Friday, August 20, 2010

In a very sudden development, an UAC formed overnite over Eastern Maharashtra, and became well marked at 500 hpa. As nt, our reader pointed out correctly, it was sudden and unexpected.

During the night, I monitored the cloud mass, and observed it moving westwards. At 9.30, saw it approaching Mumbai at "super speed". A 4.30 IST rain map s
hows its proximity to Mumbai at that hour.
Cloud tops are at -50c, and could form 2 level thunder clouds.
A sudden burst of rain became inevitable for Mumbai.

All forecasts thrown away ! No model could forecast this rain spell !

As, we do not know when an unexpected guest will leave, unlike a planned guest who tells us his programme, we do not know the duration of this spell.


5 comments:

emkay said...

what is the like time of impact on Mumbai ? am at Colaba and see dark eastern horizon. but latest weather maps dont show much progress in last 1 hour. has it crossed Pune, i doubt ?

nt said...

The GFS analysis of today morning 00 UTC does not show any significant spin around Eastern Maharashtra, however it shows one forming very close to Mumbai during the 24 hrs. ending tomorrow morning as stated some time back and then it suddenly disappears.

I guess the rain can start around mid afternoon in Mumbai. By the way in the morning the cloud tops over Mumbai were around -20 degree celcius, it now shows -40 degree cloud tops indicating a build up very high CB clouds. Climatic indications point to a very strong and heavy thunderstorm potential over Mumbai from now until tomorrow morning.

Guess Rajesh will let us know what is happening in a much better way then I understand things

rajesh said...

emkay/nt,
Heavy rains have started in South Mumbai. With Colaba getting 22 mms till now and Byculla gauging up 18 mms. Worli has measured 10 mms.

no nt, my estimate for thursday was ok, but seems to be going haywire for friday. Where are you based, nt ?

Anonymous said...

Surprisingly the IMD Mid day bulletin has absolutely nothing on this 'system'.

Strange one would say.

nt said...

Update from Andheri - West @ 3:30 pm:
Still no rains here. Infact things have gotten a bit more brighter then before at this point.