WDPN31 PGTW 270300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (SANVU) WARNING NR 24// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 03W (SANVU), LOCATED APPROXIMATELY 160 NM EAST OF CHICHI JIMA, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN EXPOSED, ELONGATED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH ISOLATED BURSTS OF DEEP CONVECTION OVER THE EASTERN SEMI-CIRCLE. MSI ALSO SHOWS THAT THE LLCC HAS BEGUN TO INTERACT WITH A BROAD BAROCLINIC ZONE TO THE NORTH AND COOL (DRY) AIR STRATOCUMULUS IS EVIDENT OVER THE WESTERN SEMI-CIRCLE. A 262059Z CORIOLIS 37H GHZ IMAGE DEPICTS A WELL-DEFINED, SHALLOW LLCC WITH TIGHTLY-CURVED CONVECTIVE BANDING WRAPPING INTO THE CENTER. THEREFORE, THERE IS GOOD CONFIDENCE IN THE CURRENT POSITION AND RECENT TRACK. UPPER-LEVEL ANALYSIS INDICATES THAT THE LLCC IS LOCATED WITHIN THE MIDLATITUDE WESTERLY FLOW AND IS UNDER STRONG VERTICAL WIND SHEAR (VWS) OF 25-30 KNOTS. THE CURRENT INTENSITY IS ASSESSED AT 50 KNOTS BASED ON AN AVERAGE OF DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM 45 TO 55 KNOTS FROM PGTW AND KNES. TS 03W IS TRACKING WITHIN RELATIVELY WEAK WESTERLY FLOW LOCATED NORTH OF THE SUBTROPICAL STEERING RIDGE. 3. FORECAST REASONING. A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TS 03W IS FORECAST TO ACCELERATE ALONG THE NORTHERN PERIPHERY OF THE SUBTROPICAL STEERING RIDGE THROUGH THE FORECAST PERIOD. TS 03W WILL CONTINUE TO WEAKEN DUE TO INCREASING VWS (GREATER THAN 40 KNOTS) AND COLDER SST (LESS THAN 22C). THE SYSTEM HAS CLEARLY COMMENCED EXTRA-TROPICAL TRANSITION (ETT) AND SHOULD COMPLETE ETT BY TAU 24. THE SYSTEM IS EXPECTED TO TRANSITION INTO A GALE-FORCE EXTRA-TROPICAL LOW. DYNAMIC GUIDANCE HAS REMAINED IN TIGHT AGREEMENT INCLUDING ENSEMBLE DATA, THEREFORE, THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.// NNNN