Weekly Introduction:
Update Of ITCZ

During the period from August 21-31 2004, the African portion of the ITCZ moved dramatically to the south in the eastern half of the continent. During the past dekad, the eastern region of the ITCZ moved from around 19N to around 15N. This contrasts with the movement in the west where the ITCZ moved relatively little from last period and is located very close to the 1988-2003 climatological mean. The southward movement of the ITCZ at this time is quite normal as the normal northward peak occurs during the second dekad of August.

The report from the Food and Agriculture Organization (FAO) of the United Nations on the locust situation in western Africa was last updated on September 3 (http://www.fao.org/NEWS/GLOBAL/locusts/Locuhome.htm). They report that the situation continues to deteriorate in West Africa where summer breeding is in progress over a large area of southern Mauritania, northern and central Senegal, in the Sahelian part and in the north of Mali, in western Niger, in northern Burkina Faso and probably in Chad. Several mature swarms were also seen in Dakar. Numerous hopper bands are forming and maturing rapidly in these countries. Laying and hatching are likely to continue in a few places. A massive amount of fledging has started in southeastern Mauritania and new swarms are beginning to form. This will also occur in the other countries in the coming weeks. Consequently, a substantial number of swarms are expected to form in September. There was one unconfirmed swarm report in Darfur, Sudan. Significant crop damage has occurred in several countries.

Additional details can be found at the USAID web site for Assistance for Emergency Locust/Grasshopper Abatement (AELGA) at http://www.aelga.net.

Weather Hazards Assessment Graphic:

1. Poor performance of seasonal rains over the past several years has resulted in a long term, multi-year drought across the Sanaag, Sool, Togdheer, Bari and Nugal Provinces of northern Somalia. The 2004 season, however, saw an overall good performance of the rains. Despite these rains, large long term moisture deficits and severe drought remain. The next chance for significant rainfall will come in October.

2. The long rains this year were much below normal across eastern Kenya, the Somali region of Ethiopia and across the Galguduud and Mudug regions of Somalia. The season started late and ended early, as little rain fell during March or May. Totals were less than half of normal for the season, with deficits of 100 to 150 mm. Some areas in the higher elevations have deficits of 250+ mm. In some areas, this was in addition to below normal rainfall during 2003. The next chance for significant rain will be with the onset of the short rains in October.

3. Multi-year drought has resulted in large long term moisture deficits across southeastern Kenya. Poor performance of the March-May rains has exacerbated long term drought conditions across the area. The long term drought will reduce water supplies and reservoir levels, degrade pastures and may result in reduced sub-soil moisture availability for the upcoming second cropping season.

4. The 2004 Belg season (February-May) was drier than normal across the South Tigray zone as well as North Wello and South Wello zones in the Ahmara region. Rainfall was about half of normal for the season. The season also started late and ended early, with most of the season's rainfall occurring during the month of April. The typical length of the Belg rains is about 10 weeks. The 2004 Belg season lasted only 4 to 5 weeks. Furthermore, rains during the Meher season have been erratic.

5. Rainfall during the past several months has been erratic and lighter than normal across extreme southeastern Sudan, portions of southwestern Ethiopia and adjacent areas in Kenya and Uganda. This has resulted in rainfall deficits of 50 to 100 mm and may have resulted in crop stress.

6. Rainfall during the 2003-04 rainy season was about 70 percent of normal across west-central portions of Tanzania. Satellite imagery show indications of pasture degradation in the agro-pastoral areas. Locally heavy pre-season rains on September 3rd and 4th may have helped to boost moisture in the area and improve vegetation and pasture conditions.

7. Rainfall has been lighter than normal and somewhat erratic during the so far this season across a large portion of central Sudan, including Darfur and Kurdufan. Dryness has also been observed over parts of central Chad and extreme southeastern Niger, This dryness has reduced moisture for local crops, pastures and water supplies. Showers are possible across central Sudan and east-central Chad, however mostly dry conditions are expected over west-central Chad.

8. Rainfall has been lighter than normal across portions of Tahoua in southwestern Niger, with seasonal precipitation totals so far around 60% of normal. Fair to poor pasture conditions have also been reported over northern portions of nearby Maradi. Recent rains have resulted in improvement across the area, with additional showers possible during the period.

9. Seasonal rains have so far been lighter than normal across Western Cape, South Africa. This may result in yield reductions for the winter wheat crop, which is typically in the heading stage during this time of year. The drier than normal conditions will also reduced moisture for irrigation supplies. Conditions are expected to be warm and dry during the period.

AUTHOR: Chester V Schmitt