WDPN32 PGTW 070900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FOURTEEN) WARNING NR 004// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.0N 134.8E INITIAL INTENSITY: 45 KTS GEOGRAPHIC REFERENCE: 690 NM SOUTHEAST OF KADENA AB, OKINAWA, JAPAN MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 14 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A MEDIUM-SIZED DEVELOPING SYSTEM WITH DEEPENING FORMATIVE BANDS FEEDING INTO A RAGGED CENTRAL DENSE OVERCAST THAT CONTINUES TO OBSCURE THE LOW LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE USING LOW CLOUD TRACING IN THE MSI LOOP INTO A NOTCH FEATURE IN THE 07530Z ENHANCED INFRARED SATELLITE IMAGE AND 070448Z ATMS MICROWAVE PASS. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE PGTW DVORAK ESTIMATE AND REFLECTS THE 6-HR STRUCTURAL IMPROVEMENT. THE ENVIRONMENT REMAINS HIGHLY FAVORABLE WITH WARM SST WITH HIGH OHC, STRONG EQUATORWARD OUTFLOW, AND LOW VWS. INITIAL WIND RADII BASIS: PERSISTENCE. CURRENT STEERING MECHANISM: MID-LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTHWEST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T1.5 - 25 KTS CIMSS SATCON: 41 KTS AT 070358Z CIMSS ADT: 37 KTS AT 070250Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 30-31 CELSIUS OUTFLOW: STRONG EQUATORWARD 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: TS 14W WILL BEGIN TO TRACK MORE WEST- NORTHWESTWARD THEN NORTHWESTWARD AS THE STR THE EAST BUILDS AND ASSUMES STEERING. THE HIGHLY FAVORABLE ENVIRONMENT WILL FUEL A STEADY THEN RAPID INTENSIFICATION TO A PEAK OF 120KTS BY TAU 72. AFTERWARD, INCREASING VWS WILL BEGIN TO SLOWLY ERODE THE SYSTEM AND BY TAU 120 WILL BE DOWN TO 100KTS. AFTER TAU 96, A DEEP MIDLATITUDE SHORTWAVE TROUGH WILL DIG OVER EASTERN CHINA AND WEAKEN THE STR, ALLOWING THE SYSTEM TO TRACK MORE POLEWARD OF NORTHWESTWARD. MODEL DISCUSSION: NUMERICAL MODELS ARE IN GENERAL AGREEMENT BUT SPREAD OUT SIGNIFICANTLY, ALBEIT EVENLY, TO OVER 400NM BY TAU 120 WITH UEMN ON THE LEFT AND AEMN ON THE RIGHT MARGIN OF THE ENVELOPE. IN VIEW OF THIS, THERE IS MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID CLOSE TO THE MODEL CONSENSUS. THERE IS ALSO MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN