Highlights

Rainfall Prediction: Heavy rainfall is predicted for Sabaragamuwa province, Nuwara Eliya & Kandy districts; fairly heavy rainfall in Western and North-western provinces, Galle & Matara districts during 5 – 11 Aug. Landslide warnings have been issued for seven districts for next few days.

Monitored Rainfalls: During the last week, the average daily rainfall over Sri Lanka was 7.5mm. People had been affected due to floods following heavy rains experienced in the past few days.

Monitored  Wind: From 25th- 31st July, up to 10 m/s of westerlies to south-westerlies were experienced over the island. Extremely high speed westerlies are predicted for the coming week.

Monitored  Temperature: Sea surface temperature was above 0.5°C to the North and East of Sri Lanka. Land surface temperature remained near normal.

Interpretation

Monitoring

Rainfall: During the last two weeks, there had been very heavy rainfall over Nuwara Eliya.

Daily Average Rainfall in the Met stations for previous week of (24th July – 31st July) = 7.5 mm
Rainfall maximum: 69.5 mm & Rainfall minimum: 0.0 mm.

Wind: Westerly to south-westerly prevailed in the sea area and around the island last week.

Temperatures: The temperature anomalies were below normal for the north half of the island, driven by the warm SST’s.

Prediction

Rainfall:During the next week (5th- 11th August) heavy rainfall is predicted for Sabaragamuwa province and Nuwara Eliya and Kandy districts and fairly heavy rainfall is expected for Western and North-western provinces and Galle and Matara districts.

Temperatures: The temperature remains above normal in the Eastern and Uva provinces during 5th– 11th August.

Teleconnections: La Niña – La Niña is favored to continue through 2022 with the odds for La Niña decreasing into the Northern Hemisphere late summer (July-September 2022) before increasing through the Northern Hemisphere fall and early winter 2022.
MJO shall near-neutral during 3rd- 12th August; and slightly enhance the rainfall during 13th – 17th August.

Seasonal Precipitation: The precipitation forecast for the August-September-October season shows a higher tendency for below-normal precipitation for the southern half of the country, while the remaining areas are more likely to experience near-normal precipitation.

Terminology for Rainfall Ranges