WDPN31 PGTW 311500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (DOLPHIN) WARNING NR 019// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.1N 160.1E INITIAL INTENSITY: 130 KTS GEOGRAPHIC REFERENCE: 368 NM WEST OF WAKE ISLAND MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 49 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: SUPER TYPHOON (STY) 12W (DOLPHIN) CONTINUES TO EXPERIENCE REPEATED EYEWALL REPLACEMENT CYCLES (ERC), AND IS CURRENTLY IN THE MIDST OF ITS THIRD ERC IN AS MANY DAYS. THERE HAVE BEEN NO RECENT HIGH-RESOLUTION MICROWAVE IMAGES TO SUPPORT A HIGH-CONFIDENCE ASSESSMENT OF THE ERC STATUS, BUT A 311148Z TMS-06 184GHZ MICROWAVE IMAGE DEPICTED A SIGNIFICANTLY DETERIORATED INNER EYEWALL, OPEN IN THE SOUTHWESTERN QUADRANT, WITH A MUCH LARGER OUTER SECONDARY EYEWALL. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A SLOWLY ENLARGING EYE, NOW ESTIMATED TO BE 20 NM WIDE, WHICH HAS REMAINED CLOUD-FREE THROUGHOUT THE ERC PROCESS. THE ASSOCIATED CENTRAL DENSE OVERCAST (CDO) DECREASED IN AREAL EXTENT, WARMED, AND BECAME INCREASINGLY RAGGED UNTIL THE 1200Z FIX, WHERE THE TREND REVERSED. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE LARGE EYE IN THE EIR. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE. LATE RECEIPT OF A 310735Z SAR PASS REVEALED MAXIMUM WINDS OF 130-135 KNOTS AT THE BEGINNING OF THE CURRENT ERC, SUGGESTING THAT WEAKENING HAD ALREADY COMMENCED. AGENCY FINAL-T VALUES ARE HOVERING IN THE T6.5 RANGE, WHILE THE CIMSS ADT AND AIDT HAVE BOTH FALLEN TO NEAR 130 KNOTS, SUPPORTING AN INITIAL INTENSITY OF 130 KNOTS. THE OVERALL ENVIRONMENT REMAINS FAVORABLE, WITH LOW VWS, WARM SSTS, MODERATE TO HIGH OHC, AND MODERATE RADIAL OUTFLOW ALOFT, ENHANCED BY A WEAKENING POLEWARD OUTFLOW CHANNEL. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) COMPLEX TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T7.0 - 140 KTS RJTD: T7.0 - 140 KTS RCTP: T7.5 - 155 KTS KNES: T6.5 - 127 KTS PHFO: T6.5 - 127 KTS CIMSS ADT: 129 KTS AT 311200Z CIMSS AIDT: 125 KTS AT 311200Z CIMSS D-MINT: 136 KTS AT 311148Z CIMSS D-PRINT: 138 KTS AT 311200Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE RADIAL OTHER FACTORS: ONGOING EYEWALL REPLACEMENT CYCLE. 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: STY 12W WILL CONTINUE TO TRACK NORTHWESTWARD ALONG THE SOUTHWESTERN FLANK OF AN EXPANSIVE STR COMPLEX FOR THE NEXT 36-48 HOURS. A DEEP UPPER-LEVEL TROUGH CURRENTLY OFF THE EAST COAST OF HONSHU WILL CONTINUE TO PROPAGATE EASTWARD AND REACH ITS MAXIMUM EQUATORWARD EXTENT WITHIN THE NEXT 12 TO 24 HOURS. THE ASSOCIATED JET MAX EXITING THE EASTERN FLANK OF THE TROUGH WILL RESULT IN THE TROUGH WEAKENING AND RECEDING POLEWARD WHILE BUILDING THE STR SOUTH OF THE ALEUTIANS. AT THE SAME TIME, THE EXPANDING WIND FIELD ASSOCIATED WITH STY 12W WILL PULL WARM AIR POLEWARD AND BUILD THE WESTERN FLANK OF THE STR TO THE NORTH OF STY 12W. AS THE DEEP TROUGH RECEDES, IT ALLOWS RIDGING TO BUILD IN ACROSS THE 35TH PARALLEL, ULTIMATELY ESTABLISHING A RIDGE THAT WILL EXTEND FROM THE KOREAN PENINSULA TO SOUTH OF THE ALEUTIANS. STY 12W WILL TURN ONTO A WESTWARD TRACK AFTER TAU 48 AND CONTINUE TRACKING WEST THROUGH THE REMAINDER OF THE FORECAST PERIOD. REGARDING INTENSITY, THE REPEATED EYEWALL REPLACEMENT CYCLES SHOW NO SIGN OF CEASING; WHILE THE CURRENT CYCLE WILL LIKELY WRAP UP IN THE NEAR-TERM, ANOTHER WILL SOON BEGIN. BOTH THE HAFS-A AND HWRF DEPICT A STEADILY INCREASING EYE DIAMETER THROUGH TAU 120, WITH A CONCOMITANT INCREASE IN THE OVERALL WIND FIELD. WHILE THE FORECAST EXPLICITLY CALLS FOR A STEADY INTENSITY, THERE WILL BE SHORT-TERM FLUCTUATIONS IN INTENSITY BOTH ABOVE AND BELOW THE FORECAST THROUGH THE NEXT 36 HOURS DUE TO THE ANTICIPATED ERCS. AFTER TAU 36, THE SYSTEM IS FORECAST TO STEADILY WEAKEN AS IT MOVES OVER MARGINALLY COOLER SSTS, DECREASED OHC, AND INTO A REGION OF MODERATE SHEAR. HOWEVER, THE MAIN DRIVER IN WEAKENING THE SYSTEM WILL BE THE MASSIVE SIZE OF THE INNER CORE THAT IS EXPECTED TO DEVELOP AFTER TAU 72. MODEL DISCUSSION: TRACK GUIDANCE IS IN STRONG AGREEMENT THROUGH THE ENTIRE FORECAST PERIOD. CROSS-TRACK SPREAD IS MINIMAL TO TAU 48, INCREASES TO 80NM AT TAU 72, AND 130NM AT TAU 120. NAVGEM AND JGSM CONTINUE TO MARK THE NORTHERN SIDE OF THE ENVELOPE, WHILE ECMWF AND GFS ARE POSITIONED ON THE SOUTHERN EDGE. ENSEMBLE GUIDANCE CONTINUES TO IMPROVE, WITH LESS MEMBER DISPERSION WITH EACH SUCCESSIVE RUN. ADDITIONALLY, THE ENSEMBLE MEANS AND THE MEAN OF THE EXPERIMENTAL SUPER-ENSEMBLE CONTINUE TO TREND SOUTH WITH EACH RUN, GETTING CLOSER TO THE DETERMINISTIC CONSENSUS MEAN. THE TIGHT GROUPING, DECREASING ENSEMBLE MEMBER DISPERSION, AND ALIGNMENT WITH THE DETERMINISTIC GUIDANCE PROVIDE HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. INTENSITY GUIDANCE IS BEGINNING TO SHOW SIGNS OF INCREASED UNCERTAINTY, WITH A SPREAD BETWEEN OUTLIERS OF 35 KNOTS. THE CTCX DEPICTS INTENSIFICATION TO 140 KNOTS, WHERE IT REMAINS THROUGH TAU 96, WHILE THE HAFS-A AND GOOGLE DEEPMIND DEPICT RAPID WEAKENING BEGINNING AT TAU 36. THE COTC, HWRF, AND CONSENSUS SPLIT THE DIFFERENCE. THE JTWC FORECAST IS PLACED NEAR THE CONSENSUS MEAN, WITH LOW CONFIDENCE DUE TO THE UNCERTAINTIES ASSOCIATED WITH THE TIMING, STRENGTH, AND DURATION OF THE ANTICIPATED ERCS. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 00-72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN