Tropical Storm CHAN-HOM Advisory dim, 12.07.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (CHAN-HOM) WARNING
NR 47//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 09W (CHAN-HOM), LOCATED APPROXIMATELY 292 NM
SOUTH-SOUTHWEST OF YONGSAN AIN, SOUTH KOREA, HAS TRACKED NORTH-
NORTHEASTWARD AT 17 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS SIGNIFICANT WEAKENING OF
THE SYSTEM EVIDENCED BY SHEARING AND CONVECTIVE EROSION. THE INITIAL
POSITION IS BASED ON THE MSI LOOP AND ON A MICROWAVE EYE FEATURE IN
THE 112300Z F18 91V IMAGE WITH HIGH CONFIDENCE. THE INITIAL
INTENSITY OF 55 KNOTS IS BASED ON AN ASSESSMENT OF ALL AGENCY DVORAK
ESTIMATES AND REFLECTS THE SYSTEMS DEGRADATION. UPPER-LEVEL ANALYSIS
INDICATES THE SYSTEM HAS DRIFTED FURTHER INTO THE COLD YELLOW SEA IN
AN AREA OF MODERATE TO STRONG (20-30 KNOT) VWS. HOWEVER, A STRONG
POLEWARD OUTFLOW IS PROVIDING VENTILATION TO THE WANING CONVECTION.
AT THE SURFACE, ALONG-TRACK SSTS ARE BELOW 25 CELSIUS. THE CYCLONE
IS ACCELERATING NORTHEASTWARD ON THE POLEWARD SIDE OF THE STEERING
STR.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 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, SHORTLY AFTER TAU 12, THEN
DISSIPATE OVER THE RUGGED HAMGYONG MOUNTAINS BY TAU 24. TS 09W WILL
CONTINUE TO WEAKEN RAPIDLY 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 TO THE
WEST COAST OF KOREA. THE NUMERIC MODELS REMAIN IN TIGHT AGREEMENT,
LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST.//
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