WDPN31 PGTW 310900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (DOLPHIN) WARNING NR 018// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 18.6N 161.0E INITIAL INTENSITY: 140 KTS GEOGRAPHIC REFERENCE: 321 NM WEST OF WAKE ISLAND MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 50 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND ENHANCED INFRARED (EIR) IMAGERY DEPICT A COMPACT CENTRAL DENSE OVERCAST (CDO) WITH A 15NM-WIDE CLEAR EYE FEATURE. OVER THE PAST FEW HOURS, THE CDO CLOUD TOPS HAVE SHOWN STEADY WARMING, WHILE THE EYE TEMP HAS COOLED. 310236Z AMSR2 89GHZ AND 310353Z GMI 89GHZ MICROWAVE PASSES DEPICT A VERY WELL-DEFINED, APPROXIMATELY 20NM INNER EYEWALL AND A VERY LARGE, CIRCULAR, APPROXIMATELY 80-100NM WIDE OUTER EYEWALL COMPLETELY SURROUNDING THE INNER EYEWALL. THE CIMSS M-PERC HOVMOLLER DIAGRAM SHOWS THAT THIS OUTER EYEWALL HAS YET TO BEGIN INWARD CONTRACTION. EIR IMAGERY AS OF 0730Z SHOWS RAPID FRAGMENTATION AND WARMING OF THE CDO, AS THE ONGOING EYEWALL REPLACEMENT CYCLE (ERC) BEGINS TO DEGRADE THE INNER CORE STRUCTURE. THE EYE HAS BEGUN TO TROCHOIDALLY WOBBLE ALONG THE GENERAL NORTHWESTWARD TRAJECTORY, INDICATIVE THAT IT IS COMPLETELY DISCONNECTED FROM INFLOWING CONVECTIVE BANDS DUE TO THE ERC. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE IN THE BD-ENHANCED INFRARED IMAGERY AND EXTRAPOLATION OF THE MICROWAVE EYE IN THE GMI IMAGE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, BASED ON AN AVERAGE OF THE AVAILABLE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES NOTED ABOVE. ENVIRONMENTAL CONDITIONS REMAIN OVERALL FAVORABLE, WITH LOW VERTICAL WIND SHEAR, WARM SSTS, HIGH OHC AND MODERATE RADIAL OUTFLOW ALOFT. UNFAVORABLE FACTORS INCLUDE THE CONTINUAL CYCLE OF ERCS, AND A STEADY EROSION OF THE POLEWARD OUTFLOW CHANNEL, AS THE SYSTEM SLOWLY BECOMES MORE ISOLATED FROM THE SYNOPTIC FLOW ALOFT. INITIAL WIND RADII BASIS: SMAP DATA CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF A COMPLEX SUBTROPICAL RIDGE (STR) EXTENDING FROM SOUTH OF THE ALEUTIANS TO WEST OF HAWAII. 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 SATCON: 130 KTS AT 310330Z CIMSS ADT: 132 KTS AT 310600Z CIMSS AIDT: 129 KTS AT 310600Z CIMSS D-MINT: 136 KTS AT 310353Z CIMSS D-PRINT: 138 KTS AT 310630Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE RADIAL OTHER FACTORS: EYEWALL REPLACEMENT CYCLE (ERC); STEADY WEAKENING IN UPPER-LEVEL POLEWARD OUTFLOW CHANNEL. 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 CONTINUES TO TRACK NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A STR COMPLEX WHICH EXTENDS ALONG A NORTHWEST-SOUTHEAST AXIS FROM SOUTH OF THE ALEUTIANS TO WEST OF HAWAII. FAR TO THE NORTHWEST, A DEEP UPPER-LEVEL TROUGH CONTINUES TO MOVE EAST OF HONSHU, WITH A JET MAX APPROACHING THE TROUGH AXIS. BY TAU 24, THE JET MAX WILL ROUND THE TROUGH AXIS, WITH THE TROUGH REACHING ITS MAXIMUM EQUATORWARD EXTENT AND GENERATING A WEAKNESS IN THE STR ALONG 30N LATITUDE. THE ORIENTATION OF THE STR RELATIVE TO THE TROUGH AXIS WILL INDUCE A SLIGHT ACCELERATION IN THE TRACK SPEED OF STY 12W AS IT CONTINUES NORTHWESTWARD. AS THE JET MAX MOVES TO THE EASTERN SIDE OF THE TROUGH, THE TROUGH WILL FILL AND RECEDE POLEWARD, ENABLING RIDGING TO BUILD IN ITS WAKE, ALONG 35N LATITUDE. BY TAU 72, THIS RIDGING WILL BE FIRMLY ENTRENCHED, EXTENDING FROM A RIDGE CENTERED OVER KOREA EASTWARD TO SOUTH OF THE ALEUTIANS. STY 12W WILL GRADUALLY SHIFT TO A MORE WESTWARD TRACK FROM TAU 72 THROUGH THE REMAINDER OF THE FORECAST ON THE SOUTHERN FLANK OF THE RIDGE. REGARDING INTENSITY, REPEATED ERCS HAVE RESTRICTED INTENSIFICATION OVER THE PAST COUPLE OF DAYS. THIS THIRD CONSECUTIVE ERC, HOWEVER, IS DISTINCT IN THAT THE OUTER EYEWALL IS APPROXIMATELY QUADRUPLE THE RADIUS OF THE INNER EYEWALL. ONCE THE INNER EYEWALL DISSIPATES AND IS SUPERSEDED BY THIS EXPANSIVE OUTER STRUCTURE, RE-INTENSIFICATION TO PEAK INTENSITY IS UNLIKELY. OTHERWISE, THE ENVIRONMENT WILL REMAIN GENERALLY CONDUCIVE TO MAINTAINING SUPER TYPHOON INTENSITY FOR AT LEAST ANOTHER 48-60 HOURS, BEFORE OHC AND SST DECREASE AND VWS INCREASES. THE FORECAST REFLECTS A SLIGHT WEAKENING IN THE NEAR-TERM BUT MAINTAINS SUPER TYPHOON INTENSITY THROUGH TAU 48, WITH MORE STEADY WEAKENING THEREAFTER AS ENVIRONMENTAL CONDITIONS DETERIORATE. MODEL DISCUSSION: TRACK GUIDANCE IS IN STRONG AGREEMENT FOR THE EARLY PORTION OF THE FORECAST. CROSS-TRACK SPREAD INCREASES TO 110NM AT TAU 72, WITH THE JGSM AND NAVGEM TRACKERS POSITIONED ON THE NORTHERN EDGE OF THE ENVELOPE, AND THE GFS AND ECMWF ON THE SOUTHERN EDGE. THE JTWC FORECAST IS PLACED NEAR THE MULTI-MODEL CONSENSUS AND THE EXPERIMENTAL GOOGLE DEEPMIND TRACKER WITH HIGH CONFIDENCE. IN THE LONG-RANGE FORECAST, TRACK GUIDANCE BEGINS TO DISPERSE, WITH CROSS-TRACK SPREAD INCREASING MODESTLY TO APPROXIMATELY 150NM BY TAU 120. ENSEMBLE GUIDANCE CONTINUES TO STEADILY IMPROVE AND COME INTO BETTER AGREEMENT, BOTH BETWEEN THE ENSEMBLE MODELS THEMSELVES AND COMPARED TO THE DETERMINISTIC GUIDANCE. THE JTWC EXPERIMENTAL SUPER ENSEMBLE SHOWS A RELATIVELY TIGHT DISPERSAL PATTERN, WITH MEMBERS CONSTRAINED TO AN ENVELOPE BETWEEN THE TIP OF KYUSHU AND 25N LATITUDE. THE JTWC LONG- RANGE FORECAST TRACK IS PLACED CLOSE TO THE CONSENSUS MEAN AND THE GOOGLE DEEPMIND TRACKER WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS IN GOOD AGREEMENT DEPICTING A GRADUAL STEPWISE WEAKENING THROUGH TAU 48 FOLLOWED BY STEADY WEAKENING THROUGH TAU 120. THE JTWC FORECAST IS PLACED CLOSE TO THE CONSENSUS MEAN, WITH MEDIUM CONFIDENCE. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN