WDPN31 PGTW 280300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01W (EWINIAR) WARNING NR 014// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 18.4N 124.9E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 512 NM SOUTH-SOUTHWEST OF KADENA AB MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 32 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A LOW-LEVEL CIRCULATION CENTER (LLCC) WRAPPING COMPLETELY BENEATH CONTINUED FLARING BUT WARMING CONVECTIVE TOPS OBSERVED THROUGHOUT THE LAST SIX HOURS. MODERATE VERTICAL WIND SHEAR (VWS) REMAINS EVIDENT ALONG THE NORTHWESTERN EDGE OF THE CONVECTION OVER THE LLC, DEFINED BY A CONTINUED AND SHARP THERMAL GRADIENT WITHIN THE WESTERN AND NORTHWESTERN QUADRANTS OF THE CIRRUS SHIELD ALOFT, BECOMING STRIATED DOWNSTREAM TO THE SOUTHEAST. DUAL-CHANNEL UPPER-LEVEL OUTFLOW IS EVIDENT WHILE TRYING TO MAINTAIN SUPPORT FOR TYPHOON (TY) 01W, WITH TRANSVERSE BANDING TRACKING POLEWARD AND A SUPPORTIVE EQUATORWARD OUTFLOW CHANNEL TO THE SOUTH OVER THE PHILIPPINES. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A 272158Z 37 GHZ SSMIS PASS, CONFIRMING THE PRIMARY CONVECTIVE FEATURE WRAPPING CYCLONICALLY AROUND THE EASTERN EDGE OF THE LLCC. THE INITIAL INTENSITY OF 75 KTS WAS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE SUBJECTIVE AGENCY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: PERSISTENCE. CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T4.5 - 77 KTS RCTP: T4.5 - 77 KTS KNES: T3.5 - 55 KTS CIMSS SATCON: 58 KTS AT 271900Z CIMSS ADT: 51 KTS AT 280030Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM 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: TY 01W IS EXPECTED TO CONTINUE TO TRACK NORTHEASTWARD UNDER THE INFLUENCE OF THE DEEP-LAYER STR POSITIONED TO THE EAST THROUGH THE END OF THE FORECAST PERIOD. THE TYPHOON IS FORECAST TO REMAIN IN A FAVORABLE ENVIRONMENT FOR SLOW INTENSIFICAITON THROUGHOUT THE NEXT 24 TO 36 HOURS, AS SUPPORTIVE UPPER-LEVEL OUTFLOW, HIGH SEA SURFACE TEMPERATURES (GREATER THAN 26 C), AND LOW TO MODERATE VWS REMAIN CONDUCIVE FOR SUSTAINMENT IN THE WESTERN PHILIPPINE SEA. AFTER TAU 36, A SOUTHWARD EXTENDING UPPER-LEVEL LONGWAVE TROUGH IS FORECASTED TO TRACK EASTWARD, INCREASING VWS TO 20-30 KTS, INITIATING THE BEGINNING STAGES OF A STEADY WEAKENING TREND. AS THE SYSTEM CONTINUES TO TRACK NORTHEASTWARD AFTER TAU 48, COOLER SEA SURFACE TEMPERATURES ARE EXPECTED TO WEAKEN THE SYSTEM NORTH OF LATITUDE 26N. BY TAU 72, TY 01W WILL BEGIN TO EXPERIENCE AN INCREASE IN COLD AIR ADVECTION WRAPPING INTO THE CORE STRUCTURE FROM THE NORTHWEST, STARTING THE EXTRATROPICAL TRANSITION THROUGH TAU 120. AT THIS POINT, VWS WILL INCREASE ABOVE 30 KTS AND SHEAR THE MID AND UPPER LEVELS, DECOUPLING THE VORTEX. MODEL DISCUSSION: THE DETERMINISTIC AND ENSEMBLE MODELS ARE IN VERY STRONG AGREEMENT THAT TY 01W WILL TRACK NORTHEASTWARD THROUGH TAU 120 ALONG THE WESTERN AND NORTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. GFS, ECMWF, AND COAMPS-TC ENSEMBLE MEMBERS CONTINUE SHOW A FEW SOLUTIONS ALONG THE EASTERN EDGE OF MAINLAND JAPAN, HOWEVER, THE JTWC CONSENSUS REMAINS STEADY THAT TY 01W WILL TRACK TO THE EAST THROUGH ITS EXTRATROPICAL TRANSITION BETWEEN TAU 72 AND TAU 96. THE TAU 36 AND TAU 48 CROSS-TRACK SPREAD REMAIN IN TIGHT AGREEMENT BETWEEN 64NM AND 100NM RESPECTIVELY. INTENSITY GUIDANCE REMAINS IN GOOD AGREEMENT THAT A STEADY TO MODERATE INTENSIFICATION TREND WILL OCCUR OVER THE NEXT 24 TO 36 HOURS WHILE THE ENVIRONMENT REMAINS FAVORABLE. FOLLOWING TAU 36, GFS, ECMWF, HAFS-A, AND COAMPS-TC ILLUSTRATE A WEAKENING TREND UNTIL THE END OF THE FORECAST PERIOD. THE COAMPS-TC INTENSITY PROBABILITY PRODUCT CONTINUES TO INDICATE A VERY LOW PROBABILITY OF RAPID INTENSIFICATION. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN