MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (KROSA) WARNING NR 035// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 11W (KROSA), LOCATED APPROXIMATELY 298 NM SOUTH OF IWAKUNI, JAPAN, HAS TRACKED NORTHWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A BROAD SYSTEM WITH A RAGGED, EXPOSED LOW LEVEL CENTER (LLC) AND A THICK BAND OF DEEP CONVECTION TO THE SOUTH THAT IS NOW FRAGMENTING. THE INITIAL POSITION IS BASED ON THE CENTROID OF ROTATION IN THE MSI IMAGERY WITH FAIR CONFIDENCE, AS THERE ARE ALSO MULTIPLE SMALLER MESOVORTICES EVIDENT. THE INITIAL INTENSITY OF 50 KNOTS IS HEDGED SLIGHTLY BELOW THE PGTW AND RJTD DVORAK CURRENT INTENSITY ESTIMATES OF T3.5 (55 KTS) AND IN CLOSE AGREEMENT WITH A 140357Z SATCON ESTIMATE OF 53 KTS AND A 140530Z AUTOMATED DVORAK INTENSITY ESTIMATE OF T3.1 (47 KTS). A 140132Z METOP-B PARTIAL ASCAT PASS SHOWS THE SYSTEM HAS MAINTAINED AN EXTREMELY BROAD WIND FIELD, WITH BANDS OF 45-49 KT WINDS DISPLACED 80 NM FROM THE CENTER. OBSERVATIONS FROM 130-245NM AWAY ALONG THE JAPANESE COAST REPORT SUSTAINED WINDS AROUND 30 KTS AND PRESSURES FROM 986-992 MB, DEMONSTRATING THE EXPANSIVE WIND FIELD; HOWEVER, OTHER COASTAL OBSERVATIONS ARE IN THE 20-30 KT RANGE, AS THE GALE-FORCE WINDS ARE NOT CONTINUOUSLY WRAPPED AROUND THE SYSTEM. UPPER LEVEL ANALYSIS INDICATES AN OVERALL MARGINAL ENVIRONMENT WITH AN UPPER LEVEL LOW DIRECTLY OVER THE LLC, WHICH IS INHIBITING CENTRAL CONVECTION. HOWEVER, UPPER LEVEL OUTFLOW HAS RECENTLY INCREASED AS TS 11W BEGINS TO TAP INTO AN APPROACHING MIDLATITUDE TROUGH TO ITS WEST, AND THE EQUATORWARD OUTFLOW CHANNEL REMAINS EXCELLENT. SEA SURFACE TEMPERATURES (SST) REMAIN CONDUCIVE (28-29 DEGREES CELSIUS). THE CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY OF AN EXTENSION OF THE SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. OVER THE NEXT 24 HOURS, TS 11W WILL CONTINUE ON ITS CURRENT TRACK AS IT ROUNDS THE WESTERN PERIPHERY OF THE AFOREMENTIONED STR. NEAR TAU 24, A MIDLATITUDE TROUGH WILL APPROACH FROM THE WEST, ERODING THE STR AND ALLOWING TS 11W TO RECURVE POLEWARD AROUND THE STR AXIS. INCREASING POLEWARD OUTFLOW AHEAD OF THE AFOREMENTIONED TROUGH WILL COMPETE WITH UNFAVORABLE LAND INTERACTION TO MAINTAIN A 45 KT INTENSITY BETWEEN TAU 24 AND 36 AS TS 11W CROSSES OVER SHIKOKU AND HONSHU. INCREASINGLY UNFAVORABLE (20-30 KNOTS) VERTICAL WIND SHEAR (VWS) AND COOLER SSTS (22-25 DEGREES CELSIUS) IN THE SEA OF JAPAN (SOJ) WILL COMBINE TO WEAKEN THE SYSTEM GRADUALLY DOWN TO 35 KNOTS BY TAU 72 AS IT TRACKS THROUGH THE SOJ. MODELS ARE IN FAIR CROSS-TRACK AGREEMENT, WITH NAVGEM THE EASTERN OUTLIER FEATURING A TIGHTER RECURVE. THE JTWC FORECAST TRACK IS HEDGED SLIGHTLY WEST OF THE MULTI-MODEL CONSENSUS TOWARDS THE ECMWF, UKMET, AND GALWEM SOLUTIONS. THE GFS SOLUTION IS IN LINE WITH, BUT FASTER THAN, THE MULTI-MODEL CONSENSUS. TS 11W WILL BEGIN EXTRATROPICAL TRANSITION AS IT INTERACTS WITH THE AFOREMENTIONED TROUGH AND IS EXPECTED TO BECOME FULLY EXTRATROPICAL AS IT APPROACHES HOKKAIDO NEAR TAU 72. THERE IS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK FOR THIS PORTION OF THE FORECAST.// NNNN NNNN