Rainfall Perfomance (Sept to Dec 2010)

REVIEW OF RAINFALL PERFORMANCE IN THE PAST SEASON (SEPTEMBER – DECEMBER 2010) AND SEASONAL RAINFALL OUTLOOK FOR MARCH TO MAY 2011 

  1. Highlights of the rainfall performance from September to December 2010

As was predicted at the end of August, the September to December 2010 rainfall season was influenced by moderate La Niña conditions which matured towards the middle of the season. The following were observed during September to December rainfall season:-

  • The onset of seasonal rainfall was established in many parts of the country by mid September especially in the western Uganda;
  • During the month of October, there was reduction in rainfall amounts over northern region. However, there was an increase over Eastern, Central, Lake Victoria Basin, South Western and Western Regions;
  • During the month of December, the reduction in rainfall was experienced several places over the country;
  • In general near normal rainfall was observed over several places during September to December rainfall season. The areas that received above normal rainfall were Lira, Arua, Mbarara and Jinja among others
  • Although in some specific months a few of the stations recorded below the long term mean (LTM), the cumulative rainfall (total seasonal rainfall) over the three months was near normal to above normal (LTM) in several parts of the country.

The overall performance based on the long term means (LTM) is shown in figure 1. 

Rainfall Perfomance 2011
Rainfall performance over several places in the country

 

EXPLANATORY NOTES TO TERMINOLOGY

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.

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.

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.

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.

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