WDPN31 PGTW 202100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (IN-FA) WARNING NR 019// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 24.1N 128.2E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 146 NM SOUTH OF KADENA AB MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 30 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) CONFIRMS THAT TY 09W IS SUCCESSFULLY COCOONING ITSELF FROM A BROAD STREAM OF DRY AIR AND MAINTAINING CORE INTEGRITY. THE DRY NORTHERLIES ARE ASSOCIATED WITH A RIDGE BUILDING OVER EASTERN CHINA AND ALTHOUGH THEY HAVE BEEN DIVING OVER THE EAST CHINA SEA AND WRAPPING AROUND THE SYSTEM FOR OVER 24 HOURS, THE SYSTEM HAS BEEN ABLE TO KEEP A MOIST LAYER AROUND THE CORE AND MAINTAIN A STEADY INTENSITY. THE STORM HAS PASSED ITS CLOSEST POINT OF APPROACH TO OKINAWA AND IS OPENING ALONG A STEADY TRACK TO THE WEST-SOUTHWEST AS A STRONG UPPER LEVEL HIGH HEIGHT CENTER ANCHORS ITSELF OVER THE SEA OF JAPAN AND BUILDS INTO THE PHILIPPINE SEA. AN EYE FIX ALLOWS FOR GOOD CONFIDENCE ON THE POSITION AND IDENTICAL DVORAK ASSESSMENTS FROM BOTH PGTW AND RJTD ALLOW FOR GOOD CONFIDENCE IN THE INTENSITY. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: THE SUBTROPICAL RIDGE ANCHORED OVER THE SEA OF JAPAN. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T4.5 - 77 KTS KNES: T5.0 - 90 KTS CIMSS ADT: 102 KTS AT 201740Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY UNFAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE POLEWARD OTHER FACTORS: THE SUBSTANTIAL AMOUNT OF DRY AIR ENTRAINMENT ON THE EQUATORWARD SIDE IS COMPLETELY SUPPRESSING OUTFLOW ON THE SOUTHERN SIDE OF THE SYSTEM AND THE SLOW MOVEMENT OF THE STORM IS CHURNING UP COOLER WATERS, KEEPING INTENSIFICATION LIMITED TO A LOWER THAN CLIMATOLOGICAL RATE. 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: THE BUILDING SUBTROPICAL RIDGE WILL STEER TYPHOON 09W STEADILY TO TO THE WEST-SOUTHWEST OVER THE NEXT 48 HOURS, UNTIL IT WEAKENS AND RETROGRADES TO ALONG THE CONTINENTAL COAST. AS IT DOES SO, IT WILL ALLOW THE STORM TO LIFT TO A MORE POLEWARD TRACK JUST AS IT IS APPROACHING THE SOUTHERNMOST SENKAKUS. THE RIDGE OVER EASTERN CHINA THAT IS SHOOTING THE DRY AIR INTO THE SYSTEM WILL WEAKEN AT ABOUT THE SAME TIME AND TY 09W WILL PEAK IN INTENSITY JUST AS IT BEGINS TO TRACK NORTH OF WEST. AS IT MOVES INTO THE NORTHWESTERLY TRACK, IT WILL WEAKEN SLOWLY OVER THE EAST CHINA SEA UNTIL IT MAKES LANDFALL AT OR JUST BELOW TYPHOON INTENSITY. MODEL DISCUSSION: MODEL GUIDANCE HAS BEEN CONSISTENT THROUGHOUT THE STORMS LIFE CYCLE UP TO THE 72 HOUR PERIOD, THEN SCATTERING TO AS FAR SOUTH AS A STRIKE ON TAIPEI (AFUM AND EGRR) AND AS FAR NORTH AS THE 28TH LATITUDE. THE ECMWF ENSEMBLE HAS BEEN STEADY AND IS CONSISTENT WITH CONSENSUS, WHILE THE GFS ENSEMBLE HAS SHOWN A TREMENDOUS VARIABILITY IN THE LATER TAUS. BASED ON THE EXCELLENT PERFORMANCE OF THE MULT-MODEL CONSENSUS THUS FAR, THE JTWC FORECAST STAYS CLOSE TO CONSENSUS THROUGHOUT THE FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN