WDPN31 PGTW 020900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (HINNAMNOR) WARNING NR 021// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 22.0N 125.1E INITIAL INTENSITY: 80 KTS GEOGRAPHIC REFERENCE: 308 NM SOUTH-SOUTHWEST OF KADENA AB, OKINAWA MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 42 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED WATER VAPOR IMAGERY INDICATES IMPROVING POLEWARD OUTFLOW OVER THE PAST 12 HOURS WITH PERSISTENT ROBUST EQUATORWARD OUTFLOW. ADDITIONALLY, THE SYSTEM IS BEGINNING TO TRACK POLEWARD AWAY FROM THE UPWELLING COOLER WATER, WHICH HAS ALLOWED THE SYSTEM TO RE-CONSOLIDATE, AND VERTICAL WIND SHEAR HAS DECREASED. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS IMPROVING DEEP CONVECTIVE BANDING WRAPPING INTO A FORMATIVE, RAGGED EYE, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. A 020441Z AMSR2 89GHZ MICROWAVE IMAGE REVEALS A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER WITH EXTENSIVE DEEP CONVECTIVE BANDING OVER THE SOUTHERN AND EASTERN SEMICIRCLES. OVER THE PAST DAY, THE SYSTEM HAS INCREASED IN SIZE WITH GALE-FORCE WINDS ASSOCIATED WITH THE CONVECTIVE BANDING. HOWEVER, A RECENT PARTIAL ASCAT IMAGE, AN AMSR2 WINDSPEED IMAGE AND SURFACE OBSERVATIONS INDICATE A HIGHLY ASYMMETRIC, COMPLEX WIND FIELD WITH STRONG NORTHERLY WINDS FUNNELING THROUGH THE TAIWAN STRAIT AND JUST EAST OF TAIWAN. THE INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE LOWER END OF THE DVORAK CURRENT INTENSITY ESTIMATES AS WELL AS THE CIMSS SATCON ESTIMATE. INITIAL WIND RADII BASIS: SCATTEROMETER DATA, AMSR2 WINDSPEED IMAGE, AND LIMITED SURFACE OBSERVATIONS CURRENT STEERING MECHANISM: PRIMARY STEERING INFLUENCE IS THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.0 - 90 KTS RJTD: T5.5 - 102 KTS KNES: T4.5 - 77 KTS CIMSS SATCON: 84 KTS AT 020442Z CIMSS ADT: 72 KTS AT 020540Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 15-20 KTS SST: 30-31 CELSIUS OUTFLOW: STRONG EQUATORWARD OTHER FACTORS: UPWELLING COOLER WATER ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: AS TY 12W CONTINUES TO TRACK NORTHWARD ALONG THE WESTERN PERIPHERY OF THE STR OVER THE NEXT FEW DAYS, POLEWARD OUTFLOW WILL CONTINUE TO IMPROVE ENHANCED BY AN APPROACHING MIDLATITUDE SHORTWAVE TROUGH, WHICH IS EXPECTED TO DEEPEN OVER NORTHEAST CHINA AND THE YELLOW SEA AFTER TAU 36. ADDITIONALLY, VERTICAL WIND SHEAR WILL DECREASE TO LOW LEVELS (10-15 KNOTS) WITH FAVORABLE SST VALUES (29-30C). THEREFORE, THE SYSTEM IS FORECAST TO RE-INTENSIFY TO A PEAK OF 105 KNOTS BY TAU 48. AFTER TAU 72, TY 12W WILL RECURVE TOWARD SOUTH KOREA AND WESTERN JAPAN AS IT TRACKS AROUND THE STR AXIS AND BEGINS TO INTERACT WITH THE MIDLATITUDE WESTERLIES. THE SYSTEM WILL COMMENCE EXTRA-TROPICAL TRANSITION (ETT) NEAR CHEJU-DO AROUND TAU 84 AND WILL RAPIDLY TRANSITION INTO AN EXTRA-TROPICAL LOW IN THE SEA OF JAPAN BETWEEN TAU 108 AND TAU 120. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH TAU 96 WITH A 100-120NM SPREAD IN SOLUTIONS FROM TAU 48 TO TAU 96. HOWEVER, THE 020000Z ECMWF ENSEMBLE (EPS) INDICATES SIGNIFICANT UNCERTAINTY WITH THE BULK OF SOLUTIONS OVER SOUTHEAST KOREA WHILE THE GFS ENSEMBLE (GEFS) INDICATES A WIDER SPREAD OF SOLUTIONS FROM BUSAN, SOUTH KOREA TO NORTHERN KYUSHU ISLAND. THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK THROUGH TAU 72 BUT LOW CONFIDENCE AFTER TAU 72 DUE TO SIGNIFICANT DIFFERENCES IN ALONG-TRACK SPEEDS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN