Media Center
Climate Bulletin for Sri Lanka (Week of 21 July – 28 July 2023)
Highlights
Rainfall Prediction: Fairly heavy rainfall (55 mm) is predicted for the Southern, Sabaragamuwa provinces and less rainfall is predicted for the rest of the country during 20 -26 July.
Monitored Rainfall: During the last week, the average daily rainfall over Sri Lanka was 1.2 mm, and hydro catchment areas received 3.4 mm. The highest average rainfall of 3.5mm/day is received in the Eastern hills.
Monitored and Predicted Wind: From 11 – 17 Jul, up to 15 m/s of northwest-westerly winds were at 850 mb (1.5 km). During 21 – 27 Jul, up to 15 m/s of northwest-westerly winds are expected at 850 mb (1.5 km).
Monitored Sea and Land Temperature: The sea surface temperature around Sri Lanka was 0.5 – 1.5°C above normal. The average maximum land temperature ranged from 31 – 32°C and the minimum ranged from 24 -25°C with a drop in the hills.
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been fairly heavy rainfall over the following area: Vavuniya
Daily Average Rainfall in the Met stations for the previous week of (12th July – 19th July) = 1.2 mm
Maximum Daily Rainfall: 43.9 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: Northwest-westerly 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, Western, and Central provinces of the country driven by the warm SSTs.
Prediction
Rainfall: During the next week (20th July – 26th July), fairly heavy rainfall (55 mm) is predicted for the Southern, and Sabaragamuwa provinces, and less rainfall is predicted for the rest of the country.
Temperatures: The temperature will remain above normal for some parts of the Eastern, Uva, Northern, North Central, and Southern provinces and below normal for some parts of the Central province from 21st – 27th July.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since the 8th of June.
MJO shall near neutral the rainfall from 20th- 24th July, and slightly suppress the rainfall from 25th July – 3rd August for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the August-September-October, 2023 season shows 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 |