Tropical Storm PABUK Advisory gio, 26.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W (PABUK) WARNING NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 19W (PABUK), LOCATED APPROXIMATELY 259 NM SOUTHEAST OF
YOKOSUKA, JAPAN, HAS TRACKED NORTHEASTWARD AT 19 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE
LOW LEVEL CIRCULATION CENTER (LLCC) HAS BEEN ACCELERATING TO THE
NORTHEAST OVER THE PAST 12 HOURS. DEEP CONVECTION ALONG THE SOUTHERN
HALF OF THE SYSTEM HAS SEEN SIGNIFICANT WEAKENING OVER THE PAST SIX
HOURS AS THE EFFECTS OF THE UPPER LEVEL TROUGH TO THE WEST HAS
STARTED TO IMPACT THE SOUTHWESTERN QUADRANT, INCREASING THE VERTICAL
WIND SHEAR (VWS) OVER THE LLCC. THE CURRENT INTENSITY HAS BEEN
DECREASED TO 80 KNOTS OVER THE PAST SIX HOURS AS THE VWS HAS
INCREASED. DVORAK ESTIMATES STILL INDICATE TY 19W REMAINS A STRONG
TYPHOON, BUT SUPPORT THE RECENT WEAKENING OBSERVED IN MSI AS THE
SYSTEM IS STARTING TO FEEL THE EFFECTS OF THE BAROCLINIC ZONE TO THE
NORTHWEST. THE TOTAL PRECIPITABLE WATER IS NOW INDICATING A SLIGHT
ELONGATION OF THE SYSTEM TO THE NORTHEAST. AS THE TROUGH TRACKS
EASTWARD, THE INTERACTION WITH THE SUBTROPICAL RIDGE (STR) TO THE
SOUTHEAST HAS ENHANCED THE GRADIENT FLOW IN THE MID-LEVELS, LEADING
TO AN ACCELERATION OF TY 19W OVER THE PAST 12 HOURS.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 19W IS FORECAST TO REMAIN ON A NORTHEAST TRACK UNDER THE
INFLUENCE OF THE STR AND THE MID-LATITUDE TROUGH OVER JAPAN.
DECREASING SEA SURFACE TEMPERATURES AND INCREASING VWS WITH THE
APPROACHING MID-LATITUDE TROUGH WILL QUICKLY DEGRADE THE STRUCTURE
OF TY 19W. COLD AIR ADVECTION ASSOCIATED WITH THE TROUGH WILL CAUSE
EXTRA-TROPICAL TRANSITION TO BEGIN WITHIN THE NEXT 06 TO 12 HOURS,
WITH THE SYSTEM EXPECTED TO BE FULLY EXTRA-TROPICAL BY TAU 36. MODEL
GUIDANCE REMAINS IN VERY TIGHT AGREEMENT THROUGHOUT THE FORECAST,
LEADING TO HIGH CONFIDENCE IN THE FORECAST TRACK.//
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