Sunday, August 31, 2008

In line with the assesment in the previous blog of 26th., there is no further positive development to halt the receding monsoon.

1. The monsoon trough has got even more disorganised, and is now over the Himalayas, almost non-effective. The westhern end of the trough is shifting eastwards.

2. The streamline from Imd shows the Pakistan region as having a north-south trough-not a monsoon trough- and the winds are looping along the trough. North-west India has started getting the "widhrawal" north-west winds.

3. The 200hpa. jet streams, are recurving along the Rajasthan area, and are at present weak over the central India region. In order that the monsoon sustains, they should be strong in a easterly direction.

4. Thunderstorm activity has started over the north Maharashtra/Gujarat areas. Marathwada had heavy thunderstorm rains-5to 8cms. today.

These are indications of a receding monsoon- from the north-west India-due to the absence of any organised monsoon low or depresiions forming. (Though a low vortex is expected to form in the Lakshdweep region in a couple of days, it will produce rain in coastal Karnatak/Kerala for a day or two. It will soon fizzle out at around 15N region by the 3/4th. September. The monsoon widhrawal will still continue in the north.)

Now, I anticipate, the monsoon to recede from Rajasthan in the 1st. week, and thence from Gujarat.

The coming week will result in "hit and miss" heavy thunderstorms in Rajasthan, moving south to Gujarat and Maharashtra. At this rate, the monsoon may widhraw from Gujarat by 2/3 week of September.

The 2nd. week of September should see a sudden rise in temperatures from the "non monsoon regions". Day temperatures could shoot up to 40c in Rajasthan and some cities of Gujarat around mid September.

Mumbai will get a few thunderstorms in the evenings, and if the receding trend continues, monsoon may leave Mumbai/north Maharashtra around the 15th.

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