WDPN31 PGTW 240900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (MINDULLE) WARNING NR 008// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 15.4N 140.3E INITIAL INTENSITY: 50 KTS GEOGRAPHIC REFERENCE: 965 NM SOUTHEAST OF KADENA AB MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 16 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS CONTINUED TO SLOWLY CONSOLIDATE AS THE CIRCULATION HAS BECOME MORE DEFINED WITH THE FEEDER BANDS WRAPPING INTO THE LOW LEVEL CIRCULATION CENTER DEEPENING. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A 240432Z AMSR2 MICROWAVE IMAGE. THE INITIAL INTENSITY OF 50 KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY AND AUTOMATED DVORAK ESTIMATES. ENVIRONMENTAL ANALYSIS INDICATES HIGHLY FAVORABLE CONDITIONS WITH LOW VERTICAL WIND SHEAR, STRONG UPPER LEVEL OUTFLOW, AND VERY WARM SSTS IN THE PHILIPPINE SEA. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED STR TO THE NORTHEAST. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHEAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.5 - 55 KTS RJTD: T2.5 - 35 KTS RCTP: T3.0 - 45 KTS KNES: T3.5 - 55 KTS CIMSS SATCON: 46 KTS AT 240600Z CIMSS ADT: 43 KTS AT 240540Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 0-5 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: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 20W WILL GENERALLY CONTINUE ON ITS CURRENT TRACK SOUTHWEST OF THE SUBTROPICAL RIDGE UP TO TAU 96. AFTER WHICH POINT IT WILL APPROACH THE RIDGE AXIS AROUND TAU 120 AS IT BEGINS A NORTHWARD TRACK. THE CURRENT FAVORABLE ENVIRONMENT IS EXPECTED TO SUSTAIN AS IT FUELS RAPID INTENSIFICATION TO 125 KNOTS BY TAU 72, WITH A PEAK OF 130KTS BY TAU 96. DECREASED UPPER LEVEL OUTFLOW WILL BEGIN TO SLIGHTLY WEAKEN THE SYSTEM, DOWN TO 115KTS BY TAU 120. MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE HAS SLIGHTLY IMPROVED WITH THE CROSS TRACK SPREAD DECREASING TO 470 NM BY TAU 120. UKMET TRACKERS ARE STILL MAINTAINING TO THE LEFT OF CONSENSUS WHEREAS GFS TRACKERS ARE THE RIGHT MOST OUTLIERS SHOWING A TIGHTER RECURVE. THE FORECAST TRACK IS LAID NEAR THE JTWC CONSENSUS. DESPITE HIGH MODEL CONFIDENCE IN INTENSITY, THERE IS ONLY MEDIUM CONFIDENCE OVERALL AS THE SYSTEM CONTINUES TO CONSOLIDATE INTO A WELL DEFINED CIRCULATION. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN