Heavy rain lashes TN and Kerala as ‘low’ is set to intensify

The 24 hours ending on Wednesday morning saw very heavy rainfall lash isolated places over Tamil Nadu, Puducherry and Karaikal. At the same time, it was heavy at isolated places over Kerala, Mahe, Rayalaseema, Telangana and North Interior Karnataka.

True to the India Meteorological Department (IMD) predictions, the causative low-pressure area had emerged into the Lakshadweep area and adjoining the South-East Arabian Sea. It will likely move North-North-West and become ‘more marked’ (intensify) during the next three days.

Throws open troughs

This would extend its life and potentially influence weather over Peninsular India for as many days, including Deepavali day. The extent to which the ‘low’ can intensify bears close watching since some global models indicate storm genesis in the region, though the IMD may not necessarily insist on one.

The ‘low’ has also thrown open a trough each from the Comorin to West-Central Bay of Bengal off the South Andhra Pradesh coast across Gulf of Mannar and Tamil Nadu coast on the one hand and in the easterlies from Lakshadweep to East-Central Arabian Sea off the Karnataka coast on the other, in a show of its potential to dictate regional weather for days together.

Ore heavy rain forecast

This formation will continue to trigger the light to moderate rainfall at many/most places with isolated thunderstorms and lightning over the South Peninsula during the next five days and at a few places over the North Peninsula across South Konkan, Goa, South Madhya Maharashtra and South Marathawada until November 7. 

Heavy rainfall is forecast over Kerala, Mahe, Coastal Andhra Pradesh, Yanam, Tamil Nadu, Puducherry, Karaikal, Rayalaseema and Interior Karnataka during the next five days; over Telangana and Coastal Karnataka on Wednesday and Thursday; over South Konkan, Goa and South Madhya Maharashtra on Friday and Saturday. 

Very heavy rainfall had been forecast over Kerala and Mahe on Wednesday and Thursday; over Tamil Nadu, Puducherry and Karaikal on Wednesday; and over Coastal Andhra Pradesh and Yanam until Sunday.

Kelvin Wave trigger

Meanwhile, the US Climate Prediction Centre has said that during the next two weeks, a helpful Kelvin Wave may move eastward over the Indian Ocean and back to the Maritime Continent where it may reinvigorate a stalled counterpart, a Madden-Julian Oscillation (MJO) wave.

As the Kelvin Wave propagates across the Indian Ocean, the US agency assessed that a likely storm might be generated from out of the incoming ‘low’ over the South-East Arabian Sea. Several ensemble members of the Global Ensemble Forecast System (GEFS) and the European Centre for Medium-Range Weather Forecasts (ECMWF) support this outlook

An extended outlook by the IMD valid from November 8 to 10 indicated the possibility of scattered to fairly widespread rainfall over the South Peninsula and Lakshadweep and Andaman & Nicobar Islands with isolated heavy falls over Interior Karnataka, interior Tamil Nadu, Kerala and Mahe. Isolated to scattered rainfall is likely over South Maharashtra and Goa.