Media Center
Climate Bulletin for Sri Lanka (Week of 18 August – 25 August 2023)
Highlights
Rainfall Prediction: Light showers are predicted for the Sabaragamuwa, Southern, Uva, Western, Central and Northern provinces during 17- 23 Aug.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was ‘light’ (2.0 mm) and hydro catchment areas received ‘light’ (2.0 mm) showers.
Monitored and Predicted Wind: From 8 – 14 Aug, up to 8 m/s of northwest-westerly winds were at 850 mb (1.5 km). During 18 – 24 Aug, up to 10 m/s of northwest- southwesterly winds are expected at 850 mb (1.5 km).
Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was 1 – 1.5ºC above normal. From 9 – 16 Aug, maximum daily temperature was recorded in Polonnaruwa (38.1ºC), Anuradhapura (37.8ºC) and Vavuniya (37.7ºC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been fairly heavy rainfall over the following areas: Monaragala, Mullaittivu, Kandy.
Daily Average Rainfall in the Met stations for previous week of (9th August – 16th August) = 2.0 mm Maximum Daily Rainfall: 63.7 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: Northwest-westerly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal for the Eastern, Southern, Sabaragamuwa, Uva, Central, North Central provinces and some parts of the Western, North Western, and Northern provinces of the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (17th August – 23rd August), light showers (15 mm) are predicted for the Southern, Sabaragamuwa, Uva, Western, Central, and Northern provinces and less rainfall is predicted for the rest of the country.
Temperatures: The temperature will remain above normal for some parts of the Eastern, Uva, Northern, North Central, Southern, and Central provinces during 18th August – 24th August.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June. MJO shall slightly suppress the rainfall during 17th – 21st August and near neutral the rainfall during 22nd – 31st August for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the September-October-November, 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 |
