Wednesday, June 24, 2009
The low pressure which established south of Gujarat, rather suddenly and unforecasted, became defined on Tuesday, and became a depression, moving northeastward into the Gujarat landmass. Some very heavy rains,between 100 to 150 mms were recorded in the southern coast of Gujarat. As of Monday night, it made landfall near Diu.
Wind shear had earliar stifled its east cloud band and whirl.
Satellite imagery shows a marked northward spread of clouds, directly a result of the depression weakening on moving on land. Anyway,it is beneficial that this weather system has pulled the Monsoon northward following almost 18-20 days of stagnancy.
And, the IMD has ,on 24th. June, advanced the monsoon into Mumbai.
Mumbai was just one day behind the all time "last date" of monsoon advance, 25th. June in 1959. The advanced area now covers south Gujarat, parts of Kutch and Madhya Mah. Inland Mah. still remains out of the monsoon reach. The monsoon progress map is available on the IMD site.
Moisture flowing from the northbound lsystem will, for about the next two days, bring precipitation, though scatterred, into Rajasthan. These are pre monsoon rains, and not rains brought by the a "Western Disturbance".
Still, I do not yet see any well formed system,such as a Bay depression moving across the heart of India to bring widespread heavy rain in the regions the monsoon is yet to cover
The Arabian Sea system may also "pull" away rain clouds from approaching the Konkan and Goa coast, at least for the next 2/3 days.
Meaning, Mumbai will get only "passing showers', and the real monsoon may not yet pick up till 27th. June in Mumbai.
And yes. The IMD updated forecast of the monsoon season , as a whole over India , shows a deficient monsoon. To the extent of 93%. But, I would wait and observe the development of the Ell-Nino, in the next 30 days. There is a 60% possibility of it gaining in the next month or so.