Saturday, December 07, 2013

Posted Saturday Night

BB-21 is now "Madi" and a Severe Cyclone,....is located at 11N and 84.3E.
Studying the sub tropical ridge, we see the Southern Limit of the ridge slightly South of 10N, and of course the Northern Limit is in the North Bay. We see a sort of  "absolute no upper wind direction and a sort of stagnancy " in the Western core section of the ridge.
Another HPA and ridge is located over the Indian mainland, though at a lower altitude. 
Madi  is located in the stagnant area of the sub tropical ridge. That is the reason why Madi is almost quasi stationary, and expected to remain with very negligible tracking next 18-24 hrs. 

Once it breaks free from the region, it will have a  steering guide, and will enter the Western edge of the sub tropical ridge and move NNE. Also the lower level ridge over the mainland can move East and push the system towards skirting the East Coast.

Some models forecast a Southerly track. It can go the SW way only if it gets "entangled" in the Southern periphery edge of the Sub Tropical ridge, and get pulled SW  with the upper winds...more on NEM Page

The HPA mentioned above is the High Pressure which was anticipated to cover the Northern and Central Indian regions from 2nd week of December.




Few places in the NCR have gone below the 24c mark (maximum temp)...we can expect a gradual fall in day and night temperatures. 

Rajastan, Gujarat and Maharashtra can expect a fall in night temperatures next few nights.
Places in Kutch may go down by 3/4c from current levels, and lowest may reach around 10c. Surat and Bharuch will have cooler nights around 15c.
Mumbai will see cooler nights, with lows around 18/19c (Scruz) and outer townships seeing a fall to 16c next few nights.
Next 2/3 nights, Pune and Nasik will be cooler around 8/9c.

Kolkata gets partly cloudy soon, so remains in the current 27- 16c range till Wednesday. After Wednesday we can expect a drop in night temperatures.

UK Storm in Pictures..Sent By Santosh Subramanian..
 See here...(Posted on International Page also)

8 comments:

emkay said...

Great blog Sir. STR mystery explained. Awaiting reply to my longitude related query put up in FB

rajesh said...

Thanks Emkay:

You see, a Sub Tropical Ridge, is big and elongated East-west, something like a seasonal trough. It also migrates in the summer .
Now, it is generally situated in this season roughly with its Northern Limit in the Northern Bay along the Bengal coast, and Southern Limit is normally around 13N. The whole Ridge as such fluctuates eastwards at times.
If still in doubt , ask>.

emkay said...

Is it oscillatory East-West? From your description the ridge is an inclined one from west to east. I can understand that bec winds above ridge have a NE to SW direction, am I right?

rajesh said...

The Ridge shifts East-West constantly...and this ridge is at upper levels, 100 hpa and 200 hpa. These are season creating winds, and ridge shifts with season or maybe the other way around.
But in season, the ridge shifts a bit esat-west...
Northern winds of ridge are westerly, and Southern Easterly

Abhijit said...

Some Maharashtra cities min temp below for today(08-12-2013) :


Pune 7.8c
Nagpur 9.3c
Nashik 9.7c
Aurangabad & Akola 10.5c
Solapur 11.4c
Ratnagiri 16.7c
Mumbai(SCZ) & Panji, Goa 18.0c

Some around Mumbai AWS min temp for today :

Karjat 13.2c
Palghar 13.4c

Neeraj said...

the nights are warmer than usual here. and the trend has continued from november. I guess, the trend will remain for the first half of december at least if not for the whole of december. Probably, its due to Bay of Bengal remaining active in nov/dec.

Arpit Sharma said...

Neither TN getting good rain from
NEM nor Delhi enjoying the cold
weather. Active BOB spoiling the
whole season.
Warm weather in Delhi
continues...
18 minutes ago

Arpit Sharma said...

Neither TN getting good rain from
NEM nor Delhi enjoying the cold
weather. Active BOB spoiling the
whole season.
Warm weather in Delhi
continues...
18 minutes ago