WDPN32 PGTW 090300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (PODUL) WARNING NR 009// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 21.5N 142.9E INITIAL INTENSITY: 50 KTS GEOGRAPHIC REFERENCE: 880 NM EAST-SOUTHEAST OF KADENA AB MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 22 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS ONLY MILD WEAKENING SINCE THE DIRURNAL MAX PERIOD WANED AFTER SUNRISE. THE CONVECTIVE SHIELD HAS BEEN SHOVED EQUATORWARD, PARTIALLY EXPOSING THE LOW LEVEL CIRCULATION CENTER (LLCC) OVER THE POLEWARD HEMISPHERE OF THE STORM. CLOUD TOPS HAVE WARMED ONLY SLIGHTLY DURING THE PAST SIX HOURS AND LIGHTNING STRIKES HAVE DECREASED MODERATELY, BUT NOT AS MUCH AS IS TYPICAL FOR THIS TIME PHASE. THIS INDICATES THAT THE SYSTEM IS HOLDING ITS OWN AGAINST THE NORTHEASTERLY VERTICAL WINDSHEAR AND STILL ON AN UPTREND. MAXIMUM SHEAR IS ASSESSED AT 16-20KTS AT 10,000 FT. THE RCTP DVORAK HAS RISEN TO MATCH THE JTWC T3.5 AND ADT IS NOW UP TO 53KTS WHILE AIDT HAS STEPPED UP TO 48KTS. 50KTS IS A GOOD MEAN BETWEEN THE AGENCY DVORAKS AND CIMSS OBJECTIVE ASSESSMENTS. THE SYSTEM LIES IS AN ENVIRONMENT WITH A STARK CONTRAST BETWEEN THE POLEWARD AND EQUATORWARD SIDES, WITH DRY AIR AND A SUBSIDENT ATMOSPHERE ON THE POLEWARD SIDE AND DEEP TROPICAL MOISTURE AND AMPLE LOW LEVEL CONVERGENCE OVER THE EQUATORWARD SIDE, ESPECIALLY IN THE SOUTHEAST QUADRANT. MODEL GUIDANCE INDICATES THE ALONG TRACK ENVIRONMENT IS ABOUT AS GOOD AS IT WILL EVER GET FOR THE NEXT 24 HOURS, WITH AN INCREASINGLY HOSTILE ENVIRONMENT CHARACTERIZED BY EVEN MORE VWS AND DRY AIR FURTHER DOWNSTREAM. THE ENVIRONMENT REALLY BEGINS TO DETERIORATE WEST OF THE 135TH MERIDIAN. THE LLCC HAS MAINTAINED A CONSTANT BEARING WHILE SLOWING SLIGHTLY DURING THE PAST SIX HOURS. A 082359Z ASCAT HOT OFF THE PRESS DURING THE PRODUCTION OF THIS BULLETIN VERIFIES BOTH POSITION AND INTENSITY. INITIAL WIND RADII BASIS: A 082359Z ASCAT. CURRENT STEERING MECHANISM: A MID-LEVEL RIDGE EXTENDING FROM AN ANTICYCLONE ANCHORED NEAR 35N 165E THROUGH THE RYUKUS. THE RIDGE IS BUILDING AND SINKING TOWARDS TAIWAN. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.5 - 55 KTS RJTD: T2.5 - 35 KTS RCTP: T3.5 - 55 KTS KNES: T3.5 - 55 KTS CIMSS ADT: 53 KTS AT 082030Z CIMSS AIDT: 48 KTS AT 082030Z CIMSS D-MINT: 39 KTS AT 081903Z CIMSS D-PRINT: 54 KTS AT 090020Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY UNFAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE EQUATORWARD 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: TS 16W WILL CONTINUE TRACKING WEST-NORTHWEST FOR ANOTHER 24 HOURS AND REACH LOW TYPHOON STRENGTH BEFORE BENDING TO A MORE WESTWARD TRACK AND REACHING PEAK STRENGTH OVER THE SECOND 24 HOUR PERIOD. A MID-TO-HIGH LEVEL RIDGE BUILDING ALONG 160E WILL EXTEND TOWARDS THE RYUKUS, KEEPING THE SYSTEM WELL SOUTH OF OKINAWA. THE HARSH ENVIRONMENT WILL SLOW DEVELOPMENT TO A LOWER THAN CLIMATOLOGICAL RATE BUT THE SYSTEM WILL STILL MANAGE TO ATTAIN TYPHOON STRENGTH. RAPID INTENSIFICATION AND TRIPLE DIGIT INTENSITY IS LOOKING HIGHLY UNLIKELY DUE TO THE HIGH VWS AND DRY AIR NORTH OF 20N. OKINAWA AND THE NORTHERN SENKAKUS ARE NOT QUITE OFF THE HOOK YET AS A POLEWARD BEND TO THE TRACK STILL REMAINS A POSSIBILITY, BUT NOT A PROBABILITY. IN FACT, THE AMERICAN ENSEMBLE (GFS) HAS JOINED SOME OF THE TRADITIONALLY WEAKER TRACKERS SUCH AS EGRR AND AGUM, BUT EVEN IN THE UNLIKELY EVENT OF A TRACK TOWARDS OKINAWA, THE ENVIRONMENT ALONG THAT TRACK IS SO HARSH THAT THE STORM WOULD LIKELY BE DRIED OUT AND SHEARED APART WELL BEFORE IT MADE IT THAT FAR. THE TAIWAN-SOUTHERN SENKAKUS SCENARIO REMAINS MUCH MORE LIKELY, AS THE DEEP SHORT WAVE CURRENTLY TRACKING OVER JAPAN PASSES HELPS AMPLIFY THE LONG WAVE PATTERN OVER THE WESTERN PACIFIC. AS THE PATTERN AMPLIFIES THE BONIN HIGH WILL BUILD A HIGH AMPLITUDE RIDGE ALONG THE 165TH MERIDIAN AND EXPAND TOWARDS TAIWAN, WITH H500 HEIGHTS EXCEEDING 5900 METERS ALL THE WAY ACROSS TAIWAN AND INTO MAINLAND CHINA. THE POINT OF DIVERGENCE IN THE TRACKERS COMES AFTER 135E, AND UNTIL THAT ISSUE IS CLARIFIED, A MINOR THREAT EXISTS TO OKINAWA. TS 16W IS EXPECTED TO BEGIN A DOWNTREND AS IT APPROACHES 130E AND DECAY RAPIDLY DUE TO HIGH SHEAR WHEN IT TRACKS INTO THE EAST CHINA SEA. MODEL DISCUSSION: THE JTWC TRACK FORECAST RUNS EQUATORWARD OF THE MULTI MODEL CONSENSUS FAVORING THE ECMWF ENSEMBLE AND SOME OF THE NEW, BUT IMPRESSIVE-SO-FAR AI TRACKERS. ALTHOUGH CROSS-TRACK SPREAD INCREASES AFTER TAU 72, ALL TRACKERS FOLLOW THE GENERAL TREND OF A WESTWARD RUN THROUGH 135E, THEN VARYING DEGREES OF A POLEWARD BEND AND A WEAKENING TREND THEREAFTER. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT SHOWING A GRADUAL UPTREND THROUGH THE NEXT 48 HOURS FOLLOWED BY A SLOW DECLINE, THEN A RAPID DECLINE OVER THE EAST CHINA SEA. THE JTWC INTENSITY FORECAST STAYS ABOVE THE MID-LINE OF GUIDANCE IN ANTICIPATION OF ANOTHER SURGE DURING THE PRE-DAWN HOURS TOMORROW. FORECAST CONFIDENCE: TRACK 00-72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN