10 Day Forecast (11 –20July, 2010)
WEATHER REVIEW FOR DEKAD 20(11TH –20TH JULY, 2010) AND OUTLOOK FOR DEKAD 21(21ST –31ST JULY, 2010)

1.1 WEATHER REVIEW FOR DEKAD 20(11TH – 31ST JULY, 2010)
During the second dekad of July 2010, the Southern Hemisphere systems (St. Helena and Mascarene anticyclones) slightly relaxed while the Siberian anticyclone in the Northern Hemisphere remained intense causing the rain-making mechanism to slightly shift southwards and resulting into collapse of the Arabian ridge over the region. The East African Ridge intensified significantly contributing to a strong low-level south-easterly wind flow pattern over the coastal areas. However, Lake Victoria trough caused occasional light activities over areas around east and west of Lake Victoria. Near Equatorial Trough (NET) and warmer Sea Surface Temperatures (SSTs) over the Indian Ocean near the coast of Tanzania towards Somali coast continued to contribute some favorable rainfall conditions to the northern coastal belt and north-eastern highlands. High grounds of south western highlands experienced light rains caused by south-easterly wind flow.

1.2 WEATHER SUMMARY FOR DEKAD 20(11TH –20TH JULY, 2010)
Generally, due to injection of cold air-mass from the southern tip of Africa where winter is currently prevailing, most parts of the country had generally cold nights and mornings. Moderate southerly wind which was stronger at times continued over the country with mainly dry conditions were experienced over most areas except parts of north-eastern and south-western highlands occasionally including the Island of Pemba where occasional precipitation continued to be observed. Light showers were observed over eastern parts of Lake Victoria basin. Other regions remained dry and cool during the dekad.

1.3 WEATHER OUTLOOK FOR DEKAD 21(21ST – 31ST JULY, 2010)
1.3.1 EXPECTED SYNOPTIC SITUATION
For the last dekad of July 2010, the Southern Hemisphere Systems (the St. Helena anticyclones and Mascarene together with the associated East African ridge) are expected to continue sustain their intensity while the Azores and Siberian anticyclones together with the Arabian ridge in the Northern Hemisphere are likely to remain relaxed maintaining the position of the ITCZ over the northern Africa. However the lake trough is expected to continue causing few outbreaks of isolated showers over the areas surrounding Lake Victoria. Mainly southerly to southeasterly flow at lower levels is expected over the greater part of the country. A trough near the coast of Tanzania coupled with warm SSTs over extreme northern to Somali coast are likely to supply moisture to the northern coastal belt and the high grounds of north-eastern highlands.

1.3.2 EXPECTED WEATHER OUTLOOK FOR DEKAD 21(21ST – 31ST JULY, 2010)
Generally cool nights and mornings are expected to persist over most parts of the country while over the high grounds are likely to feature chilly nights and mornings.
Lake Victoria Basin (Kagera and Mara regions) is likely to experience thundery activities and light showers are likely to feature over the eastern and western part of the Lake basin, while Shinyanga and Mwanza are expected to experience mainly partly cloudy conditions.

Northern coast and hinterland (Dar es Salaam, Morogoro, Tanga and Coastal regions together with the Islands of Unguja and Pemba) are expected to experience partly cloudy conditions and occasional rains mainly over the extreme northern coast.

Southern Coast (Mtwara and Lindi regions): Most areas are expected to experience mainly dry conditions.

Northeastern Highlands (Arusha, Kilimanjaro and Manyara regions) are expected to experience relatively low temperatures at nights and mornings. Occasional orographical rainfall is expected to persist over high grounds.

Southwestern highlands (Rukwa, Mbeya and Iringa regions) are expected to experience reduced night temperatures associated with chilly weather mainly over high grounds. Light rains are expected over high grounds.

Southern region (Ruvuma region) and part of Mahenge are expected to experience mainly partly conditions with light rains over the high grounds.

Kigoma region is expected to feature mainly dry conditions.

Central areas (Dodoma and Singida regions), and Tabora region are expected to feature relatively low temperatures during night and early morning hours. Occasionally windy and dust devil conditions are also likely to persist.