MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 013// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 09W (BAVI), LOCATED APPROXIMATELY 412 NM SOUTH- SOUTHWEST OF CHINHAE, SOUTH KOREA, HAS TRACKED NORTH- NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A COMPACT SYSTEM WITH DENSE, SUSTAINED CONVECTION WRAPPING AROUND A TRANSIENT EYE WHICH HAS DEVELOPED AND FILLED OVER THE PAST 6 HOURS. THE CURRENT POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE PRESENT IN THE EIR AND COMPOSITE RADAR LOOPS AND ON THE MICROWAVE EYE FEATURE PRESENT IN A 241003Z SSMIS 97 GHZ IMAGE. THE CURRENT INTENSITY IS PLACED WITH FAIR CONFIDENCE BASED ON A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T5.0(90KTS). THE STRONG CONVECTIVE SIGNATURE AND EYE DEVELOPMENT IN THE EIR LOOP OVER THE PAST 6 HOURS SUPPORT AN INTENSITY CLOSER TO THE HIGHER END OF THE DVORAK INTENSITY ESTIMATE. TY BAVI HAS CONTINUED TO TRACK ALONG THE WESTERN PERIPHERY OF A BUILDING SUBTROPICAL RIDGE POSITIONED TO THE EAST AND HAS CONTINUED TO INTENSIFY OVER THE PAST SIX HOURS DUE TO THE CONTINUED FAVORABLE ENVIRONMENT OF LOW (10-15 KNOTS) VERTICAL WIND SHEAR (VWS), VERY WARM (29-30C) SEA SURFACE TEMPERATURES (SSTS) AND ESTABLISHED EQUATORWARD OUTFLOW ALOFT. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 09W WILL CONTINUE TO TRACK POLEWARD OVER THE NEXT 72 HOURS ALONG THE WESTERN PERIPHERY OF THE BUILDING SUBTROPICAL RIDGE TO THE EAST. THE ENVIRONMENT WILL MOVE FROM FAVORABLE TO MARGINALLY FAVORABLE OVER THE NEXT 12 HOURS DUE TO INCREASING, MODERATE (15-25 KTS) VWS AND CONVERGENT FLOW ALONG THE NORTHERN PERIPHERY OF THE SYSTEM. DESPITE THIS, CONTINUED VERY WARM SSTS WILL ALLOW THE SYSTEM TO TO INTENSIFY TO 105 KTS DURING THIS DECREASING VWS THEREAFTER ALONG WITH CONTINUED WARM SSTS WILL ALLOW THE SYSTEM TO INTENSIFY FURTHER TO 115 KTS BY TAU 24. AS THE SYSTEM ROUNDS THE STEERING RIDGE AND CONTINUES TO TRACK POLEWARD, IT WILL BEGIN TO ENCOUNTER COOLING SSTS AND INCREASING VWS, WHICH WILL LEAD TO GRADUAL WEAKENING TO 85 KTS BY TAU 48. THEREAFTER, THE SYSTEM WILL MAKE LANDFALL OVER THE KOREAN PENINSULA AND TRACK INLAND OVER MAINLAND CHINA. INTERACTION WITH AN INCOMING TROUGH IN THE UPPER LEVELS AND THE UNDERLYING TERRAIN WILL CAUSE THE SYSTEM TO WEAKEN TO 40 KTS BY TAU 72. ADDITIONALLY, IT WILL BEGIN EXTRATROPICAL TRANSITION BY THIS TIME AS IT BECOMES EMBEDDED IN THE BAROCLINIC ZONE. NUMERICAL MODEL TRACK SOLUTIONS ARE IN TIGHT AGREEMENT WITH A CROSS TRACK SPREAD OF 66 NM AT TAU 48 INCREASING TO 208 NM BY TAU 72. MODEL SOLUTIONS HAVE CLUSTERED ABOUT THE JTWC MULTI-MODEL CONSENSUS WITH GFS, NAVGEM AND UK MODELS TO THE WEST AND JGSM, GFS ENSEMBLE AND ECMWF MODEL SOLUTIONS TO THE EAST. NONE OF THE AVAILABLE MODEL SOLUTIONS INDICATE STORM CENTER PASSAGE OVER SOUTH KOREA, BUT THE EASTERN GROUP DOES CARRY THE STORM CENTER ALONG THE WESTERN SHORE. THE JTWC MULTI-MODEL CONSENSUS HAS BEEN HIGHLY CONSISTENT FOR MULTIPLE MODEL RUNS. THE INITIAL PORTION OF THE JTWC FORECAST TRACK IS THEREFORE PLACED WITH HIGH CONFIDENCE AS IT IS SITUATED NEAR THE CONSENSUS AND NEAR PREVIOUS JTWC FORECAST TRACKS. C. AS THE SYSTEM TRACKS OVER MAINLAND CHINA, IT WILL ACCELERATE POLEWARD AS IT BECOMES FULLY EMBEDDED IN THE BAROCLINIC ZONE. RAPID WEAKENING IS ANTICIPATED DUE TO UNFAVORABLE UPPER-LEVEL CONDITIONS AND THE FRICTIONAL EFFECTS OF LAND. THE SYSTEM WILL COMPLETE EXTRATROPICAL TRANSITION BY TAU 96 AS IT BECOMES EMBEDDED IN THE DEEP WESTERLY FLOW ALOFT. NUMERICAL MODEL SOLUTIONS BIFURCATE AFTER TAU 72 WITH A CROSS TRACK SPREAD > 1000 NM AT TAU 96. DESPITE THIS HIGH DEGREE OF SPREAD IN THE FINAL PORTION OF THE FORECAST TRACK, THERE REMAINS HIGH CONFIDENCE IN THE OVERALL JTWC FORECAST TRACK DUE TO THE TIGHT PACKING OF MODEL SOLUTIONS OVERALL. NNNN NNNN