WDPN31 PGTW 180300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (DOLPHIN)
WARNING NR 31//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TROPICAL STORM (TS) 27W (DOLPHIN) HAS CONTINUED TO WEAKEN
AND ACCELERATE TO THE NORTHEAST OVER THE PAST 12 HOURS. VERTICAL 
WIND SHEAR AHEAD OF A DEEPENING UPPER LEVEL TROUGH APPROACHING
FROM THE NORTHWEST HAS AIDED IN THIS WEAKENING AND HAS ALSO LED
TO THE INCREASE IN FORWARD SPEED. OVERALL CONVECTION HAS SHALLOWED
CONSIDERABLY WITH ALL BUT A SMALL CENTRAL DENSE OVERCAST FEATURE
REMAINING. 
   B. THE CURRENT INTENSITY IS BASED ON RECENT SATELLITE INTENSITY
FIXES FROM RJTD AND PGTW THAT RANGED FROM 35 TO 45 KNOTS. VERTICAL
WIND SHEAR IS MODERATE TO HIGH UNDER THE INFLUENCE OF THE STRONG
MID-LATITUDE WESTERLIES NORTH OF THE SUBTROPICAL RIDGE AXIS. 
   A. THE FORECAST PHILOSOPHY HAS CHANGED SLIGHTLY SINCE THE
LAST PROG REASONING, WITH DISSIPATION OF TS 27W NOW EXPECTED 
JUST AFTER TAU 24.
   B. TS 27W WILL CONTINUE TO TRACK RAPIDLY EAST-NORTHEASTERLY
THROUGH TAU 12. AFTER THIS TIME THE SYSTEM WILL TRACK MORE EASTERLY
AND THE TRACK SPEED WILL SLOW, AS TS 27W TRACKS AT A LOWER STEERING
LEVEL.  TS 27W WILL CONTINUE TO WEAKEN UNDER THE COMBINED INFLUENCES
OF STRONG VERTICAL WIND SHEAR AND LOWER SEA SURFACE TEMPERATURES.
DISSIPATION WILL OCCUR SHORTLY AFTER TAU 24.
FORECAST TEAM: ALPHA//
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