WDXS31 PGTW 280300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (VERNON) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.9S 87.5E INITIAL INTENSITY: 40 KTS GEOGRAPHIC REFERENCE: 999 NM EAST-SOUTHEAST OF DIEGO GARCIA MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 20 KTS SIGNIFICANT WAVE HEIGHT: 15 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A PARTLY EXPOSED LOW LEVEL CIRCULATION (LLC) WITH TWO SHEARED AREAS OF DEEP FLARING CONVECTION - ONE TO THE NORTH AND ANOTHER TO THE SOUTH. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE PARTLY EXPOSED LLC IN THE EIR LOOP, LINED UP WITH AN LLC FEATURE IN THE 272223Z SSMIS 91GHZ IMAGE. THE INITIAL INTENSITY OF 40KTS IS ASSESSED SLIGHTLY LOWER THAN AGENCY CURRENT INTENSITY DVORAK ESTIMATES AND MORE IN LINE WITH THE FINAL INTENSITY ESTIMATES AND A RECENT HSAT WINDSPEED DIRECT PASS TO REFLECT THE RAPID WEAKENING. ENVIRONMENTAL ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH WARM SST AND STRONG POLEWARD OUTFLOW OFFSET BY MODERATE TO STRONG VWS. THE CYCLONE IS NOW TRACKING ALONG THE NORTHWEST PERIPHERY OF THE STR TO THE SOUTHEAST. INITIAL WIND RADII BASIS: SCATTEROMETER DATA. CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS FMEE: T3.0 - 45 KTS FIMP: T3.0 - 45 KTS CIMSS ADT: 47 KTS AT 280015Z 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: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 14S WILL CONTINUE ON A SOUTHWESTWARD TRACK UNDER THE STR UP TO TAU 96. AFTERWARD, AS IT BEGINS TO ROUND THE STR AXIS, IT WILL TRACK MORE SOUTHWARD. THE INITIALLY MARGINALLY FAVORABLE ENVIRONMENT WILL FUEL A MODEST INTENSIFICATION TO 50KTS BY TAU 36; AFTERWARD, THE INFLUX OF COOL DRY AIR IN THE LOWER LEVELS WILL HINDER ANY FURTHER INTENSIFICATION. AFTER TAU 96, COOLING SST WILL CONTRIBUTE TO FURTHER WEAKENING DOWN TO 45KTS BY TAU 120. CONCURRENTLY BY TAU 96, TC VERNON WILL BEGIN SUBTROPICAL TRANSITION AS IT APPROACHES THE COLD BAROCLINIC ZONE. MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH MINIMAL AND GRADUAL SPREADING TO 283NM BY TAU 120 WITH NAVGEM THE SOLE LEFT OF TRACK OUTLIER, LENDING MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID JUST TO THE RIGHT OF CONSENSUS TO OFFSET NAVGEM. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN