WDIO31 PGTW 092100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06B (MANDOUS) WARNING NR 009// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 12.7N 80.7E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 132 NM SOUTHWEST OF CHENNAI, INDIA MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 16 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A DISORGANIZED BLOB OF CONVECTION BEING DISPLACED OVER LAND TO THE WEST-NORTHWEST OF THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE SYSTEM HAS STRUGGLED TO REMAIN INTACT AS THE UPPER-LEVEL SOUTHEASTWARD WIND FLOW OF 25-30 KTS IS PRODUCING A MODERATE SHEAR ENVIRONMENT, WHICH IS RESPONSIBLE FOR THE ASSOCIATED CONVECTION BEING PUSHED AWAY FROM THE CENTER. IN ADDITION, THE LAND INTERACTION HAS INCREASED IMMENSELY OVER THE PAST SIX HOURS, CONTRIBUTING TO THE INITIAL INTENSITY DROPPING FROM 45 KTS TO 35 KTS. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON A PARTIAL 091609Z ASCAT-B PASS SHOWS A SMALL POCKET OF 35 KT WINDS TO THE NORTHEAST OF THE ASSESSED LLCC, AND PREDOMINATELY 25 KTS WINDS ENCOMPASSING THE EASTERN PERIPHERY. A 091900Z OBSERVATION FROM CHENNAI'S AIRPORT IS SHOWING 25 KTS, WITH GUSTS OF 40 KTS. PGTW DVORAK ESTIMATE IS 2.5 AND ADT IS 33 KTS AS OF 091815Z. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON PGTW FIX AND THE AFOREMENTIONED EIR IMAGERY. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS CIMSS ADT: 33 KTS AT 091815Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 15-20 KTS SST: 26-27 CELSIUS OUTFLOW: MODERATE POLEWARD OTHER FACTORS: LAND INTERACTION AND LOSS OF CONVECTION WILL CONTRIBUTE TO DISSIPATION. ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: HIGH INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS MANDOUS HAS BEGUN ITS DISSIPATION STAGE DUE THE AFOREMENTIONED DISPLACEMENT OF CONVECTION AND LAND INTERACTION. AFTER TAU 06, THE CENTER OF THE SYSTEM WILL BE OVER LAND AND THE INTENSITY WILL FALL BELOW 30 KTS. BY TAU 12, TS MANDOUS WILL CONTINUE TO DECREASE IN INTENSITY AS IT MOVES DEEPER INLAND OVER SOUTHERN INDIA. BY TAU 24, TS MANDOUS WILL BE COMPLETELY DISSIPATED. MODEL DISCUSSION: THE JTWC MODEL CONSENSUS IS IN RELATIVELY GOOD AGREEMENT WITH ALL MEMBERS AGREEING ON A WESTWARD TRACK OVER LAND OVER THE NEXT 24 HOURS. THE JTWC FORECAST TRACK IS PLACED WITH MEDIUM CONFIDENCE DUE TO EIR LOOP APPEARS TO BE SHOWING TS MANDOUS ON A MORE NORTHWESTERLY TRACK. HOWEVER, IT IS REALLY DIFFICULT TO SPOT THE LLCC IN THIS LOOP. THE JTWC INTENSITY CONSENSUS IS IN VERY TIGHT AGREEMENT THAT TS MANDOUS WILL UNDERGO DISSIPATION FROM NOW AND THROUGHOUT ITS FORECAST TRACK OVER SOUTHERN INDIA. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM INTENSITY 0 - 72 HR: HIGH// NNNN