WDPN31 PGTW 130300 COR MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 15W (MERBOK) WARNING NR 010 CORRECTED// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 23.9N 163.3E INITIAL INTENSITY: 55 KTS GEOGRAPHIC REFERENCE: 332 NM NORTH-NORTHWEST OF WAKE ISLAND MOVEMENT PAST 6 HOURS: NORTHWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 22 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEPENING CONVECTIVE BANDING WRAPPING TIGHTLY AROUND A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON RECENT SATELLITE FIXES FROM PGTW, KNES AND RJTD, AS WELL AS 122012Z SSMIS 37 GHZ IMAGERY SHOWING AN UPSTREAM LOW-LEVEL EYE FEATURE. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON RECENT AUTOMATED AND SUBJECTIVE DVORAK INTENSITY ESTIMATES AS WELL AS RECENT ASCAT PASSES COVERING THE EASTERN PORTION OF THE CIRCULATION. INITIAL WIND RADII BASIS: SCATTEROMETER DATA (METOP-B ASCAT FROM 122215Z) FOR THE EASTERN PORTION OF THE CIRCULATION AND OBJECTIVE BEST TRACK DATA FOR THE WESTERN PORTION. CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) EXTENSION TO THE EAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS RJTD: T3.5 - 55 KTS KNES: T4.0 - 65 KTS CIMSS SATCON: 55 KTS AT 122014Z CIMSS ADT: 55 KTS AT 122330Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH 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: TS 15W WILL TRACK POLEWARD THROUGH TAU 36 AND TURN TOWARD THE NORTH-NORTHEAST FOR THE REMAINDER OF THE FORECAST PERIOD FOLLOWING THE FLOW ASSOCIATED WITH SUBTROPICAL RIDGING TO THE EAST AND NORTHEAST. STEADY INTENSIFICATION WILL LIKELY CONTINUE FOR THE NEXT 36 HOURS AS THE SYSTEM PASSES OVER WARM WATER, VERTICAL WIND SHEAR REMAINS LOW AND THE OUTFLOW PATTERN IS GENERALLY SUPPORTIVE. THEREAFTER, COOLING ALONG-TRACK SEA SURFACE TEMPERATURES AND INCREASING VERTICAL WIND SHEAR ASSOCIATED WITH A MID-LATITUDE TROUGH APPROACHING FROM THE NORTHWEST WILL INDUCE WEAKENING. BETWEEN TAU 48 AND TAU 72, TS 15W WILL BECOME EMBEDDED IN THE AFOREMENTIONED TROUGH AND COMPLETE EXTRATROPICAL TRANSITION. FAVORABLE BAROCLINIC INTERACTION BETWEEN THE SYSTEM AND THE TROUGH WILL ENABLE 15W TO TRANSITION INTO A VERY STRONG EXTRATROPICAL LOW BY TAU 72. MODEL DISCUSSION: NUMERICAL MODEL TRACK FORECASTS REMAIN IN EXCELLENT AGREEMENT THROUGH THE ENTIRETY OF THE FORECAST PERIOD. INTENSITY GUIDANCE IS IN FAIR AGREEMENT AS WELL, PARTICULARLY REGARDING THE OVERALL TREND, TIMING OF PEAK INTENSITY AND HIGH POST-EXTRATROPICAL TRANSITION INTENSITY. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH INTENSITY 0 - 72 HR: MEDIUM// 4. JUSTIFICATION FOR CORRECTION: GRAMMATICAL CORRECTION TO PARA 3. NNNN