Easterly wave may be compressed to extreme south

The northeast monsoon has managed to carry its surplus run so far (nine per cent until December 16) with almost entire peninsula and central India recording excess to normal rain.

However, the extreme northwest (Saurashtra-Kutch, west Rajasthan, Haryana and Punjab) continued to throw up deficits ranging from 72 per cent to 96 per cent, an India Meteorological Department (IMD) update said.

Chhattisgarh, Gangetic West Bengal, coastal Andhra Pradesh and the entire Northeasttern State, too, have totted up deficits though comparably lower (22 per cent to 39 per cent).

Easterly wave

Going forward, an IMD outlook on Sunday said that an easterly wave is likely to affect extreme south peninsular India during the first four days of the week.

International models had forecast this possibility earlier last week, but they have lately concluded that the resultant precipitation would be confined mostly to extreme south peninsular India.

This is so because they see the rain-suppressing anti-cyclone (high-pressure area with sinking air) being pushed anomalously to the south by rampaging dry westerlies.

Some of them still see the prospect of the easterly wave setting up a blow-up of rain over southeast Tamil Nadu, adjoining Gulf of Mannar and north Sri Lanka around Thursday (December 24).

Parts of coastal Tamil Nadu to the immediate north and south Kerala, too, are forecast to be brought under sporadic showers during this phase.

The warmest seas has now retreated to the south of Sri Lanka and to the northwest along the Kerala coast stretching across southwest to the east African coast.

Trough of low

The European Centre for Medium-Range Weather Forecasts (ECMWF) sees a weak trough of low pressure building progressively from the equatorial Indian Ocean to the northeast Arabian Sea during the whole of the week.

Satellite cloud imagery on Sunday showed convective clouds over parts of south Bay of Bengal, south Andaman Sea and Jammu and Kashmir.

Meanwhile, the Chennai Regional Met Centre has predicted isolated rain or thundershowers for Tamil Nadu, Puducherry, Kerala and Lakshadweep during the next two days.

Towards the north, minimum temperatures were above normal by over Gujarat, southwest Madhya Pradesh, peninsular India, Saurashtra and Kutch, Chhattisgarh, Orissa, Jharkhand, Gangetic West Bengal, parts of Arunachal Pradesh and Rajasthan and remaining parts of Madhya Pradesh.

The lowest minimum temperature of 1.6 deg Celsius was recorded at Sarsawa (Uttar Pradesh).

A feeble western disturbance as an upper air system lay over north Pakistan and adjoining Jammu and Kashmir. Isolated to scattered rain or snow has been forecast over parts of western Himalayan region during next two days.