WDPN31 PGTW 191500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (KROVANH) WARNING 
NR 20//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 20W (KROVANH), LOCATED APPROXIMATELY 425 NM
SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHEASTWARD AT 15
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) 
SATELLITE IMAGERY AND A 191136Z METOP-A MICROWAVE IMAGE DEPICT THE 
SYSTEM HAS WEAKENED SIGNIFICANTLY WITH THE BULK OF THE DEEP 
CONVECTION SHEARED TO THE NORTHEAST DUE TO THE STRONG SOUTHWESTERLY 
VWS. THE CURRENT POSITION IS BASED ON THE EIR ANIMATION, MICROWAVE 
EYE FEATURE ON THE AFOREMENTIONED METOP-A IMAGE AND PGTW SATELLITE 
FIX WITH HIGH CONFIDENCE. THE INITIAL INTENSITY HAS LOWERED TO 60 
KNOTS BASED ON AN OVERALL DECREASE OF DVORAK INTENSITY ESTIMATES 
FROM ALL REPORTING AGENCIES AND WEAKENING STRUCTURE. UPPER-LEVEL 
ANALYSIS INDICATES KROVANH IS NOW LOCATED IN AN UNFAVORABLE 
ENVIRONMENT WITH STRONG (30+ KNOT) VWS PARTIALLY OFFSET BY VIGOROUS 
POLEWARD OUTFLOW. TS 20W IS TRACKING ALONG THE NORTHWESTERN 
PERIPHERY OF A DEEP-LAYERED STR.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 20W WILL REMAIN ON A NORTHEASTWARD TRAJECTORY THROUGH THE 
REMAINDER OF THE FORECAST PERIOD. CONTINUED STRONG VWS ASSOCIATED 
WITH THE MIDLATITUDE WESTERLIES AND DEGRADED ENVIRONMENTAL 
CONDITIONS WILL QUICKLY DECAY KROVANH AS IT TRANSITIONS TO EXTRA-
TROPICAL. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, LENDING 
TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS POSITIONED 
CLOSE TO MULTI-MODEL CONCENSUS.//
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