Friday, November 16, 2012

"98B" - Now a huge circulation over Bay.

"98B" - Now a huge elongated circulation over Bay. Exact position cannot be pin pointed at this moment. It may be around 14N & 89E.
And it has slightly moved W-N-W in last 6 hrs.
Latest satellite IR at 7:30pm shows a lots of convective activity seen all along the circulation.


NOGAPS still suggests more of Westerly movement in next 2 days.
COLA model suggests a N-W movement and linger over N,N-W Bay and die without making a landfall.


#chennai - 8:15pm, Almost No breeze. Temp. at 25 deg C and going down. Another COLD night and morning ahead.
Moderate rain forecast for S.Tamilnadu, S.Kerala during next 2 or 3 days.

Due to W.D..Scattered rain or Snow for Kashmir, isolated Rain for Punjab, Himachal expected during next 2 days.. http://ow.ly/i/18p0s 
"98B" - COLA still suggests a Northerly movement from here in next 2 days and die over N.Bay without making landfall.. http://ow.ly/i/18oS9

If 98B moves north .. then a weak circulation is expected over Gulf Mannar along S.tip of Tamilnadu .. http://ow.ly/i/18oUg

This analysis by WRF model represents the present elongated nature of the Bay circulation "98B".. http://ow.ly/i/18oVB

Present "98B" may drop an UAC along S-W Bay in next 36hrs.. showers for E,N-E Srilanka... http://ow.ly/i/18oY2 
#chennai - now its 29.3°C.. Scattered low cloud formation seen with mild wind from North.
"98B" - Almost defying ALL model predictions... now what will happen?? ... http://ow.ly/fkXtY 

More detail about "98B"

BB-11 has defied and challenged ALL International weather models (not comparing Vagaries with them) and taken its own course, first North and now West. 
Positioned at 13.6N AND 88.7E, West of Chennai.

It is necessary to understand the forecasts and estimates given by various models. No model goes on guess work. There are certain presumptions and assumptions, with reasoning behind each forecast. And, forecasts may be diametrically opposite to each other. 

a) NOGAP as on today (Friday) forecasts a W/NW movement towards TN/AP coast, and become a depression. (http://ow.ly/i/18830)
Vagaries also had subscribed to this view from the initial stage. The reason behind this forecast by all models: TD-25 was to send in a pulse, and form a low/depression (BB-18) in the Andaman region by the 16th and influence the initial movements of BB-11. The advent of BB-18 would have curved the trough in which BB-11 is nestled towards the West. And, the 200 hpa jet streams were seen flowing towards the NW in the Southern Bay. 
BB-11 would have moved into TN as a depression.Though some models like IMD GFS and FNMOC had mentioned this track, they changed it as they observed the change in the jet streams and pressure "play" in the Bay. 

b) Some models predicted, FNMOC, UKM, COLA a North/North-East track, presuming the ridge in the Bay will prevail. Ridge ? Yes, instead of a trough. This ridge in our seas was dependant on the High in the Phillipines region.TD-25 was nestled between these 2 Highs. 

What's actually happening now ? The extreme East Phillipines ridge has weakend, the TD-25 is fizzling out, the parent pulse itself is fading.
BB-11, is now moving West. But, the low is stagnent in strength, and seems to be getting elongated. Now, this elongation was expected, and BB-12 was to get more strengthened by merging in this "big" low. But where is BB-12 ? 

Ok, leave all this, what's to happen now? What can happen if BB-12 does not come ? Well, BB-11 will be on its own, and merge into the larger region of 1008 mb. Till survival, NW movemnet not ruled out for the next 18-24 hrs. That is, it will elongate to form a huge Low region of 1008 mb(weaken) in the Bay. Showers will push into Oriissa/West Bengal coast from 18th/19th.
Showers also possible in coastal and interior TN. 

Taken from http://rajesh26.blogspot.in/ 

"98B" - moving West now

1:30pm, "98B" - moving West now.
Pressure around 1007mb
Here's the latest poistion plot on map.


NOGAPS model prediction is coming into effect now. It's too early to predict that whether the system will track West or not. But latest NOGAPS model still predicts a Deep Depression (or) Cyclone on 19-Nov over W.Bay tracking towards N.Tamilnadu & S.Andhra coast.


Latest JTWC report at 8:30am IST
--------------------------------------------------------

AN AREA OF CONVECTION HAS PERSISTED NEAR 13.6N 89.0E, 
APPROXIMATELY 500 NM EAST OF CHENNAI, INDIA. RECENT ANIMATED 
INFRARED SATELLITE IMAGERY SHOWS BUILDING DEEP CONVECTION OVER THE 
EASTERN BAY OF BENGAL. SCATTEROMETER DATA FROM 151814Z INDICATES A 
MONSOON DEPRESSION-LIKE WIND FIELD WITH 05-10 KNOT CENTRAL WINDS 
SURROUNDED BY 20-25 KNOT WINDS ON THE EASTERN AND WESTERN 
PERIPHERIES. UPPER-LEVEL ANALYSIS DEPICTS THE DISTURBANCE UNDERNEATH 
THE SUBTROPICAL RIDGE (STR) AXIS IN AN AREA OF LIGHT (05-10 KNOT) 
VERTICAL WINDSHEAR (VWS). IN ADDITION TO THE GOOD DIVERGENCE BEING 
PRODUCED BY THE STR AXIS, THERE IS MODERATE SPEED DIVERGENCE INTO 
THE MID-LATITUDE WESTERLIES TO THE NORTH. HOWEVER, THE 850MB 
VORTICITY SIGNATURE IS VERY ELONGATED NORTHEAST TO SOUTHWEST; 
INDICATIVE OF THE GENERAL TROUGHING IN THE AREA BUT CURRENTLY NOT 
SHOWING ANY SIGNATURE OF A WELL DEVELOPED CIRCULATION. SEA SURFACE 
TEMPERATURES ARE EXTREMELY CONDUCIVE FOR TROPICAL CYCLOGENESIS AT 28-
30 DEGREES CELSIUS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 
10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 
1007 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL 
CYCLONE WITHIN THE NEXT 24 HOURS IS LOW


A moderate W.D has started affecting Kashmir .. Scattered Snow / Rain possible during next 2 days.
RT @rajugana:  Bangalore 11.45am, Cloudless Clear skies, Sunny, cold n shivering as temp dips to 13C yesterday. Rain, Rain come again!!! 
Low in the Bay is independent of any forecast...defying and going its own way...now moves westwards. Though models still defer, we must know where it can go....
detailed analysis on vagaries.