Media Center
Climate Bulletin for Sri Lanka (Week of 22 May – 25 May 2024)
Highlights
Rainfall Prediction: High likelihood of heavy rainfall (100 – 150mm) is predicted for the Western, Sabaragamuwa, North Western, Southern provinces and fairly heavy rainfall (50 – 100mm) is predicted for the Central, North Central, and Uva provinces during 21 – 27 May.
Monitored Rainfall: For SL, 150 mm rainfall was received during 15 – 20 May. Apart from Western region, upto 4 – 12mm deficit of rainfall was observed during April. Depression 99B in the BoB is predicted to reach cyclone status and then track away from SL.
Monitored and Predicted Wind: Winds at 850mb (1.5km) were north westerly from 12 – 18 May reaching up to 3 m/s. Winds at 850mb (1.5km) are predicted north westerly from 22 – 28 May reaching up to 20 m/s due to depression 99B(JTWC classification).
Monitored Sea and Land Temperature: Average land surface temperature was 30.3°C in the last week with warmer anomalies of +1-3°C. Sea surface temperature around Sri Lanka was 0.5 – 2.0°C above normal. The temperature has dropped slightly.
Interpretation
Monitoring
Rainfall:
During the last two weeks, there had been very heavy rainfall over the following area:
Kesbewa.
Daily Average Rainfall in the Met stations for previous week of (18th May – 21st May) = 23.1 mm
Maximum Daily Rainfall: 214.5 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 for the country except some parts of the Northern, Eastern, and Western provinces driven by the warm SST’s.
Prediction
Rainfall: During the next week (21st May – 27th May), heavy rainfall (100 – 150 mm) is predicted for the Western, Sabaragamuwa, North Western, and Southern provinces and fairly heavy rainfall (50 -100 mm) is predicted for the rest.
Temperatures: The temperature will remain below normal for some parts of the Central, Western, North Western, Southern, and Northern provinces and above normal some parts of eastern province during 22nd – 28th May.
Teleconnections: MJO shall moderately enhance the rainfall during 21st- 25th May, near neutral the rainfall during 26th – 30th May, and moderately suppress the rainfall during 31st May – 4th June for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the June-July-August, 2024 season shows a 50% or more tendency toward above normal precipitation for the country.
Terminology for Rainfall Ranges
| Rainfall | |
| 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 |
