WDPN31 PGTW 150300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 27W (DOLPHIN) WARNING NR 19//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TYPHOON (TY) 27W (DOLPHIN) HAS SLOWED DOWN AND BEGUN
TO TURN WEST-NORTHWESTWARD OVER THE PAST 12 HOURS. DURING THE LAST
06 HOURS, TS DOLPHIN HAS INTENSIFIED SLIGHTLY AS CONVECTIVE BANDING
AROUND THE LOW LEVEL CIRCULATION CENTER (LLCC) DEEPENED AS EVIDENCED
BY THE COLDER TOPS ON INFRARED SATELLITE IMAGERY. ANIMATED WATER 
VAPOR IMAGERY SHOWS VERY GOOD RADIAL OUTFLOW OVER TY 27W WITH THE 
CONVECTIVE AREA ELONGATED NORTH-NORTHEAST TO SOUTH-SOUTHWEST.
   B. THE CURRENT INTENSITY IS DERIVED FROM RECENT SATELLITE 
INTENSITY FIXES FROM KNES, RJTD AND PGTW THAT RANGED FROM 45 TO 65 
KNOTS. THE POSITION IS BASED ON ANIMATED SATELLITE IMAGERY AND 
MICROWAVE IMAGES, INCLUDING TRMM AND AMSR-E, SHOWING A WARM SPOT 
OVER THE LLCC. UPPER LEVEL ANALYSIS INDICATES THAT A MESOSCALE 
ANTICYCLONE REMAINS OVER TY 27W PROVIDING EFFICIENT OUTFLOW. THE 
ANTICYCLONE IS ALSO TEMPERING INCREASED VERTICAL WIND SHEAR AHEAD OF 
AN APPROACHING MID-LATITUDE TROUGH THAT APPEARS TO BE CAUSING THE 
ELONGATION OF THE CONVECTION.
3. FORECAST REASONING.
   A. THE FORECAST PHILOSOPHY HAS NOT CHANGED SINCE THE PREVIOUS
FORECAST.
   B. TYPHOON DOLPHIN WILL CONTINUE TO TRACK WEST-NORTHWEST BECOMING 
MORE NORTHWEST TOWARDS A WEAKNESS IN THE STEERING RIDGE CAUSEDBY THE 
AFOREMENTIONED MID-LATITUDE TROUGH. THE STORM WILL GRADUALLY WEAKEN 
AS IT DRIFTS INTO A SURGE OF COOL DRY NORTHEAST MONSOON WINDS 
EXTENDING ALL THE WAY INTO THE PHILIPPINE SEA. THE RATE OF DECAY OF 
TS 27W WILL DETERMINE THE SHARPNESS OF ITS RECURVATURE. A 
WEAKER/SHALLOWER STORM WILL TEND TO BE RETARDED BY GRADIENT LEVEL 
WINDS AND FROM A SHARPER, MORE NORTHERLY TRACK.
   C. TY 27W IS EXPECTED TO DISSIPATE AS A SIGNIFICANT TROPICAL 
CYCLONE IN THE NORTHERN PHILIPPINE SEA BEYOND TAU 72 AS VERTICAL 
WIND SHEAR INCREASES.
FORECAST TEAM: ALPHA//
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