Media Center
Climate Bulletin for Sri Lanka (Week of 28 July – 4 August 2023)
Highlights
Rainfall Prediction: •Moderately rainfall (35 mm) is predicted for the Southern, Sabaragamuwa provinces and less rainfall is predicted for the rest of the country during 27 Jul – 2 Aug.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 1.7 mm and hydro catchment areas received 4.5 mm. Highest average rainfall of 5.4 mm/day received in Western plains.
Monitored and Predicted Wind: From 18 – 24 Jul, up to 20 m/s of north westerly winds were at 850 mb (1.5 km). During 28 Jul – 3 Aug, up to 15 m/s of northwest- westerly winds are expected at 850 mb (1.5 km).
Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was 0.25 – 1.5oC above normal. Average maximum land temperature ranged from 31 – 33oC and minimum ranged from 24 – 25oC with a drop in the hills.
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been fairly heavy rainfall over the following area: Nuwara Eliya
Daily Average Rainfall in the Met stations for previous week of (19th July – 26th July) = 1.7 mm
Maximum Daily Rainfall: 52.4 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: North westerly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal forsome parts of the Sabaragamuwa, Southern, Western, Uva, Central, Eastern, and Northern provinces of the country driven by the warm SST’s.
Prediction
Rainfall: During the next week (27 th July – 2 nd August), moderately rainfall (35 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 during 28 th July – 3 rd August.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June.
MJO shall near neutral the rainfall during 27th July – 10th 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 |
