Tuesday, August 24, 2010

The low in the bay finally appeared today,24th. August, and, is off the North T.N./ A.P. coast. At 1000 mb, it is persisiting, and lingering in the region since the last 24 hrs.From tomorrow, 25th.it should strenghten and move towards the A.P. coast. I estimate the system to cross the coast by the 26th, and at 998 mb pressure.
The WD25, mentioned in the "vagaries" has entered India from the west, as expected, and aligned itself with the monsoon axis. Resultantly, the Northern regions continued to
recieve heavy rains from the 23rd. and today's satellite image shows excessive clouding in
the U.P. and Bihar regions.

Today,the WD having moved away, now may not impact the direction of the bay low.The bay system should now take the axis corridor. The axis has now joined into the low as its eastern end. On crossing land, moving across A.P. and into M.P, it should precipitate rains along its path, and thru Vidharbha, and Northern Maharashtra, on 26th/27th August.

By the 27th.,it should fizzle out. BUT, a pulse emerging from the system, at 700/850 hpa,
should move ahead, and culminate into a vortex, or maybe a low, off the North Maharashtra/Gujarat coast around the 28th. Simultaneously, the off shore trough off the west coast will "liven up". Most models are in agreement.
Consequently, a much heavier rainfall regime should commence along the west co
ast. The rainfall areas will be from Karnataka coast/ Konkan and South Gujarat coast.
Some models are showing a very deep vortex, within the trough, and linked to the projected low which may form off the Gujarat/North Maharashtra coast. If it materialises, North Maharashtra coast (North of Mumbai) and Gujarat coast could recieve extremely heavy rains, upto 300/350 mms, around 28th. Saturday/ 29th. Sunday. The affected region, as of estimates now, would be North of Mumbai.Its a bit early to forecast t
oday, and we shall monitor this on daily basis.

To summarise, I would estimate precipitation as per these 2 weekly accumalated weekly rainfall maps of the next 2 weeks from NCEP/GFS. Of all the various models and estimates, I feel, these m
aps summarises the system's most probable rainfall track.





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Mumbai: On reading the above, I feel, Mumbai should start with rains again f
rom Friday/Saturday
Friday: Frequent showers. Cloudy and overcast. Rainfall upto 20 mms.
*Saturday: Rainy condtions, and by evening frequency of rains increasing. Squally weather, with about 50 mms of rain, more at night.
*Sunday: Overcast. Windy and rainy. Heavy showers, with flooding. Rainfall on Sunday could be upto 100 mms.
*Saturday and Sunday forecast are subject to revision. Depends on the exact location of the Arabian Sea low, and the vortex, to be formed. As mentioned above, will be monitored daily, as important for Mumbai weather.

3 comments:

Anonymous said...

Rajesh, any chances of rain in KHI with this projected low?

rajesh said...

I estimate some light rain creeping up the coast, upto Karachi,around 1-3 sept. But rain amounts in the city will be less than 7-10 mms.

Anonymous said...

ok thanks