Africa: Drought and Floods Hazards Assessment: 09 Apr 2003
CCA Guidance for the Greater Horn of Africa Rainfall in June-July-August 2003 at One Month Lead
The Greater Horn of Africa (GHA) is defined here as the region between 10 S and 10 N; 25-50 E. The prediction for June-July-August rainfall atone month lead (GHAJJA.gif) is weak and calls for climatology across much of GHA. Slightly higher than climatological probabilities for below normal rainfall are predicted for parts of southern Ethiopia, eastern Kenya, southern Somalia, east central and northwestern Tanzania, Rwanda, and Burundi. Slightly higher than climatological probabilities for above normal rainfall are predicted for southern Sudan. For the Afar region, which we have continued to carry as a drought area, the International Research Institute's (IRI) long-term forecast calls for climatological probability for rainfall for JJA. The declining El Nino event does not have substantial influence on this June-August 2003 GHA rainfall forecast.
The first week of April featured a change to much drier weather across the African Horn, as total rainfall was generally negligible from Ethiopia southward through Kenya and into north-central Tanzania. Dry weather also covered most of Uganda, and rainfall remained light across Rwanda and parts of Burundi. The first season, belg rains have been erratic this year in Ethiopia, so dry spells now, in the midst of this growing season, could pose problems. To the south, in Kenya, as well as in northern Tanzania, the main season rains were slow to start, so dry weather now is especially untimely. Scattered heavy rains, with amounts exceeding 75 mm in places, continued to relieve dryness in western and eastern Tanzania. Heavy rains exceeding 100 mm covered northern Madagascar. Heavy rains again hit northern Tunisia and northeastern Algeria, as amounts reached 75 to 100 mm for the week.
WEEKLY AFRICAN WEATHER HAZARDS ASSESSMENT STATEMENT APRIL 10 - 16, 2003 DISCUSSION:
1) Long-term dryness from the last 2 years continues across southern Mauritania resulting in poor pasture conditions and low water levels.Reports indicate that similar conditions exist in northern Senegal. Farmers are struggling as cattle are being moved southward towards The Gambia. The seasonal rains should start around the first of July and last through October. Current climate forecasts indicate that the region should receive near-normal rainfall during the upcoming wet season.
2) Dryness throughout recent years has resulted in poor pasture conditions and low water supplies across north-central Ethiopia, and adjacent portions of Eritrea and Djibouti. The widespread seasonal rainfall that began last month has diminished to more isolated rain events over the past week. However, the drought hazard has been optimistically scaled back in the east and south because of the earlier rains. From a long-term climalogical perspective, below normal conditions continue in portions of southern Eritrea, Djibouti, eastern and central Ethiopia, Somalia, and northern Kenya.
3) Below normal rainfall totals in Guinea have resulted in low reservoir levels, which aid in the generation of hydro-electric power.Several rain events were reported along the southern border and more improvement is expected during the middle to end of this month.
4) Numerical predictions from last week verified as northern Tanzania and most of Kenya received very little rainfall during the period.However, some isolated regions did receive heavier amounts. All forecasts indicate that below normal rains will continue for the highlighted area this week. The hazard area has been expanded further northward into Kenya and to other surrounding areas that include Burundi and Rwanda.
5) Poor seasonal rains throughout portions of Botswana, South Africa, Mozambique, and Zimbabwe have resulted in lower than normal crop yields for much of the highlighted region. Rain-free days over the next month should actually help farmers as they begin to harvest the surviving crops. The supplemental area highlighted by the orange cross-hairs should be monitored for hydrological deficits that will affect drinking water and irrigation in the upcoming secondary growing season.
Author: Kevin B Laws