WDXS31 PGTW 240300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 24S (JASMINE) WARNING NR 001// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.5S 40.3E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 282 NM NORTH OF EUROPA ISLAND MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 12 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A SMALL SIZED SYSTEM IN THE MOZAMBIQUE CHANNEL WITH THE CENTRAL CONVECTION OFFSET SOUTHEASTWARD FROM THE LOW LEVEL CIRCULATION (LLC). A SECONDARY BALL OF CONVECTION HAS SPLINTERED NORTHWARD AND IS COLLAPSING RAPIDLY. THE MAIN CONVECTION IS UNDER STRONG NORTHWESTERLY VERTICAL WIND SHEAR BUT THE WARM SST IN THE CHANNEL AND STRONG POLEWARD OUTFLOW ARE SUSTAINING THE DEEP CONVECTION AND PROMOTING CONSOLIDATION. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE USING LOW-CLOUD TRACING IN THE EIR LOOP INTO THE PARTLY OBSCURED LLC AND LINED UP WITH A SIMILAR MICROWAVE FEATURE IN THE 232243Z AMSR2 IMAGE. THE INITIAL INTENSITY OF 35KTS IS ASSIGNED WITH MEDIUM CONFIDENCE AND SUPPORTED BY THE HIGH END OF AGENCY DVORAK ESTIMATES AND CONSISTENT WITH THE 6-HR CONVECTIVE IMPROVEMENT. INITIAL WIND RADII BASIS: RECENT SCATTEROMETER DATA. CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS FMEE: T2.5 - 35 KTS FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 20-25 KTS SST: 28-29 CELSIUS OUTFLOW: STRONG POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TC JASMINE WILL CONTINUE GENERALLY SOUTHWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE EAST. THE MARGINALLY FAVORABLE ENVIRONMENT WILL FUEL A MODEST INTENSIFICATION TO 40KTS AT TAUS 12-24. AFTERWARD, INCREASING VWS AND THE INFLUX OF COLD DRY AIR IN THE LOWER LEVELS WILL TEMPER ANY INTENSIFICATION AND EVENTUALLY LEAD TO A SLOW DISSIPATION TO 30KTS BY TAU 72, POSSIBLY SOONER. AROUND TAU 36, A MID-LATITUDE TROUGH TRANSITIONING FROM THE SOUTHWEST WILL WEAKEN THE STR. THIS WILL RESULT IN A QUASI- STATIONARY MOTION DUE TO THE WEAK STEERING ENVIRONMENT. MODEL DISCUSSION: NUMERICAL MODELS ARE WIDELY SPLIT WITH NAVGEM, UKMET, AND AFUM INDICATING A CLOCKWISE LOOP TOWARD MOZAMBIQUE. THE MAJORITY OF THE MEMBERS, INCLUDING UEMN, ECMWF, AEMN, AND GFS ARE ON THE OTHER SIDE OFFERING A COUNTERCLOCKWISE (CCW) LOOP. NAVGEM AND GFS ARE ON THE OPPOSITE MARGINS OF THE ENVELOPE THAT SPANS 500NM ACROSS AT TAU 72. IN VIEW OF THIS, THE JTWC TRACK FORECAST IS LAID CLOSE TO THE CONSENSUS ON THE CCW SIDE WITH LOW CONFIDENCE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: LOW INTENSITY 0 - 72 HR: LOW// NNNN