Media Center
Climate Bulletin for Sri Lanka (Week of 10 November – 17 November 2023)
Highlights
Rainfall Prediction: High probability of heavy rainfall (100 – 130 mm) is predicted for Sabaragamuwa, Uva, Northern provinces and fairly heavy rainfall is predicted for rest of the country during 10 – 16 November.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 17.7 mm and hydro catchment was 22.4 mm. Extreme rainfall (≥ 150 mm/day) was in Ratnapura, Kurunegala and Anuradhapura. The rainfall of last week was twice as normal.
Monitored and Predicted Wind: From 30 Oct – 5 Nov, up to 3 m/s of east-south easterly winds were at 850 mb (1.5 km). During 9 – 15 Nov, up to 5 m/s of north easterly winds are expected at 850 mb (1.5 km).
Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was 1.0 – 2.0oC above normal. From 1 – 8 Nov, maximum daily temperature was recorded in Ratnapura (33.9oC) and Maha Illuppallama (33.1oC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following areas: Ratnapura, Kurunegala
Daily Average Rainfall in the Met stations for previous week of (1st November – 8th November) = 17.7 mm
Maximum Daily Rainfall: 146.9 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: East-south easterly 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 and Central provinces of the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (10th November – 16th November), heavy rainfall is predicted for the Sabaragamuwa, Uva, and Northern provinces and fairly heavy rainfall is predicted for the rest of the country.
Temperatures: The temperature will remain seasonably near normal for the country during 9th November – 15th November.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June. MJO shall slightly suppress the rainfall during 8th – 17th November and near neutral the rainfall during 18th – 22nd November for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the November-December-January, 2024 season shows a 40 – 45% tendency toward above 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 |
