Media Center
Climate Bulletin for Sri Lanka (Week of 06 October – 13 October 2023)
Highlights
Rainfall Prediction: Heavy rainfall (≥ 115 mm) is predicted for the Southern, Sabaragamuwa, Western, Uva, Central and Eastern provinces and fairly heavy rainfall (≥ 65 mm) is predicted for the North Western and North Central provinces during 5 – 11 Oct.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 17.0 mm and hydro catchment area received 18.0 mm. Extreme rainfall was recorded in southern coast.
Monitored and Predicted Wind: During 6 – 12 Oct, up to 6 m/s of southwesterly 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 27 Sep – 4 Oct, maximum daily temperature was recorded in Vavuniya (36.5ºC), Polonnaruwa (35.8ºC) and Mullaitivu (35.4ºC).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following areas: Hambantota, Ratnapura.
Daily Average Rainfall in the Met stations for previous week of (27th September – 4th October)=17.0 mm.
Maximum Daily Rainfall: 226.4 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 near normal for the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (5th October – 11th October), heavy rainfall (≥ 115 mm) is predicted for the Southern, Sabaragamuwa, Western, Uva, Central, and Eastern provinces and fairly heavy rainfall (≥ 65 mm) is predicted for the North Western and North Central provinces and less rainfall is predicted for the rest of the country.
Temperatures: The temperature will remain above normal for some parts of the Northern and Eastern provinces and below normal for some parts of the Central and Uva provinces during 6th – 12th October.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June. MJO shall near neutral the rainfall during 5th – 14th October and slightly enhance the rainfall during 15th – 19th October for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the October-November-December, 2023 season shows a 50 – 60% tendency toward above normal precipitation for the country.
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 |
