MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (FENGSHEN) WARNING NR 08// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 13W (FENGSHEN), LOCATED APPROXIMATELY 233 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 16 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TIGHTLY-CURVED BANDING OVER THE NORTHERN PERIPHERY WRAPPING INTO A WELL-DEFINED LLCC AND A CLOUD FILLED EYE FEATURE. A 081810Z TRMM MICROWAVE IMAGE ALSO REVEALS A MICROWAVE EYE WITH THE MAJORITY OF THE DEEP CONVECTION OVER THE NORTHERN SEMI-CIRCLE. THE CURRENT POSITION IS BASED ON THE EIR ANIMATION AND MICROWAVE IMAGE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 60 KNOTS IS BASED ON DVORAK INTENSITY ESTIMATES AND A 081210Z ASCAT PASS. UPPER-LEVEL ANALYSIS INDICATES TS FENGSHEN CONTINUES TO HAVE EXCELLENT POLEWARD OUTFLOW DUE TO A MID-LEVEL JET TO THE NORTHEAST OF THE SYSTEM, WHICH OFFSETS THE HIGH LEVELS (40 TO 50 KNOTS) OF VERTICAL WIND SHEAR. TS 13W CONTINUES TO TRACK ALONG THE NORTHERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE (STR) WITHIN A MID-LATITUDE TROUGH NORTH OF THE SYSTEM. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 13W WILL CONTINUE TO TRACK NORTHEASTWARD ALONG THE STR THROUGHOUT THE FORECAST PERIOD AS IT CONTINUES TO BECOME EXTRATROPICAL (XT). INDICATION OF A SLIGHT WARMING OF THE LOWER LEVELS BASED ON AN AMSU CROSS SECTION SHOWS THE SYSTEM STARTING TO BECOME BAROCLINIC AND DEVELOPING A WEAK WARM FRONTAL PATTERN. FENGSHEN WILL CONTINUE TO BECOME XT AS THE WESTERLIES CONTINUE TO ENVELOP THE SYSTEM THROUGH TAU 24, COMPLETING XT BY TAU 36. THIS WILL BE ACCOMPANIED BY GREATER TRACK SPEEDS AND GRADUAL WEAKENING IN INTENSITY. MODELS ARE IN VERY GOOD AGREEMENT, LEADING TO HIGH CONFIDENCE IN THE JTWC FORECAST.// NNNN NNNN