Monday, March 22, 2010

Sub_Continent Heat Wave may subdue a bit:
The Heat Wave in the Southern Asian region has today shifted focus on Northern India and Sindh. The highest today, 22nd March, was at Nawabshah (Sindh), recording 44.5c. The highest in India was at Nagpur, 42.5c. The map has the distribution of today's highs.

Ok, marginally less, but at Hissar, which saw 41c, it waqs +9c ! That is, instead of 33c, it was 41c ! The IMD anomaly map shows the red region in the Northern Indian areas. Of-course not much relief, as the entire country is in the above normal range.

Just for comparisons, and to subdue the din of Global Warming",, I am attaching a map of 22 March 2004. Equally hot ! Maybe more ! So lets not jump to any conclusions (about GW) now. :)

This early heat is mainly due to the fact that a high, a ridge, in the 500hpa height, stationed itself over Sindh/Gujarat initially, and then is moving east, and gradually weakening. This has pushed the jet streams further north, and in simple terms,pushed the W.D.s,and cooler fronts far northwards.
Somewhat Good sign: The ridge is weakening, in the next few days. And, at the most, Northern regions may not see temperatures 7/9c above normal....but, a little less above the normal!

I would have made a lot of ''Monsoon Predictions" if this heat wave was to happen in say..sometime in the 2nd. week of April. I would have predicted a faster seasonal low over Rajasthan, and quick heating of the seas to create a pre monsoon low.BUT, all these pre monsoon predictions cannot be made in March. In short, these heat waves and ridges have to make a repeat performance, say after a month, for a proper build up to the monsoon.
Hopefully, we should not recieve heat convection rains in central/north-west India now in March. This would dampen the real build up of heat required next month.

Mumbai's northern suburb S'cruz suddenly reported a high of 38c today. A bit surprising, as the downtown reported 34.5c. A big difference in the two.
Not very surprising though, as Thane, also north of Mumbai and about 40kms from downtown , saw a high of 39.5c on the AWS.
Expect no respite for least as far as I can see, that is till the end of march. The reminder of this month will be hot, arounf 35c, and a bit more stuffy and hot on Thursday, 25th, maybe at 36/37c, and 26/27c at night. Thats warm, and normally should be our April end readings.

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