Low over Arabian Sea could spur activity in N-E monsoon

The low-pressure area that has formed over the South-East Arabian Sea and adjoining Lakshadweep, as predicted by the India Met Department (IMD) early this (Thursday) morning, may drive up activity in the day-old North-East monsoon to peak activity over the next few days.

http://www.imd.gov.in/pages/allindiawxfcbulletin.php

This could also help entrench extended weather activity over the South-East Arabian Sea and the adjoining East-Central Arabian Sea, even after the current 'low' runs its course and fades out.

This is because a circulation forming over the Bay of Bengal, off the Tamil Nadu coast, would cross into the South Peninsula and drift into the South-East Arabian Sea, setting up perch around the area vacated by its predecessor.

http://nwp.imd.gov.in/gfsproducts00_all.php

The result would be an envelop of heavy to very heavy wet weather over the East Coast, the South Peninsula and adjoining Peninsular India and the West Coast, into the next week.

This is more or less corroborated by predictions available for the next week and beyond, by the US National Centres for Environmental Prediction and the European Centre for Medium-Range Weather Forecasts.

Weather

Precipitation

Meanwhile, the atmospheric system matrix in the Arabian Sea underwent a change from Thursday morning into the afternoon, after the low-pressure area materialised over the region slightly earlier than expected.

As a result, a prevailing circulation over the East-Central Arabian Sea and a trough that linked it up with North Sri Lanka became less marked, as did a counterpart trough in the Bay of Bengal, off the South Tamil Nadu coast, into the West Central Bay of Bengal.

Instead, a brand new trough has been generated from the cyclonic circulation over the Maldives close to the 'low', into as far East as Telangana across Kerala, South Interior Karnataka and Rayalaseema.

The IMD has warned that these systems may trigger heavy rainfall over major parts of Peninsular India during the next three days.

Heavy to very heavy falls are likely over Tamil Nadu and Kerala during next 24 hours (until Friday) and over coastal Karnataka during the subsequent two days.

A weather tracker featured by the Climate Prediction Centre of the US National Weather Service says the intense churn initiated in the Arabian Sea could shoot off a depression in the direction of Oman/ Yemen by October-end.

Weather

Indications to this development are also available in the projections of the US National Centres for Environmental Prediction. Interestingly, the UK Met Office model sees a strong system headed towards the Mumbai/ Gujarat coast.

CWB Fuzzy Likelihood Map

The US Naval Global Environmental Model, the Japanese and the Canadian Met Agencies see similar prospects for the Arabian Sea basin, but only a conventional 'low' instead of a severe storm system, doing the rounds off the Karnataka, Goa and Konkan coasts.

Meanwhile, for the 24 hours ending Thursday morning, heavy to very heavy rain (in cm) was reported from Etayapuram (14), Kanyakumari (13), Kottayam (11), Kodaikanal (10), Tuni (8), Dharmapuri, Tuticorin and Newport (6 each), Ongole, Chennai, Coonoor, Kochi, and Nagappattinam (5 each), Paradeep and Madurai (4 each) and K Paramathy, Cuddalore and Karaikal (3 each).

The forecast for tomorrow (Friday) predicts heavy to very heavy rainfall in coastal Karnataka, while it would be heavy over Konkan, Goa, Tamil Nadu, Puducherry, Kerala, Lakshadweep, coastal Andhra Pradesh, and interior Karnataka.

Thunderstorms accompanied by lightning are likely over madhya Maharashtra, Marathwada, Konkan, Goa and interior Karnataka. Squally weather with winds clocking speeds of up to 55 km/hr (of the strength of a depression) have been warned over the East-Central Arabian Sea and the adjoining Karnataka and South Konkan coasts. Fishermen are advised not to venture into these areas.