Media Center
Climate Bulletin for Sri Lanka (Week of 01 December – 08 December 2023)
Highlights
Rainfall Prediction: HHigh probability of extreme rainfall is predicted during next week. Heavy rainfall (≥ 100 mm) is predicted for Central, Uva, Sabaragamuwa, Southern provinces and fairly heavy rainfall is predicted for Northern, Western provinces during 30 Nov – 6 Dec.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 10.3 mm and hydro catchment was 6.6 mm. Extreme rainfall (> 150 mm/day) was in Nuwara Eliya and Galle. The rainfall of last week was twice as normal.
Monitored and Predicted Wind: From 20 – 26 Nov, up to 5 m/s of north easterly winds were at 850 mb (1.5 km). During 30 Nov – 6 Dec, up to 8 m/s of north westerly winds are expected at 850 mb (1.5 km).
Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was 0.25 – 1.5oC above normal. From 23 – 29 Nov, maximum daily temperature was recorded in Ratnapura (34.3oC) and Puttalam (33.7oC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following areas:
Nuwara Eliya, Galle
Daily Average Rainfall in the Met stations for previous week of (22 nd November – 29th November) = 10.3 mm
Maximum Daily Rainfall: 95.1 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: North easterly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal forsome parts of the Sabaragamuwa, Central, Uva, Eastern, North Western, Western, and Southern provinces of the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (30th November – 6th December), heavy rainfall is predicted for the Central, Sabaragamuwa, Uva, and Southern provinces and fairly heavy rainfall is predicted for the Northern and Western provinces, and less rainfall is predicted for rest of the country.
Temperatures: The temperature will remain seasonably near normal for the country during 30th November – 6th December.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June. MJO shall moderately enhance the rainfall during 29th November -3rd December and slightly enhance the rainfall during 4th – 13th December for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the December-January-February, 2024 season shows near normal precipitation.
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 |
