Media Center
Climate Bulletin for Sri Lanka (Week of 27 October – 03 November 2023)
Highlights
Rainfall Prediction: Heavy rainfall (≥ 105 mm) is predicted for the Southern,Sabaragamuwa, Western, Uva, Central, North Western provinces during 26 Oct – 1 Nov. Heavy rainfall (≥ 125 mm) is predicted for the country during 2 – 8 Nov.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 13.5 mm and hydro catchment was 15.7 mm. Heavy rainfall (> 100 mm) is predicted for Southern and Western regions during next week and following week.
Monitored and Predicted Wind: From 17 – 23 Oct, up to 3 m/s of north westerly winds were at 850 mb (1.5 km). During 27 Oct – 2 Nov, up to 5 m/s of easterly winds are expected at 850 mb (1.5 km).
Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was 0.25 – 1.0ºC above normal. From 18 – 25 Oct, maximum daily temperature was recorded in Vavuniya (34.5ºC), Polonnaruwa (33.1ºC), and Anuradhapura (33.1ºC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following areas: Anuradhapura, Hambantota.
Daily Average Rainfall in the Met stations for previous week of (18 th October – 25 th October) = 13.5 mm
Maximum Daily Rainfall: 161.5 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: North westerly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were seasonably near normal for the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (26 th October – 1 st November), heavy rainfall (≥ 105 mm) is predicted for the Southern, Sabaragamuwa, Western, Uva, Central, and North Western provinces and fairly heavy rainfall (≥ 85 mm) is predicted for the Eastern, Northern, and North Central provinces.
Temperatures: The temperature will remain seasonably near normal for the country during 27 th October – 2 nd November.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8 th of June.
MJO shall slightly suppress the rainfall during 26 th – 30 th October, slightly enhance the rainfall during
31 st October – 4 th November, and moderately enhance the rainfall during 5 th – 9 th 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 |
