Wednesday, September 02, 2009

Central, north-west India may get more rains

India Meteorological Department (IMD) maintained the outlook for a low-pressure area in the Bay of Bengal on Tuesday when international models indicated building buzz in the South China Sea almost simultaneously.

Some of the monsoon flows might get drawn into the South China Sea system initially but the Bay ‘low’ and its cousin next door are forecast to break away from each other later to set up their independent perches.

May recurve


The South China Sea system will track north-northeast to start with, but will recurve to move west-northwest to make landfalls on Taiwan and southwest China one after the other around September 11.

The west or west-northwest track of storms from the West Pacific/South China Sea is known to reverberate in the Bay of Bengal with a remnant meandering its way in four or five days later.

This could possibly go on to set off another wave of rains from the Bay into mainland India, although in the instant case, this would bear some watching given that the monsoon would be preparing to leave the country.

Meanwhile, the US National Centres for Environmental Prediction (NCEP) has observed that the west and parts of peninsular and central India would continue to receive rains until September 17 according to updated forecasts.

The NCEP forecast clearly shows a concentrated wave of sustained rains entering the Bay across Indochina-Myanmar. This could well mean the extension of the wet weather triggered from the South China Sea. Back home, the monsoon trough passed through Anoopgarh, Churu, Alwar, Nowgaon, Pendra and Puri before plunging into east-central Bay of Bengal. The Noida-based National Centre for Medium Range Weather Forecasting (NCMRWF), the monsoon trough is likely to remain south of its normal position during next five days, boosting the cause of seasonal rains.

Whirl persists


The parent cyclonic circulation of the brewing ‘low’ persisted overnight in the upper levels over west-central and adjoining north-west Bay of Bengal.

Model prediction suggests that under its influence, the ‘low’ is likely to develop over west-central Bay of Bengal and neighbourhood during the next two days and is likely to move to the north-west.

The ECMWF forecasts suggest that the ‘low’ moving north-west over land will encounter a trough in the westerlies (western disturbance) dipping low to set off a wet session over large parts of north India.

The NCEP, more or less, agrees with the outlook, saying that the core of the rains will sit over north India – north Madhya Pradesh, west Uttar Pradesh, Haryana-Delhi and possibly Punjab. Rains of varying intensity are indicated for the rest of the country as well.

An IMD forecast valid for the next few days indicated the possibility of fairly widespread rainfall activity with isolated heavy falls over parts of central and adjoining north peninsula during the next four days.

Fairly widespread rainfall activity with isolated heavy falls is also likely over parts of north-west India from Thursday. Satellite pictures on Tuesday showed convective clouds over southeast Arabian Sea, southwest and adjoining west-central Bay of Bengal, the Andaman Sea and extreme south peninsular India.

More showers


A warning valid for the next two days said that isolated heavy rainfall is likely over Andhra Pradesh, Coastal Karnataka and the Andaman and Nicobar Islands during the next two days and over Himachal Pradesh, Uttarakhand, Tamil Nadu, Kerala and Lakshadweep during the next 24 hours. The three days from Friday will see an increase in rainfall activity along the west coast. Fairly widespread rainfall activity with isolated heavy falls is likely to continue over central and north-west India.

A Chennai Met Centre update said on Tuesday that the monsoon was vigorous overnight in Rayalaseema and active over Telangana, coastal Andhra Pradesh and Karnataka. Rainfall occurred at most places in Rayalaseema; at many places in Telangana, coastal Andhra Pradesh, Kerala and Karnataka; at a few places in Tamil Nadu, and Lakshadweep

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