WDPN32 PGTW 050300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (DANAS) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 20.2N 117.5E INITIAL INTENSITY: 45 KTS GEOGRAPHIC REFERENCE: 368 NM SOUTHWEST OF TAIPEI, TAIWAN MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 01 KTS SIGNIFICANT WAVE HEIGHT: 16 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL STORM (TS) 05W (DANAS) WITH VIGOROUS CONVECTIVE BURSTS OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC). A 050016Z GMI 89 GHZ MICROWAVE IMAGE REVEALED A DEFINED BAND OF CONVECTION WRAPPING INTO THE SYSTEM WITHIN THE SOUTHERN SEMICIRCLE. THE VORTEX HAS BECOME MORE VERTICALLY ALIGNED AND THE POLEWARD OUTFLOW HAS BECOME LESS RESTRICTED DUE TO THE NORTHERLY SHEAR LESSENING. THE ENVIRONMENT IS NOW CHARACTERIZED AS HIGHLY FAVORABLE WITH STRONG RADIAL OUTFLOW ALOFT, LOW (10-15 KTS) VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE MENTIONED GMI MICROWAVE IMAGE AND THE ANIMATED MSI. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT WITH A SUBTROPICAL RIDGE POSITIONED TO THE NORTH AND A NEAR-EQUATORIAL RIDGE BUILDING TO THE SOUTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T2.5 - 35 KTS RCTP: T3.0 - 45 KTS KNES: T3.5 - 55 KTS CIMSS ADT: 43 KTS AT 050000Z CIMSS AIDT: 39 KTS AT 050000Z CIMSS DPRINT: 40 KTS AT 050000Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM 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: TS 05W IS FORECAST TO TRACK SLOWLY NORTHWARD OVER THE NEXT 12 HOURS AS THE STEERING PATTERN REMAINS COMPETING. AFTER TAU 12, THE NEAR-EQUATORIAL RIDGE TO THE SOUTHEAST WILL BUILD AND CAUSE THE STEERING PATTERN TO BECOME MORE DEFINED. 05W WILL THEN INCREASE TRACK SPEEDS IN THE NORTH-NORTHEASTWARD DIRECTION, ALONG THE NORTHWESTERN PERIPHERY OF THE RIDGE THROUGH TAU 72. NEAR TAU 72, RIDGING WILL EXTEND OVER TO THE NORTH OF THE VORTEX, WHICH WILL CAUSE IT TO MAKE A SHARP WESTWARD TURN INTO MAINLAND CHINA. REGARDING INTENSITY, 05W IS FORECAST TO NEARLY RAPIDLY INTENSIFY OVER THE NEXT 24 HOURS AS THE ENVIRONMENT REMAINS HIGHLY CONDUCIVE. A PEAK INTENSITY OF 80 KTS IS FORECAST TO OCCUR AROUND TAU 36, AS THE SYSTEM BEGINS TO ENTER THE TAIWAN STRAIT. INTERACTION WITH TAIWAN AND THE EASTERN COAST OF CHINA WILL CAUSE 05W TO BEGIN MARGINALLY WEAKENING AS IT TRACKS THROUGH THE STRAIT. NEAR TAU 72, AS THE VORTEX INCHES TOWARD THE COAST, INCREASING LAND INTERACTION AND DRY AIR ADVECTION FROM THE MOUNTAINS WILL CAUSE THE SYSTEM TO FURTHER WEAKEN. ONCE 05W MAKES THE SHARP TURN INTO CHINA, DISSIPATION WILL BE IMMINENT. DISSIPATION IS FORECAST TO OCCUR AROUND TAU 96, AS THE REMNANT VORTEX TRACKS FURTHER OFF TO THE WEST. MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN MODERATE AGREEMENT THROUGH TAU 72, WITH A 170 NM CROSS-TRACK SPREAD AT TAU 72. ECMWF AND ITS ENSEMBLE MEAN ARE THE MOST WESTWARD LEANING MEMBERS, KEEPING THE VORTEX CLOSER TO THE COAST OF CHINA THAN THE REMAINDER OF GUIDANCE SUGGESTS. AFTER TAU 72, MODELS GREATLY DIVERGE. SOME MODELS TAKE A SHARP TURN TOWARD THE SOUTHWEST (UKMET, JGSM, AND GFS) WHILE OTHERS TAKE A BROADER TURN TO THE WEST-NORTHWEST (ECMWF AND GALWEM). THE JTWC TRACK FORECAST IS PLACED MORE IN LINE WITH THE LATTER SCENARIO WITH LOW CONFIDENCE AFTER TAU 72. INTENSITY GUIDANCE AGREES ON INTENSIFICATION THROUGH TAU 36. PEAK INTENSITIES RANGE FROM 70-100 KTS WITH THE HIGHER END CONSISTING OF THE RAPID INTENSIFICATION AIDS THAT CONTINUE TO TRIGGER. THE JTWC PEAK IS FORECAST TO BE 80 KTS, IN LINE WITH THE MULTI-MODEL CONSENSUS. AFTER TAU 48, ALL MODELS DEPICT WEAKENING THROUGH THE REMAINDER OF THE FORECAST PERIOD. HOWEVER, THE JTWC INTENSITY FORECAST IS PLACED WITH OVERALL LOW CONFIDENCE DUE TO THE VORTEX BEING SO CLOSE TO LAND ON EITHER SIDE OF THE TRACK. SMALL VARIATIONS IN THE TRACK COULD CAUSE LARGE CHANGES TO THE INTENSITY OF THE STORM AS IT TRAVERSES THE TAIWAN STRAIT. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN