Highlights

Rainfall Prediction: During the next week, “fairly heavy rainfall” (50-100 mm) is predicted for the Eastern and North- Central province, and “moderate rainfall” is predicted for the Uva, Sabaragamuwa, Southern, Northern and North Western provinces and “Light showers” shows some parts of western province.

Monitored Rainfall: During the last 8 days (1 Jan-8 Jan), SL received an average of 10.7 mm/day of rainfall, while in the hydro catchments, the average rainfall was 7.7 mm/day. Highest daily rainfall was in Mannar on 14 Jan (90.5 mm).

Monitored and Predicted Wind: From 6–12 Jan, winds at 850 mb (1.5 km) from the East reached up to 10 m/s. From 16–22 Jan, winds are predicted to come from the East, reaching up to 10 m/s.

Monitored Sea and Land Temperature: Average land surface temperature was 28.0°C in the last week with warmer anomalies from seasonal average of 1-3°C. The western plains were the warmest, followed by the northern and southern plains. Sea surface temperature around Sri Lanka was 0.5°C above average from 7 Jan – 13 Jan 2025

 

Accumulated Rainfall and Daily Rainfall from 25 Nov 2024

Climate Bulletin for Sri Lanka (Week of 17 – 24 January 2025)

 

Interpretation

Monitoring

Rainfall: Average Rainfall in the Met Stations for the previous week of (9 Jan – 15 Jan) = 10.7 mm/day. Maximum Daily Rainfall: 90.5 mm & Minimum Daily Rainfall: 0.0 mm.

Wind: Easterly winds prevailed in the sea area and around the island last week.

Temperatures: The temperature anomalies were near-neutral for Sri Lanka except for some parts of Sabaragamuwa, Western and Central provinces driven by the warm SSTs anomalies.

Prediction

Rainfall: During the next week (15 – 21 Jan), “fairly heavy rainfall” (50–100 mm) is predicted for the Eastern and North-Central provinces. “Moderate rainfall” is expected in the Uva, Sabaragamuwa, Southern, North-Western, Central, and Northern provinces, while “light to moderate rainfall” is predicted for the Western province

Temperatures: The temperature will remain normal for the SL during 17 –25 Jan.

Teleconnections: MJO will slightly enhance the rainfall during 14-18 January, Significantly enhance the rainfall during 19-28 January.

Seasonal Precipitation: The precipitation forecast for the February-March-April, 2025 season shows a 45% or more tendency toward above-normal precipitation for the Southern half of the country, while it shows a 50% or more tendency toward above-normal precipitation for the Northern half of the country.

Terminology for Rainfall Ranges

TerminologyRainfall (mm/week)
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