WDPN31 PGTW 221500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (IN-FA) WARNING NR 026// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 23.6N 125.9E INITIAL INTENSITY: 85 KTS GEOGRAPHIC REFERENCE: 202 NM SOUTH-SOUTHWEST OF KADENA MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 01 KTS SIGNIFICANT WAVE HEIGHT: 34 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND RADAR IMAGERY INDICATE A LARGE 55NM ROUND EYE WITH EXTENSIVE SPIRAL BANDING. OVERALL, THE SYSTEM APPEARS TO BE SLOWLY WEAKENING AS DEPICTED IN A 221005Z SSMIS 91GHZ MICROWAVE IMAGE, WHICH REVEALS TIGHTLY CURVED BANDING OVER THE SOUTHERN SEMICIRCLE WRAPPING AROUND THE LARGE, EXPANDING EYE AND WEAKER, FRAGMENTED BANDING OVER THE NORTHERN PERIPHERY. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE EIR IMAGERY AND RJTD RADAR FIXES. THE INITIAL INTENSITY OF 85 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF THE PGTW AND KNES DVORAK ESTIMATES AND THE 221051Z SATCON ESTIMATE. UPPER-LEVEL ANALYSIS INDICATES FAVORABLE CONDITIONS WITH LOW VERTICAL WIND SHEAR AND MODERATE RADIAL OUTFLOW ALTHOUGH A SMALL UPPER-LEVEL CYCLONE REMAINS POSITIONED OVER THE SYSTEM'S CENTER DIVERGING AWAY FROM THE CENTER. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.0 - 90 KTS RJTD: T5.5 - 102 KTS RCTP: T4.5 - 77 KTS KNES: T4.5 - 77 KTS CIMSS SATCON: 84 KTS AT 221051Z CIMSS ADT: 94 KTS AT 221140Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 0-5 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM 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: TY 09W IS TRACKING SLOWLY ALONG THE SOUTHERN PERIPHERY OF THE STR DUE TO THE PRESENCE OF A COMPETING NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTH. THE BULK OF THE MODELS INDICATE THE STR SHOULD RE-ORIENT, AS A MIDLATITUDE TROUGH PROPAGATES OVER NORTHEAST ASIA, AND ACCELERATE THE SYSTEM NORTH-NORTHWESTWARD THROUGH TAU 72 TOWARD THE SHANGHAI REGION. SLIGHT INTENSIFICATION TO 90 KNOTS IS EXPECTED IN THE SHORT-TERM THEN GRADUAL WEAKENING AS TY 09W APPROACHES THE CHINA COAST DUE TO WEAK POLEWARD OUTFLOW. AFTER TAU 72, THE SYSTEM WILL SLOW AS A MAJOR SHORTWAVE TROUGH DIGS OVER EASTERN CHINA AND TRACK OVERLAND LEADING TO RAPID WEAKENING AND EVENTUAL DISSIPATION DUE TO INTERACTION WITH LAND. MODEL DISCUSSION: THERE IS A DISTINCT SPLIT IN THE NUMERICAL MODELS WITH THE BULK OF THE GUIDANCE SUPPORTING THE JTWC FORECAST TRACK OVERLAND. THE GFS AND GEFS TRACKERS, HOWEVER, DEPICT A QUASI-STATIONARY MOTION THEN A POLEWARD TRACK AFTER TAU 120 TOWARD THE KOREAN PENINSULA. THE GFS TRACK SCENARIO IS BASED ON SIGNIFICANT WEAKENING OF THE STR VERSUS THE OTHER MODELS WHICH MAINTAIN A WEAK STEERING RIDGE SUFFICIENT TO TURN THE SYSTEM WEST OVER CHINA. THE CURRENT FORECAST SCENARIO IS MAINTAINED WITH MEDIUM CONFIDENCE THROUGH TAU 72 THEN LOW CONFIDENCE IN THE EXTENDED PERIOD BUT THE GFS SOLUTION WILL BE CLOSELY MONITORED AND EVALUATED OVER THE NEXT COUPLE DAYS. THERE IS MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST WITH CLOSE AGREEMENT IN THE INTENSITY GUIDANCE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN