WDPN32 PGTW 220900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (TOKAGE) WARNING NR 001// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 24.9N 151.7E INITIAL INTENSITY: 40 KTS GEOGRAPHIC REFERENCE: 880 NM SOUTHEAST OF YOKOSUKA, JAPAN MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 15 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TS TOKAGE HAS RAPIDLY CONSOLIDATED AND INTENSIFIED OVER THE PAST 12 HOURS IN THE OPEN WATERS EAST OF JAPAN. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS BANDS OF DEEP CONVECTION WRAPPING INTO A WELL-DEFINED LOW LEVEL CIRCULATION CENTER. A 220541Z SSMIS 91GHZ MICROWAVE IMAGE SHOWED THE MUCH IMPROVED STRUCTURE, WITH INTENSE BANDS OF CONVECTIVE ACTIVITY WRAPPING IN A COMMA-SHAPED ARC FROM WEST TO SOUTHEAST OF THE LLCC. A 212311Z ASCAT-B BULLSEYE MEANWHILE REVEALED A TIGHT LLCC WITH LIGHT WINDS TO THE WEST AND AN RELATIVELY LARGE AREA OF 25 KNOT OR HIGHER WINDS EXTENDING THROUGH THE REMAINDER OF THE CIRCULATION, WITH A PATCH OF 35 KNOT WINDS TO THE SOUTHEAST OF THE CENTER. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE SSMIS DATA AND THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE SCATTEROMETER DATA, PROVIDING GOOD CONFIDENCE TO HEDGE ABOVE THE BULK OF THE AGENCY FIX INTENSITIES. THE SYSTEM IS MOVING NORTHWARD ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST. THE ENVIRONMENT IS FAVORABLE FOR ADDITIONAL INTENSIFICATION, AS THE SYSTEM LIES UNDER DIFFLUENT UPPER-LEVEL FLOW TO THE EAST OF A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) PROVIDING VERY GOOD POLEWARD OUTFLOW AND LOW VWS, SUPPORTED BY WARM (29-30C) SSTS. WIND RADII BASIS: SCATTEROMETER DATA. CURRENT STEERING MECHANISM: SOUTHWEST PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS RJTD: T2.0 - 30 KTS KNES: T3.0 - 45 KTS FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG POLEWARD OTHER FACTORS: NONE ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES. THIS IS THE FIRST WARNING AND ESTABLISHES THE FORECAST REASONING. FORECAST DISCUSSION: TS 11W IS CURRENTLY MOVING RELATIVELY SLOWLY ALONG THE SOUTHWESTERN SIDE OF A DEEP STR TO THE NORTHEAST. OVER THE NEXT 12 HOURS THE RIDGE IS ANTICIPATED TO BUILD TOWARDS THE WEST-SOUTHWEST AND TS 11W IS FORECAST TO TURN THE RUDDER OVER TO THE NORTHWEST. THE GENERALLY NORTHWEST TRACK IS EXPECTED TO CONTINUE THROUGH ABOUT TAU 36, BEFORE THE SYSTEM WILL ROUND THE RIDGE AXIS AND ACCELERATE NORTHEASTWARD AHEAD OF AN APPROACHING MID-LATITUDE TROUGH THROUGH THE REMAINDER OF THE FORECAST PERIOD. BY TAU 72, THE SYSTEM WILL BEGIN TO INTERACT WITH THE BAROCLINIC ZONE, BECOME IN-PHASE WITH A MINOR SHORTWAVE TROUGH EAST OF JAPAN AND CROSS OVER COLDER WATERS, MARKING THE ONSET OF EXTRATROPICAL TRANSITION (ETT), WHICH IS EXPECTED TO BE COMPLETE NO LATER THAN TAU 96. IN TERMS OF INTENSIFICATION, THE ENVIRONMENT WILL SUPPORT STEADY INTENSIFICATION FOR THE NEXT 48 HOURS, THOUGH THE UPPER-LEVEL OUTFLOW IS EXPECTED TO WEAKEN A BIT AFTER TAU 24, AND SHOULD BUT THE BRAKES ON ANY RAPID INTENSIFICATION, WITH ALL OTHER PARAMETERS BEING GENERALLY FAVORABLE. AS THE SYSTEM ROUNDS THE RIDGE AXIS IT WILL START TO BE IMPACTED BY SOME NORTHERLY, CONVERGENT FLOW AT THE 200MB LEVEL, WHICH COMBINED WITH INCREASING SHEAR AND DECREASING SSTS, WILL LEAD TO GENERALIZED WEAKENING FROM THERE TO THE END OF THE FORECAST. MODEL DISCUSSION: MODEL DATA IS SOMEWHAT LIMITED AT PRESENT DUE TO TECHNICAL ISSUES AT JTWC, THUS THE FORECAST IS GENERATED USING GLOBAL MODEL FIELD ANALYSIS, BOTH IN TERMS OF TRACK AND INTENSITY. THE ONLY TRACKER AVAILABLE IS THE GFS, BUT FIELD ANALYSIS OF BOTH DETERMINISTIC AND ENSEMBLE MODELS SUGGEST THEY ARE ALL IN GOOD AGREEMENT ON THE OVERALL TRACK. THE JTWC FORECAST LIES ALONG THE GFS TRACK FOR NOW, BUT CONFIDENCE IS LOW DUE TO THE LACK OF SPECIFIC GUIDANCE AT THIS TIME. SIMILARLY FOR INTENSITY GUIDANCE, JTWC IS CURRENTLY LIMITED, BUT THE DECAY-SHIPS GFS SUGGESTED A PEAK OF 65 KNOTS, WHICH IS A POSSIBILITY, BUT SEEMS UNLIKELY AT THIS TIME AND THE JTWC FORECAST CALLS FOR A PEAK OF 55 KNOTS AT TAU 48. CONFIDENCE IS LOW HOWEVER DUE TO THE LACK OF GUIDANCE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: LOW TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN