WDIO31 PGTW 082100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02B (ASANI) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 13.2N 86.8E INITIAL INTENSITY: 65 KTS GEOGRAPHIC REFERENCE: 571 NM SOUTH OF KOLKATA, INDIA MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: 26 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN EXPANDING SYSTEM THAT SPANS OVER 500NM AS ITS CIRRUS CANOPY STRETCHES WESTWARD ALL THE WAY TO THE NORTH INDIAN OCEAN WHILE MAINTAINING A SYMMETRICAL COLD DENSE OVERCAST (CDO) THAT IS OBSCURING THE LOW LEVEL CIRCULATION (LLC). THE EIR LOOP CONTINUES TO SHOW PRESSURE ALONG THE EASTERN SIDE, AN INDICATION OF STRONG EASTERLY VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A DEFINED LLC IN THE 081515Z ASCAT BULLSEYE PASS. THE INITIAL INTENSITY IS BASED ON THE PGTW AND ADT DVORAK ESTIMATES AND REFLECTS THE SUSTAINED 6-HR EIR SIGNATURE. INITIAL WIND RADII BASIS: SCATTEROMETER DATA. CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST AND EAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS CIMSS ADT: 63 KTS AT 081515Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 25-30 KTS SST: 31-32 CELSIUS OUTFLOW: STRONG WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 02B IS EXPECTED TO CONTINUE TRACKING NORTHWESTWARD ALONG THE PERIPHERY OF THE STR THROUGH TAU 24 UNDER THE STEERING INFLUENCE OF THE STR. AFTERWARD, IT WILL TURN MORE NORTHWARD THEN NORTHEASTWARD AS IT ROUNDS THE STR AXIS AS THE STR RECEDES IN RESPONSE TO AN APPROACHING MID-LATITUDE SHORTWAVE. THE SYSTEM HAS PEAKED INTENSITY AND THE OVERALL UNFAVORABLE ENVIRONMENT DUE TO HIGH VWS AND COOL DRY AIR ENTRAINMENT FROM THE NORTH WILL GRADUALLY WEAKEN THE CYCLONE TO DISSIPATION BY TAU 120 AS IT MAKES LANDFALL OVER WESTERN BANGLADESH. MODEL DISCUSSION: THE NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH THE FORECAST TRACK WITH THE NAVGEM AND AFUM ON THE LEFT MARGIN AND GFS THE RIGHT-OF-TRACK OUTLIER DRIVING THE VORTEX DUE EASTWARD AFTER TAU 36. IN VIEW OF THIS, THERE IS MEDIUM CONFIDENCE IN THE JTWC FORECAST TRACK. THERE IS ALSO MEDIUM CONFIDENCE IN THE FORECAST INTENSITIES THAT ARE HELD SLIGHTLY HIGHER THAN CONSENSUS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN