Rains likely to relent as Arabian Sea `low' weakens

The low-pressure area over Kanyakumari-Lakshadweep region weakened during the 24 hours ending Tuesday morning presumably after incessant rains cooled down sea-surface temperatures.

Satellite pictures on Monday indicated that the system may just have lost traction after encountering cooler waters over east-central Arabian Sea.


WARM OFF COAST
But coastal waters off the southwest coast of India continued to feature sea-surface temperatures of up to 30 degree Celsius, well above the threshold limit of 27.5 degree Celsius for weather systems to sustain.

Satellite pictures by international models also indicated that the `warm pool' may have withdrawn from around Sri Lanka to extend south and southeast bordering the island- nation's territorial waters but touching the west coast of Indonesia.

This is where models see the next significant weather activity being triggered, culminating in an easterly wave that India Meteorological Department (IMD) expects to buffet the country's southeast coast by the weekend.

Still, a remnant cyclonic circulation hovered over Lakshadweep and neighbourhood on Monday. A trough of low pressure extended from here to north Maharashtra coast where easterlies could still rain down their moisture.

Forecast for the next two days said that rain or thundershowers are likely at many places over Kerala, Lakshadweep and coastal Karnataka.

A few places over Tamil Nadu, Puducherry, south interior Karnataka and coastal Andhra Pradesh too may receive thundershowers.

NEXT WAVE

Isolated rain or thundershowers have been forecast over Rayalaseema, Telangana and north interior Karnataka in what is largely a weakening trend in intensity ahead of the next southerly rain wave.

This wave, with a cyclonic circulation or even a full-fledged `low' in tow, is picked by international models, including the European Centre for Medium-Range Weather Forecasts (ECMWF), to mostly track across or just off the south of Sri Lanka taking away with it a bulk of the rains.

Secondary gains are indicated for the whole of Sri Lanka and the adjoining southeast Tamil Nadu coast and south Kerala. Some of the rains may get radiated to north along coastal Tamil Nadu.

The causative cyclonic circulation/`low' is forecast to die out over south-southeast Arabian Sea off the peninsular tip.

Meanwhile, IMD too has joined the outlook for the existing rainfall regime over peninsular India to slightly shift towards central and east-central India as the week wears on.

WIND PATTERN

Guidance by numerical weather prediction models signalled the presence of an upper air trough extending from the Kanyakumari coast to Konkan (Maharashtra) coast.

This formation will continue to support a regime of westerly to west-northwesterly winds over the plains of northwest India and Indo-Gangetic plains during the next 24 hours.

Thereafter, the winds will turn northwesterly with gradual strengthening, which will colder climes into the region. Forceful winds would help blow away the threat of dense fog as well.

IMD satellite pictures showed convective clouds over parts of southeast and adjoining east-central Arabian Sea. Low to medium-high clouds were seen over parts of northwest, central, east, northeast and peninsular India.

Scattered to fairly widespread rainfall activity is likely over the North-East during the next three days. Maximum temperatures could rise by 3-4 degree Celsius over the plains of northwest India during the four days.

Moderate fog conditions are likely to continue over plains of northwest India during the next three days.