Media Center
Climate Bulletin for Sri Lanka (Week of 17 November – 24 November 2023)
Highlights
Rainfall Prediction: High probability of heavy rainfall (100 – 130 mm) is predicted for Sabaragamuwa, Uva, Western provinces and fairly heavy rainfall is predicted for Southern, Central provinces during 16 – 22 Nov.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 16.7 mm and hydro catchment was 16.6 mm. Extreme rainfall (≥ 150 mm/day) was in Ampara and Badulla. The rainfall of last week was twice as normal.
Monitored and Predicted Wind: From 6 – 12 Nov, up to 4 m/s of north easterly winds were at 850 mb (1.5 km). During 16 – 22 Nov, up to 4 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 0.5 – 1.5ºC above normal. From 8 – 15 Nov, maximum daily temperature was recorded in Ratnapura (34.1ºC) and Puttalam (33.7ºC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following areas:
Ampara, Badulla
Daily Average Rainfall in the Met stations for previous week of (8 th November – 15th November) = 16.7 mm
Maximum Daily Rainfall: 131.5 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, and Western provinces of the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (16 th November – 22nd November), heavy rainfall is predicted for the Sabaragamuwa, Uva, and Western provinces and fairly heavy rainfall is predicted for the Southern and Central provinces and less rainfall is predicted for rest of the country.
Temperatures: The temperature will remain seasonably near normal for the country during 16th November – 22nd November.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June. MJO shall slightly suppress the rainfall during 15th – 19th November, slightly enhance the rainfall during 20th – 24th November, and moderately enhance the rainfall during 25th – 29th November 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 |
