WDPN31 PGTW 301500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (DOLPHIN) WARNING NR 015// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.5N 163.9E INITIAL INTENSITY: 130 KTS GEOGRAPHIC REFERENCE: 188 NM SOUTHWEST OF WAKE ISLAND MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: 43 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: OVER THE PAST FEW HOURS, STY 12W HAS TRANSITIONED FROM A WELL-DEFINED 14-NM WIDE CLEAR EYE, TO A COMPLETELY CLOUD-FILLED AND RAPIDLY SHRINKING EYE FEATURE, WHICH THEN DISAPPEARED BRIEFLY. THE MOST RECENT FRAMES OF ENHANCED INFRARED (EIR) IMAGERY, HOWEVER, PROVIDE INITIAL INDICATION OF A NEW EYE FORMING. THERE HAS NOT BEEN A HIGH-RESOLUTION MICROWAVE IMAGER PASS SINCE 300154Z, AND THE STATUS OF THE EYEWALL REPLACEMENT CYCLE (ERC) REMAINS AMBIGUOUS. A 301017Z MHS 89GHZ IMAGE SHOWED A NASCENT OUTER EYEWALL WITH A DIAMETER OF ROUGHLY 30NM, WHICH REMAINED OPEN IN THE NORTHEASTERN QUADRANT; IT CAN BE SURMISED THAT THE ERC IS NEARLY COMPLETE BASED ON THE EVOLUTION OF THE EYE OVER THE PAST 12 HOURS. IT IS LIKELY IN THE NEAR-TERM THAT THE EYE WILL REAPPEAR AND CLEAR OUT, AT ROUGHLY DOUBLE THE SIZE OF THE ORIGINAL EYE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE RAPIDLY DIMINISHING EYE IN THE EIR AND EXTRAPOLATION OF THE MICROWAVE EYE IN THE MHS IMAGE NOTED ABOVE. THE INITIAL INTENSITY IS A BIT MORE CHALLENGING AND IS ASSESSED WITH LOW CONFIDENCE. DVORAK CURRENT INTENSITY (CI) ESTIMATES REMAIN ELEVATED WHILE THE FINAL-T VALUES HAVE DROPPED PRECIPITOUSLY, WITH MOST AGENCIES REPORTING A FINAL-T BETWEEN T6.0 AND T6.5. CIMSS ADJUSTED T- VALUES HAVE DECREASED TO T6.3, AND THE AIDT AND DPRINT ALSO CONTINUE TO DECREASE RAPIDLY. THE INITIAL INTENSITY IS PLACED NEAR THE AVERAGE OF THE AVAILABLE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES. THE ENVIRONMENT REMAINS FAVORABLE, WITH LOW DEEP-LAYER VERTICAL WIND SHEAR, VERY WARM SSTS, HIGH OHC, AND STRONG RADIAL OUTFLOW WHICH IS ENHANCED BY A POLEWARD OUTFLOW CHANNEL INTO THE REAR ENTRANCE REGION OF A SUBTROPICAL JET FAR TO THE EAST. THE PRIMARY FACTOR CAPPING INTENSIFICATION IS SUCCESSIVE EYEWALL REPLACEMENT CYCLES AND THE CONCOMITANT EXPANSION OF THE EYE. INITIAL WIND RADII BASIS: SMAP, SMOS, AND SAR DATA. CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF AN EXPANSIVE SUBTROPICAL RIDGE (STR) COMPLEX EXTENDING FROM SOUTHWEST OF THE ALEUTIANS SOUTHEASTWARD TO NEAR 20N 170W. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T6.5 - 127 KTS RJTD: T7.0 - 140 KTS RCTP: T7.5 - 155 KTS KNES: T7.0 - 140 KTS PHFO: T7.0 - 140 KTS CIMSS ADT: 132 KTS AT 301200Z CIMSS AIDT: 125 KTS AT 301200Z CIMSS D-MINT: 140 KTS AT 301021Z CIMSS D-PRINT: 140 KTS AT 301200Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 30-31 CELSIUS OUTFLOW: STRONG RADIAL OTHER FACTORS: EYEWALL REPLACEMENT CYCLE (ERC). ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: LOW INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE FORECAST NO LONGER EXPLICITLY CALLS FOR INTENSIFICATION THROUGH THE FORECAST PERIOD. FORECAST DISCUSSION: STY 12W CONTINUES TRACKING NORTHWESTWARD ALONG THE SOUTHWESTERN FLANK OF AN EXPANSIVE, NORTHWEST-SOUTHEAST-ORIENTED STR COMPLEX TO THE EAST. FAR TO THE NORTHWEST, A RELATIVELY STRONG AND DEEP UPPER-LEVEL TROUGH IS CURRENTLY MOVING OFF THE EAST COAST OF HONSHU. BY TAU 36, THE TROUGH WILL REACH ITS MAXIMUM EQUATORWARD EXTENT BEFORE RAPIDLY FILLING AND WITHDRAWING NORTHWARD AS THE ASSOCIATED JET MAX MOVES UP THE EASTERN SIDE OF THE TROUGH. WHILE THE TROUGH WILL BE RAPIDLY FILLING AND MOVING AWAY, AND HENCE UNABLE TO RECURVE STY 12W NORTHWARD, IT WILL GENERATE A WEAKNESS IN THE STEERING RIDGE, CAUSING THE SYSTEM TO DECELERATE BY A FEW KNOTS BETWEEN TAU 48 AND TAU 72. BY TAU 72, THE TROUGH WILL HAVE RECEDED FAR ENOUGH POLEWARD TO ALLOW A STR OVER KOREA TO RAPIDLY BUILD EASTWARD AND CONNECT WITH A BUILDING RIDGE SOUTH OF THE ALEUTIANS, SETTING UP A GENERAL ZONAL RIDGE AXIS NEAR 35N. STY 12W WILL TURN WESTWARD AFTER TAU 72 UNDER THE INFLUENCE OF THIS STEERING RIDGE. REGARDING INTENSITY, THE SYSTEM HAS CLEARLY DETERIORATED OVER THE LAST SIX HOURS DUE TO THE IMPACT OF THE ONGOING ERC. CURRENT EIR IMAGERY SUGGESTS THE EYE MAY BE RE-EMERGING IMMINENTLY AT ROUGHLY DOUBLE THE SIZE OF THE PREVIOUS EYE. NO SIGNIFICANT CHANGE IN THE ENVIRONMENT IS EXPECTED THROUGH TAU 36, AND WHILE THE FORECAST INTENSITY REMAINS FLAT, THERE WILL BE SHORT-TERM FLUCTUATIONS BOTH ABOVE AND BELOW THE FORECASTED INTENSITY DUE TO RAPID ERCS. AFTER TAU 36, INCREASING DEEP-LAYER SHEAR ALONG WITH SLOWLY DECREASING SSTS AND OHC WILL CONSPIRE TO SLOWLY BUT STEADILY WEAKEN STY 12W AS IT CONTINUES WESTWARD. ADDITIONALLY, BOTH THE HWRF AND HAFS-A DEPICT DEVELOPMENT OF A DRAMATICALLY LARGER EYE AND WIND FIELD AFTER TAU 72, WHICH WILL CONTRIBUTE TO A GENERAL WEAKENING OF THE SYSTEM. MODEL DISCUSSION: TRACK GUIDANCE IS IN TIGHT AGREEMENT THROUGH THE ENTIRE FORECAST PERIOD. CROSS-TRACK SPREAD IS 90NM AT TAU 72, INCREASING TO 140NM BY TAU 120. THE GEFS MEAN CONTINUES TO MARK THE NORTHERN EDGE OF THE ENVELOPE, WHILE THE ECMWF AND GFS LIE ON THE SOUTHERN EDGE, AND THE ARTIFICIAL INTELLIGENCE (AI) AND REMAINING DETERMINISTIC TRACKERS ARE TIGHTLY CLUSTERED BETWEEN THE TWO OUTLIERS. ENSEMBLE GUIDANCE CONTINUES TO TREND TOWARDS BETTER AGREEMENT, BOTH AMONGST THE ENSEMBLE MODELS AND AS COMPARED TO THE DETERMINISTIC AND AI MODELS. THE EXPERIMENTAL JTWC SUPER ENSEMBLE MEAN IS CLOSELY ALIGNED WITH THE MULTI-MODEL CONSENSUS. SPREAD AMONGST THE INDIVIDUAL ENSEMBLE MEMBERS IS ALSO DECREASING, INCREASING CONFIDENCE IN THE JTWC TRACK FORECAST, WHICH IS PLACED NEAR THE CONSENSUS MEAN AND THE EXPERIMENTAL SUPER ENSEMBLE MEAN. INTENSITY GUIDANCE IS IN GOOD AGREEMENT OVERALL, DEPICTING A GRADUAL AND VERY SLOW WEAKENING TREND THROUGH TAU 36 BEFORE DEPICTING A SLIGHTLY FASTER RATE OF WEAKENING BEFORE LEVELING OFF AT TAU 96. THE TWO EXCEPTIONS ARE THE HAFS-A, WHICH SHOWS 10 KNOTS OF INTENSIFICATION THROUGH TAU 12, AND THE CTCX, WHICH DEPICTS A PEAK OF 140 KNOTS FROM TAU 24 TO TAU 60 BEFORE STEADILY WEAKENING. NEITHER IS OUT OF THE REALM OF POSSIBILITY, ESPECIALLY IF THE POST-ERC EYE CAN QUICKLY REFORM. THE JTWC FORECAST CALLS FOR A STEADY INTENSITY THROUGH TAU 36, BUT SHORT-TERM FLUCTUATIONS ABOVE AND BELOW THE PREDICTED INTENSITY ARE EXPECTED DUE TO FUTURE ERCS. CONSEQUENTLY, THE INTENSITY FORECAST IS ISSUED WITH LOW CONFIDENCE. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 00-72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN