Monsoon Update - Low Pressure Area

A low-pressure area formed over east-central Bay of Bengal on Tuesday a day ahead of projections and at a location farther out into the sea than was originally thought.

The emerging scenario has crucial implications in that it affords the system extended "ocean residency" and longer distances to travel over warm seawaters, which could combine to alter its growth dynamics overnight.

Calibrated progression to cyclonic strength is not being entirely ruled out now.

The India Meteorological Department (IMD) has said the system could deepen into a depression by Wednesday itself.

Dr Akhilesh Gupta, Advisor to the Department of Science and Technology, said he would not be surprised to see it spinning further as a deep depression, even a cyclone.

ALERT FOR MUMBAI

Significantly, after crossing the Andhra Pradesh coast, the system will be able to traverse the north-northwest track over land without much weakening and cap it all in a blow-up of rainfall over North Konkan (including Mumbai) and south Gujarat.

A rare combination of atmospheric features may actually help the heavy to exceptionally heavy precipitation in the region to last for some time.

The Andhra Pradesh, Maharashtra and Gujarat administrations are being separately notified to take rearguard action.

RARE CONVERGENCE

Dr Gupta said the system would witness a convergence of monsoon flows from both the Arabian Sea and the Bay of Bengal for four days from Saturday.

Predicted circulation features and convergence are quite favourable to trigger exceptionally heavy rains over North Konkan and South Gujarat. There is, of course, no comparison to the cloudburst that caused the Mumbai deluge of July 2005.

But the heavy rains could sustain for a much longer period in this case, spread over a much larger geography.

In this manner, monsoon focus will shift to the peninsula, while it would remain stagnant towards the east of the country. The system will help strength the monsoon flow over the Arabian Sea.

This clearly indicates that monsoon is likely to enter into an active phase beginning Wednesday.

TORRENTIAL RAIN

The system has not only got the potential to intensify into a depression by Wednesday and move west-northwestwards but also the power to sustain over land for at least five days.

North Andhra Pradesh, south Maharashtra, north Konkan and south Gujarat will bear the brunt of the torrential rains.

Kerala and Tamil Nadu will also experience heavy downpour.Rainfall activity is likely to increase over Andhra Pradesh, Orissa and south Chhattisgarh on Thursday and Friday.

The enhanced rainfall belt would shift to Maharashtra, Goa, Karnataka, south Madhya Pradesh and Gujarat for four days from Saturday.

During this period, the monsoon is likely to advance further into remaining parts of Orissa, Chhattisgarh and Maharashtra and some parts of Madhya Pradesh and Gujarat.

The active offshore trough will bring widespread rainfall with heavy to very heavy falls along the west coast during the next five days.

FRESH `LOW'

High-resolution global model predictions further indicate that subsequent to the system moving over to north Konkan/south Gujarat on June 26, another `low' could spring up in the Head Bay by Wednesday next.

Since the predicted event is more than a week from now, the accuracy of prediction may be low.

But what is more important is that the monsoon flow is expected to remain intact even after the present system moves westward and weakens.

This opens up the prospect of monsoon rains reaching other parts (northwest India, for instance) on time, Dr Gupta said.