Highlights

Rainfall Prediction: High likelihood of heavy rainfall (> 100mm) is predicted for Eastern, Northern, North Central provinces and fairly heavy rainfall is predicted for rest of the country during 3 – 9 Jan. Extreme rainfall is predicted for east coast of Kalmunai to Jaffna.

Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 15.5mm and hydro catchment was 21.1mm. Rufuskula (EP) experienced 215mm on 29 Dec and Batuwangala (SP) experienced 197 mm on 1 Jan. The rainfall of last week was twice as normal.During the last week, average daily rainfall over Sri Lanka was 7.0 mm and hydro catchment was 6.2 mm. Extreme rainfall (> 70 mm/day) was in Northern province. The rainfall of last week was twice as normal.

Monitored and Predicted Wind: From 25 – 31 Dec, up to 10m/s of north easterly winds were at 850 mb (1.5 km). During 4 – 10 Jan, up to 8 m/s of easterly winds are expected at 850mb (1.5 km).

Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was 0.25 – 1.5ºC above normal. Strong EL Nino and positive indian ocean dipole patterns sustained. Maximum daily temperature was in Ratnapura (35.4ºC) and Ratmalana (34.0ºC) .

Climate Bulletin for Sri Lanka (Week of 05 January – 12 January 2024)

Interpretation

Monitoring

Rainfall: During the last two weeks, there had been very heavy rainfall over the following areas:
Rufuskulam, Batuwangala.
Daily Average Rainfall in the Met stations for previous week of (27th December – 3rd January) = 15.5 mm
Maximum Daily Rainfall: 169.4 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 forsome parts of the Eastern, North Central, Central, Southern, Western, Sabaragamuwa, and North Western provinces of the country driven by the warm SST’s.

Prediction

Rainfall: During the next week (3rd January – 9th January), heavy rainfall is predicted for the Eastern, Northern, North Central provinces and fairly heavy rainfall is predicted for rest of the country.

Temperatures: The temperature will remain seasonably near normal for the country during 4thJanuary – 10th January.

Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June. MJO shall significantly enhance the rainfall during 3rd – 7th January, moderately enhance the rainfall during 8th – 12th January, and near normal the rainfall during 13th – 17th January for Sri Lanka.

Seasonal Precipitation: The precipitation forecast for the January-February-March, 2024 season shows near normal precipitation.

Terminology for Rainfall Ranges

Rainfall (During 24 hours of the period)
Light ShowersLess than 12.5 mm
Light to ModerateBetween 12.5 mm and 25 mm
ModerateBetween 25 mm and 50 mm
Fairly HeavyBetween 50 mm and 100 mm
HeavyBetween 100 mm and 150 mm
Very HeavyMore than 150 mm