Wednesday, September 02, 2009

Still Bay region east of Chennai is active ... .. while Heavy monsoon activity over Maharastra.

IMD sees fresh Bay ‘low’ in 2 days

ISSUED ON: 31-Aug-09
The monsoon has been vigorous in Saurashtra and Kutch and active in Nagaland-Manipur-Mizoram-Tripura, west Rajasthan, coastal Andhra Pradesh and Telangana during the 24 hours ended Monday morning.

Widespread overnight rainfall was reported from Gujarat and coastal Andhra Pradesh while it was fairly widespread over Konkan, Goa, coastal Karnataka, Orissa and Punjab.

PARENT WHIRL The India Met Department (IMD) has put the west-central Bay of Bengal and the neighbourhood for watch for signs of a brewing low-pressure area around September 3 (Thursday).

A preparatory upper air cyclonic circulation is already present over west-central and adjoining northwest Bay of Bengal. It is expected to descend to the lower levels of the atmosphere and deepen to set up the ‘low.’

Satellite pictures on Monday showed convective clouds over north Arabian Sea, west-central and adjoining southwest Bay of Bengal, Punjab, Himachal Pradesh, Andhra Pradesh and Uttar Pradesh.

The IMD has forecast fairly widespread rainfall with isolated heavy falls over Gujarat during the next 24 hours. This is attributed to the remnant of the ‘low’ that triggered a revival of monsoon earlier last week.

On Monday, this upper air cyclonic circulation had shifted moorings from south Rajasthan and adjoining Gujarat to right above Gujarat and neighbourhood.

Fairly widespread rainfall has been forecast also over Andhra Pradesh, south Chhattisgarh and east Madhya Pradesh during the next two to three days in tandem with the evolution of the ‘low.’

A second round of revived monsoon rains will sweep across the west coast, central and adjoining peninsular India, the Andaman and Nicobar Islands and parts of northwest India during the three days from Thursday, the IMD said.

Forecasts by the European Centre for Medium-Range Weather Forecasting (ECMWF) show a trough squatting wide across north peninsular and adjoining central India by this time.

According to the ECMWF predictions, a ‘low’ could get embedded into this trough by September 7 and move west over central India for sometime before encountering a western disturbance dipping low from the north.

Entire northern two-thirds of the country would be brought under varyingly active monsoon conditions and resultant precipitation. This could hold on past September 10.
The US National Centres for Environmental Prediction (NCEP) sees the rain regime extending north from central India as well to the east, apart from the west coast until September 16.


Meanwhile, the Chennai Met Centre said that the monsoon has been vigorous over coastal Andhra Pradesh and active over Telangana and coastal Karnataka during the 24 hours ending Monday morning.

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

Coldest, driest, calmest place on Earth found

In a study to assess the many factors that affect astronomy, a joint US-Australian research team has found the ideal location for an observatory – known simply as “Ridge A”.

The untouched stretch of Antarctic terrain has been dubbed the coldest, calmest and driest place on Earth. No human is thought to have ever been there but it is expected to yield images of the heavens three times sharper than any ever taken from the ground.

The team combined data from satellites, ground stations and climate models to assess factors that affect astronomy -cloud cover, temperature, sky-brightness, water vapour, wind speeds and atmospheric turbulence.

The researchers pinpointed a site, known simply as Ridge A, that is 4,053m high up on the Antarctic Plateau. It is not only particularly remote but extremely cold and dry.

The study revealed that Ridge A has an average winter temperature of minus 70 degree Celsius and that the water content of the entire atmosphere there is sometimes less than the thickness of a human hair.

It is also extremely calm, which means that there is very little of the atmospheric turbulence elsewhere that makes stars appear to twinkle: “It’s so calm that there’s almost no wind or weather there at all,” says Dr Will Saunders, of the Anglo-Australian Observatory and visiting professor to UNSW, who led the study.

“The astronomical images taken at Ridge A should be at least three times sharper than at the best sites currently used by astronomers,” says Dr Saunders.

“Because the sky there is so much darker and drier, it means that a modestly-sized telescope there would be as powerful as the largest telescopes anywhere else on earth,” the expert added.

They found that the best place in almost all respects was not the highest point on the Plateau – called Dome A – but 150km away along a flat ridge.

“Ridge A looks to be significantly better than elsewhere on the Antarctic plateau and far superior to the best existing observatories on high mountain tops in Hawaii and Chile,” says Dr Saunders.

The finding is published today in the Publications of the Astronomical Society.
Tourism:: "Pushkar Camel Fair" ..
GFS predicts that the southern Bay is going to be active for another 3 days ... after that Heavy rains will be over Andaman sea.
More widespread heavy showers forecast for Entire south-caostal Andhra, This will have an affect in Chennai too ...
Satellite shows more cloud formations over Bay near Chennai ..
Chennai - Against the forecast for NO night rain, we got some mild showers during early hrs of 2-Sep-2009.