Wednesday, June 03, 2009

LOW in north Bay of Bengal

There's a possibility of a LOW pressure formation over the Northern extreme of Bay of Bengal... these kind of formations are typical during the South-west monsoon season.
These lows will trigger more monsoon rains for Northern Bay region and to the western ghats region.
Latest GFS also predicts a LOW to the extreme north of Bay.

And latest satellite shot also shows some sign of it.

Monsoon will revive over the western coast in next 2 or 3 days along with the LOW formation over the northern Bay.
Chennai was so hot for the past 2 weeks from 20-May-09.
City is experiencing temperature of around and over 40 deg Celsius for the past 13 days. Today we had signs of a GOOD thunder cell formation and then fading away.
We'll have a share of late evening thunder shower in next 2 or 3 days.
Today also the temperature was near 40 deg Celsius.

IMD watch for fresh Bay ‘low’ even as lull persists

India Meteorological Department (IMD) has joined the vigil for what likely is a brewing ‘low’ in North Bay of Bengal later this week (June 4, Thursday).

The European Centre for Medium-Range Weather Forecasts (ECMWF) is already on record with its projection of a churn in North Bay but had little found little support from peer models.


The ECMWF says that the system would be triggered as an itinerant westerly trough dips into the Head Bay.

The causative western disturbance moved into Jammu and Kashmir on Sunday with a trough in the upper levels of the atmosphere.

The entourage is predicted to get a move to east India during the course of the week.

The ECMWF sees the system locking itself to a slot over the Head Bay and staying there for a while.

Proximity to land grants it hardly any elbowroom to move around the waters to intensify.

But the system may beat odds to intensify before making a landfall, yet again, over West Bengal.

This is the track chosen by predecessor Cyclone Aila as it crossed land earlier last week.


Given that there is no much room for lateral movement, what could likely fuel the growth of the Bay system is its staying power over waters (June 4 to a likely landfall date of June 9 according to ECMWF) and the low vertical wind shear from a still poorly developed monsoon.

Early monsoon and end monsoon stages offer themselves as windows of opportunities for cyclone formation thanks to low vertical wind shear.

High wind shear during peak monsoon lops off towering heads of building storms and prevents cyclogenesis.

ECMWF projections also indicate the monsoon getting a leg-up over the southeast coast as also parts of east-central India (parts of interior Orissa, Andhra Pradesh and Maharashtra) as the Bay system gets anchored.

The IMD update on Sunday also noted that there has been no progress in the monsoon from its May-25 bearing.

Numerical models suggest that further advance is not likely during next three to four days.


The activity is likely to remain subdued over south peninsula except west coast where rainfall activity is likely to increase during the next two days.

A persistent trough/wind discontinuity along the ‘trunk’ of the mainland amplified the poorly endowed monsoon features obtaining on Sunday.

The trough ran down from Jharkhand to north coastal Andhra Pradesh through Chhattisgarh headed by cyclonic circulation over Jharkhand.

It featured the confluence of opposing wind streams and resultant unstable weather.

Rainfall occurred at many places over Kerala and interior Tamil Nadu during the 24 hours ending Sunday morning.

Isolated rainfall occurred over Lakshadweep, coastal Andhra Pradesh, Telangana, coastal Tamil Nadu and Karnataka.

Forecast for the next two days said rain or thundershowers are likely at many places over Kerala and Lakshadweep and at a few places over interior Tamil Nadu, coastal and south interior Karnataka.

Isolated rain or thundershowers have been forecast over coastal Tamil Nadu, Puducherry, north interior Karnataka and coastal Andhra Pradesh.

A warning spoke about the possibility of isolated heavy rain over Kerala and Lakshadweep.

June likely to be less hot for Chennai

Original from::
posted on 31-May-09

CHENNAI: The hot, stuffy weather prevailing over the past few days may not last long. "It is still summer, but in June the mercury is unlikely to
cross 40 degrees Celsius on consecutive days as it did in May, or touch 42 degrees C," said Y E A Raj, deputy director general, Regional Meteorological Centre (RMC). Day temperatures may not go beyond 38 or 39 degree C. "Whether it will lead to better comfort level depends on the revival of the southwest monsoon, which has been dormant after setting in early," he added.

The formation of heavy clouds over the Bay of Bengal on Saturday is an encouraging sign and there are indications that the southwest monsoon may revive in the coming few days. "Already many districts received rainfall on Saturday and the weather is likely to improve," said Raj. Chennai, too, fared better, with the mercury recording 39 degrees C on Friday and Saturday, with the forecast for Sunday being 39 degrees C.

In the past decade, barring 1994 and 2004, day temperatures in May crossed 41 degree C. The highest ever - 45 degree C - was recorded on May 31, 1910 and in 2003. However, with the Met department forecasting 39 degree C for Sunday, it could mark the the beginning of better weather.
Chennai - now 9:35am it's already 35.0°C.. going to be a very hot day with 65% chance of thunder shower late in evening.
Yesterday, thunder storm activity was low all thru India. There were signs of monsoon revival, now it's subdued.