-eastern Cameroon and CAR, southern South Sudan, much of Congo, DRC, Uganda, Rwanda, Burundi, Tanzania and Malawi, eastern Zambia, northern and southern Mozambique and northern Below to well below average precipitation was observed over northern Morocco, Algeria and Tunisia, western Gabon, eastern Ethiopia, western Somalia, south-eastern Zambia, southern Angola, much of Namibia, Botswana northern Zimbabwe and eastern South Africa. Figure 6a: Monthly precipitation in percent of average for february, 2019 (Source : NOAA/NCEP) Figure 6b: Precipitation in percent of average for December, 2018- January-February 2019 (Source : NOAA/NCEP) 5
2.2 Surface Temperature 2.2.1 Monthly Temperature Anomalies Positive temperature anomalies greater than or equal to 2 C were observed in February 2019 over Côte d Ivoire, Ghana, Togo, Benin, Nigeria, much of Namibia, Botswana southern Zimbabwe, northern and western South Africa and central Figure 7 : Temperature anomaly for february 2019 (Source : NOAA/NCEP) 2.2.2 Seasonal Temperature Anomalies Seasonal temperature anomalies greater than or equal to 2 C were observed in December 2018- Janaury-February 2019 over Senegal, Guinea, Sudan, Somalia, Namibia, southern Botswana and Zimbabwe, northern South Africa and western. 3. OUTLOOK This section provides the predicted Sea Surface Temperature (SST) anomalies, exhibiting the future characteristics of ENSO and the precipitation outlook for the coming months. 3.1 El Niño/La Niña Figure 10 shows the forecasts by dynamical and statistical models over Niño 3.4 (5 N 5 S, 120 W 170 W). In February 2019, most of the dynamical and statistical models predicted near to above average SSTs during March to May 2019. Figure 8 : Seasonal temperature anomaly for December, 2018-January-February 2019(Source : NOAA/NCEP) Figure 9 : Ensemble multi model forecast February, 2019 (Source : IRI) 6
3.2 Seasonal Precipitation forecast for March-April-May 2019 The precipitation forecast for March- April-May 2019 season (Figure 10), issued on February 28 2019 reveals that: During March to May 2019, below average precipitation is very likely over north Morocco, extreme north-western Algeria, much of Guinea, Sierra Leone, Liberia, Gabon, south-easternmost of DRC, eastern Zambia, northernmost of Malawi, central and southern Tanzania, south-eastern Kenya and southwesternmost of Somalia. Near to below average precipitation from March to May 2019 is expected over south-western Angola and northwestern Namibia and central Figure 10 : Seasonal precipitation forecast for March-April-May 2019 Over southernmost Côte d Ivoire, Benin, south-western and Nigeria, southwestern and south-eastern Cameroon, much of Lesotho and south-eastern South Africa, normal to above average precipitation is very likely during March to May 2019. From March to May 2019 above average precipitation is very likely over most parts of Congo, northern and southwestern DRC, southern CAR, South Sudan, northern and western Uganda, and south-western South Sudan 3.3 Seasonal temperature forecast for March-April-May 2019 The temperature forecast for March-April- May 2019 season (Figure 11), issued on January 28 2019 shows that: Near to above average temperature is very likely over most parts of Northern Africa region, northern and central parts of Sahel region and much of Southern Africa region during March to May 2019. From March to May 2019, above average temperature is very likely over southern Algeria, Libya, south-western Egypt, southwestern Angola, eastern Namibia, southwestern Botswana and north-easternmost South Africa. Figure 11: Temperature forecast March-April-May 2019 7