India Meteorological Department (IMD) has predicted very heavy rainfall for Kerala and Tamil Nadu on Thursday and Friday with north-east monsoon expected to establish over larger South Peninsula anytime from now. 

The 24 hours ending Wednesday morning saw heavy to very heavy rain at isolated places over Kerala and Mahe while it was heavy at isolated places over Tamil Nadu, Puducherry and Karaikal. A low-pressure area is likely to form over south-east Arabian Sea and Lakshadweep area off Kerala-Karnataka coasts by Sunday.

Clouds mass up

Satellite pictures on Wednesday evening showed heavy clouding over the Equatorial Indian Ocean (to south and west of Sri Lanka covering Lakshadweep Sea) as well as over land over extreme southern parts of Kerala and adjoining Tamil Nadu; hilly tracts of western Tamil Nadu; South Interior Karnataka; Goa and Konkan.

Light to moderate rain or thunderstorms are forecast at some/isolated places with isolated heavy rainfall overTamil Nadu for six days; over Kerala and Mahe for seven days; Lakshadweep for five days; Coastal Andhra Pradesh and Yanam and Rayalaseema for three days; and Coastal and South Interior Karnataka for two days. 

Background setting

Elsewhere over the South Peninsula, the line of withdrawal of preceding south-west monsoon (or the June-September season) passed through Karwar; Kalaburagi; Nizamabad; Kanker; and Chandbali. Conditions are favourable for further withdrawal from remaining parts of country anytime. 

Simultaneously, with the setting in of easterly and northeasterly winds over South Peninsula and south and adjoining central Bay, the north-east monsoon rainfall activity is likely to commence initially over south-east peninsular region (Tamil Nadu, Puducherry and Karaikal; Rayalaseema; Coastal Andhra Pradesh et al). 

Heavy rain forecast

The European Centre for Medium-Range Weather Forecasts (ECMWF) signalled to the possibility of heavy to very heavy rain unfolding over parts of the West Coast and East Coast until Saturday based on the quantum of ‘vertically integrated total column water (vapour + cloud water + cloud ice but with no precipitation included) in units of kg/m2 (equivalent to mm of precipitation if all the moisture were to fall out).’ 

This projection identifies regions where there is greater potential for significant precipitation given development of convection or large scale uplift (low- pressure centres or cyclones). Accordingly, parts of adjoining land along coast in Tamil Nadu and Andhra Pradesh may receive highest amounts of rainfall during this period, apart from a swathe out into the seas over the south-east Arabian Sea off Kerala and around Lakshadweep. 

Ockhi clone in offing?

This sits well with the forecast of the ‘low’ forming over the seas off Kerala and Lakshadweep, in near-repeat of conditions identified with genesis of destructive cyclone Ockhi seven years ago, around the region. Short-to-medium predictions of IMD on Wednesday hinted at a likely cyclone forming, but headed out to Oman/Yemen.

The ECMWF picked Tamil Nadu, Andhra Pradesh, Odisha and Bengal coasts and adjoining interior for highest possibilities of heavy rain; and only a shade lower over south and adjoining north peninsula (Kerala, Tamil Nadu, Karnataka, Andhra Pradesh, Telangana and Maharashtra including Goa and Konkan) until Saturday. 

Published on October 15, 2025