Tropical Storm RAMMASUN Advisory Fri Jul 18

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (RAMMASUN) WARNING NR 33//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 09W (RAMMASUN), LOCATED APPROXIMATELY 250 NM EAST OF
HANOI, HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX
HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE
EYE HAS BEGUN TO DEVOLVE AND BECOME LESS CLEAR AS THE TYPHOON
TRACKS THROUGH THE HAINAN STRAIT. DVORAK INTENSITY ESTIMATES FROM
ALL AGENCIES HAVE DECREASED OVER THE PAST SIX HOURS LEADING TO AN
INITIAL INTENSITY OF 125 KNOTS. THE INITIAL POSITION IS BASED UPON
THE EYE FEATURE IN THE EIR LOOP WITH HIGH CONFIDENCE. TY 09W IS
STEADILY TRACKING WEST-NORTHWEST ALONG THE SOUTHWESTERN PERIPHERY
OF THE SUBTROPICAL RIDGE (STR) EXTENDING OVER SOUTH EAST CHINA.
3. FORECAST REASONING.
   A. NO CHANGE TO FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 09W IS FORECAST TO CONTINUE NORTHWESTWARD AS THE STR
INFLUENCES THE TROPICAL CYCLONE FOR THE REMAINDER OF THE FORECAST.
WHILE THE UPPER LEVEL ENVIRONMENT STILL SUPPORTS THE SYSTEM AND SEA
SURFACE TEMPERATURES IN THE GULF OF TONKIN ARE FAVORABLE, THE
SYSTEM WILL TRACK INTO SOUTHERN CHINA, WHICH WILL CAUSE RAPID
WEAKENING DUE TO FRICTIONAL EFFECTS OF THE REGION WITH COMPLETE
DISSIPATION OF THE SYSTEM BY TAU 36. NUMERIC MODEL GUIDANCE IS IN
VERY TIGHT AGREEMENT WITH THE TRACK FORECAST, WHICH IS POSITIONED
WITH HIGH CONFIDENCE.//
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