WDPN31 PGTW 300900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (JANGMI) WARNING NR 013// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 18.3N 129.6E INITIAL INTENSITY: 65 KTS GEOGRAPHIC REFERENCE: 502 NM SOUTH-SOUTHEAST OF KADENA AB MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: 33 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD, IRREGULAR LOW LEVEL CIRCULATION CENTER (LLCC), WITH A WAVENUMBER-4 ASYMMETRY PATTERN. THE MSI SHARPLY DEPICTS AT LEAST THREE WELL-DEFINED MESOVORTICES ALONG THE INNER EDGE OF THE EYEWALL, WITH A WEAKER FOURTH MESOVORTEX, IMPARTING A QUASI-QUADRILATERAL EYEWALL GEOMETRY. THE RADIUS OF MAXIMUM WINDS (RMW) AND EYEWALL DIAMETER HAVE DECREASED SLIGHTLY, FROM 70 NM TO 60 NM, BASED ON ANALYSIS OF EARLIER SYNTHETIC APERTURE RADAR (SAR) DATA AND CURRENT MSI OBSERVATIONS. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE, PLACED IN THE CENTROID OF THE MESOVORTICES SEEN IN THE ANIMATED MSI. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, BASED ON A BLEND OF SUBJECTIVE AGENCY DVORAK CURRENT INTENSITY ESTIMATES, INFORMED BY CIMSS SATCON AND D-PRINT GUIDANCE. CIMSS ADT AND AIDT ESTIMATES ARE SIGNIFICANTLY UNDERESTIMATED, DUE TO THEIR UTILIZATION OF THE CURVED BAND METHOD RATHER THAN THE EYE TECHNIQUE EMPLOYED BY THE OTHER AGENCIES, AS WELL AS THE LARGE SIZE OF THE SYSTEM. ENVIRONMENTAL CONDITIONS ARE GENERALLY FAVORABLE FOR ADDITIONAL INTENSIFICATION, BY LOW DEEP-LAYER VERTICAL WIND SHEAR (VWS), WARM SEA SURFACE TEMPERATURES (SSTS), AND MODERATE RADIAL OUTFLOW. HOWEVER, THE BROAD MORPHOLOGY OF THE INNER CORE, THE WAVENUMBER-4 ASYMMETRIES, AND THE PATHWAY OVER A POCKET OF LOW (40-50 KJ PER SQUARE CENTIMETER) OCEAN HEAT CONTENT (OHC) WILL ACT AS A PRIMARY CONSTRAINT ON THE INTENSIFICATION RATE. INITIAL WIND RADII BASIS: SAR DATA CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) POSITIONED NEAR IWO TO. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS RJTD: T3.0 - 45 KTS RCTP: T3.5 - 55 KTS KNES: T4.0 - 65 KTS CIMSS SATCON: 57 KTS AT 300630Z CIMSS ADT: 31 KTS AT 300630Z CIMSS AIDT: 41 KTS AT 300630Z CIMSS D-MINT: 53 KTS AT 300408Z CIMSS D-PRINT: 65 KTS AT 300600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH 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: TYPHOON (TY) 06W (JANGMI) CONTINUES ITS NORTHWESTWARD TRAJECTORY ALONG THE SOUTHWESTERN PERIMETER OF THE DEEP-LAYER STR CENTERED NEAR IWO TO. NO SIGNIFICANT CHANGE IN THE OVERALL STEERING PATTERN IS EXPECTED OVER THE NEXT 24 TO 36 HOURS. BEGINNING NEAR TAU 36, THE SYSTEM WILL DECELERATE IN FORWARD TRANSLATION SPEED AS IT APPROACHES THE STR AXIS AND TURNS NORTHWARD TOWARDS OKINAWA. TY 06W IS FORECAST TO ROUND THE RIDGE AXIS JUST SOUTH OF OKINAWA NEAR 010600Z, THEN BEGIN A STEADY ACCELERATION TOWARDS THE NORTHEAST THROUGH TAU 96. THE FORECAST CALLS FOR THE CENTER OF TY 06W TO TRACK JUST WEST OF THE NORTHERN RYUKYU ISLAND CHAIN, THEN TURN NORTHEASTWARD TO THE SOUTH OF KYUSHU AND REMAIN OFFSHORE OF SHIKOKU AND HONSHU THROUGH THE FORECAST PERIOD, THOUGH A CLOSE APPROACH TO THE SOUTHERN BOSO PENINSULA IS EXPECTED NEAR TAU 96. A SLIGHT DECELERATION IS EXPECTED BY THE END OF THE FORECAST PERIOD AS THE STR WEAKENS AND DISPLACES SOUTHWESTWARD, ATTENUATING THE STEERING GRADIENT. REGARDING INTENSITY, THE SYSTEM IS CONSOLIDATING AT A GRADUAL RATE, WITH A STEADY REDUCTION IN RMW OBSERVED OVER THE LAST 10 HOURS. HOWEVER, THE SYSTEM RETRAINS A MULTI-VORTEX ASYMMETRY, WHICH WILL INHIBIT RAPID CONSOLIDATION OF THE INNER CORE. THE MAJORITY OF THE MESOSCALE MODELS INDICATE CORE CONSOLIDATION WITHIN THE NEXT 24 TO 36 HOURS; HOWEVER, BY THIS TIMEFRAME, THE SYSTEM WILL BE TRANSITIONING OVER A SHARP OCEANIC THERMAL GRADIENT, THEREBY RAPIDLY DIMINISHING THE THERMODYNAMIC SUPPORT REQUISITE FOR RAPID INTENSIFICATION. NONETHELESS, AN ADDITIONAL 15-20 KNOTS OF INTENSIFICATION OVER THE NEXT 24 HOURS IS REASONABLE PRIOR TO THE SYSTEM ENCOUNTERING COOLER WATERS. TY 06W WILL THEREFORE REACH A PEAK INTENSITY OF 85 KNOTS BY TAU 24, THEN MAINTAIN INTENSITY FOR APPROXIMATELY 12 HOURS BEFORE COMMENCING A GRADUAL WEAKENING TREND THROUGH THE REMAINDER OF THE FORECAST. THE SYSTEM WILL BEGIN EXTRATROPICAL TRANSITION (ETT) AS IT APPROACHES ITS CLOSEST POINT OF APPROACH (CPA) TO YOKOSUKA, AND COMPLETE TRANSITION AS A STORM-FORCE EXTRATROPICAL LOW BY TAU 120. MODEL DISCUSSION: THE PHYSICS-BASED MODELS AND THE AI-BASED MODELS HAVE BEGUN TO CONVERGE ON A COMMON TRACK SOLUTION, WITH THE DISTINCT BIFURCATIONS OBSERVED IN EARLIER MODEL RUNS NOW RESOLVED. THE AI- BASED MODELS ARE PRIMARILY POSITIONED ALONG THE EASTERN EDGE OF THE ENVELOPE, WHILE THE DETERMINISTIC NWP MODELS OCCUPY THE WESTERN SIDE OF THE CONSENSUS MEAN. THROUGH THE CPA TO OKINAWA (TAU 48), CROSS- TRACK SPREAD HAS DECREASED TO JUST 70 NM BETWEEN THE GFS AND UKMET ENSEMBLE MEANS ON THE WEST SIDE, AND THE EC-AIFS AND GDM FNV3 ON THE EAST SIDE, WITH MINIMAL ALONG-TRACK SPREAD. BY TAU 72, CROSS-TRACK SPREAD INCREASES TO 100 NM, AND ALONG-TRACK UNCERTAINTY BEGINS TO MANIFEST BETWEEN THE FASTER AI-BASED MODELS AND SLOWER DETERMINISTIC GUIDANCE. BY THE TERMINATION OF THE FORECAST PERIOD, CROSS-TRACK SPREAD INCREASES TO NEARLY 200 NM, WHILE ALONG-TRACK SPREAD INCREASES TO 250 NM BETWEEN THE LAGGING GFS AND ACCELERATED AI-BASED GUIDANCE. THE JTWC FORECAST IS POSITIONED NEAR THE EXPERIMENTAL SUPER-ENSEMBLE (A COHORT OF FIVE ENSEMBLE MODELS) TRACKER AND SLIGHTLY FASTER THAN THE TRADITIONAL CONSENSUS MEAN, WITH A HIGH DEGREE OF FORECAST CONFIDENCE. INTENSITY GUIDANCE REMAINS DIVERGENT. THE MESOSCALE MODELS (HWRF, HAFS-A, COTC, CTCX) INDICATE MINIMAL ADDITIONAL INTENSIFICATION, PEAKING BETWEEN 70-80 KNOTS. THE DECAY-SHIPS GUIDANCE PEAKS AT 85 KNOTS, IN AGREEMENT WITH THE GDM FNV3 MODEL. ADDITIONALLY, MULTIPLE RAPID INTENSIFICATION (RI) AIDS CONTINUE TO TRIGGER, BUT THE THERMODYNAMIC AND STRUCTURAL ENVIRONMENT DOES NOT SUPPORT RI CONDITIONS. IT IS HIGHLY IMPROBABLE THAT THE SYSTEM POSSESSES THE CAPACITY TO ATTAIN 110-120 KNOTS IN THE NEXT 36 HOURS AS INDICATED BY THE RI GUIDANCE. THE JTWC FORECAST IS PLACED FIVE KNOTS HIGHER THAN THE CONSENSUS MEAN THROUGH THE FORECAST PERIOD, WITH MEDIUM CONFIDENCE. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN