WDPN31 PGTW 121500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (CHAN-HOM) WARNING 
NR 49//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 09W (CHAN-HOM), LOCATED APPROXIMATELY 100 NM 
WEST-SOUTHWEST OF INCHON, SOUTH KOREA, HAS TRACKED NORTH-
NORTHEASTWARD AT 20 KNOTS OVER THE PAST SIX HOURS.  ANIMATED 
ENHANCED IR IMAGERY SHOWS CONTINUED DISSIPATION OF THE SYSTEM THAT 
APPEARS TO HAVE COMPLETELY UNRAVELED WITH AN EXPOSED LLCC AND NO 
CONVECTION IN THE SOUTHEAST QUADRANT.  A 121207Z AMSU-B IMAGE 
REVEALS THE DEEP CONVECTION IN THE NORTHEAST QUADRANT ONLY. THE 
INITIAL POSITION IS PLACED WITH LOW CONFIDENCE DUE TO THE 
DISORGANIZED NATURE OF THE SYSTEM. THE INTENSITY IS HELD AT 45 
KNOTS, HOWEVER, AS RECENT OBSERVATIONS OFF THE KOREAN COAST STILL 
HAVE SIGNIFICANT WINDS. THE 40 KNOTS OF SOUTHERLY VWS IS SLIGHTLY 
OFFSET BY GOOD POLEWARD OUTFLOW. TS 09W IS TRACKING ON THE NORTHWEST 
SIDE OF THE STR AXIS.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS CHAN-HOM WILL TRACK TO THE NORTHEAST AND ACCELERATE AROUND 
THE STR. THERE WILL BE CONTINUED DECAY THROUGHOUT THE FORECAST DUE 
TO LOW OHC, HIGH VWS AND LANDFALL. EXPECT COMPLETE DISSIPATION OF 
THE SYSTEM OVER THE COURSE OF THE FORECAST AS IT TRACKS OVER THE 
MOUNTAINOUS TERRAIN OF CENTRAL AND NORTHERN NORTH KOREA, WITH ITS 
TERMINUS IN THE FOOTHILLS OF THE MACH-OL RANGE. NUMERICAL DYNAMIC 
MODELS REMAIN IN TIGHT AGREEMENT, LEADING TO HIGH CONFIDENCE IN THE 
JTWC TRACK FORECAST.//
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