Sunday, May 12, 2013

#Chennai - After 11am, it was cloudy with a high cloud cover. Temperature was around 35 C till 4pm.

#Chennai - Showers seen around city at around 100, 150 km. Rain possible around midnight / early hours and  showers forecast for tomorrow !
RT @rajugana: Bangalore 6.00pm, Sunny n Partly cloudy day- 23-31C; After consecutive eve showers for 5 days, No T.Clouds formation Yet?! 

5:30pm, T.showers lined up along S-E Peninsula from N-E Tamilnadu, coastal, N-E Andhra, Odisha and S,central Bengal.. http://ow.ly/i/261gI 

RT @shafianin: @weatherofindia nice showers in Gurgaon... #Rainbow (6:17pm)

5:30pm, Showers seen over N-central,N.India due to W.D ... http://ow.ly/i/261gI

T.showers witnessed over S-W from #Chennai at around 125 to 150km. Showers also seen over S.Andhra as well.

Cyclone "Mahasen" - Moved N-W, slight weakening witnessed.

Analysis show a slight weakening during past 6 hrs.
Moved N-W. According to JTWC, the system should slow down and move N-N-E in next 12 hrs.
Pressure now is around 989 mb.
Winds gusting up to 85 kmph.


JTWC warning and Path projection at 2:30pm IST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

TROPICAL CYCLONE 01B (MAHASEN), LOCATED APPROXIMATELY 760 NM SOUTH 
OF CALCUTTA, INDIA, HAS TRACKED NORTHWESTWARD AT 12 KNOTS OVER THE 
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) 
REVEALS FLARING DEEP CENTRAL CONVECTION WITH FRAGMENTED CONVECTIVE 
BANDING WRAPPING INTO A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER 
(LLCC) WITH SEVERAL LARGE OUTFLOW BOUNDARIES APPARENT IN THE EASTERN 
AND SOUTHERN SEMI-CIRCLES. THIS IS ALSO APPARENT IN A 120342Z AMSU-B 
MICROWAVE IMAGE. THE PAST FEW MICROWAVE IMAGES HAVE SHOWN A RE-
CONSOLIDATION OF THE LLCC FURTHER EAST OF THE PREVIOUS POSITION AND 
HAVE ADDITIONALLY SHOWN DRY CONTINENTAL AIR IS BEING INGESTED FROM 
THE COAST OF INDIA. THIS CAN ALSO BE SEEN IN THE LATEST MICROWAVE 
DERIVED TOTAL PRECIPITABLE WATER LOOP. OBSERVATIONS IN KOLKATA, 
INDIA SHOW A LARGE DEW POINT SPREAD OF 20 DEGREES. THIS DRY AIR 
INGESTION IS REASON FOR THE FRAGMENTED AND FLARING NATURE OF THE 
SYSTEM OVER THE LAST 12 HOURS. THE INITIAL POSITION IS BASED UPON 
THE MSI LOOP AND EXTRAPOLATION FROM THE 120342Z AMSU IMAGE WITH LOW 
CONFIDENCE. THE INITIAL INTENSITY HAS BEEN SLIGHTLY LOWERED TO 45 
KNOTS BASED ON LOWER DVORAK INTENSITY ESTIMATES FROM ALL AGENCIES 
AND THE OVERALL CONVECTIVE ORGANIZATION OF THE SYSTEM. UPPER-LEVEL 
ANALYSIS REVEALS A FAVORABLE ENVIRONMENT OF STRONG DIFFLUENCE ALOFT 
PROVIDING FAVORABLE OUTFLOW AND LOW TO MODERATE VERTICAL WIND SHEAR 
(VWS), WHICH IS BEING OFFSET BY THE STORM MOTION, RESULTING IN AN 
OVERALL LOW VWS (05-10 KNOTS) ENVIRONMENT. TC 01B IS FORECAST TO 
CONTINUE NORTHWESTWARD FOR THE NEXT 12 HOURS ALONG THE SOUTHWESTERN 
PERIPHERY OF THE SUBTROPICAL RIDGE (STR) SITUATED OVER THE NORTHERN 
ANDAMAN SEA. AFTER TAU 12, IT IS EXPECTED TO SLOW DOWN BEFORE IT 
TURNS NORTHEASTWARD AS THE STR WEAKENS AND RE-ORIENTS IN RESPONSE TO 
AN APPROACHING MID-LATITUDE SHORTWAVE TROUGH CURRENTLY OVER NORTHERN 
INDIA. TC 01B WILL CONTINUE TO INTENSIFY TO A PEAK OF 80 KNOTS BY 
TAU 72 AS THE SYSTEM CROSSES THE RIDGE AXIS INTO AN AREA OF 
INCREASED POLEWARD OUTFLOW, WITH ITS EXPOSURE INTO THE STRONG 
WESTERLIES. AFTER TAU 96, THE SYSTEM WILL MAKE LANDFALL NEAR 
CHITTAGONG, BANGLADESH, AS A SIGNIFICANT CYCLONE ALL WHILE WEAKENING 
DUE TO THE LAND INTERACTION. DYNAMIC MODEL GUIDANCE HAS DEVELOPED A 
BIFURCATION IN THE LATEST RUN AS GFDN AND NAVGEM HAVE GREATLY 
DEVIATED TO THE NORTHWEST INTO NORTHEASTERN INDIA. THIS IS BELIEVED 
TO BE DUE TO THE MODEL TRACKERS ERRONEOUSLY TRACKING INTO THE 
PREVIOUSLY MENTIONED SHORTWAVE TROUGH. GFS, ECMWF AND EGRR HAVE 
STAYED CONSISTENT WITH THE RECURVE SCENARIO INTO BANGLADESH. DUE TO 
THIS, THE JTWC FORECAST IS FASTER AND EAST OF MULTI-MODEL CONSENSUS 
TO OFFSET THE NAVGEM AND GFDN SOLUTIONS AND IS CONSISTENT WITH THE 
PREVIOUS FORECAST. DUE TO LARGE SPREAD IN THE MODEL SOLUTIONS AND 
AMBIGUITY IN THE INITIAL POSITION FORECAST CONFIDENCE IS LOW. 
JUSTIFICATION FOR RELOCATION: RELOCATED 12/00Z POSITION OF TC 01B 
BASED ON NEWLY AVAILABLE MICROWAVE DATA. MAXIMUM SIGNIFICANT WAVE 
HEIGHT AT 120600Z IS 18 FEET.
IMD Warning at 1pm
~~~~~~~~~~~~~~~~~~~~~~~~~~~
The cyclonic storm MAHASEN over southeast Bay of Bengal moved slightly
westwards at a speed of 15kmph and lay centred at 1130 hrs IST of 12th May 2013 near latitude 10.00 N and longitude 87.00 E, about 650 km west-northwest of Car Nicobar, 650 km east-northeast of Trincomalee, 800 km southeast of Chennai and 1440 km south-southwest of Chittagong. It would move initially northwestwards during next 36 hours and recurve thereafter northeastwards towards Bangladesh-Myanmar coast.

Latest NAVGEM (NOGAPS) model expects a N-E Andhra and S.Odisha coast landfall on 16-May.

Today, T.showers expected over N,N-W,central Tamilnadu, Coastal Andhra, S,S-W Karnataka and N,central Kerala http://ow.ly/i/25XIq

Cyclone "Mahasen" - Rapidly moving N-W, Now have 2 different path forecast !

Analysis show that Cyclone "Mahasen" has moved N-W during past 12hrs at a fast pace.
Latest position is 10.5N , 86.6E. (south central Bay)
No further intensification seen during past 12 hrs.
Pressure remains the same around 985 mb.
Winds gusting up to 90 kmph.

JTWC warning and path projection at 8:39am IST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

TROPICAL CYCLONE 01B (MAHASEN), LOCATED APPROXIMATELY 749 NM
SOUTHWARD OF CALCUTTA, INDIA, HAS TRACKED NORTHWESTWARD AT 15
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS THE LARGE CENTRAL DENSE OVERCAST FEATURE THAT WAS
OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS BROKEN UP AND
MERGED INTO THE CONVECTIVE BANDS FEEDING INTO THE LLCC. ALTHOUGH THE
CONVECTION HAS BECOME FRAGMENTED, THE FEEDER BANDS HAVE WRAPPED
TIGHTER INTO THE LLCC. THE INITIAL POSITION IS BASED ON THE ABOVE
ANIMATION AND FROM A NOTCH FEATURE ON AN 112159Z TRMM MICROWAVE IMAGE
WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS MAINTAINED AT 50
KNOTS. UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM IS 05 DEGREES SOUTH
OF THE RIDGE AXIS IN AN AREA OF LOW (05-10 KNOT) VERTICAL WIND SHEAR
(VWS) AND EXCELLENT RADIAL OUTFLOW. TC 01B IS FORECAST TO CONTINUE
NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL
RIDGE (STR). AFTER TAU 12, IT IS EXPECTED TO SLOW DOWN BEFORE IT
TURNS NORTHEASTWARD AS THE STR WEAKENS IN RESPONSE TO AN APPROACHING
MID-LATITUDE SHORTWAVE TROUGH CURRENTLY OVER NORTHERN INDIA. TC 01B
WILL CONTINUE TO INTENSIFY TO A PEAK OF 85 KNOTS BY TAU 96 AS THE
SYSTEM CROSSES THE RIDGE AXIS INTO A ZONE OF SUSTAINED LOW VWS AND
INCREASED POLEWARD OUTFLOW WITH ITS EXPOSURE INTO THE STRONG
WESTERLIES. AFTER TAU 96, THE SYSTEM WILL MAKE LANDFALL JUST NORTH OF
CHITTAGONG, BANGLADESH, AS A MODERATE TYPHOON-STRENGTH CYCLONE.
DYNAMIC MODEL GUIDANCE IS IN BETTER AGREEMENT WITH THE RECURVE
SCENARIO TOWARDS BANGLADESH BUT WITH VARYING MODEL TRACK SPEEDS AND
MODERATE SPREADING AT THE LATER TAUS. WBAR IS ERRONEOUSLY SKEWED LEFT
OF AND MUCH SLOWER THAN THE MODEL ENVELOPE DURING THE TURN. THE JTWC
FORECAST IS POSITIONED JUST TO THE RIGHT OF THE MULTI-MODEL CONSENSUS
(CONW) DURING THE TURN AND FASTER THAN CONW AFTER THE TURN TO OFFSET
WBAR. THERE IS IMPROVED CONFIDENCE IN THE TRACK FORECAST. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 120000Z IS 18 FEET.

Latest COLA and NAVGEM (NOGAPS) model is now differing on the track forecast from this time.
COLA model suggests that "Mahasen" will track N-W for another 12hrs and then re-curve N-N-E towards Bangladesh. And expects the system to make landfall over South Bangladesh coast on 16-May.
Why this N-E movement?? For answer refer to JTWC warning above.!

NAVGEM (NOGAPS) model suggest that the system will continue to move N-W during next 24hrs and then will try to re-curve N-N-E. Eventually the model expects the system to make landfall over N-E Andhra and South Odisha coast on 15-May.
This is a possibility like that of Cyclone "Laila" during same time of year in 2010. Similar kind of predictions where in place during that time as well. Some of the other environmental conditions may differ.

Monsoon - The onset of monsoon over S,S-E Bay and South Andaman islands is expected to happen today. The Northerly movement expected from "Mahasen" will make way for the strong monsoon winds to reach S.Andaman islands. Latest analysis show that strong winds are already reaching South Andamans.
Today, the Somali jet is also seen picking up strength.

Evening T.showers over S.Karnataka, Bangalore and N.Tamilnadu



rajuganaMay 11, 10:36pm via Web
@weatherofindia Bangalore 10.30pm, Heavy rain lashing for the past 3 hours with lightning and thunder.
manibond32May 11, 8:15pm via Twitter for Android
@weatherofindia raining in veeranam village (Salem district) N.Tamilnadu
thisismmkMay 11, 8:08pm via Twitter for Android
@weatherofindia 7pm Good drizzle and lightning in and around Vellore, Katpadi. N-E Tamilnadu
Show Conversation
AxPnMay 11, 8:02pm via Mobile Web (M2)
Raining heavily 7.45pm Jayanagar, Bangalore @weatherofindia

Cyclone "Mahasen" - Intensified slightly, Moved N-W, Remember Cyclone "Laila" - May-2010

Latest analysis show that Cyclone "Mahasen" has moved N-W during past 12hrs.
Intensified slightly.
Now positioned at 9.1N , 88.4E.
Pressure is around 985 mb.
Wind gusts up to 93 kmph.

11:30pm, Satellite IR shows that the Huge core is over S-central Bay .

JTWC warning and projected path at 8:30pm
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

TROPICAL CYCLONE 01B (MAHASEN), LOCATED APPROXIMATELY 830 NM SOUTH-
SOUTHWEST OF CHITTAGONG, BANGLADESH, HAS TRACKED NORTHWESTWARD AT 15 
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) REVEALS A LARGE CENTRAL DENSE OVERCAST (CDO) FEATURE 
HAS DEVELOPED OVER THE LOW-LEVEL CIRCULATION CENTER (LLCC) WITH 
MULTIPLE FEEDER BANDS IN THE PERIPHERIES. AN 111140Z SSMIS 91 GHZ 
MICROWAVE IMAGE SHOWS DEEP CONVECTION PERSISTING OVER THE LLCC WHILE 
THE CONVECTION IN THE BANDING FEATURES REMAIN FRAGMENTED. THE 
INITIAL POSITION IS BASED ON THE MICROWAVE IMAGE DUE TO THE LLCC 
BEING OBSCURED BY THE LARGE CDO FEATURE WITH FAIR CONFIDENCE. THE 
INITIAL INTENSITY IS ASSESSED AT 50 KNOTS, WHICH IS SLIGHTLY HIGHER 
THAN CONGRUENT DVORAK INTENSITY ESTIMATES OF 45 KNOTS FROM PGTW AND 
KNES, DUE TO DEEPENING CONVECTION NEAR THE LLCC. UPPER-LEVEL 
ANALYSIS INDICATES A FAVORABLE ENVIRONMENT AS DIFFLUENCE ALOFT 
CONTINUES TO PROVIDE FAVORABLE OUTFLOW WHILE THE CURRENT STORM 
MOTION HAS BECOME IN PHASE WITH THE SOUTHEASTERLY VERTICAL WIND SHEAR
(VWS), RESULTING IN LOW (05-10 KNOTS) VWS. TC 01B IS FORECAST TO 
CONTINUE NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE 
SUBTROPICAL RIDGE (STR) POSITIONED OVER THE NORTHEASTERN BAY OF 
BENGAL FOR THE NEXT 24 HOURS. THEREAFTER, TC 01B IS EXPECTED TO SLOW 
AND TURN NORTHEASTWARD AS THE STR WEAKENS DUE TO AN APPROACHING 
MIDLATITUDE SHORTWAVE TROUGH CURRENTLY OVER NORTHERN INDIA AND THE 
NORTHEASTERN ARABIAN SEA. TC 01B WILL CONTINUE TO INTENSIFY TO A 
PEAK OF 85 KNOTS BY TAU 96 AS THE SYSTEM GAINS LATITUDE AND POLEWARD 
OUTFLOW INCREASES INTO THE WESTERLIES. BY TAU 120 THE SYSTEM WILL 
MAKE LANDFALL AS A SIGNIFICANT TC AND BEGIN TO WEAKEN DUE TO LAND 
INTERACTION AND INCREASING VWS AHEAD OF THE AFOREMENTIONED SHORTWAVE 
TROUGH. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT WITH RECURVE 
SCENARIO TOWARDS BANGLADESH THROUGH TAU 72, BUT TWO SEPARATE 
SOLUTIONS HAVE DEVELOPED IN THE LATEST MODEL RUN PAST TAU 72. 
NAVGEM, EGRR AND GFDN ACCELERATE THE SYSTEM IN THE LATER TAUS AS THE 
TROUGH TRANSITS THROUGH THE AREA. GFS AND ECMWF STALL THE TROUGH 
OVER NORTHEASTERN INDIA RESULTING IN A SLOWER TRACK SPEEDS. DUE TO 
THIS DISAGREEMENT, THE JTWC FORECAST IS POSITIONED CLOSE TO MULTI-
MODEL CONSENSUS WHICH HEDGES BETWEEN THE TWO SEPARATE SOLUTIONS. 
HIGH CONFIDENCE REMAINS IN THE FORECAST THROUGH TAU 72 DUE TO THE 
TIGHT GROUPING OF THE MODELS. AFTER TAU 72, FORECAST CONFIDENCE IS 
LOW DUE TO THE TWO SEPERATE SOLUTIONS OF THE MODELS. MAXIMUM 
SIGNIFICANT WAVE HEIGHT AT 111200Z IS 16 FEET. 

Now the COLA and NOGAPS model suggests that "Mahasen" will track N-W for one more day and then North for one day and then N-N-E.
According to COLA model the Landfall estimate is now over S.Bangladesh on 16-May.

Latest NOGAPS model suggests that the landfall may be over North Odisha coast and South Bengal coast on 16-May.
Latest Upper level wind analysis show that the system will be steered N-W during next 24 hrs and then it will come under the influence of S-W to N-E strong upper level winds. This will make "Mahasen" to re-curve N-N-E or even N-E.


Remember, Cyclone "Laila"... same time of the year in 2010.
It also tracked the same path as that of "Mahasen" ... Laila continued to track N-W and made landfall over S.Andhra coast on 20-May-2010.
Please refer our coverage on this Cyclone here...
http://indianweatherman.blogspot.in/search?q=laila