Media Center
Climate Bulletin for Sri Lanka (Week of 12 May – 19 May 2023)
Highlights
Rainfall Prediction: Fairly heavy rainfall is predicted for the Sabaragamuwa, Western, Southern, North Western, and Central provinces and less rainfall is predicted during 11th – 17th May.
Monitored Rainfall: During the last week, average daily rainfall over Sri Lanka was 13.2mm and hydro catchment areas received 8.9 mm.
Monitored and Predicted Wind: From 2nd – 8th May, up to 8 m/s of North westerly winds were experienced at 850 mb level (1.5km). During 12th – 18th May, up to 8 m/s of Easterly winds are expected at 850 mb level (1.5km).
Monitored Sea and Land Temperature: Sea surface temperature around Sri Lanka was about 0.5 – 1 degree above the seasonal norm. Land surface temperature remained near normal.
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over Katunayake.
Daily Average Rainfall in the Met stations for previous week of (3rd May – 10th May) = 13.2 mm
Maximum Daily Rainfall: 171.1 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 below normal for Northern, North Central, and North Western provinces and some parts of the Eastern, and Central provinces driven by the warm SST’s.
Prediction
Rainfall : During the next week (11th May – 17th May), fairly heavy rainfall (≥ 65 mm) is predicted for the Western, Sabaragamuwa, Southern, North Western, and Central provinces and less rainfall is predicted for rest of the country.
Temperatures: The temperature will remain above normal for some parts of the Northern, Eastern, North Central, Southern, and Uva provinces during 12th May – 18th May.
Teleconnections: ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring, followed by a 62% chance of El Nino developing during May-July 2023.
MJO shall slightly suppress the rainfall during 11th May – 25th May for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the May-June-July, 2023 season shows near 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 |
Prediction
Rainfall: During the next week (27th April – 3rd May), heavy rainfall (≥ 125 mm) is predicted for the Sabaragamuwa, Western, Southern, and Central provinces and ≥ 105 mm rainfall is predicted for the Uva, North Western, North Central, and Eastern provinces of the country.
Temperatures: The temperature will remain above normal for some parts of the Northern, North Western, North Central, Uva, Eastern, and Southern provinces during 2th April – 4th May.
Teleconnections: ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring, followed by a 62% chance of El Nino developing during May and July 2023.
MJO shall moderately enhance the rainfall from 27th April – 11th May for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the May-June-July, 2023 season shows near-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 |
