Friday, November 27, 2009

Isolated rain, thundershowers to continue in South

The low-pressure area over south-east Bay of Bengal has become less marked during the 24 hours ending Thursday morning but an associated upper air cyclonic circulation is moving slowly in a west-northwest direction.

Significant cooling

This should take the circulation towards the south Tamil Nadu and Sri Lanka coasts by Monday (November 30) and spark off some rain activity, the India Meteorological Department (IMD) said in an update on Thursday. Seawaters along the till-now productive stretch linking south-west Bay of Bengal to the south-east have cooled down significantly compared with those prevailing in the upper Bay of Bengal basin as well to the south.

This robbed the ‘low’ off the much-needed support at the ground level, reducing the moisture feed as well. International models have been indicating the progression of a cyclonic circulation towards the sub-continent, if not the ‘low.’

An update from the Chennai Met Centre said that isolated rainfall has been reported from Kerala, Tamil Nadu, coastal and south interior Karnataka during the 24 hours ending Thursday morning.

The north-east monsoon is currently in a weak phase with the southern peninsula slipping under a dry spell over the last couple of days. Weather models, though, suggest that isolated rain or thundershower activity would continue.

The outlook from the Chennai Met Centre has said that isolated rain or thundershowers are likely over Tamil Nadu, Puducherry, Kerala, Lakshadweep, coastal and south interior Karnataka over the next two days.

The satellite cloud imagery put out by the IMD showed convective clouds over parts of south Arabian Sea.

According to the US National Centres for Environmental Prediction (NCEP), the rain-or-thundershower regime over the southern peninsula would last until December 3 with slightly concentrated wet regime over the Tamil Nadu coast.

December 4 to 12 would witness a renewed push of rains from the south and south-east ahead of the next wet phase of the Madden-Julian Oscillation (MJO) wave that travels in the upper levels from west to east.

The wave provides guidance for weather to play out over ground by helping set off convection, cloud-building and precipitation. The alternating suppressed rainfall phase (dry phase) of the MJO event is currently in operation over the peninsular seas.

Towards the north, minimum temperatures were below normal over many parts of east and northwest India and the North-eastern States on Thursday, an IMD update said.

The lowest minimum temperature of 5.0 deg Celsius was recorded at Sarsawa in Uttar Pradesh as colder north-westerly winds continued to blow into the country.

Outlook for the next two days said that minimum temperatures are likely to fall further over parts of central and east India and plains of northwest India.

A fresh western disturbance is likely to affect western Himalayan region from Sunday. The arrival phase would reverse the dip in mercury for a while, but would again turn colder after the westerly system moves away to the east.

Informative Sweet little reader comments

READER:: sset said...
Very strange. Last year same time we had cyclone Nisha. This year weakest of monsoon. In fact we can't even say this is monsoon. Back to dog days for TamilNadu.

Sweet & informative reponse from another READER::
Dear SSET,
Asian Summer Monsoon which is a giant wind pattern originating from Mascerene High {30 S /60 E.The moisture laden winds blow across Indian Ocean and also [1] Arabian sea [2] Bay of Bengal [3] south China Sea and brings rainfall to all Asian countries like India, China, Bangladesh, Srilanka etc. This monsoon rain is life line for people live in these countries. In India 90% of the entire continent except Tamilnadu is getting rainfall during SW monsoon period. [TN too gets rainfall 36-42 percent of annual rainfall.
North East Monsoon is smaller system compared to SW monsoon. Further NEM is nothing but reversal of wind pattern or retreating SW monsoon. During this season only TN is mainly benefited.
Of course Mumbai recorde 94.7 cm rainfall during July 2005. Even in Tamilnadu there are places like Kuthiraivetty in Tirunelveli district which during 1991 November cyclone received 97.0cm rainfall. This is ONE DAY ANNUAL MAXIMUM RAINFALL recorded in TN. Recently KETTY recorded 82.0 cm rainfall. NEM is also life line for TN.
CHINNA KALLAR, DEVALA, UPPR KOTHIYAR, are the wettest places in TN where the annual rainfall is more than 3000 mm to 5500 mm.
Chinna Kallar is the wettest place in south India. It receives more than 5500 mm rainfall annually.
So Please do not blame it.

Chennai - All thru the day, DRY, MILD and with cold winds from North.
13 new dengue cases in Delhi, total reaches 1054 ...
NOGAPS model predicts a wet start to December for TN coast ..
GFS still holds the prediction of a wet 1st week of december for North TN coast
Some showers along kerala coast, other than that its a clear India again ..
Chennai - Bit of a cold morning 24.2°C (5:49am) with some DEW around. Now 9:22am its clear skies.