Tuesday, June 22, 2010

Starting with the developments aliong the West coast of India,we see the UAC (Upper Air Circulation) in the trough has become less marked.
Now, this development means that there is no UAC present to cross the coast near Mumai as estimated earlier, and as a result, I would scale down the quantum of rainfall estimated earlier.



Since the coastal trough still hangs on (see IMD map),we can expect rains on a lesser scale to continue along the coast North of Karnataka this week.
As mentioned yesterday, I personally think that the Monsoon axis trough running west-east along the Northern plains of India, has had some role to play in the vanishing of the UAC. I have always been sceptical when this axis shifts northwards, as it heralds a "break" period for the peninsula regions, and can weaken the trough, or any embedded low in it.
With the trough intact, as it will be till Friday 25th. at least,rainfall to some extent will continue along the coast and in the interior areas of Maharashtra and Karnataka thru this week.

If, after this week, the axis of the monsoon shifts further north towards the Himalayas, and deepens,then the entire peninsula region is in for an unwanted "break". This may delay the monsoon progress into the Northern regions and subsequently into the North-West corner.
Though nobody wants a break now, the MJO forecast (see this link) shows the "unwanted negative" MJO waves during the next 15 days. When positive, it creates the "lows" and the depressions, and the rain bearing systems into the monsoon currents. When forecasts show a negativity, it reads as less systems in the regions.It is one of the few aspects of the weather that can be skilfully predicted beyond about 2 weeks into the future.
But, I really hope that things change for the better, and Nature eventually ridicules man's forecasting. We will keep our observations updated and monitor the same.

Meanwhile, the extreme in the Northern belt continues with a special mention of a minimum of 33.8c at Gwalior last night, and 32.6c as the low at New Delhi.

Mumbai: Will continue to get the passing showers on Tuesday, with about 10 mms of rain. Wednesday's forecast may have to be scaled down due to the reasons discussed. City can expect a few more showers, with rainfall during the day totaling 20mms. Thru Friday, Mumbai can get passing thunder rain, and with the rainfall scaled down, city may just about recieve 25-30mms till Friday.

3 comments:

Anonymous said...

Mumbai has recieved moderately heavy rainfall since yesterday evening and the rainfall continues through the day today as well. Looks like the good old Trough is 'acting' up. Most of the rainfall on the west coast seems to be in and around Mumbai at this point

emkay said...

seems this monsoon forecasters are having a tough time inspite of all tools being available.
i suppose all boils down to the Western disturbances synchronising with these UAC / LPs in the Arabian Sea and dragging them into mainland !!

rajesh said...

Lesser rain was forecasted in this blog for the entire coastal regions, as the UAC vanished. It held true. Only the Mumbai region, belapur to Uran recieved rains upto 9-12cms.rest was subdued rains.Even the ghats recieved only 2-4 cms.