Weekly Africa Weather Hazards Assessment Explanation

September 12-18, 2002

1) Rainfall was lighter from September 2-9 than the previous week over
Senegal, southern Mauritania, and west-northwestern Mali, as westward
moving thunderstorm clusters continued to decrease in intensity as they
moved over the area.  Although parts of western Mali recorded rainfall
amounts in excess of 50 mm for the week, central and southern Senegal
received generally less than 30 mm.  These fairly consistant rains have
helped to restore the moisture that was depleted during the extremely
dry weeks in July and August which normally accumulate much greater
rainfall amounts.  The recent rains, however, arrived too late to prevent
substantial agricultural and hydrological problems throughout the area.
Rains are expected to weaken during the next few weeks as the ITCZ
continues to fall back to the south.

2) An intense low pressure system near the northern coast of Morocco is
expected to form during the first half of the period and drift slowly to
the east over the remainder of the week.  This storm system has the 
potential to bring very heavy rainfall to coastal and somewhat inland
areas of northern Morocco and northern Algeria as it nears the area.
Models currently forecast the system to intensify before it begins to 
interact with the Africa coast near the 15th of the month, but timing and
location of the low pressure center will greatly affect the area receiving
potentially flood procuding rainfall.

3) Areas of northern and central Ethiopia received moderate rainfall
during past week, with totals generally 20-50 mm throughout the area.
To date, seasonal rains near and south of the Afar region have been normal,
and this has helped to avert a hydrological crisis in most of the region.
Dryness continues to exist locally throughout the area, but overall
conditions have improved from the past two years.  Rainfall forecast 
models are showing weakened rainfall for the next week, and this pattern
should continue through September.

4) Short term dryness that has emerged in parts of southwestern Ethiopia
and extreme southeastern Sudan continues through the current Hazard
period.  Widespread rainfall, though less than 10 mm, did fall over most
of the dry area during the past week, and light rain is expected locally
during the next week.

5) Widespread rains, from 2-30 mm, fell throughout drought affected areas
in southwestern Mozambique, southern Zimbabwe, eastern Botswana, and
northeastern South Africa during the past 7 days.  This has undoubtedly
helped to increase surface wetness in the region, but much additional
rainfall is needed to offset dryness that occurred during the 2001-2002
monsoonal season.  Little precipitation is expected during the next week.

6) Heavy rains up to 200 mm may fall over saturated soils of eastern
Nigeria and northern Cameroon during September 12-18 and could bring
local flooding to the area.  Areas of concern are mainly downstream,
flatland basins where accumulated rainfall may spread out from a flooding
water channel.