Massive Cloud Surge Over Bay of Bengal Signals Birth of New Weather System Circulation over Malacca Strait expected to seed fresh low; IMD warns of intensified rains across South India

November 20, 2025 

A powerful cloud mass over the south-east Bay of Bengal is showing clear signs of transformation, as a fresh upper-air cyclonic circulation took shape over the central Strait of Malacca on Thursday. Meteorologists say this developing feature is poised to evolve into the season’s next low-pressure area by Saturday, setting the stage for a renewed spell of active weather over India’s southern coastline.

Low-Pressure Area Brewing

According to the India Meteorological Department (IMD), the emerging low is expected to strengthen into a depression by Monday. Dynamic model projections — including the IMD’s own suite of forecasts — indicate a further upgrade into a deep depression or even a cyclone as it tracks over the south-west Bay by mid-week.

The system’s anticipated movement is west-northwestward, initially steering toward Sri Lanka and south Tamil Nadu before intensifying over open waters.

South India Braces for Prolonged Rain

With the brewing system gathering strength, weather agencies warn of an extended period of rainfall across multiple southern states:

• Tamil Nadu: Moderate rain or thunderstorms expected for six consecutive days starting Friday, with isolated heavy spells likely.
• Kerala & Mahe: Three days of rainfall from Friday.
• Coastal Andhra Pradesh & Yanam, Rayalaseema: Showers forecast next Wednesday.
• Andaman & Nicobar Islands: Heavy to very heavy rain on Friday and Saturday, with additional showers on Sunday and Monday.

Thunderstorms accompanied by lightning are also forecast across Tamil Nadu, Kerala, Coastal Andhra Pradesh, Yanam, Rayalaseema, and the Andaman & Nicobar Islands. Gusty winds are expected to reach 40–50 km/hr on Monday, escalating to 50–60 km/hr from Friday onward in some pockets.

Overnight Deluge Soaks Tamil Nadu

Meanwhile, an existing low-pressure area over the Lakshadweep–Maldives region and a weakening circulation over the south-west Bay teamed up to unleash heavy overnight rainfall across Tamil Nadu, Puducherry, and Karaikal during the 24 hours ending Thursday morning.

Lakshadweep and parts of the Andaman & Nicobar Islands also recorded intense showers.

Significant Rainfall Totals

Noteworthy rainfall amounts (in cm) during this period include:

• Ayikudi (Tenkasi) – 14
• Tenkasi – 12
• Ambasamudram – 11
• Kannadian Anicut (Tirunelveli) – 10
• Tenkasi AWS, Nalumukku, Oothu (Tirunelveli) – 9 each
• Karuppanadhi Dam (Tenkasi), Kakkachi (Tirunelveli), Long Island (North & Middle Andaman) – 8 each
• Manjolai (Tirunelveli), Minicoy (Lakshadweep) – 7 each

Looking Ahead

With the Bay of Bengal set to host another strengthening system, meteorologists advise residents along the Tamil Nadu, Kerala, and south Andhra Pradesh coasts to stay alert for updates. As ocean and atmospheric conditions align, the region may be heading into another active spell of early-winter monsoon dynamics.