Atmospheric disturbance expected over southwest Sri Lanka on 7th December, with heavy rains likely to continue until the 14th.

Nagamuthu Piratheeparajah, Professor in Geography at the University of Jaffna

06 December 2025, Saturday, 9:00 PM

Tomorrow (07 December 2025), an atmospheric disturbance is expected to develop over the southwestern part of Sri Lanka, accompanied by the arrival of easterly winds with high humidity.

As a result, from 07 December to 14 December 2025, moderate to heavy rainfall is likely across many regions of the country. In particular, from 09 December to 12 December, heavy rain is expected in most areas, especially in the Central, Southern, Western, Uva, Sabaragamuwa, Northern, Eastern, and North Central Provinces. The Central, Uva, Western, and Sabaragamuwa Provinces are likely to receive the highest rainfall during this period.

It is advisable to remain in safe locations, away from landslide and flood-prone areas, for a few more days. This is because:

1. The soil in many hill country areas remains saturated with moisture.
2. Since Cyclone Ditwah, there has been little evaporation due to low temperatures. For example, the average temperature in Nuwara Eliya over the past three days has been just 11°C.
3. Many reservoirs and rivers are still at full capacity.
4. The expected atmospheric disturbance may bring further heavy rain to the hill country.

These conditions increase the risk of landslides in hilly regions. Therefore, it is important to stay in safe places, and authorities should alert the public accordingly.

For the Northern, Eastern, and North Central Provinces, reservoir water levels can be maintained slightly below the Full Supply Level (FSL) rather than at maximum, as the northwest monsoon is expected until mid-January and upcoming rains can help replenish water supplies.

Additionally, in the third and fourth weeks of December, there is a possibility of two air circulations forming in the Bay of Bengal and moving towards Sri Lanka, but this can only be confirmed in the coming days.

Given the forecast for heavy rain from 08 December to 14 December, residents of low-lying areas in the Northern and Eastern Provinces, especially those near ponds and rivers, should remain vigilant.

— Nagamuthu Piratheeparajah Face Book