Tropical Storm CHAN-HOM Advisory 12 Ιουλ.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (CHAN-HOM) WARNING NR 46//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 09W (CHAN-HOM), LOCATED APPROXIMATELY 298 NM
SOUTH-SOUTHWEST OF KUNSAN AB, SOUTH KOREA, HAS TRACKED
NORTH-NORTHEASTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED
ENHANCED IR IMAGERY SHOWS SIGNIFICANT WEAKENING OF THE SYSTEM AS
EVIDENCED BY SHEARING AND CONVECTIVE EROSION ESPECIALLY ALONG THE
NORTHERN FLANK. THE INITIAL POSITION IS BASED ON THE IR LOOP AND
EXTRAPOLATED FROM RECENT MICROWAVE IMAGERY. THE INITIAL INTENSITY OF
65 KNOTS IS BASED ON AN ASSESSMENT OF ALL AGENCY DVORAK ESTIMATES AND
REFLECTS THE SYSTEMS DEGRADATION. UPPER-LEVEL ANALYSIS INDICATES THE
SYSTEM HAS DRIFTED INTO THE COLD YELLOW SEA IN AN AREA OF MODERATE TO
STRONG (20-30 KNOT) VWS. HOWEVER, THERE REMAINS A STRONG OUTFLOW
CHANNEL THAT IS PROVIDING VENTILATION TO THE WANING CONVECTION. AT
THE SURFACE, ALONG-TRACK SSTS HAVE DIPPED TO BELOW 25 CELSIUS. THE
CYCLONE HAS ROUNDED THE WESTERN EDGE OF THE STEERING STR AND IS NOW
ACCELERATING NORTHEASTWARD.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY CHANG-HOM IS EXPECTED TO CONTINUE ACCELERATING NORTHEASTWARD
THROUGH THE REMAINDER OF THE FORECAST PERIOD. IT WILL MAKE LANDFALL
OVER NORTH KOREA, JUST NORTH OF THE DMZ, JUST PRIOR TO TAU 24, THEN
DISSIPATE OVER THE RUGGED HAMGYONG MOUNTAINS BY TAU 36.
TY 09W WILL WEAKEN AT A RELATIVELY FAST RATE DUE TO INCREASING VWS
AND COOLING SSTS; BY THE TIME IT MAKES LANDFALL, IT WILL BE AT
MINIMAL TROPICAL STORM INTENSITY. HOWEVER, THE CYCLONE PACKS A LARGE
WIND RADIUS AND IS STILL EXPECTED TO USHER IN A WIDE SWATH OF
GALE-FORCE WINDS INTO THE WEST COAST OF KOREA. THE NUMERIC MODELS
HAVE COME INTO A TIGHTER AGREEMENT, LENDING HIGH CONFIDENCE TO THE
JTWC TRACK FORECAST.//
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