WDPN32 PGTW 191500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W WARNING NR 20//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TYPHOON (TY) 19W (SONCA), LOCATED APPROXIMATELY 395 NM EAST-
SOUTHEAST OF MISAWA, HAS TRACKED NORTHEASTWARD AT 26 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY SHOWS A
COMPACT SYSTEM WITH A SMALL, IRREGULAR EYE WITH WEAKENING CONVECTION,
ESPECIALLY ALONG THE NORTHERN PERIPHERY. THE INITIAL POSITION IS
BASED ON THE IR IMAGERY WITH GOOD CONFIDENCE. THE INITIAL INTENSITY
IS BASED ON PGTW, KNES, AND RJTD DVORAK ESTIMATES. WATER VAPOR
IMAGERY SHOWS THE SYSTEM IS FAST BECOMING ASYMMETRICAL AS IT BECAME
EXPOSED TO THE STRONG WESTERLIES. THE SYSTEM HAS CRESTED THE WESTERN
EDGE OF THE DEEP-LAYERED SUBTROPICAL RIDGE TO THE EAST AND RECURVED
TOWARD EXTRA-TROPICAL TRANSITION.
3. FORECAST REASONING
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING BULLETIN.
   B. TY 19W WILL CONTINUE TO ACCELERATE NORTHEASTWARD AND BECOME
EMBEDDED IN THE BAROCLINIC ZONE, BECOMING A COLD CORE LOW BY TAU 36.
IT WILL STEADILY WEAKEN AS VERTICAL WIND SHEAR INCREASES AND SEA
SURFACE TEMPERATURES DECREASE. THE AVAILABLE NUMERICAL MODEL 
GUIDANCE IS IN EXCELLENT AGREEMENT. THIS TRACK FORECAST IS IN LINE
WITH BUT SLIGHTLY FASTER THAN MODEL CONSENSUS TO ACCOUNT FOR KNOWN
MODEL TENDENCY TO SLOW DOWN DURINGH EXTRA-TROPICAL TRANSITION.//
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