WDXS31 PGTW 271500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (VERNON) WARNING NR 006// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 12.2S 88.4E INITIAL INTENSITY: 70 KTS GEOGRAPHIC REFERENCE: 989 NM EAST-SOUTHEAST OF DIEGO GARCIA MOVEMENT PAST 6 HOURS: EASTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: 23 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS THE SYSTEM WEAKENING DRAMATICALLY AS IT ENCOUNTERS AN UNFAVORABLE EASTERLY SHEAR ENVIRONMENT. A COL AREA TO THE NORTH AND ANOTHER TO THE WEST HAS IMPEDED TC 14S FORWARD AND WESTWARD PROGRESSION. THE LLC EJECTED TO THE EAST OF THE MAIN CONVECTIVE STRUCTURE AND IS NOW PARTIALLY EXPOSED. THEREFORE, THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE 271048Z SSMIS 91GHZ IMAGE. THE INITIAL INTENSITY IS ASSESSED WITH LOW CONFIDENCE DUE TO THE EXPOSED LLC LACK OF OBJECTIVE DATA AND REMAINS HIGHER THAN THE AUTOMATED DVORAK ESTIMATES. ANALYSIS INDICATES AN UNFAVORABLE ENVIRONMENT WITH UNFAVORABLE VWS AND SUBSIDENCE ON THE EAST SIDE OF TC 14S, OFFSET BY WARM SST AND MOSTLY STRONG EQUATORWARD OUTFLOW AND WEAK POLEWARD OUTFLOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST, NEAR EQUATORIAL RIDGE TO THE NORTHWEST, BINARY INTERACTION WITH INVEST 93S. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS FMEE: T3.5 - 55 KTS FIMP: T3.5 - 55 KTS CIMSS SATCON: 59 KTS AT 270801Z CIMSS ADT: 59 KTS AT 270915Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 25-30 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: LOW INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC VERNON IS EXPECTED TO TURN TOWARD THE SOUTHWEST AFTER COMPLETING THE BINARY INTERACTION WITH 93S. AFTER TAU 12, THE STR TO THE SOUTHEAST WILL RESUME STEERING AND DRIVE THE SYSTEM SOUTHWESTWARD FOR THE REMAINDER OF THE FORECAST. AS THE CYCLONE TRACKS POLEWARD, THE HIGH VWS, THEN THE INFLUX OF COOL DRY AIR IN THE LOWER LEVELS, AND COOLING SST WILL CONTRIBUTE TO A GRADUAL WEAKENING - DOWN TO 55KTS BY TAU 120. MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT WITH THE TRACK FORECAST. HOWEVER, THERE ARE DIFFERENCES IN THE TIMING AS TO WHEN THE VORTEX WILL EXIT FROM THE COL AND BEGIN ITS SOUTHWESTWARD TRACK. THIS UNCERTAINTY WILL ALSO AFFECT THE INTENSITY FORECAST. IN VIEW OF THIS, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: LOW TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN