WDPN31 PGTW 070900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15E (NOLO) WARNING NR 067// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 25.9N 162.0E INITIAL INTENSITY: 70 KTS GEOGRAPHIC REFERENCE: 1682 NM WEST-NORTHWEST OF JOHNSTON ISLAND MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 18 KTS SIGNIFICANT WAVE HEIGHT: 33 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: BUFFETED BY 25-30 KTS OF NORTHEASTERLY VERTICAL WIND SHEAR (VWS), THE CONVECTION ASSOCIATED WITH TYPHOON (TY) 15E HAS PERSISTED OVER THE LOW-LEVEL CIRCULATION CENTER. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COMPACT CENTRAL DENSE OVERCAST (CDO) THAT HAS BECOME MORE RAGGED AND SLIGHTLY DISPLACED SOUTH OF THE LLCC. A TIMELY 070526Z SSMIS PASS REVEALED AN INNER CORE OPEN TO THE NORTH, WITH DEEP CONVECTION DISPLACED SOUTH OF THE LLCC, INDICATING SOUTHWARD VORTEX TILT WITH HEIGHT. ALTHOUGH TY 15E IS TRACKING OVER SEA SURFACE TEMPERATURES (SST) OF 28 DEGREES CELSIUS, HIGH VWS IS OFFSETTING THIS OTHERWISE FAVORABLE CONDITION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MICROWAVE EYE FEATURE IN THE SSMIS IMAGERY. THE INITIAL INTENSITY HAS BEEN LOWERED TO 70 KTS WITH MEDIUM CONFIDENCE, REFLECTING THE CONTINUED DETERIORATION OF THE CONVECTIVE STRUCTURE. THIS ASSESSMENT IS NEAR THE T4.5 DVORAK CLASSIFICATIONS FROM PGTW, PHFO, RJTD, AND RCTP BUT LIES ON THE HIGHER END OF THE OBJECTIVE ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T4.5 - 77 KTS RCTP: T4.5 - 77 KTS PHFO: T4.5 - 77 KTS CIMSS ADT: 59 KTS AT 070530Z CIMSS AIDT: 69 KTS AT 070530Z CIMSS D-MINT: 68 KTS AT 070526Z CIMSS D-PRINT: 70 KTS AT 070530Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 25-30 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY 15E WILL CONTINUE WESTWARD TO WEST-NORTHWESTWARD ALONG THE SOUTHERN FLANK OF AN AMPLIFIED STR. DURING THE NEXT 60 HOURS, THE WESTERN EXTENSION OF THE RIDGE WILL WEAKEN, ALLOWING THE SYSTEM TO GRADUALLY DECELERATE FROM 18 KTS TO 8 KTS BY TAU 60. CONCURRENTLY, TY 15E WILL TURN POLEWARD AS IT ROUNDS THE STR AND CROSSES THE RIDGE AXIS AFTER TAU 60. FINALLY, IT WILL ACCELERATE EAST-NORTHEASTWARD UNDER THE INCREASING INFLUENCE OF DEEP-LAYER MID-LATITUDE WESTERLY FLOW. VWS WILL EASE TO 15-20 KTS BY TAU 12, WHICH WILL SLOW THE ONGOING WEAKENING TREND. AFTER TAU 36, THE VORTEX WILL BRIEFLY GAIN ACCESS TO A FAVORABLE POLEWARD OUTFLOW CHANNEL AND UPPER-LEVEL DIVERGENCE, SUPPORTING SLIGHT INTENSIFICATION. AFTER THE SYSTEM ROUNDS THE STR AXIS, INCREASING VWS, COOLER SSTS, AND INCREASING BAROCLINICITY WILL PROMOTE A RENEWED WEAKENING TREND AND EXTRATROPICAL TRANSITION NEAR THE END OF THE FORECAST PERIOD. MODEL DISCUSSION: CROSS-TRACK SPREAD AMONG THE TRACK GUIDANCE IS IMPROVING, PARTICULARLY SURROUNDING RECURVATURE. ALONG-TRACK SPREAD GROWS AFTER TAU 72, REFLECTING UNCERTAINTY IN THE TIMING AND LOCATION OF RECURVATURE. THE DYNAMICAL AIDS GENERALLY INITIATE THE POLEWARD TURN FARTHER WEST AND MORE SLOWLY THAN THEIR AI COUNTERPARTS. THE JTWC FORECAST TRACK IS POSITIONED USING A BLEND OF THE MULTI-MODEL CONSENSUS AND GOOGLE DEEPMIND. THE INTENSITY AIDS ARE IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD, DEPICTING WEAKENING THROUGH TAU 24 FOLLOWED BY SLIGHT INTENSIFICATION FROM TAU 36 TO TAU 60. THE JTWC INTENSITY FORECAST IS SET NEAR THE CENTER OF THE GUIDANCE ENVELOPE, NEAREST TO DEEPMIND AND GFS THROUGH TAU 72, THEN NEAR THE AVERAGE OF THE DEEPMIND AND GFS SOLUTIONS AT TAU 96 AND TAU 120. FORECAST CONFIDENCE: TRACK 00-72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN