WDPN31 PGTW 231500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (MINDULLE) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 13.8N 142.8E INITIAL INTENSITY: 40 KTS GEOGRAPHIC REFERENCE: 1136 NM SOUTHEAST OF KADENA AB MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 20 KTS SIGNIFICANT WAVE HEIGHT: 13 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS SPIRAL BANDS OF DEEP CONVECTION WRAPPING AROUND A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION AND INTENSITY IS BASED ON AGENCY AND AUTOMATED DVORAK INTENSITY ESTIMATES, AS WELL AS A 231030Z METOP-A ASCAT PASS. THE ENVIRONMENT IS HIGHLY FAVORABLE WITH LOW VERTICAL WIND SHEAR, AN UPPER LEVEL POINT SOURCE NEARLY OVERHEAD, AND VERY WARM SSTS. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE LOCATED TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS RJTD: T1.5 - 25 KTS KNES: T3.0 - 45 KTS CIMSS SATCON: 40 KTS AT 230903Z CIMSS ADT: 35 KTS AT 231140Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG POLEWARD AND EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: FINAL TWO TAUS HAVE BEEN SHIFTED SOUTH AND SLIGHTLY WEST ON A MORE NORTHWESTERLY HEADING IN ALIGNMENT WITH LATEST GUIDANCE. FORECAST DISCUSSION: TS 20W WILL CONTINUE NORTHWEST THROUGH AN INCREASINGLY FAVORABLE ENVIRONMENT OF WARM SEA SURFACE TEMPERATURES (30-31 DEGREE CELSIUS), LOW SHEAR AND STRONG UPPER LEVEL OUTFLOW. THE HIGHLY FAVORABLE ENVIRONMENT WILL FUEL RAPID INTENSIFICATION TO 115 KNOTS BY TAU 72, PEAKING AT 125 KNOTS BY TAU 96. AFTERWARDS, TS 20W WILL BE SLIGHTLY HAMPERED BY DECREASED UPPER LEVEL OUTFLOW. AROUND TAU 120, TS 20W WILL REACH THE STR AXIS BEFORE BEGINNING A GRADUAL RECURVE SOUTH OF JAPAN. MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE HAS SIGNIFICANTLY IMPROVED WITH ALL MEMBERS NOW SHOWING A RECURVE SCENARIO. GFS AND GFS ENSEMBLE HAVE BOTH SHIFTED 250-300NM WESTWARD AT TAU 120 TOWARDS THE REMAINING SOLUTIONS. UKMET AND THE UKMET ENSEMBLE TRACKS ARE DELAYED IN THEIR RECURVE TIMING NEAR THE VICINITY OF KADENA. THE JTWC TRACK IS LAID ALONG CONSENSUS. NEAR TERM JTWC INTENSITY GUIDANCE IS IN OVERALL AGREEMENT WITH RAPID INTENSIFICATION EXPECTED FOR THE NEXT 48 HOURS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: HIGH INTENSITY 72-120 HR: MEDIUM// NNNN