WDPN31 PGTW 251500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (IN-FA) WARNING NR 
35//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 27W (IN-FA), LOCATED APPROXIMATELY 343 NM
SOUTHWEST OF IWO TO, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 12
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY
SHOWS THE ASSOCIATED DEEP CONVECTION CONTINUES TO BE SHEARED TO THE
NORTHEAST, PARTLY EXPOSING THE LOW-LEVEL CIRCULATION CENTER (LLCC).
THE INITIAL POSITION IS BASED ON THE ABOVE ANIMATION AND SUPPORTED BY
A 250924Z F17 MICROWAVE IMAGE. THE INITIAL INTENSITY OF 40 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.//
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