Media Center
Climate Bulletin for Sri Lanka (Week of 24 November – 01 December 2023)
Highlights
Rainfall Prediction: High probability of heavy rainfall ( > 130 mm) is predicted for Sabaragamuwa, Uva provinces and fairly heavy rainfall is predicted for Central, Southern, Western provinces during 23 – 29 Nov.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 16.3 mm and hydro catchment was 22.8 mm. Extreme rainfall (> 150 mm/day) was in Nuwara Eliya and Jaffna. The rainfall of last week was twice as normal.
Monitored and Predicted Wind: From 13 – 19 Nov, up to 3 m/s of south westerly winds were at 850 mb (1.5 km). During 23 – 29 Nov, up to 5 m/s of north easterly winds are expected at 850 mb (1.5 km). Wind direction will predominantly transition from SW to from NE.
Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was 0.5 – 1.5ºC above normal. From 16 – 22 Nov, maximum daily temperature was recorded in Ratnapura (35.0ºC) and Moneragala (33.4ºC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following areas: Nuwara Eliya, Jaffna
Daily Average Rainfall in the Met stations for previous week of (16th November – 22nd November) = 16.3 mm.
Maximum Daily Rainfall: 96.3 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 Sabaragamuwa, Central, Western, Uva, and Eastern provinces of the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (23rd November – 29th November), heavy rainfall is predicted for the Sabaragamuwa, Uva provinces and fairly heavy rainfall is predicted for the Central, Southern, 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 23rd November – 29th November.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June.
MJO shall significantly enhance the rainfall during 22nd November – 1st December and moderately enhance the rainfall during 2nd – 6th 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 |
