Global Weather Hazards Summary: July 20 - 26, 2018
Torrential rains trigger flooding in Nigeria
Africa Weather Hazards
- During mid-July, torrential rains in Nigeria triggered floods, damages to infrastructure and fatalities in the Ogun and Katsina states. Heavy rainfall is forecast to continue over northern Nigeria during the next seven days.
Heavy rainfall continues over the Sahel region
During the last week, seasonable rainfall was recorded throughout West Africa. The highest weekly accumulations (>50 mm) were recorded across parts of Chad, Nigeria, southern Mali, and Ghana (Figure 1). Locally heavy rainfall in parts of Nigeria has resulted in flooding over the Ogun and Katsina states of the country. Towards the west, little rainfall was registered for the second consecutive week over Senegal.
As of mid-July, the overall performance of the West Africa has been favorable. Areas that had experienced anomalous dryness since April and May have since generally recovered, and the latest dryness trends appear to be quite localized. Since mid-June, local portions of western Senegal, eastern Burkina Faso and central Nigeria remain below-average between 50-80% of their normal rainfall totals (Figure 2). While the moisture anomalies in Burkina Faso and Nigeria have remained stable over the past several weeks, the moisture deficits in western Senegal appear to have been slightly strengthening since early July.
Next week, moderate to locally heavy rainfall is expected across the western Gulf of Guinea region, with the potential for average rainfall over Senegal. Further east, moderate to locally heavy rainfall is also forecast over parts of northern Nigeria and southern Niger.
Dryness develops in Ethiopia
Another week of heavy rainfall over eastern Sudan helped to sustain high seasonal moisture surpluses across eastern and western Sudan, and in parts of northwestern Ethiopia. The continuation of moderate to locally heavy rainfall over saturated areas may trigger floods and other adverse ground impacts across the region during the next week.
However, southern Ethiopia has experienced much less rainfall. Since mid-June, many areas have received less than half of their normal rainfall accumulation (Figure 2). As the Kiremt rains typically migrate northward during July and into August, the opportunity for adequate recovery may not occur until later in the season.
Average to above-average rainfall is expected next week in western Ethiopia, with the possibility of locally moderate to heavy rainfall amounts (>75mm) in some areas.