WDPN32 PGTW 241500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 33W (USAGI) WARNING NR 26//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON 33W (USAGI), LOCATED APPROXIMATELY 110 NM SOUTHEAST OF HO
CHI MINH CITY, VI, HAS TRACKED WESTWARD AT 06 KNOTS OVER THE PAST
SIX
HOURS. THE INITIAL POSITION IS PLACED WITH POOR CONFIDENCE USING
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY WHICH SHOWS SIGNIFICANT
DECAY IN THE CONVECTIVE STRUCTURE NEAR THE OBSCURED LOW LEVEL
CIRCULATION CENTER (LLCC). THE INITIAL INTENSITY OF 65 KNOTS IS
CONSISTENT WITH MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF
T4.0 (65 KNOTS). DESPITE LOW (10-15 KT) VERTICAL WIND SHEAR, WARM
(27-28 CELSIUS) SEA SURFACE TEMPERATURE, AND GOOD EQUATORWARD
OUTFLOW, DRY AIR ENTRAINMENT FROM THE NORTHWEST HAS LED TO THE
CYCLONE WEAKENING. TY 33W IS TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. AFTER TAU 36, TY 33W WILL TURN MORE WESTWARD AS THE CYCLONE
WEAKENS AND A SHALLOW STR TO THE NORTH BEGINS TO DOMINATE THE
STEERING. THE CYCLONE WILL MAKE LANDFALL NEAR HO CHI MINH CITY JUST
PRIOR TO TAU 24. DRY AIR ENTRAINMENT AND LAND INTERACTION WILL CAUSE
THE CYCLONE TO DISSIPATE BY TAU 48. THE REMNANTS OF TY 33W WILL
EMERGE OVER THE GULF OF THAILAND AFTER TAU 48 AND THERE IS A SLIGHT
CHANCE IT COULD RE-INTENSIFY. THE JTWC FORECAST TRACK IS PLACED
NEAR,
BUT SLIGHTLY FASTER THAN, THE MULTI-MODEL CONSENSUS WITH LOW
CONFIDENCE DUE TO POOR AGREEMENT IN THE NUMERICAL MODELS.//
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