Highlights

Rainfall Prediction: Heavy rainfall above 100 mm is expected in Sabaragamuwa, Western and Southern provinces during 25th – 31st May.

Monitored Rainfalls: During the last week, the average daily rainfall over Sri Lanka was 4.5mm and hydro catchment areas have received 11.1 mm on average.

Monitored  Wind: From 16th- 22nd May, up to 20 m/s of south-westerlies were experienced over the island.

Monitored  Temperature: Sea surface temperature was observed to be below average of 0.5°C around the island. Land surface temperature remained near normal during the last week.

Interpretation

Monitoring

Rainfall: During the last two weeks, there had been very heavy rainfall over the following area: Colombo
Daily Average Rainfall in the Met stations for previous week of (17th- 24th May) = 4.5 mm

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

Temperatures: The temperature anomalies were slightly below normal for the north central province, driven by the warm SST’s.

Prediction

Rainfall: During the next week (27th- 31st May) heavy rainfall (>100 mm) is predicted for the Southern, Western and Sabaragamuwa provinces.

Temperature : The temperature remains slightly above normal in the Northern and Eastern provinces and slightly below normal in the central province during 27th May – 4th June.

Teleconnections:

La Niña – Though La Niña is favored to continue, the odds for La Niña decrease into the late Northern Hemisphere summer (August-October 2022).

MJO shall neutral during 25th- 29th May; shall moderately suppress the rainfall during 30th May – 3rd June and significantly suppress the rainfall during 4th – 8th June.

Seasonal Precipitation:

The precipitation forecast for the June-July-August season shows below-normal precipitation for the Southern province and above-normal precipitation to the Northern province.

Terminology for Rainfall Ranges