Uganda Climate Forecast March, April and May

Map of Uganda showing March-May Rainfall Forecast

THE RAINFALL OUTLOOK FOR MARCH TO MAY 2009 RAINFALL SEASON

1. EXECUTIVE SUMMARY

1.1 Introduction
Following the conclusion of the 23rd Climate Outlook Forum for the Greater Horn of Africa held in Mombasa, Kenya from 2nd to 4th March 2009, the International, Regional and National scientists reviewed the state of the global climate systems and their implications on the seasonal climate of the sub-region.

1.2 Highlights for the past season (September to December 2008)
During the season of September to December 2008 the rainfall was concentrated in the first two months of the season (September and October) and normal to above normal rainfall was recorded in most areas. In the first week of November heavy episodic rainfall events, which caused flash floods, were experienced in Soroti and Tororo in eastern Uganda. However the season ended earlier than anticipated, around mid-November, over most parts of the country.

During the second half of January to early February 2009, unseasonable rains, triggered by tropical cyclone activity in the Mozambique Channel, were experienced over wide areas of Uganda. This apparent early onset of the March – May seasonal rains was followed by long dry spells in line with the update forecast that was issued at the end of January 2009..

1.3 Forecast March to May 2009 seasonal rainy periods.
It was observed that among the principal factors that are likely to influence Uganda’s weather for the forecast period of March to May 2009 would be the prevailing slightly colder than average Sea Surface Temperatures (SSTs) observed over the equatorial Pacific Ocean and the above average SSTs over south-western parts of the Indian Ocean as well as the observed neutral Indian Ocean Dipole.

Based on the above considerations as well as details of the country’s climate systems, the nature and trends of the ongoing weather patterns since July 2008 and physical features of the different regions of the country, the summary of the detailed national forecast is as follows;

• In terms of total rainfall amounts, most parts of Lake Victoria basin, central, western, south eastern, northern and north western Uganda have got high probabilities of receiving near normal to above normal rainfall.
• On the other hand north-eastern parts of the country which have been experiencing occurrences of prolonged dry spells are expected to receive near normal to below normal rainfall during this season. This implies that the prolonged dry spells resulting into drought conditions may continue in some of these areas. Hence relief measures should therefore be put in place to avert any loss of life and property.
• It should be noted that episodic wet spells and flash floods could occur even in areas with a likelihood of near to below normal rainfall.
• The onset of steady rains is likely to be delayed due to the prevailing warm SST anomalies over south-western Indian Ocean. This is likely to keep the rain bearing belt (Inter-Tropical Convergence Zone – ITCZ) to the south a bit longer.

The onset and cessation of the rains is expected to vary from region to region as follows:

• Northern: Onset of steady rains is expected late March/early April and the rains are expected to continue up to the end of the forecast season.
• Eastern and Lake Basin: Onset is expected around mid/late March and steady rains are expected to continue and relax around early June.

• Western: Onset is expected mid March and cessation early May for south-western and early June for central western.

2. DETAILED REGION BY REGION FORECAST

2.1 EASTERN REGION

2.1.1 Eastern Lake Victoria and South Eastern (Jinja, Kamuli, Iganga, Mayuge, Bugiri, Busia and Tororo).

The region is currently experiencing a dry spell with occasional outbreaks of showers and thunderstorms. Onset of steady rains is expected around mid/late March. The rains are expected to intensify with the peak around late April through to mid May. Occurrences of rather prolonged dry spells are expected during the month of April. The decline of the rains is expected around late May and cessation is expected around early June. Overall there is a high chance for this region receiving near to above normal rains.

2.1.2 Eastern Central: (Pallisa, Mbale, Manafa, Sironko, Kapchorwa, Kumi, Kaberamaido, Soroti).

This region has been experiencing a rather prolonged dry spell with occasional outbreaks of showers and thunderstorms. Steady rains are expected around late March and a peak around late April to mid May. Thereafter the rains are expected to reduce sharply by late May. Overall the region is expected near normal to above normal rainfall.

2.1.3 North Eastern region: (Katakwi, Moroto, Kotido, Nakapiripiriti).

The region has been experiencing a prolonged dry season since mid-November. The onset of steady rains is expected early April. and a peak late April. Intermittent rains are likely to continue into June. Overall near normal to below normal rainfall is expected in this region.

2.2 CENTRAL NORTHERN REGION

2.2.1 Eastern Parts: (Lira, Pader, Kitgum).

The region has been mainly dry with occasional outbreaks of light rain showers. The onset of steady rains is expected late March / early April. The peak of steady rains is expected around mid-May with a moderate relaxation during June. Overall near normal to above rainfall is expected during this season.

2.2.2 Central Northern Parts :( Amuru, Gulu, Apac)

Currently the area is mainly dry with occasional outbreaks of light rain showers. The onset of steady rains is expected around late March to early April. The steady rains are expected to increase with the peak being experienced around early to mid May. This will be followed by a moderate relaxation during the month of June. Normal to above normal rainfall is expected to prevail during this season.

2.3 WESTERN REGION

2.3.1 North Western: (Moyo, Yumbe, Adjumani, Arua, Maracha, Terego and Nebbi)

This region has been mainly dry with occasional outbreaks of light rain showers. The onset is expected late March with a peak around mid-May. A relaxation is expected around mid June. There is a high chance of this region receiving near normal to above normal rainfall during the season.

2.3.2 Western Central: (Masindi, Hoima, Kibaale, Kyenjojo, Kamwenge, Kabarole and Bundibugyo)

The region is currently experiencing intermittent showers and thunderstorms but steady rains are expected around mid March. Peak rains are expected around mid April to mid May. Rainfall is expected to relax late May with the cessation occurring early June. This region is expected to receive near normal to above normal rainfall.

2.3.3 South Western: (Kasese, Bushenyi, Rukungiri, Kanungu, Ibanda, Mbarara, Kiruhura, Ntungamo, Kisoro, Kabale)

The region is currently receiving intermittent rains. Steady rains are expected to be established around mid March. However the steady rains are likely to be interrupted by occurrences of rather prolonged dry spells. The peak of the steady rains is expected early April and the cessation mid-May. Overall the region is expected to receive near to above normal rainfall amount during this season.

2.4 LAKE VICTORIA BASIN AND CENTRAL AREAS

2.4.1 Central and Western Lake Victoria Basin: (Kalangala, Kampala, Wakiso, Entebbe, South Mpigi, Eastern Masaka, Mityana)

This region is currently experiencing intermittent showers and thunderstorms but steady rains are expected around mid March. The rains are expected to intensify with the peak occurring around late April to early May. The cassation is expected around mid June. Overall, there are high chances of normal to above normal rainfall.

2.4.2 Western Parts of Central: (Nakasongola, Luwero, Kiboga, Mubende, Sembabule, Western Masaka, Lyantonde, Rakai)

This region is currently experiencing sporadic out breaks of showers and thunderstorms but steady rains are expected mid March. The rains are expected to intensify with the peak occurring around mid April. The cassation is expected around mid May. Overall, there are high chances of normal to above normal rainfall over the region.

2.4.3 Eastern parts of Central: (Mukono, Kayunga).

This region is currently receiving outbreaks of showers and thunderstorms. The onset of steady rains is expected around mid-March and intensifies to reach a peak mid – April. Thereafter, the rains are expected to relax with cessation occurring mid- June. Overall, near normal to above normal rainfall is expected.

S.A.K Magezi

FOR: COMMISSIONER FOR METEOROLOGY
Note: This forecast will be updated monthly as and when necessary and the
Department of Meteorology will keep users informed of any new
developments.

EXPLANATORY NOTES TO TERMINOLOGY

i) Above Normal
This is when the total rainfall is above 125% of the long term average. Impact on socio – economic activities is mostly boosted especially in the modest degrees of above average.

ii) Normal
This is when the total rainfall is in the range of 75% to 125% of the long term average rainfall. This range of rainfall is expected to adequately support the normal socio – economic activities for the various areas.

iii) Below Normal

This is when the total rainfall is below 75% of the long-term average rainfall. Under this range there are high chances for socio – economic activities being stressed; the level of stress increasing with increasing rainfall deficiency.

iv) Accuracy

This forecast is up to 70% accurate. It is supported by products from Regional and Global forecast centres. It will be updated in our regular Bulletins and as when necessary.

THE REPUBLIC OF UGANDA
MINISTRY OF WATER AND ENVIRONMENT,
DEPARTMENT OF METEOROLOGY,
P.O. BOX 7025,
KAMPALA
UGANDA

TELEPHONE: +41-233559, 251798
DIRECT: +41-255609
FAX: +41-251797
E-mail:com.met@imeteo-uganda.net
IN ANY CORRESPONDENCE ON THIS SUBJECT PLEASE QUOTE APS/102/02