Media Center
Climate Bulletin for Sri Lanka (Week of 03 November – 10 November 2023)
Highlights
Rainfall Prediction: High probability of heavy rainfall (100 – 135 mm) for the entire country during 1 – 7 November. >100 mm of Heavy rainfall is predicted during 8 – 14 November.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 10.0 mm and hydro catchment was 13.7 mm. The rainfall of last week was twice as normal.
Monitored and Predicted Wind: From 23 – 29 Oct, up to 3 m/s of north easterly winds were at 850 mb (1.5 km). During 3 – 9 Nov, up to 2 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 0.5 – 1.5ºC above normal. From 25 Oct – 1 Nov, maximum daily temperature was recorded in Kurunegala (33.5ºC) and Ratnapura (33.4ºC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following area: Ratnapura
Daily Average Rainfall in the Met stations for previous week of (25th October – 1st November) = 10.0 mm
Maximum Daily Rainfall: 92.1 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 for some parts of the Sabaragamuwa and Central provinces of the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (1st November – 7th November), heavy rainfall (> 135 mm) is predicted for the Southern, Sabaragamuwa, Western, Uva, and Central provinces and ≥ 125 mm rainfall is predicted for the Eastern, North Western, North Central, and Northern provinces.
Temperatures: The temperature will remain seasonably near normal for the country during 3rd November – 9th November.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June. MJO shall slightly enhance the rainfall during 1st – 5th November and moderately enhance the rainfall during 6th – 15th 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 |
