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Global Weather Hazards Summary: April 12 - 18, 2019

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Drought conditions remain in southern Africa as abnormal dryness strengthens across the Greater Horn

Africa Weather Hazards

  1. Seasonal rainfall deficits since October have resulted in significant dryness across Angola, Namibia, Zambia, and Zimbabwe

  2. Below-average rainfall since mid-February combined with high temperatures, have strengthened moisture deficits in Ethiopia, Uganda, Kenya, and Tanzania.

Africa Overview

Rainfall continues in Ethiopia as dryness persists further south Last week, decreased seasonal precipitation over Kenya was observed following more favorable rainfall in late March. The highest weekly rainfall accumulations (50- 100 mm) were received over eastern Tanzania and Ethiopia in higher elevations and the Afar region, with fewer amounts (<25 mm) registered across the Oromia, and Somali regions (Figure 1). Throughout Kenya, Somalia, northern Uganda, southern South Sudan, and northern Tanzania, little to no rainfall activity was observed.

Across many parts of southern Ethiopia, Uganda, Kenya, and northern Tanzania, drier conditions have returned earlier than normal. The highest rainfall activity is supposed to occur during this time of the year however, many areas have experienced poor and delayed rainfall since the start of the season last month.

During this past week, recent below-average precipitation has strengthened seasonal moisture deficits. There is a large area experiencing below-average conditions, most parts receiving less than a quarter of their normal precipitation since March (Figure 2). Much of the abnormal dryness has been associated with a low number of rainy days. Below-average conditions have also been notable in southern Somalia, suggesting a delayed start to rainfall across the Jubba and Shabelle river basin.

Next week, there is little potential for rainfall over the Horn.
The highest weekly rainfall accumulations are forecast over Ethiopia, with moderate amounts expected in Kenya, Uganda and northeastern Tanzania. Continued below-average rainfall is likely to strengthen dryness in many areas.

Late seasonal rainfall received across southern Africa
Following several months of significantly poor precipitation across southern Angola, northern Namibia and Botswana, late seasonal rainfall continued for a second week, with well distributed amounts ranging between 5-25 mm registered over the region. While the increase in moisture has helped to relieve dryness, particularly over central Namibia for the short term (Figure 2), the rest of southwestern Africa remains impacted by long term dryness and drought. Meanwhile, favorably late increased rainfall has been observed across Lesotho and South Africa during the past week.
Next week, more rainfall is forecast for southern Africa where conditions are usually drier during mid-April. Widespread moderate weekly rainfall amounts (10- 50 mm) are forecast to span from southern Angola to South Africa.