Tropical Storm HAGUPIT Advisory 8月4日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 03W (HAGUPIT) WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 03W (HAGUPIT), LOCATED APPROXIMATELY 203 NM SOUTH OF
SHANGHAI, CHINA, HAS TRACKED NORTH-NORTHWESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
SHOWS A 17NM ELONGATED AND RAGGED EYE WITH COMPACT, ALBEIT DEEP, SPIRAL
BANDING OVER THE SOUTHERN SEMICIRCLE WRAPPING INTO THE EYEWALL. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE DEFINED
EYE FEATURES IN EIR AND COMPOSITE RADAR LOOPS. THE SYSTEM IS ABOUT TO
MAKE LANDFALL INTO WENZHOU CITY, CHINA. THE INITIAL INTENSITY OF 70
KNOTS IS BASED ON THE WEAKENING DVORAK INTENSITY ESTIMATES OF T4.0/4.5
(65/77KTS) FROM PGTW AND RCTP AND CONSISTENT WITH NEARBY SURFACE
OBSERVATIONS. DESPITE THE IMMINENT LANDFALL INTO CHINA, PERSISTENT
NORTHERLY VWS, AND CONVERGENCE ALOFT OVER THE NORTHERN PERIPHERY, TY
03W HAS REMAINED SOLID WITH MINIMAL DEGRADATION PRIMARILY DUE TO ROBUST
EQUATORWARD OUTFLOW EVIDENT IN ANIMATED WATER VAPOR IMAGERY. TY 03W IS
TRACKING ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL
RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY HAGUPIT WILL TRACK MORE NORTHWARD OVER THE RAGGED TERRAIN OF
EASTERN CHINA WEST OF SHANGHAI AS IT ROUNDS THE STR AXIS. SHORTLY AFTER
TAU 30, IT WILL EXIT INTO THE YELLOW SEA AND ACCELERATE NORTHEASTWARD.
STRONG VWS AND LAND INTERACTION WILL RAPIDLY ERODE THE SYSTEM DOWN TO
35KTS BEFORE EXITING BACK INTO WATER. THE ADDITION OF COOL SST IN THE
YELLOW SEA WILL LEAD TO DISSIPATION BY TAU 48, POSSIBLY SOONER, AS IT
APPROACHES NORTH KOREA. NUMERICAL MODELS ARE IN TIGHT AGREEMENT BUT
GIVEN THE UNCERTAINTY OF LAND PASSAGE, THERE IS MODERATE CONFIDENCE IN
THE FORECAST TRACK, WHICH IS POSITIONED NEAR THE MULTI-MODEL
CONSENSUS.//
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