WDPN31 PGTW 300900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (DOLPHIN) WARNING NR 014// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 16.9N 164.9E INITIAL INTENSITY: 140 KTS GEOGRAPHIC REFERENCE: 174 NM SOUTHWEST OF WAKE ISLAND MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 45 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND ENHANCED INFRARED (EIR) DEPICT A HIGHLY SYMMETRICAL CENTRAL DENSE OVERCAST (CDO) FEATURE WHICH HAS STEADILY DECREASED IN SIZE OVER THE PAST SIX HOURS. THE LAST FEW FRAMES OF VISIBLE IMAGERY DEPICTS MULTIPLE MESOVORTICES WITHIN THE 14NM WIDE EYE. CDO CLOUD TOP TEMPERATURES STEADILY WARMED THROUGH 300200Z BEFORE DECREASING THROUGH THE 0600Z HOUR. MEANWHILE EYE TEMPERATURES HAVE COOLED OVER THE PAST FEW HOURS, APPROXIMATELY 7C COOLER THAN AT 0000Z AND THE EYE APPEARS TO BE CONTRACTING. EARLIER DATA SUPPORTED THE ONSET OF AN EYEWALL REPLACEMENT CYCLE (ERC) SIX HOURS AGO; HOWEVER, DUE TO A LACK OF MICROWAVE IMAGERY SINCE 0200Z, THERE IS NO DIRECT DATA TO CONFIRM THE PRESENT STATUS OF THE ERC. NEVERTHELESS, THE CDO HAS STEADILY COOLED AND BECOME MORE SYMMETRICAL OVER THE PAST FEW HOURS, SUGGESTING THAT THE ERC MAY BE COMPLETE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EYE IN THE MSI. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AN OVERALL BLEND OF THE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES NOTED BELOW. ENVIRONMENTAL CONDITIONS REMAIN HIGHLY FAVORABLE WITH STRONG RADIAL OUTFLOW, ENHANCED BY A WEAK POLEWARD OUTFLOW CHANNEL INTO THE ENTRANCE REGION OF A SUBTROPICAL JET TO THE EAST, VERY WARM (30-31C) SSTS, LOW DEEP-LAYER WIND SHEAR, AND HIGH OHC (120 KJ PER CM2). INITIAL WIND RADII BASIS: PERSISTENCE WITH EARLIER SCATTEROMETER AND SAR DATA. CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF LARGE SUBTROPICAL RIDGE (STR) CENTERED SOUTHWEST OF THE ALEUTIANS. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T7.5 - 155 KTS RJTD: T7.0 - 140 KTS RCTP: T7.5 - 155 KTS KNES: T7.5 - 155 KTS PHFO: T7.5 - 155 KTS CIMSS SATCON: 138 KTS AT 300220Z CIMSS ADT: 134 KTS AT 300600Z CIMSS AIDT: 133 KTS AT 300600Z CIMSS D-MINT: 151 KTS AT 300229Z CIMSS D-PRINT: 143 KTS AT 300600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 30-31 CELSIUS OUTFLOW: STRONG RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: STY 12W CONTINUES TO TRACK NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER STR. NO SIGNIFICANT CHANGES IN THE UPPER-LEVEL STEERING PATTERN ARE EXPECTED THROUGH TAU 72. A DEEP UPPER-LEVEL TROUGH CURRENTLY MOVING OVER NORTHERN JAPAN WILL SLOWLY MOVE EASTWARD WHILE STEADILY FILLING AS THE ASSOCIATED JET MAX EXITS TO THE NORTHEAST. THE TROUGH WILL NOT BE STRONG ENOUGH TO PULL STY 12W NORTHWARD, BUT IT WILL SERVE TO WEAKEN THE STEERING GRADIENT SLIGHTLY. STY 12W WILL DECELERATE SLIGHTLY AFTER TAU 60 AS IT REACHES AN INFLECTION POINT SOUTH OF THE TROUGH- INDUCED WEAKNESS IN THE RIDGE. AS THE TROUGH FILLS AND LIFTS NORTHWARD, SUBTROPICAL RIDGING WILL BUILD EASTWARD FROM JAPAN ALONG 35N. STY 12W WILL SHIFT TO A WESTWARD TRACK AFTER TAU 72, TRACKING ALONG THE SOUTHERN FLANK OF THE RIDGE. REGARDING INTENSITY, UPON ERC COMPLETION, THE SYSTEM IS LIKELY TO REINTENSIFY UNDER VERY FAVORABLE ENVIRONMENTAL CONDITIONS. MULTIPLE MESOSCALE MODELS STILL INDICATE THE ONSET OF ANOTHER ERC WITHIN THE NEXT 12-24 HOURS, WHICH WILL RESULT IN ANOTHER ROUND OF WEAKENING AFTER TAU 12. THE FORECAST CALLS FOR A STEADY INTENSITY TREND FROM TAU 12 TO TAU 36, BUT SHORT-TERM FLUCTUATIONS IN INTENSITY AROUND THE MEAN ARE FULLY ANTICIPATED DUE TO ONGOING ERCS. AFTER TAU 36, STY 12W WILL STEADILY WEAKEN AS IT ENCOUNTERS LOWER OHC, SLIGHTLY COOLER SSTS, AND AN OVERALL DECREASE IN UPPER-LEVEL OUTFLOW AS IT BECOMES ISOLATED FROM ANY OUTFLOW CHANNELS. MODEL DISCUSSION: TRACK GUIDANCE IS IN STRONG AGREEMENT, WITH CROSS- TRACK SPREAD INCREASING GRADUALLY TO 70NM AT TAU 72. THE NAVGEM AND GEFS MEAN ARE POSITIONED ON THE NORTHERN EDGE OF THE GUIDANCE ENVELOPE, WHILE ECMWF AND JGSM MARK THE SOUTHERN EDGE OF THE ENVELOPE. THE JTWC FORECAST IS PLACED CLOSE TO THE EXPERIMENTAL GOOGLE DEEPMIND AND CONSENSUS MEAN WITH HIGH CONFIDENCE. BEYOND TAU 72, THE GUIDANCE PACKAGE BEGINS TO DIVERGE TO APPROXIMATELY 190NM BY THE END OF THE FORECAST PERIOD, MAINTAINING A SIMILAR TRACK ORIENTATION AMONGST THE MODELS. ENSEMBLE GUIDANCE HAS COME INTO BETTER AGREEMENT WITH DECREASED MEMBER SPREAD OVER THE PAST 12 HOURS, WHILE ENSEMBLE MODEL MEANS ARE CONVERGING ON A SIMILAR TRACK TO THE DETERMINISTIC GUIDANCE. THE JTWC FORECAST BEYOND TAU 72 IS PLACED WITH HIGH CONFIDENCE NEAR THE MULTI-MODEL CONSENSUS MEAN. INTENSITY GUIDANCE IS IN GOOD AGREEMENT, WITH ALL MEMBERS CONFINED TO A 10-20KT ENVELOPE THROUGH THE FORECAST PERIOD. THE JTWC FORECAST IS PLACED ON THE UPPER EDGE OF THE ENVELOPE WITH MEDIUM CONFIDENCE DUE TO UNCERTAINTIES REGARDING THE ONSET, STRENGTH, AND DURATION OF POSSIBLE FUTURE ERCS. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN