Highlights

Rainfall Prediction: Heavy rainfall above 100 mm is expected in Sabaragamuwa Western & Southern provinces during 20th to 24th May.

Monitored Rainfalls: During the last week, average daily rainfall over Sri Lanka was 5.6mm and hydro catchment areas have received 24.1mm on average.

Monitored  Wind: From 9th- 15th May, up to 15 m/s South-westerlies were experienced over the island.

Monitored  Temperature: Sea surface temperature was near-neutral around the island. Land surface temperature remained near normal during the last week.

Climate Bulletin for Sri Lanka (Week of 20 May – 27 May 2022)
Climate Bulletin for Sri Lanka (Week of 20 May – 27 May 2022)

Interpretation

Monitoring

Rainfall:

During the last two weeks, there had been heavy rainfall over the following area: Kalutara
Daily Average Rainfall in the Met stations for previous week of (10th- 17th May) = 5.6 mm

Wind: South-westerly prevailed in the sea area surrounding the island last week.

Temperatures: The temperature anomalies were near-neutral for the country, driven by the warm SST’s.

Prediction

Rainfall: During the next week (20th- 24th May) heavy rainfall (>100 mm) is predicted for the Southern, Western and Sabaragamuwa provinces.

Temperature : The temperature remains slightly above normal in the Eastern province during 20th – 28th May.

Teleconnections:

La Niña – The SST forecast indicates a continuation of the La Niña event with high probability during May-Jul. And there is some disagreement between the two forecast methods thereafter. MJO shall slightly suppress the rainfall during 20th- 22nd May and moderately enhance the rainfall during 23rd May – 1st June.

Seasonal Precipitation:

The precipitation forecast for the May-June-July season shows below-normal precipitation for the island, but above-normal precipitation for the Northern province.

Terminology for Rainfall Ranges

Rainfall (During 24 hours of period)
Light ShowersLess than 12.5 mm
Light to ModerateBetween 12.5 mm and 25 mm
ModerateBetween 25 mm and 50 mm
Fairly HeavyBetween 50 mm and 100 mm
HeavyBetween 100 mm and 150 mm
Very HeavyMore than 150 mm