Early Monsoon Alert: IMD Says Weather Systems Signal Ahead-Of-Time Arrival Over Bay Of Bengal

The India Meteorological Department (IMD) has said that conditions are becoming favourable for the early onset of the southwest monsoon over the south Bay of Bengal, with weather systems over the region gradually organising and intensifying.

According to IMD and multiple supporting forecasts, a low-pressure area over the southwest Bay of Bengal continues to persist and is expected to become better marked over the next 24 to 48 hours. This system is part of normal pre-monsoon activity, where warm, moist air rises and forms clouds, helping initiate large-scale rainfall development over oceanic regions.

In weather terms, the system is now showing signs of becoming more structured, meaning cloud clusters are becoming denser and winds are beginning to circulate more clearly around the low-pressure zone. Meteorologists say such developments improve moisture inflow from the ocean and support sustained rainfall activity.

A cyclonic circulation extending up to 4.5 km above sea level has also been observed over the region. This upper-air rotation helps pull moist air into the system and strengthens cloud formation, making rainfall more widespread over the surrounding sea areas.

Recent forecasts indicate that the southwest monsoon may reach the Andaman and Nicobar Islands between May 14 and May 16 , marking its first entry point over Indian territory. This is slightly ahead of the usual climatological onset around May 20 and represents the first stage of the monsoon’s advance over the Bay of Bengal region.

Meteorologists also note that pre-monsoon thunderstorms and cloud activity are already increasing over parts of the Bay of Bengal and adjoining coastal regions, which is consistent with the transition phase into the monsoon season.

However, IMD has clarified that while early signs are strengthening over the islands, the monsoon onset over Kerala around June 1 remains the benchmark for the official arrival over mainland India .

Separately, the weather department has maintained its seasonal outlook of below-normal rainfall for 2026 , with India expected to receive around 80 cm of rainfall compared to the long-period average of 87 cm (1971–2020). This outlook is linked to evolving El Niño conditions , which typically suppress monsoon rainfall by weakening large-scale wind circulation patterns.