WDPN31 PGTW 312100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (HINNAMNOR) WARNING NR 015// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 24.0N 126.5E INITIAL INTENSITY: 125 KTS GEOGRAPHIC REFERENCE: 166 NM SOUTH-SOUTHWEST OF KADENA AB, OKINAWA, JAPAN MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 14 KTS SIGNIFICANT WAVE HEIGHT: 50 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A HIGHLY SYMMETRICAL COMPACT SYSTEM, VOID OF FEEDER BANDS, THAT HAS RECENTLY UNDERGONE AN EYEWALL REPLACEMENT CYCLE WITH A NEW WELL-DEFINED 10-NM EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE IN THE EIR LOOP AND ALSO IN THE COMPOSITE RADAR LOOP FROM JMA. THE INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND CONSISTENT WITH THE 6-HR SUSTAINED EIR STRUCTURE. THE ENVIRONMENT REMAINS FAVORABLE WITH LOW VWS, STRONG RADIAL OUTFLOW AND WARM SSTS. INITIAL WIND RADII BASIS: PERSISTENCE. CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHWEST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T6.5 - 127 KTS RJTD: T6.5 - 127 KTS CIMSS SATCON: 131 KTS AT 311748Z CIMSS ADT: 129 KTS AT 311740Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 30-31 CELSIUS OUTFLOW: STRONG RADIAL 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: TY HIMMNAMNOR WILL BEGIN TO SLOW DOWN THEN BECOME QUASI-STATIONARY (QS) AS A BUILDING STR TO THE NORTHWEST AND A NEAR EQUATORIAL RIDGE COMPETE FOR STEERING AGAINST THE CURRENT STEERING STR TO THE NORTH THAT WILL WEAKEN AND RECEDE EASTWARD WITH THE APPROACH OF A MID-LATITUDE TROUGH FROM THE WEST. AFTER TAU 36, THE CURRENT STR, NOW POSITIONED TO THE NORTHEAST WILL RE-BUILD AND REGAIN STEERING, DRIVING THE SYSTEM NORTHWARD THEN NORTH-NORTHEASTWARD TOWARD SOUTH KOREA. COOLING SST DUE TO UPWELLING DURING THE QS STATE WILL SLIGHTLY WEAKEN THE CYCLONE TO 105KTS. AFTERWARD, AS IT BEGINS TO TRACK NORTHWARD, WARM SST AND INCREASED POLEWARD OUTFLOW WILL FUEL A SECONDARY, ALBEIT WEAK, INTENSIFICATION, TO 105KTS AT TAUS 72-96. AFTER TAU 96, INCREASING VWS AND COOLING SST WILL BEGIN TO ERODE THE SYSTEM, DOWN TO 95KTS AS IT APPROACHES BUSAN, S. KOREA. MODEL DISCUSSION: THE MAIN PACK OF NUMERICAL MODELS ARE IN VERY GOOD AGREEMENT ACROSS TRACK. HOWEVER, THERE ARE DIFFERENCES IN SPEED ALONG TRACK ESPECIALLY ON THE DURATION OF QS STATE. IN VIEW OF THIS, THERE IS ONLY MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS ADJUSTED JUST TO THE RIGHT OF CONSENSUS TO OFFSET THE TWO UNLIKELY OUTLIERS - AFUM AND JGSM - THAT BRING THE VORTEX ON A MORE NORTHWESTWARD TRAJECTORY TOWARD CHINA AFTER THE QS STATE. THE INTENSITY FORECAST CONFIDENCE IS HIGH TO TAU 72 THEN MEDIUM AFTERWARD. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: HIGH INTENSITY 72-120 HR: MEDIUM// NNNN