Sunday, August 1, 2010

Chance of a Tropical Depression in Bay of Bengal in first week of August

Akshay Deoras,
Severe Weather Forecaster

With sufficiently low formations of low pressures and particularly solid tropical depressions in bay of bengal, The SW monsoon witnessed a major disappearance in Mid July period. The portion faced relief in late July when some low pressures started forming from widespread convections in bay of bengal. I have already mentioned that August and September will be very active for the SW Monsoon even more than June and July. I will like to modify this statement some and use terminology THAT MID AUGUST TO MID SEPTEMBER WILL BE ACTIVE FOR SW MONSOON OVER INDIA ESP CENTRAL INDIA

I was expecting a La Nina condition to develop this year end by August which has happened and La Nina is in a DEVELOPING STAGE. A La Nina event is sufficient to trigger good rains over India and better if the Indian Ocean Dipole remains positive. But according to the latest datas from DMI, July DMI (Dipole Mode Index) has again negative index of -0.4 which means less rainfall activity until DMI recovers. I am sure that this will rise to positive side after a sufficient La Nina has triggered thus allowing trade winds to do so...
As per the datas updated from MJO oscillations, MJO over 70-100E is -1.5 which has to be positive at this time for good rains and also Tropical cyclones
Third thing
The GFS forecast models are impressive for the formation of a Tropical Depression having an expected central pressure lower than 996mb. I see a good low level circulation with a nice mid level vorticity. But, I don't find any organised rain bands around the low which is required for strengthning of storm system. BUT since models are getting better in each run, I w'd expect a tropical depression or IF LUCKY a Tropical Storm by 5-6th August in bay of Bengal.
I will keep on updating on it

No comments:

Post a Comment