Satellite pictures showed clouds massing up over the west coast and southern parts of Tamil Nadu as north-east monsoon braces to open a new front over Kerala and Mahe and South Interior Karnataka. | Photo Credit: www.windy.com

Heavy rain clouds enveloped much of the west coast across Kerala, Karnataka and Maharashtra on Monday, as the north-east monsoon prepared to open a fresh spell of stormy weather over the South Peninsula. North coastal Tamil Nadu and adjoining interior districts, meanwhile, experienced alternating sunshine and showers.

India Meteorological Department (IMD) has forecast isolated very heavy rainfall over Tamil Nadu, Puducherry and Karaikal on Tuesday and Wednesday. Isolated heavy rain is likely over Kerala and Mahe over next six days; Lakshadweep and Tamil Nadu, Puducherry and Karaikal for four days from Thursday; South Interior Karnataka for four days from Wednesday; Coastal Andhra Pradesh and Yanam for two days; and Rayalaseema on Wednesday.

The evolving weather is being driven by a trough extending from a cyclonic circulation over the south-west Bay of Bengal and adjoining north Tamil Nadu coast towards the north-west Bay of Bengal, alongside an upper-air cyclonic circulation over North Interior Karnataka. Together, these features are promoting wind convergence, cloud formation and rainfall across the region.

Satellite imagery at 4.30 pm on Monday showed extensive cloud cover stretching from Kolhapur in Maharashtra and Panaji in Goa and across Karnataka’s Belagavi, Hubballi, Sirsi, Udupi and Mangaluru; and Kerala’s Kannur and Kozhikode. In Tamil Nadu, Coimbatore, Theni, Sivakasi, Madurai, Tiruchirappalli, Salem and Dharmapuri were among the places under the cloud shield. A zone of wind convergence extended from Mumbai to Thiruvananthapuram, spilling into southern Tamil Nadu and covering the Cauvery delta districts.

The 24 hours ending Monday morning had already brought heavy to very heavy rainfall to Tamil Nadu, Puducherry and Karaikal, with isolated heavy falls over Coastal Karnataka and Kerala. Periyanaickenpalayam in Coimbatore district topped the rainfall chart with 18 cm, followed by Coimbatore AWS with 11 cm. TNAU Coimbatore and Kovilankulam in Virudhunagar district recorded 8 cm each, while Munakkal AWS in Thrissur received 7 cm and Sivakasi in Virudhunagar district 6 cm. Subramanya in Dakshina Kannada recorded 9 cm.

An incoming circulation from the Gulf of Thailand will be closely watched as it moves westwards towards the Andaman Sea, where it could likely develop into a low-pressure area and intensify. The IMD broadly shares this outlook, pointing to the possibility of a new rain-bearing system emerging over the Bay of Bengal.

The more uncertain prospect is whether a second system will develop over the Arabian Sea. The European Centre for Medium-Range Weather Forecasts (ECMWF) has maintained its outlook for a low-pressure area to form around Lakshadweep on the Arabian Sea side, and intensify, while moving towards the north Karnataka-Goa coast. The IMD, however, appears less convinced about this scenario.

If both systems develop, they could influence the distribution of moisture and rainfall across the South Peninsula. A review of model forecasts suggest it would be premature to conclude the two would necessarily weaken the north-east monsoon. It is their eventual tracks, intensity and interaction with prevailing circulation that could determine whether rainfall is enhanced in some areas, suppressed in others, or redistributed across the region. 

Published on October 19, 2026