WDIO32 PGTW 241500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06B (HAMOON) WARNING NR 006// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 20.8N 91.2E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 96 NM SOUTH-SOUTHWEST OF CHITTAGONG MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 08 KTS SIGNIFICANT WAVE HEIGHT: 30 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL CYCLONE (TC) 06B (HAMOON) CONTINUES TO PRESENT A ROBUST APPEARANCE IN THE ENHANCED INFRARED (EIR) IMAGERY, WITH PERSISTENT DEEP CONVECTION AND A SINGLE HOT TOWER IN THE SOUTHWEST PORTION OF THE CIRCULATION PERSISTING FOR THE PAST FOUR HOURS. HOWEVER, THE EIR LOOP IS DECEIVING AS IT OBSCURES THE LOW LEVEL CIRCULATION CENTER (LLCC). A FORTUITOUS 241145Z SSMIS COLOR ENHANCED 89GHZ IMAGE SHOWS EXPOSED LOW LEVEL BANDING FEATURES WRAPPING INTO A CENTER WHICH IS PARTIALLY EXPOSED TO THE WEST OF THE UPPER-LEVEL MICROWAVE EYE. THIS SUGGESTS THE VORTEX IS ALREADY BEGINNING TO DECOUPLE. THE CIMSS SHEAR ANALYSIS INDICATES 30 KNOTS OF SHEAR FROM 220 DEGREES, WHICH ALIGNS ALMOST PERFECTLY WITH THE BEARING BETWEEN THE ASSESSED LLCC AND THE UPPER-LEVEL MICROWAVE EYE, PROVIDING ADDITIONAL SUPPORT TO THE ANALYSIS OF THE INITIAL POSITION, WHICH IS ASSESSED WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 75 KNOTS WITH MEDIUM CONFIDENCE, IN LINE WITH THE PGTW DVORAK CURRENT INTENSITY ESTIMATE AND THE CIMSS AIDT, DPRINT AND DMINT ESTIMATES. THE SYSTEM IS TRACKING NORTHEAST ALONG THE WEST SIDE OF THE SUBTROPICAL RIDGE (STR) BUT HAS SLOWED AS EXPECTED, AS IT APPROACHES THE COAST OF MYANMAR, WITH TRACK SPEED LOWERING FROM 12 KNOTS TO 8 KNOTS OVER THE PAST SIX HOURS. ENVIRONMENTAL CONDITIONS ARE INCREASINGLY HOSTILE, WITH HIGH SOUTHWESTERLY SHEAR AND MID-LEVEL DRY AIR OFFSETTING BEGINNING TO EXERT THEIR INFLUENCE AND OVERWHELM THE ROBUST POLEWARD OUTFLOW AND WARM SSTS. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER STR CENTERED NEAR HONG KONG. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS KNES: T5.0 - 90 KTS DEMS: T4.0 - 65 KTS CIMSS SATCON: 65 KTS AT 240656Z CIMSS ADT: 79 KTS AT 241130Z CIMSS DPRINT: 74 KTS AT 241200Z CIMSS DMINT: 74 KTS AT 241145Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY UNFAVORABLE VWS: 30+ KTS SST: 29-30 CELSIUS OUTFLOW: STRONG POLEWARD OTHER FACTORS: VERY DRY AIR MASS ABOVE 500MB MOVING IN FROM THE WEST. ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 06B IS FORECAST TO CONTINUE TRACKING TOWARDS THE GENERALLY TOWARDS THE NORTHEAST THROUGH THE FORECAST PERIOD. LANDFALL IN THE VICINITY OF COXS BAZAAR IS ANTICIPATED WITHIN THE NEXT SIX TO EIGHT HOURS. WITH THE MOST RECENT MICROWAVE IMAGERY SUGGESTING THE VORTEX IS ALREADY STARTING TO DECOUPLE DUE TO 30+ KNOTS OF SOUTHWESTERLY SHEAR, THE SYSTEM IS FORECAST TO RAPIDLY WEAKEN AS IT APPROACHES LANDFALL. AN INTENSITY BETWEEN 60-65 KNOTS IS EXPECTED AS THE SYSTEM CROSSES THE COASTLINE. RAPID WEAKENING WILL OCCUR THEREAFTER AS THE SYSTEM IS SHEARED APART BY THE STRONG SHEAR FROM ABOVE, AND THE RUGGED TERRAIN TEARS THE LOW-LEVEL VORTEX APART AT THE SURFACE. THE SYSTEM IS EXPECTED TO DISSIPATE BETWEEN TAU 36 AND TAU 48 ALONG THE BORDER BETWEEN MYANMAR AND EASTERN INDIA. MODEL DISCUSSION: TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 24, BUT THEN BECOMES HIGHLY UNCERTAIN AS THE MODELS LOSE THE VORTEX AS IT IS SHREDDED BY THE MOUNTAINOUS TERRAIN. THE JTWC TRACK IS SET CLOSE TO THE CONSENSUS WITH MEDIUM CONFIDENCE AFTER TAU 24. INTENSITY GUIDANCE IS IN STRONG AGREEMENT ON A RAPID WEAKENING TREND AND THE JTWC FORECAST IS ON THE CONSERVATIVE SIDE, ON THE HIGH END OF THE GUIDANCE PACKAGE THROUGH THE FORECAST PERIOD. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM// NNNN