27W(NYATOH): smap validates 125knot intensity(CAT 4): expected dramatic weakening next 48h// TC 05B develops over the BOB,03/03utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON 27W AND 05B. 3HOURLY SATELLITE BULLETINS ARE STILL ISSUED ON THE REMNANTS OF TC 02S(TERATAI).

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY 27W HAS SOMEWHAT SURPRISINGLY HELD FIRM IN THE FACE OF RAPIDLY DETERIORATING ENVIRONMENTAL CONDITIONS. PER HWRF AND GFS MODEL CROSS-SECTIONS AND SKEW-T ANALYSIS, MID-LEVEL DRY AIR IS POURING INTO THE CORE FROM THE WEST, AND SHEAR ESTIMATES ARE NOW APPROACHING 45-50 KNOTS. CIMSS ANALYSIS CONFIRMS THE HIGH SHEAR ESTIMATES. YET THE SYSTEM HAS TO DATE FOUGHT OFF THESE INHIBITING FACTORS, AND WHILE THE EYE HAS WIDENED AND BECOME MORE RAGGED, IT IS STILL GOING STRONG. HOWEVER, THE LIGHT ON THE FREIGHT TRAIN IS GETTING LARGER AND THE HEADY DAYS OF BEING A NEAR-SUPER TYPHOON STRENGTH SYSTEM WILL SOON COME TO AN END. THE SYSTEM IS FORECAST TO CONTINUE TRACKING NORTHEAST WHILE STEADILY SLOWING THROUGH 36H. IT IS EXPECTED THAT THE STEADILY INCREASING SHEAR AND DRY AIR ENTRAINMENT WILL ERODE THE EYE AND BEGIN TO DECAPITATE THE SYSTEM WITHIN THE NEXT 12 TO 24 HOURS, AND ONCE THIS OCCURS, RAPID WEAKENING WILL ENSUE. THE SYSTEM IS FORECAST TO BECOME FULLY DECOUPLED BY 36H, AND THUS THE STEERING LEVEL WILL LOWER PRECIPITOUSLY, DOWN TO THE 850MB LEVEL. THE SURFACE-850MB MEAN FLOW IN THE AREA IS FROM THE NORTH-NORTHEAST, AND THIS FLOW WILL PUSH THE RAPIDLY WEAKENING TY 27W ONTO A SOUTHWESTWARD TRACK BY 48H. THE SYSTEM IS EXPECTED TO FULLY DISSIPATE TO A REMNANT LOW LEVEL CIRCULATION BY 72H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TY 27W HAS MAINTAINED ITS INTENSITY OVER THE PAST SIX HOURS, THOUGH IT IS BEGINNING TO EXHIBIT SIGNS OF ITS IMPENDING DEMISE. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT THE CONVECTIVE CORE HAS ERODED SIGNIFICANTLY OVER THE PAST SIX HOURS, WITH CLOUD TOPS WARMING ABOUT 8C, AND THE EXTENT OF THE COLD CONVECTIVE SHRINKING DRAMATICALLY, ESPECIALLY IN IMAGERY AFTER THE 0000Z HOUR. ADDITIONALLY, THE CONTINUED ENCROACHMENT OF DRY AIR AND HIGH WESTERLY SHEAR ARE STARTING TO ERODE THE WESTERN SIDE OF THE CONVECTIVE CORE. WHILE THE STRUCTURE IS MANIFESTLY DETERIORATING, THE OBJECTIVE AND SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES REMAIN HIGH, AT OR ABOVE 125 KNOTS. ADDITIONALLY, A 022117Z SMAP PASS SHOWED 115 KNOT MEASUREMENTS IN THE SOUTHWESTERN PORTION OF THE EYEWALL, WHICH WHEN APPLYING THE .93 CONVERSION FACTOR RESULTS IN A 124 KNOT 1-MIN WIND ESTIMATE. THESE FACTORS COMBINE TO LEND HIGH CONFIDENCE TO THE INITIAL INTENSITY. THE INITIAL POSITION IS BASED ON THE CONGRUENCE OF AGENCY FIX POSITIONS WITHIN THE 30-NM RAGGED EYE FEATURE WITH HIGH CONFIDENCE. THE OVERALL ENVIRONMENT IS BECOMING INCREASINGLY UNFAVORABLE WITH INCREASING MID-LEVEL DRYNESS DARTING DIRECTLY INTO THE LOW LEVEL VORTEX. ADDITIONALLY, THE HIGH (40-45 KNOTS) WEST-SOUTHWESTERLY WIND SHEAR IS STARTING TO DOMINATE THE ROBUST POLEWARD OUTFLOW.

022117Z SMAP PASS SHOWED 115 KNOT MEASUREMENTS IN THE SOUTHWESTERN PORTION OF THE EYEWALL, WHICH WHEN APPLYING THE .93 CONVERSION FACTOR RESULTS IN A 124 KNOT 1-MIN WIND ESTIMATE.

MODEL DISCUSSION: TRACK GUIDANCE UNCERTAINTY HAS INCREASED SINCE THE PREVIOUS RUN. WITH THIS RUN, THE GFS, GFS ENSEMBLE, UKMET ENSEMBLE AND HWRF CONTINUE TO SHOW THE DISSIPATING SYSTEM TURNING SHARPLY SOUTHWARD AFTER 36H. WITH THIS RUN HOWEVER, THE NAVGEM, ECMWF, ECMWF ENSEMBLE AND GALWEM BLOW RIGHT THROUGH THE TURN AND CONTINUE RACING THE VORTEX TO THE NORTHEAST, LEADING TO SIGNIFICANT MODEL SPREAD AND UNCERTAINTY. THE JTWC FORECAST REMAINS CONSISTENT WITH THE PREVIOUS FORECASTS AND CLOSELY TRACKS THE GFS THROUGH 48H, THOUGH IS MUCH SLOWER THROUGH 72H. DUE TO THE UNCERTAINTY INTRODUCED IN THIS RUN OF THE GUIDANCE, THERE IS NOW LOW CONFIDENCE IN THE FORECAST. CONVERSELY, INTENSITY GUIDANCE IS IN GOOD AGREEMENT ON A RAPID AND STEADY WEAKENING THROUGH THE FORECAST PERIOD WITH DISSIPATION NO LATER THAN 72H, LENDING MEDIUM CONFIDENCE TO THE FORECAST.

MID-LEVEL DRY AIR IS POURING INTO THE CORE FROM THE WEST, AND SHEAR ESTIMATES ARE NOW APPROACHING 45-50 KNOTS. CIMSS ANALYSIS CONFIRMS THE HIGH SHEAR ESTIMATES.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TS 05B HAS SLOWLY BUT STEADILY CONSOLIDATED OVER THE PREVIOUS TWO DAYS, AND HAS NOW REACHED WARNING CRITERIA. THE SYSTEM IS CURRENTLY TRACKING QUICKLY TOWARDS THE NORTHWEST ALONG THE SOUTHWEST SIDE OF A DEEP SUBTROPICAL RIDGE(STR)TO THE EAST. OVER THE NEXT 24 HOURS, THE SYSTEM WILL SLOW AS IT REACHES THE RIDGE AXIS, ROUND THE AXIS NEAR 36H, THEN ACCELERATE NORTH THEN NORTHEAST THROUGH THE REMAINDER OF THE FORECAST. THE FORECAST CALLS FOR THE SYSTEM TO MAKE LANDFALL NEAR 48H, THEN SKIRT THE COASTLINE AND PASSING NEAR KOLKATA BETWEEN 72H AND 96H BEFORE MOVING INTO CENTRAL BANGLADESH BY THE END OF THE FORECAST. DUE TO THE PERSISTENT EASTERLY UPPER-LEVEL FLOW, THE VORTEX OR CORE OF THE SYSTEM IS TILTED A BIT TO THE WEST. WHILE UPPER-LEVEL FLOW IS EXPECTED TO SLACKEN SLIGHTLY OVER THE NEXT 24 HOURS, THE VORTEX TILT IS FORECAST TO REMAIN IN PLACE, WHICH WILL ACT AS A BRAKING MECHANISM ON THE RATE OF INTENSIFICATION, EVEN IN LIGHT OF THE ROBUST POLEWARD OUTFLOW IN THE BASE OF A PASSING MID-LATITUDE TROUGH. THUS THE SYSTEM IS FORECAST TO INTENSIFY AT A LESS THAN CLIMATOLOGICAL RATE, PEAKING AT 50 KNOTS BY 36H, JUST OFFSHORE OF VISAKHAPATNAM, INDIA. INCREASING SHEAR, DRY AIR ENTRAINING IN FROM THE INDIA SUBCONTINENT AND FRICTIONAL EFFECTS OVER LAND WILL CONSPIRE TO STEADILY WEAKEN AND ULTIMATELY DISSIPATE THE SYSTEM OVER BANGLADESH BY 96H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A WELL DEFINED MID-LEVEL ROTATION SIGNATURE, WITH STRONG FLARING CONVECTION DISPLACED TO THE NORTHWEST OF THE ASSESSED LOW LEVEL CIRCULATION CENTER. WHILE THE DEEPEST OF THE CONVECTION IS DISPLACED A BIT TO THE NORTHWEST, THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS TUCKED UNDER THE SOUTHEASTERN CORNER OF THE CONVECTIVE ENVELOPE. THE INITIAL POSITION IS PLACED WITH ONLY MEDIUM CONFIDENCE DUE TO A LACK OF RECENT SCATTEROMETER DATA AND INCONCLUSIVE MICROWAVE DATA FROM 022116Z. THE INITIAL INTENSITY IS ASSESSED AT A GENEROUS 35 KNOTS WITH LOW CONFIDENCE BASED ON A PGTW FIX AT 0000Z OF T2.5 (35 KTS) WITH A .40 WRAP. DEMS IS FIXING AT T2.0 (30 KTS). THE SYSTEM IS TRACKING QUICKLY NORTHWEST ALONG THE WESTERN PERIPHERY OF DEEP SUBTROPICAL RIDGE CENTERED OVER NORTHERN THAILAND. THE ENVIRONMENT IS MARGINALLY FAVORABLE, TRENDING FAVORABLE, WITH WARM SSTS (28-29C) AND ROBUST POLEWARD OUTFLOW. AT THE CURRENT TIME, VWS IS MODEST, THE CIMSS ANALYSIS DEPICTING A SMALL POCKET OF LOW SHEAR IN DIRECT VICINITY OF THE LLCC, COCOONED WITHIN A LARGER AREA OF MODERATE TO HIGH EASTERLY SHEAR. THE ENVIRONMENTAL EASTERLY FLOW IS HIGHLY DIVERGENT NEAR THE SYSTEM, PROVIDING STRONG SUPPORT FOR THE ENHANCED CONVECTION, BUT IS RESULTING IN A WESTWARD TILT WITH HEIGHT OF THE VORTEX BASED ON GFS AND HWRF CROSS-SECTIONS.

MODEL DISCUSSION: TRACK GUIDANCE, WITH THE EXCEPTION OF GFS, IS IN GOOD AGREEMENT ON THE OVERALL SCENARIO, WITH CROSS-TRACK SPREAD INCREASING AFTER 24H, PLACING THE ECMWF AND ECMWF ENSEMBLE TRACKERS OVER LAND BY 36H. THE REMAINDER OF THE TRACKERS KEEP THE CENTER OFFSHORE UNTIL 48H. THE GFS TURNS THE SYSTEM SHARPLY EASTWARD AFTER 12H, WITH A LANDFALL NEAR CHITTAGONG, BUT THIS SCENARIO IS UNREALISTIC AS THE SYSTEM IS UNLIKELY TO TRACK DIRECTLY INTO THE STRONG RIDGE. THE JTWC FORECAST LIES JUST INSIDE AND SLIGHTLY FASTER THAN THE CONSENSUS MEAN WITH MEDIUM CONFIDENCE. INTENSITY GUIDANCE IS MIXED, WITH THE SHIPS GUIDANCE INDICATING A PEAK INTENSITY NEAR 65 KNOTS, WHILE THE COAMPS-TC SUGGESTS A PEAK CLOSER TO 45 KNOTS. THE JTWC FORECAST CLOSELY TRACKS THE HWRF SOLUTION, JUST SLIGHTLY LOWER THAN CONSENSUS THROUGH 36H, THEN SLIGHTLY ABOVE IT THEREAFTER. OVERALL CONFIDENCE IS LOW DUE TO UNCERTAINTIES WITH THE AMOUNT OF LAND INTERACTION, WHICH IS DEPENDENT UPON THE EXACT TRACK.

03/0540UTC.