Media Center
Climate Bulletin for Sri Lanka (Week of 26 May – 02 June 2023)
Highlights
Rainfall Prediction: Fairly heavy rainfall is predicted for the Sabaragamuwa, Western, Southern, North Western, and Central provinces during 25 – 31 May. Heavy rainfall is predicted for the Western, Sabaragamuwa, Southern, and North Western provinces during 1 – 7 June.
Monitored Rainfall: During the last week, the average daily rainfall over Sri Lanka was 2.7mm and hydro catchment areas received 2.6 mm.
Monitored and Predicted Wind: From 16 – 22 May, up to 5 m/s of southwesterly winds were at 850mb (1.5 km). During 26 May – 1 June, up to 10 m/s of westerly winds are expected at 850mb (1.5 km).
Monitored Sea and Land Temperature: The sea surface temperature around Sri Lanka was 0.5 – 1.5°C above normal. The average maximum land temperature ranged from 32-33°C and the average minimum ranged from 23 – 25°C with a drop in the hills.
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been fairly heavy rainfall over Galle
Daily Average Rainfall in the Met stations for the previous week of (17th May – 24th May) = 2.7 mm
Maximum Daily Rainfall: 46.6 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: South Westerly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal for some parts of the Western, Sabaragamuwa, Central, and North Western provinces and normal for rest of the country driven by the warm SSTs.
Prediction
Rainfall: During the next week (25 May – 31 May), fairly heavy rainfall (≥ 55 mm) is predicted for the Western, Sabaragamuwa, Southern, North Western, and Central provinces, and less rainfall is predicted for the rest of the country.
Temperatures: The temperature will remain above normal for some parts of the Northern, Eastern, North Central, Uva, and Southern provinces during 26 May – 1st June.
Teleconnections: A transition from ENSO-neutral conditions in the next couple of months, with a greater than 90% chance of El Niño persisting into the Northern Hemisphere winter.
MJO shall significantly suppress the rainfall during 24 – 28 May, slightly suppress the rainfall from 29 May – 2 June, and slightly increase the rainfall from 3 – 7 June for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the June-July-August, 2023 season shows above-normal precipitation for the country.
Terminology for Rainfall Ranges
| Rainfall (During 24 hours of the period) | |
| Light Showers | Less than 12.5 mm |
| Light to Moderate | Between 12.5 mm and 25 mm |
| Moderate | Between 25 mm and 50 mm |
| Fairly Heavy | Between 50 mm and 100 mm |
| Heavy | Between 100 mm and 150 mm |
| Very Heavy | More than 150 mm |
