WDPN31 PGTW 200300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (IN-FA) WARNING NR 016// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 24.4N 130.8E INITIAL INTENSITY: 60 KTS GEOGRAPHIC REFERENCE: 206 NM SOUTHEAST OF KADENA AB, OKINAWA, JAPANN MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 32 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO SLOWLY CONSOLIDATE AS THE CENTRAL CONVECTION DEEPENED AND RAIN BANDS, THE LARGEST SWATH FEEDING IN FROM THE SOUTHEAST, WRAPPED TIGHTER INTO A FORMATIVE EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE FORMATIVE EYE IN THE MSI LOOP. THE INITIAL INTENSITY OF 60 KTS IS HELD HIGHER THAN AGENCY DVORAK AND AUTOMATED FIXES WITH HIGH CONFIDENCE BASED ON THE IMPROVED 6-HR METSAT SIGNATURE. INITIAL WIND RADII BASIS: PERSISTENCE WITH SLIGHT EXTRAPOLATION FROM PREVIOUS WIND RADII. CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTH ANCHORED OVER JAPAN. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.5 - 55 KTS RJTD: T3.5 - 55 KTS KNES: T3.5 - 55 KTS CIMSS ADT: 39 KTS AT 192340Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 0-5 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH 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 09W WILL TRACK MORE WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR TOWARD NORTHERN TAIWAN. AFTER TAU 72, IT WILL TURN MORE NORTHWESTWARD, NEAR TAIPEI, TAIWAN, AS IT BEGINS TO ROUND THE WESTERN EDGE OF THE STR, THEN MAKE A FINAL LANDFALL OVER SOUTHEAST CHINA NEAR FUZHOU NEAR TAU 108. THE FAVORABLE ENVIRONMENT WILL PROMOTE A STEADY INTENSIFICATION TO A PEAK OF 90KTS AROUND TAU 48. AFTERWARD, INCREASING VWS AND SUBSIDENCE ASSOCIATED WITH A MID-LATITUDE TROUGH TO THE NORTHWEST WILL GRADUALLY WEAKEN THE SYSTEM. AFTER LANDFALL IN CHINA, LAND INTERACTION WITH THE RUGGED TERRAIN WILL RAPIDLY ERODE THE SYSTTEM DOWN TO 35KTS BY TAU 120. MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT UP TO TAU 48 THEN GRADUALLY SPREAD TO JUST 90M AT TAU 72, LENDING HIGH CONFIDENCE TO THE NEAR TO MID-TERM PORTION OF THE JTWC TRACK FORECAST. AFTERWARD, FORECAST TRACK CONFIDENCE IS LOW AS THE MODELS SIGNIFICANTLY DIVERGE WITH NVGM ON THE EXTREME RIGHT OF THE ENVELOPE SUGGESTING A SHARP RECURVATURE NORTHEASTWARD, AND UKMET ON THE LEFT MARGIN OF THE ENVELOPE WITH A FLAT WESTWARD SOLUTION RESULTING IN A 730+ NM SPREAD. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: HIGH INTENSITY 72-120 HR: MEDIUM// NNNN