The India Meteorological Department (IMD) on Tuesday issued a bulletin forecasting light to moderate rain and thunderstorms at many or some places until September 28. The region may also experience isolated heavy rainfall, prompting the IMD to issue yellow alerts for select districts.

District-wise forecast

  • September 25 (Thursday): Alappuzha, Kottayam, Idukki, Ernakulam, Thrissur
  • September 26 (Friday): Pathanamthitta, Alappuzha, Kottayam, Idukki, Ernakulam, Thrissur
  • September 27 (Saturday): Malappuram, Kozhikode, Wayanad, Kannur, Kasaragod

Isolated heavy rainfall is expected, defined as 64.5 mm to 115.5 mm of rainfall in 24 hours.

Reason for rain

A Low-Pressure Area (LPA) was located over coastal areas of Gangetic West Bengal and adjoining north Odisha and northwest Bay of Bengal on September 23. This system is expected to persist for 24 hours before weakening.

A trough from the cyclonic circulation associated with the LPA runs to Telangana across Odisha at lower tropospheric levels. Another trough from the upper air cyclonic circulation linked to the LPA extends to the south Maharashtra coast across Odisha, south Chhattisgarh, Telangana, and north interior Karnataka at lower and middle tropospheric levels.

A fresh low-pressure area is likely to form over northwest and adjoining central Bay of Bengal around September 25. It is expected to move westwards and become a depression over northwest and adjoining west-central Bay of Bengal off South Odisha–North Andhra Pradesh coasts on September 26. The depression is likely to cross the South Odisha–North Andhra Pradesh coasts around September 27.

An upper air cyclonic circulation is present over central parts of Madhya Maharashtra and neighbourhoods at 3.1 km above mean sea level.