Highlights

• Rainfall Prediction : Heavy rainfall is predicted for Sabaragamuwa, Southern and Western provinces during 17th – 21st Sept. Greater likelihood of dry tendency than normal is predicted in the southern SL from October to December.
• Monitored Rainfalls : Fairly heavy rains were experienced in the Western, Sabaragamuwa, Southern & North Western provinces with max of 91.7 mm in Ratnapura district on 15th September.
• Monitored Wind : From 7th – 13th September: up to 15 km/h from Southwesterly were experienced over the island.
• Monitored Sea Surface : Sea surface temperature was observed above 0.5°C to the South and West of Sri Lanka and neutral to the rest.

Interpretation

Monitoring

Rainfall  : During the last two weeks, there had been fairly heavy rainfall over the following Provinces: Sabaragamuwa, Western, North-Western and Southern.

Wind : South westerly winds prevailed in the sea area and around the island during last week.

Temperatures: The temperature anomalies were near-neutral for the whole country last week – driven by the warm SST’s.

Prediction

Rainfall : During the next week (17th – 21st September) heavy rainfall is predicted for Sabaragamuwa, Southern and Western provinces.

Temperatures : The temperature remains slightly normal for September. During 17th – 25th September, the temperature remains high especially in the Eastern, Northern, North Central and Uva provinces.

Teleconnections:
La Nina – The SST forecast indicates that the La Niña event has transitioned to ENSO-neutral and will likely remain so through the boreal summer.
MJO shall be active, thus giving slightly enhanced rainfall during 17th – 29th September.

Seasonal Precipitation : October to December is the main rainfall season in Sri Lanka. The consensus has switched from neutral to having a dry tendency. If so, it can hurt agriculture adding to fertilizer bans and hydro- power generation, given $ scarcity.

Understanding the Forecast :