WDPN31 PGTW 211500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (OMAIS) WARNING NR 037// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 22.7N 127.1E INITIAL INTENSITY: 50 KTS GEOGRAPHIC REFERENCE: 231 NM SOUTH OF KADENA AB, OKINAWA, JAPAN MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 16 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS SLIGHT IMPROVEMENT AS THE COMPACT FEEDER BANDS WRAPPED TIGHTER INTO THE LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE USING LOW CLOUD TRACING IN THE EIR LOOP INTO A PARTLY OBSCURED LLCC. THE INITIAL INTENSITY IS PLACED WITH HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE 6-HR IMPROVEMENT IN THE EIR SIGNATURE. ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH LOW TO MEDIUM VWS, WARM SSTS, AND MODERATE RADIAL OUTFLOW OFFSET BY SUBSIDENCE ALONG THE NORTHWESTERN FLANK AHEAD OF A MID-LATITUDE TROUGH. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED STR TO THE NORTHEAST. INITIAL WIND RADII BASIS: PERSISTENCE, EXPANDED SLIGHTLY USING NEARBY SURFACE WIND OBSERVATIONS. CURRENT STEERING MECHANISM: DEEP LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T2.5 - 35 KTS KNES: T3.5 - 55 KTS CIMSS ADT: 53 KTS AT 211150Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE TERMINATION OF THE FORECAST HAS BEEN CHANGED TO EXTRA-TROPICAL, OTHERWISE, THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 16W WILL TURN MORE NORTHWARD AS IT ROUNDS THE WESTERN EDGE OF THE STR AND CREST THE STR AXIS BY TAU 18 IN THE EAST CHINA SEA. AFTERWARD, IT WILL ACCELERATE NORTH- NORTHEASTWARD, CROSS SOUTH KOREA, AND BY TAU 72 WILL EXIT INTO THE SEA OF JAPAN (SOJ). THE MARGINALLY FAVORABLE ENVIRONMENT WILL FUEL A SLIGHT INTENSIFICATION TO A PEAK OF 55KTS AT TAU 12. AFTERWARD, INCREASING VWS ON THE BACK SIDE OF THE AFOREMENTIONED MIDLATITUDE TROUGH AND LAND INTERACTION WILL GRADUALLY ERODE THE SYSTEM DOWN TO 30KTS BY TAU 72. CONCURRENTLY AT TAU 48, IT WILL BEGIN EXTRA-TROPICAL TRANSITION AS IT ENTERS THE COLD BAROCLINIC ZONE THEN TRANSFORM INTO A NEAR-GALE COLD-CORE LOW BY TAU 72 IN THE COLDER WATERS OF THE SOJ. MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH THE EXCEPTION OF AFUM, THE LEFT-OF-TRACK OUTLIER DRIVING THE VORTEX INTO THE CHINESE COAST. THE JTWC TRACK FORECAST IS LAID WITH MEDIUM CONFIDENCE JUST TO THE RIGHT AND SLIGHTLY AHEAD OF THE MODEL CONSENSUS TO OFFSET AFUM. THERE IS ALSO MEDIUM CONFIDENCE IN THE INTENSITY FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM// NNNN