Highlights

• Rainfall Prediction : Heavy rainfall is predicted in Central, Sabaragamuwa, Southern and Western provinces during 24th – 28th Sept. Greater likelihood of dry tendency than normal is predicted for southern Sri Lanka from Oct to Dec.
• Monitored Rainfalls : Heavy rainfall was experienced in Eastern, North Central, Sabaragamuwa and Western provinces with max of 135.2 mm in Trincomalee district on 17th Sept.
• Monitored Wind : From 14th – 20th Sept, up to 35 km/h Southwesterlies were experienced across the island.
• Monitored Sea Surface : Sea surface temperature was observed above 0.5°C to the South and 1.00C to the North of Sri Lanka.

Interpretation

Monitoring

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

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

Temperatures: The temperature anomalies were in between 10C – 30C in Central and Sabaragamuwa provinces while near-neutral for the rest of the country last week, driven by the warm SST’s.

Prediction

Rainfall : During the next week (24th – 28th September) heavy rainfall is predicted for Central, Sabaragamuwa, Southern, Western and Central provinces.

Temperatures : The temperature remains slightly normal for September. During 24th September – 2nd October, the temperature remains high especially in the Eastern, Southern and Uva provinces.

Teleconnections:
La Nina -The SST forecast indicates that ENSO-neutral are present and a transition from ENSO-neutral to La Niña is favored in the next couple of months.
MJO shall be active, thus giving slightly enhanced rainfall during 24th September – 6th October.

Seasonal Precipitation : October to December is the main rainfall season in Sri Lanka. The consensus predictions has switched from neutral to favoring a dry tendency. A dry tendency can hurt agricultural production and it adds to farmer difficulties due to the fertilizer bans. However, since this is the wet season the impact will not be as severe.

However, the bigger impact shall be that it shall reduce the generated hydropower in the coming months. This can hurt the economy due to the scarcity in Foreign Exchange within the country due to the Central Bank regulations.

Understanding the Forecast :