MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (IN-FA) WARNING NR 34// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 27W (IN-FA), LOCATED APPROXIMATELY 411 NM SOUTHWEST OF IWO TO, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE ASSOCIATED DEEP CONVECTION SHEARED OVER THE NORTHEAST, PARTLY EXPOSING THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS BASED ON THE MSI WITH GOOD CONFIDENCE. THE INITIAL INTENSITY OF 45 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF DVORAK INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES AND REFLECTS THE DETERIORATING STATE OF THE SYSTEM. UPPER LEVEL ANALYSIS INDICATES TS IN-FA IS LOCATED IN AN AREA OF STRONG (30 TO 40 KNOTS) SOUTHWESTERLY VERTICAL WIND SHEAR; HOWEVER. VIGOROUS POLEWARD OUTFLOW IS SUSTAINING THE WANING DEEP CONVECTION. THE CYCLONE IS TRACKING ALONG THE NORTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS IN-FA WILL CONTINUE TRACKING NORTHEASTWARD DEEPER INTO THE STRONG MIDLATITUDE WESTERLIES. THE SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) BY TAU 12 AS IT ENTERS THE COLD BAROCLINIC ZONE. TS 27W SHOULD COMPLETE ETT BY THE END OF THE FORECAST PERIOD AS IT GAINS FRONTAL CHARACTERISTICS. DYNAMIC GUIDANCE IS IN TIGHT AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN