Friday, September 14, 2007

The widhdrawal phase of the monsoon seems to have halted at the extreme west of Rajasthan. True to its nature as throughout the season, this monsoon has become erratic and unnatural in its behaviour. The low humidity level, is now restricted to the extreme corner of India, where I think the monsoon is over. Also, the main factor of widhrawal, the 200 hpa winds, are now surprisingly moving back northwards.

Having moved north, it may allow the current new low in the bay to creep inwards, and cause some rain. As the low is too close to the coast, chances of its gaining strength is dim. Another low is predicted in the bay around the 20th. which is expected to gain strength, and by the 23rd. be near cyclonic stage. Its expected movement is to move inland through central India.

An interesting development forecast is a low forming over south Maharashtra around the 19th. and coming upto the konkan coast on the 20th. With this, it is expected that konkan should get heavy rain by then.

Mumbai, as a result, will get heavy rains from the 18th/19th.(around 20 mms/day), culminating into heavy rains by the 20th.(around 50-60 mms). Thus the temporary dry spell should end (with thundershowers), in a day or two.

The 2 lows from the bay, will bring in a fresh surge of rainfall into the northern parts of the Indian Peninsula, the west coast and parts of southern states too. However, the northwest region of India is expected to remain dry and out of reach of the new wave of rain.The seasonal "ridge like" setting over Pakistan and west Rajasthan ,which has started will prevent the systems from taking the normal north-west route, but push into central India.

At this stage, the monsoon overall is 3.5% above the normal average on all India basis. This IMD map shows the distribution of rain.

1 comment:

Anonymous said...

True to what you have mentioned, the IMD has forecasted increasing rains for Maharashtra and Goa from 18th Sept. onwards, also the Vorticity diagrams show formation of a very well marked low just over Mumbai on 22nd Sept there by bringing about even more rains, well looks like we all have to wait a bit longer to see the last of rains. I think the end of monsoon for Mumbai city would be around mid - October, don't know if it has ever delayed by so much.

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