WDPN32 PGTW 081500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (PODUL) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 20.8N 144.2E INITIAL INTENSITY: 45 KTS GEOGRAPHIC REFERENCE: 428 NM NORTH OF ANDERSEN AFB MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 15 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL STORM (TS) 16W APPEARS TO BE UNDERGOING ANOTHER ATTEMPT AT VORTEX CONSOLIDATION AND ALIGNMENT, VERY SIMILAR TO THE ATTEMPT MADE 24 HOURS AGO. TIME WILL TELL IF THIS TIME IT WILL ACTUALLY SUCCEED. OVER THE PAST SIX HOURS OR SO, ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWED DEEP CONVECTION FORMING IN THE SOUTHEASTERN QUADRANT AND THEN WRAPPING UPSHEAR WHERE IT EVENTUALLY ENVELOPED THE LOW LEVEL CIRCULATION CENTER (LLCC). SUBSEQUENT IMAGERY SHOWS POWERFUL BURSTS OF DEEP CONVECTIVE ACTIVITY, WITH OVERSHOOTING TOP TEMPERATURES EXCEEDING -85C AND IMPRESSIVE AMOUNTS OF LIGHTNING ACTIVITY, CONTINUING TO FLARE UP IN THE VICINITY OF THE ASSESSED LLCC. A 081037Z ASCAT-B PASS REVEALED THE LLCC TUCKED UP UNDER THE NORTHERN EDGE OF THE CONVECTIVE MASS IN THE EIR AND PROVIDED HIGH CONFIDENCE TO THE INITIAL POSITION. A 080832Z RCM-3 SAR PASS SHOWED A COMPACT WIND FIELD, WITH THE HIGHEST WINDS LOCATED ALONG THE EASTERN FLANK OF THE CIRCULATION, THOUGH THERE APPEARS TO BE SOME ICE CONTAMINATION IN THE SAR IMAGERY AND THUS THE WINDSPEED MEASUREMENTS ARE TOO HIGH. BUT BETWEEN THE TWO WINDSPEED MEASUREMENTS, AND THE T3.0 DVORAK CURRENT INTENSITY ESTIMATES FROM MULTIPLE AGENCIES, THERE IS AMPLE SUPPORT FOR A HIGH CONFIDENCE INITIAL INTENSITY ESTIMATE. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE, WITH LOW NORTHEASTERLY DEEP-LAYER SHEAR, WARM SSTS AND GOOD EQUATORWARD OUTFLOW. CIRA DERIVED MOTION VECTOR (DMV) WINDS INDICATE INCREASING WESTWARD OUTFLOW AND SPLIT FLOW UPSTREAM (NORTHEAST) OF THE LLCC. INITIAL WIND RADII BASIS: SCATTEROMETER AND SAR DATA. CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T2.5 - 35 KTS RCTP: T3.0 - 45 KTS KNES: T3.0 - 45 KTS CIMSS ADT: 43 KTS AT 081130Z CIMSS AIDT: 40 KTS AT 081130Z CIMSS D-PRINT: 37 KTS AT 081130Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE EQUATORWARD OTHER FACTORS: SMALL REGION OF DRY MID-LEVEL AIR DRAPED ACROSS THE NORTHERN PORTION OF THE CIRCULATION. ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH 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 16W MADE A FAIRLY SHARP WESTWARD TURN OVER THE PAST SIX HOURS, NOW HEADING WEST-NORTHWEST, ALONG THE SOUTHWESTERN SIDE OF THE DEEP STR. OVER THE NEXT 24 TO 36 HOURS, TS 16W WILL GRADUALLY COME TO A WESTWARD HEADING AS THE RIDGE BUILDS WESTWARD TO THE NORTH. TS 16W WILL COME TO AN INFLECTION POINT IN THE FORECAST AFTER TAU 48, WITH SIGNIFICANT UNCERTAINTY IN THE TRACK TRAJECTORY AFTER THIS POINT CONTINUING TO MANIFEST ITSELF IN THE MODEL DATA, FULLY DEPENDENT UPON THE STRENGTH OF THE SYSTEM AT THAT TIME. IF THE SYSTEM ACTUALLY SUCCEEDS IN ITS CURRENT ATTEMPT AT VORTEX ALIGNMENT AND SYMMETRIZATION, IT WILL OBTAIN A HIGHER INTENSITY PRIOR TO THE INFLECTION POINT AND TRAVEL ON A FLATTER TRAJECTORY TOWARDS THE WEST ROUGHLY BETWEEN 20N-22N. ON THE OTHER HAND, IF TS 16W FAILS IN THIS SECOND ATTEMPT TO SYMMETRIZE, THEN IT WILL REMAIN SIGNIFICANTLY WEAKER THROUGH UP TO TAU 48, AND TRAVEL ON A MORE NORTHWESTWARD TRACK GENERALLY TOWARDS THE RYUKYU CHAIN. ADDITIONAL DETAILS OF THE MODEL LAYDOWN WILL BE DISCUSSED IN THE NEXT SECTION. THE CURRENT FORECAST REMAINS CONSISTENT WITH THE PREVIOUS ONE AND ASSUMES THE SYSTEM IS ULTIMATELY SUCCESSFUL IN INTENSIFYING TO TYPHOON STRENGTH BY TAU 48, HOWEVER THIS WILL LIKELY OCCUR IN FITS AND STARTS, HENCE THE SLOW PACE OF INTENSIFICATION. AT TAU 48, THE SYSTEM MOVES UNDER A STRONG BAND OF NORTHEASTERLY FLOW, NEAR JET STRENGTH IN SOME MODELS. A STRONGER SYSTEM, OR ONE POSITIONED A BIT FURTHER SOUTH, WILL BE ABLE TO FEND OFF THE ENHANCED SHEAR ASSOCIATED WITH THESE HIGHER NORTHEASTERLY WINDS, WHILE A WEAKER STORM WILL NOT. THE JTWC FORECAST CALLS FOR A STEADY INTENSITY THROUGH TAU 72, THOUGH THE SYSTEM MAY VERY WELL WEAKEN DURING THIS PERIOD. AFTER TAU 72, THE SHEAR BEGINS TO DECREASE ALONG THE FLATTER TRACK OF THE JTWC FORECAST, ALLOWING FOR REINTENSIFICATION. ON THIS PATH, THE ACTUAL PEAK INTENSITY WILL LIKELY OCCUR PRIOR TO LANDFALL IN TAIWAN AND IS NOT DIRECTLY CAPTURED IN THE FORECAST. AFTER LANDFALL, THE SYSTEM RAPIDLY WEAKENS DUE TO INTERACTIONS WITH THE RUGGED TERRAIN. FOR A WEAKER SYSTEM ON A MORE NORTHWESTWARD PATH, THE INCREASED SHEAR AND DRY AIR WILL RESULT IN A FASTER PACE OF WEAKENING THROUGH THE FORECAST PERIOD. MODEL DISCUSSION: THERE CONTINUES TO BE A CONSIDERABLE AMOUNT OF UNCERTAINTY IN BOTH THE DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE, AS WELL AS IN THE INTENSITY GUIDANCE. THE DETERMINISTIC CONSENSUS PACKAGE SHOWS INCREASED DISPERSAL IN THE AGGREGATE, THOUGH SOME INDIVIDUAL MODELS ARE FLIP-FLOPPING NORTH AND SOUTH OVER THE PAST COUPLE OF RUNS, PARTICULARLY THE ECWMF AND THE GFS WHICH JUMPED FAR TO THE NORTH AT 06Z BUT HAVE NOW CROSSED BACK TO THE SOUTH OF THE CONSENSUS. OVERALL, CROSS-TRACK UNCERTAINTY INCREASES TO 300NM BY TAU 72, BETWEEN THE EGRR AND GEFS MEAN ON THE NORTH SIDE, AND THE GALWEM AND JGSM ON THE SOUTHERN EDGE. BY TAU 120, THE MODELS CONTINUE TO FAN OUT, WITH NAVGEM LYING NEAR SASEBO WHILE THE GALWEM IS POSITIONED ON THE CHINESE COAST WEST OF TAIWAN. THE ECMWF, ECMWF ENSEMBLE, ECMWF-AIFS, UKMET ENSEMBLE, AND JGSM ARE POSITIONED SOUTH OF THE CONSENSUS MEAN, WHILE THE GFS, GEFS, NAVGEM, AND EGRR ARE ON THE NORTH SIDE. THE JTWC FORECAST IS POSITIONED NEAR THE ECMWF AND ECENS MEAN THROUGH THE FORECAST PERIOD. INTENSITY GUIDANCE IS A MIXED BAG WITH EXTREME UNCERTAINTY AND RANGE OF POTENTIAL OUTCOMES. THE MESOSCALE MODELS ARE PEAKING BETWEEN 80-110 KNOTS, WHILE THE DECAY-SHIPS AND CONSENSUS ARE HOVERING NEAR 65-70 KNOTS. LASTLY, THE RICN, RIDE AND CTR1 RI AIDS CONTINUE TO TRIP, BRINGING THE SYSTEM TO 110 KNOTS WITHIN 48 HOURS. THE JTWC FORECAST IS PLACED CLOSE TO THE CONSENSUS MEAN THROUGH TAU 72, THEN BREAKS 10 KNOTS HIGHER AT TAU 96 IN LIGHT OF THE CTCX, COTC, AND EVEN THE ECMWF WHICH SHARPLY INTENSIFY THE SYSTEM PRIOR TO LANDFALL IN TAIWAN TO BETWEEN 90-110 KNOTS. AS MENTIONED, THE ACTUAL PEAK WILL LIKELY OCCUR BETWEEN TAU 96 AND LANDFALL. FORECAST CONFIDENCE: TRACK 00-72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN