WEEKLY AFRICAN WEATHER HAZARDS ASSESSMENT
                                
   AUGUST 14, 2002 DISCUSSION:  

1)   Recent northward advancement of the ITCZ has allowed easterly waves to finally move
across Senegal. This has resulted in 10 to 75 mm of beneficial rainfall across parched portions of
Senegal, Mauritania and Gambia. In addition to welcome rains, cooler temperatures across the
area brought relief from the scorching heat. However, the recent rains were not enough to relieve
the large moisture deficits accumulated during July and the first week of August due to a lack of
rainfall and unseasonably hot temperatures. The trend of wetter, cooler weather is expected to
continue across Gambia, Senegal and adjacent parts of Mauritania throughout the period. As a
result, further improvement is expected. 

2)   Heavy seasonal rains have resulted in saturated soils and swollen rivers across portions of
western Eritrea and northern Ethiopia. An additional 75 to 150 mm of rainfall is expected during
the period. As a result, flooding is possible in some areas. 

3)   Dryness in recent years has resulted in poor pasture conditions and low water supplies across
the Afar region of Ethiopia. Recent rainfall across the region has eased long term dryness across
the area. Additional rains are needed to replenish water supplies and to revive pastures damaged
by long term moisture deficits. Although recent rains have resulted in improvement, a premature
end of the main (Karma) rains across this region may result in rapid deterioration. The main rains
typically last into September. Rainfall is expected to continue throughout the week. Therefore,
continued improvement is expected.  

4)   A drought during the last half of the 2001-02 rainy season has resulted in large moisture          
deficits across much of the Limpopo River Basin in southeastern Africa. This has reduced water
availability to reservoirs, wells and rivers across the area. A storm system is expected to bring
rain to portions of southern Botswana and north-central South Africa, south of the hazard area.
Runoff from this storm system may increase river flows across parts of the upper Limpopo Basin. 
Major improvement, however,  is not expected until at least November, when the rainy season
usually begins. 
 
5)   A storm system originating over the South Atlantic is expected to interact with moisture from
the Indian Ocean. This will result in unseasonably heavy rains across much of central and eastern
South Africa, southern portions of Botswana and all of Lesotho. 50 to locally 150 mm of
precipitation is expected to fall between Aug 16th and Aug 18th. This could result in flooding
problems across the hazard area, which includes Botswana's capital of Gaborone, Lesotho's
capital of Maseru, the South African cities of Bloemfontein, Kimberly, Bethlehem and Port
Elizabeth. The heaviest rains should remain south and west of the Johannesburg/Pretoria area.
The precipitation should fall mostly in the form of rain. However, the precipitation could end as a
period of moderate-to-heavy wet snow or sleet across the higher elevations of Lesotho,
KwaZulu-Natal and Eastern Cape. 

Author: Chester V. Schmitt