MW-4 (Part-2) 2013...Seasonal Quantum Performance of SWM.

Very Briefly, explaining the Factors considered for Seasonal Forecast:
Situation assessed after the arrival  of the SWM..and the scenario mentioned below are after the Monsoon sets in.

To take and assess the SWM performance, we refer back to the MW-4 (Part-1). We have to take into consideration most of the 15 parameters (Gowariker Method) before making an assessment, and these have to be analysed one by one. The prominent among the 15 are , ENSO, Mar temperatures of North India and East Coast, Himalayan Snow cover till March and SOI to name a few.
Of-course, I am not going to take each and every one of the 15 here, but, derive at an estimate on these basis and on the new model developed. I hope readers of vagaries trust that I have tried my best to estimate as accurately as possible.

If we take into account, that the ENSO will be Neutral, but "leaning" towards a weakish El-Nino phase by, say, August, then:

a) Till July end, we can see normal rainfall and progress of the SWM in the Sub_continent regions. Normal conditions in the Pacific Oceans will send a few "pulses" to create "in situ" systems in the Bay, and the first 2 months will see around 3/4 noteworthy systems traversing the Sub continent. WDs will be few, hence, we can expect a few systems to track towards Central and Northern India, resultig in good rains in the plains of N.India and Central Pakistan regions..and fairly good above normal rains in Nepal.
During the Northern track of the system, the monsoon trough could be pulled far North into the Himalayas, and possibility of "short "break Monsoon in 3rd week of July or near around thar time period.
Break monsoon situations, and winds bringing in moisture from the Bay (diverted to the NW directions) will result in excessive rainfall this season in Nepal, more so the Eastern regions. NE states of India will get continuous feeding from the Bay. (Cherrapunji seems the likely candidate for the highest SWM rains).

b) In such a scenario, even the Easterly 200 hps jet streams would move further Northwards. Could bring  rainfall to Upper Pakistan regions. Hence, rainfall could be  normal in rest Northern Pakistan and Kashmir.

c) Due to systems reluctant to track southwards, we may see lesser rains in the Southern Peninsula regions. Even the support to the west coast (South of Mumbai)may be lesser than normal.
Hence, rain shadow regions in TN and interior Karnataka may be slightly deficient. Normal gradient along the West coast will show rainfall along West Coast of India.
 
Things, if and when they change (drastically) will be posted and Vagaries readers will be kept well informed, of any variation in the forecast.
These are my personal views, and should be depended upon commercially or otherwise. They may differ from other models.

See Map on vagaries..

Mahasen (BB-1) moved swiftly NW . Curently positioned at 9N and 88.5E, with core pressure of 996 mb and winds 40/45 knts at peak. Cloud top temperature is at -86c in the core regions of the system....posted at 9.00 pm IST...next update at 11.30 pm IST

The North-South trough from Bihar to S-W Karnataka persists even today ... http://ow.ly/i/25HeJ 

North-South trough is expected to persist for another 2 days, with a re-position of the Southern end to N.Tamilnadu.  http://ow.ly/i/25Hg3 

The weak Low level circulation over Northern N-E states is also expected to persist for another 2 days !

During next 2 days, T.showers expected for North W-Ghats of Kerala, N-W Tamilnadu and over S,S-W Karnataka ... http://ow.ly/i/25HiH 

On Sunday, Monday.. T.showers expected for N,N-E,S-E Tamilnadu, #Chennai and over S,central,N-E Andhra ... http://ow.ly/i/25Hk6 

During next 2 days, Isolated T.showers expected for W,N.Uttarpradesh, N.Bihar and over N,central, S-W Bengal ... http://ow.ly/i/25HnO 

In next 3 days, Scattered Heavy rain expected for most of N-E states, Sikkim, Bangladesh and N.Bengal... http://ow.ly/i/25HrS 

Cyclone "Mahasen" - Now a named cyclone, winds upto 83 kmph and moving N-W.

Latest analysus show that the system has intensified into a Cyclone from Deep Depression.
Now it is named as "Mahasen".
Present location is 8.0N 89.8E
Pressure has further reduced during the past 6 hrs to 989 mb.
Winds gusting up to 83 kmph.
2:30pm, Satellite visible shot shows Heavy convective activity all along the core and over N-E,E,N-W,S-W Quadrant and over its over periphery.

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

TROPICAL CYCLONE 01B (ONE), LOCATED APPROXIMATELY 880NM SOUTH OF 
CHITTAGONG, BANGLADESH, HAS TRACKED NORTHWESTWARD AT 11 KNOTS OVER 
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) 
DEPICTS A LARGE AREA OF MULTIPLE BANDING FEATURES LEADING INTO A LOW-
LEVEL CIRCULATION CENTER (LLCC) WHICH IS CURRENTLY BEING OBSCURED BY 
FLARING DEEP CENTRAL CONVECTION. THIS IS ALSO EVIDENT ON A 110403Z 
AMSU-B MICROWAVE IMAGE. THE INITIAL POSITION IS BASED ON THE 
AFOREMENTIONED IMAGERY WITH FAIR CONFIDENCE. THE INITIAL INTENSITY 
IS ASSESSED AT 45 KNOTS BASED UPON CONGRUENT DVORAK INTENSITY 
ESTIMATES OF THE SAME VALUE FROM PGTW AND KNES. UPPER-LEVEL ANALYSIS 
INDICATES THAT FAVORABLE DIFFLUENCE ALOFT IS ASSISTING IN THE BUILD 
UP OF DEEP CONVECTION WHILE VERTICAL WIND SHEAR HAS SLIGHTLY RELAXED 
TO LOW TO MODERATE LEVELS (10 TO 20 KNOTS), OVERALL RESULTING IN A 
FAVORABLE ENVIRONMENT. TC 01B IS FORECAST TO CONTINUE TRACKING 
NORTHWESTWARD THROUGH TAU 36 ALONG THE WESTERN PERIPHERY OF THE 
SUBTROPICAL RIDGE (STR) POSITIONED OVER THE NORTHEASTERN BAY OF 
BENGAL. THEREAFTER, TC 01B IS EXPECTED 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 SHOULD INTENSIFY TO A PEAK OF 85 KNOTS BY TAU 96 AS 
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. DYNAMIC MODEL GUIDANCE CONTINUES TO AGREE 
ON THE RECURVE SCENARIO TOWARDS BANGLADESH, BUT HAS STARTED TO SLOW 
AND SPREAD IN THE EXTENDED TAUS. THE JTWC FORECAST IS SLIGHTLY 
FASTER THAN MULTI-MODEL CONSENSUS TO OFFSET WBAR, WHICH IS SLOWER 
AND WEST OF THE OVERALL TIGHT GROUPING IN THE EARLY TAUS. HIGH 
CONFIDENCE REMAINS IN THE FORECAST DUE TO THE WELL UNDERSTOOD 
STEERING ENVIRONMENT AND TIGHT GROUPING OF THE DYNAMIC MODELS PRIOR 
TO TAU 72. AFTER TAU 72, FORECAST CONFIDENCE IS LOW DUE TO THE 
SPREAD AND DIFFERING SPEEDS OF THE MODELS. MAXIMUM SIGNIFICANT WAVE 
HEIGHT AT 110600Z IS 14 FEET.

IMD warning at 1:30pm IST

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The cyclonic storm MAHASEN over southeast Bay of Bengal moved northwestwards at a speed of 15 kmph and lay centred at 1130 hrs IST of 11th May 2013 near latitude 07.50 N and longitude 90.00 E, about 350 km southwest of Car Nicobar, 970 km eastsoutheast of Trincomalee, 1230 km southeast of Chennai and 1650 km south-southwest of Chittagong. The system would intensify further into a severe cyclonic storm during next 24 hours. It would move initially northwestwards during next 36 hours and recurve thereafter northeastwards towards Bangladesh-Myanmar coast.

Fishermen of Nicobar Islands are advised not to venture into the sea during next 48
hrs.

Latest COLA, IMD and NOGAPS model suggest that "Mahasen" will travel N-W for next 1/2 days up to W-central Bay. Then it will move N-N-E and then N-E. 

Models expect a landfall along North Myanmar coast and S-E Bangladesh coast on early hrs of 16-May as a depression not as a Cyclone. 

Monsoon - The South west monsoon will move into S,S-E Bay and South Andaman Islands on tomorrow.

RT @gaganchauhan90: @weatherofindia  strong winds and thundershowers in chandigarh right now. (4:01pm)

"01 B" is now named as Cyclone "Mahasen" ... more on it in our 3:15pm update !

On 10-May, highest maximum  temperatures of  46.0°C  was  recorded at Allahabad  (Uttar
Pradesh) and Nagpur (Maharashtra)

#HOT at 1:30pm, Hyderabad, Varanasi = 43 C, Ahmedabad, Thiruchirapalli = 40 C, #Kolkata = 37 C, Amristar, #Delhi = 36 C (Due to W.D)

2pm, Rain & cloudy due to W.D over Kashmir, Himachal, upper reaches of Uttarakand, N,N-W Rajasthan, Punjab, Haryana.. http://ow.ly/i/25G0O 

Due to W.D, in next 2 days, rain expected for Kashmir, Punjab, Himachal, N,N-E Rajasthan, Haryana, #Delhi, Uttarakand http://ow.ly/i/25GkA 

"01B" - Cyclone not named yet! Slightly intensified and moved N-W

Analysis show that the system has moved N-W into Bay during past 12hrs.
Even it had slightly intensified.
Present location is 7.3N , 90.6E
Pressure has reduced to 993 mb
Winds gusting up to 75 kmph
"01B" will be a named Cyclone in another 8 hrs.

JTWC warning and path forecast at 8:30am IST

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

TROPICAL CYCLONE 01B (ONE), LOCATED APPROXIMATELY 919 NM SOUTHWARD 
OF CHITTAGONG, BANGLADESH, HAS TRACKED NORTHWESTWARD AT 13 KNOTS
OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY 
DEPICTS BUILDING CENTRAL CONVECTION WITH A NOTICEABLE WARM SPOT OVER 
THE LOW-LEVEL CIRCULATION CENTER (LLCC). FEEDER BANDS CONTINUE TO 
GROW OVER THE WESTERN SEMI-CIRCLE. THE INITIAL POSITION IS BASED ON 
THE DEVELOPING WARM SPOT NOTICED IN IR AND A TIGHTLY CURVED NOTCH 
FEATURE IN THE 110011Z SSMIS 37H IMAGE WITH FAIR CONFIDENCE. THE 
INITIAL INTENSITY IS HELD SLIGHTLY HIGHER THAN DVORAK ESTIMATES OF 
30-35 KNOTS FROM PGTW AND KNES BASED ON THE 101810Z OSCAT PASS THAT 
SHOWED MULTIPLE 40-KNOT WIND BARBS. UPPER-LEVEL ANALYSIS SEEMS TO 
INDICATE THAT THE POINT SOURCE ALOFT MAY HAVE DISSOLVED FOR THE TIME 
BEING BUT EXCELLENT RADIAL OUTFLOW REMAINS OVER THE LLCC. VERTICAL 
WIND SHEAR VALUES FROM CIMSS ARE ESTIMATED AT 20-30 KNOTS BUT THE 
ROBUST OUTFLOW IS OFFSETTING THIS NEGATIVE FACTOR. TC 01B IS 
FORECAST TO TRACK NORTHWESTWARD THROUGH TAU 36 UNDER THE STEERING 
INFLUENCE OF WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) 
POSITIONED OVER THE NORTHEASTERN BAY OF BENGAL. THEREAFTER, TC 01B 
IS EXPECTED TO TURN POLEWARD AS THE STR WEAKENS DUE TO AN 
APPROACHING MIDLATITUDE SHORTWAVE TROUGH CURRENTLY DRAPED OVER  
NORTHERN INDIA AND THE NORTHEASTERN ARABIAN SEA. AFTER TAU 48, 
THE SYSTEM WILL RE-CURVE TOWARDS THE MYANMAR/BANGLADESH BORDER AS 
MIDLATITUDE WESTERLY FLOW DOMINATES INDIA AND THE WESTERN BAY OF 
BENGAL. TC 01B IS A LARGE CIRCULATION ENCOMPASSING ALMOST THE 
ENTIRETY OF THE BAY OF BENGAL. THEREFORE, BETA ADVECTION IS EXPECTED 
TO SUSTAIN THE NOSE OF THE STEERING STR. THIS EFFECT SHOULD CAUSE 
THE TC TO TRACK SLIGHTLY FURTHER WESTWARD OVER THE BAY OF BENGAL 
BEFORE EVENTUALLY RE-CURVING. TC 01B SHOULD INTENSIFY TO A PEAK OF 
85 KNOTS BY TAU 96 DUE TO INCREASED POLEWARD OUTFLOW TAPPED INTO THE 
WESTERLIES. BY TAU 120 THE SYSTEM SHOULD HAVE MADE LANDFALL AS A 
SIGNIFICANT TC AND BEGUN TO SPIN-DOWN DUE TO LAND INTERACTION. THERE 
IS HIGH CONFIDENCE IN THE FORECAST TRACK AS MODEL TRACKERS CONTINUE 
TO CONVERGE ON THIS SOLUTION. THE ONLY CONCERNING FACTOR IS THE SLOW 
TRACK SPEEDS OF THE ECMWF TRACKER. HOWEVER, IT IS NOW INLINE WITH 
THE RE-CURVE TOWARDS BANGLADESH AND MAY COME FURTHER INLINE WITH 
TRACK SPEEDS OVER THE NEXT COUPLE OF DAYS. MAXIMUM SIGNIFICANT WAVE 
HEIGHT AT 110000Z IS 12 FEET.

Most weather models agree to this path for "01 B"

W.D is slowly nearing N,N-W India... http://ow.ly/i/25sn9 

12am, W.D rains has pushed into S-W Kashmir and into N.Punjab... N-W Rajasthan is cloudy ... http://ow.ly/i/25srw 

In next 2 days, Heavy & scattered rain expected over Kashmir, Himachal, Uttarakand, Punjab, Haryana, N,N-W Rajasthan http://ow.ly/i/25svF 

Due to W.D, #Delhi can also expected rain today, 12,13-May .!

"01B" - Slowly Intesifying and drifting N-W into Bay.

Analysis show that the Cyclone has drifted N-W into Bay during past 6 hrs.

Present location is 5.8N , 92.4E.

Pressure has remained the same from Noon, at around 996 mb

Winds gusts reaching up to 65 Kmph.

11:30pm, Satellite IR shows a good core and a good circulation around it. The cyclone is expected to attain a named cyclone "Mahasen" strength in next 18 hrs.

JTWC warning at 8:30pm IST

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

TROPICAL CYCLONE 01B (ONE), LOCATED APPROXIMATELY 1009 NM SOUTH OF 
CHITTAGONG, BANGLADESH, HAS TRACKED NORTHWESTWARD AT 07 KNOTS OVER 
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) 
DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH 
WITH IMPROVED DEEP CONVECTIVE BANDING. THERE IS FAIR CONFIDENCE IN 
THE INITIAL POSITION BASED ON A 101130Z SSMIS IMAGE, WHICH DEPICTS 
DEEP CONVECTIVE BANDING WRAPPING FROM THE NORTH QUADRANT INTO THE 
SOUTHWEST QUADRANT OF A DEFINED LLCC. DESPITE THE RECENT 
IMPROVEMENT, DVORAK ESTIMATES REMAIN LOW AT 30 KNOTS; HOWEVER, A 
100244Z ASCAT IMAGE AND A 100544Z OCEANSAT IMAGE BOTH SHOW 35-KNOT 
WINDS NEAR THE CORE AND SUPPORT THE INTENSITY ASSESSMENT OF 35 
KNOTS. ADDITIONALLY, A 10/12Z SHIP REPORT, LOCATED ABOUT 60 NM NORTH 
OF THE CENTER, INDICATES SUSTAINED EASTERLY WINDS OF 29 KNOTS WITH 
SLP NEAR 1002 MB, SUPPORTING THE INITIAL INTENSITY ASSESSMENT. THE 
LLCC IS LOCATED UNDER A POINT SOURCE, WHICH IS PRODUCING NEAR-RADIAL 
OUTFLOW; HOWEVER, VERTICAL WIND SHEAR (VWS) REMAINS MODERATE TO 
STRONG (20 TO 30 KNOTS). TC 01B IS FORECAST TO TRACK NORTHWESTWARD 
THROUGH TAU 36 UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE 
(STR) POSITIONED OVER THE NORTHEASTERN BAY OF BENGAL. THEREAFTER, TC 
01B IS EXPECTED TO TURN POLEWARD AS THE STR WEAKENS DUE TO AN 
APPROACHING DEEP MIDLATITUDE SHORTWAVE TROUGH, CURRENTLY POSITIONED 
OVER PAKISTAN AND THE NORTHERN ARABIAN SEA. AFTER TAU 60, THE SYSTEM 
WILL RE-CURVE INTO MYANMAR AS MIDLATITUDE WESTERLY FLOW DOMINATES 
INDIA AND THE WESTERN BAY OF BENGAL. WITH THE EXCEPTION OF ECMWF, 
WHICH INDICATES RAPID WEAKENING AND DISSIPATION IN THE EXTENDED 
TAUS, DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT. THE JTWC FORECAST 
IS POSITIONED FASTER THAN THE MULTI-MODEL CONSENSUS TO OFFSET ECMWF 
AND IS CONSISTENT WITH THE PREVIOUS FORECAST. OVERALL, THERE IS HIGH 
CONFIDENCE IN THE FORECAST. TC 01B IS FORECAST TO INTENSIFY TO A 
PEAK OF 90 KNOTS BY TAU 96 DUE TO DECREASING VWS AND IMPROVING 
POLEWARD OUTFLOW ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE 
TROUGH. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 101200Z IS 10 FEET.

JTWC tracking and forecasted path:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Latest NOGAPS and COLA models agree to North Myanmar coast and S-E Bangladesh coast landfall as a weak Cyclone on evening of 15-May.