Archive · 13 Nov 2025
Widespread Rainfall Expected Across Southern India and Andaman Sea
Get ready for a lot of rain!
Southern India, including Tamil Nadu and Kerala, is expected to have widespread rain and thunderstorms starting this weekend and into next week.
This is because of a swirling weather pattern forming in the Bay of Bengal.
Some storms might even get strong enough to become a cyclone off the coast of Tamil Nadu.
This weather pattern could be influenced by typhoons far away in the Pacific Ocean.
Forecasters in the US and Europe are watching closely, with slightly different ideas about when a bigger storm might form, but they agree that the Bay of Bengal is becoming active.
It's important to stay updated on the weather alerts.
Widespread rainfall and thunderstorms are predicted for Tamil Nadu and Kerala from Saturday and Monday, respectively.
Isolated heavy rainfall is expected over Tamil Nadu for three days from Saturday, and over Kerala, Mahe, Andhra Pradesh, Yanam, and Rayalaseema from Monday.
A cyclonic circulation in the Bay of Bengal and a trough impacting coastal areas are causing the current and expected weather.
There's a possibility of a major storm system developing off the Tamil Nadu coast, with different timelines suggested by US and European weather agencies.
Weather activity in the South China Sea and northwest Pacific, including the remnants of Typhoon Fung Wong, could influence storm formation in the Bay of Bengal.
- Who
- India Meteorological Department (IMD), US National Weather Service, European Centre for Medium-Range Weather Forecasts, Myanmar Department of Meteorology and Hydrology
- What
- Widespread rainfall, thunderstorms, and lightning are forecast, with the potential for a storm system to develop off the Tamil Nadu coast.
- When
- From Saturday (November 15, 2025) for Tamil Nadu, and from Monday (November 17, 2025) for Kerala, Mahe, Andhra Pradesh, Yanam, and Rayalaseema. Potential storm development from November 19 or November 24.
- Where
- Tamil Nadu, Kerala, Mahe, Andhra Pradesh, Yanam, Rayalaseema, Andaman Sea, Sri Lanka coasts, South China Sea, Taiwan, Philippines, northwest Pacific.
- Why
- Due to an upper air cyclonic circulation over the Bay of Bengal, a trough impacting coastal regions, and potential influence from systems originating in the South China Sea/northwest Pacific.
US National Weather Service
European Centre for Medium-Range Weather Forecasts
Storm System Development Timeline
US National Weather Service
Assesses a 20-40% chance of a major storm system developing off the Tamil Nadu and Sri Lanka coast starting November 19 (Wednesday next week).
European Centre for Medium-Range Weather Forecasts
Hints at a storm formation in the Bay of Bengal as a remnant system from the South China Sea drifts in, posing off the Tamil Nadu coast during the week beginning November 24 (Monday next week).
- Expected Rainfall Areas
- Tamil Nadu, Kerala, Mahe, Andhra Pradesh, Yanam, Rayalaseema, Andaman Sea
- Expected Rainfall Timing
- From Saturday over Tamil Nadu; from Monday over Kerala, Mahe, Andhra Pradesh, Yanam, Rayalaseema.
- Associated Phenomena
- Thunderstorms and lightning activity
- Contributing Factors
- Circulation over Bay of Bengal, trough impacting Tamil Nadu and Sri Lanka coasts, potential influence from South China Sea and northwest Pacific systems.
- Potential Storm Development Forecast
- US National Weather Service: 20-40% chance of major storm system developing off Tamil Nadu/Sri Lanka coast from Nov 19. ECMWF: Storm formation in Bay of Bengal from Nov 24.
- Typhoon Fung Wong Influence
- Expected to set up a precursor low over South China Sea that could move into the Bay of Bengal.
