Tropical Storm KAI-TAK Advisory 12月16日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 32W (KAI-TAK)
WARNING NR 09//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 32W (KAI-TAK), LOCATED APPROXIMATELY 386 NM
EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT
08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS THE SYSTEM HAS UNDERGONE A DEEP CONVECTIVE
DIURNAL MAXIMUM WITH OVERSHOOTING CLOUD TOP TEMPERATURES BELOW -80C
AT THEIR COLDEST. HOWEVER, OVER THE LAST FEW HOURS, THE DEEP
CONVECTION HAS SINCE COLLAPSED, EXPOSING THE LOW-LEVEL
CIRCULATION CENTER (LLCC) ONCE AGAIN. THE INITIAL POSITION IS BASED
ON THE EXPOSED LLCC IN THE EIR LOOP WITH HIGH CONFIDENCE. THE INITIAL
INTENSITY OF 45 KNOTS IS BASED ON A PGTW DVORAK ESTIMATE OF T3.0.
UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT
WITH STRONG (30 TO 35 KNOT) EASTERLY VERTICAL WIND SHEAR (VWS) OFFSET
BY STRONG DIFFLUENCE ALOFT. TS 32W IS NOW TRACKING ALONG THE
SOUTHWEST PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 32W WILL FLATTEN ON A WESTWARD THEN WEST-SOUTHWESTWARD TRACK
AS THE STR TO THE NORTHWEST ASSUMES STEERING. THE UPPER LEVEL
DYNAMICS WILL PREVAIL, HOWEVER, INTERACTION WITH THE VISAYAN ISLANDS
WILL WEAKEN THE SYSTEM DOWN TO 35 KNOTS BY TAU 48. BY TAU 72, THE
CYCLONE WILL EXIT INTO THE SOUTH CHINA SEA (SCS) JUST WEST OF
PALAWAN.
   C. AFTER TAU 72, THE STEERING STR IS FORECAST TO BUILD AND DRIVE
TS KAI-TAK MORE SOUTHWESTWARD AS IT INTERACTS WITH A STRONG
NORTHEASTERLY SURGE EVENT IN THE SCS. SLIGHT RE-INTENSIFICATION IS
EXPECTED BUT THIS IS PRIMARILY DUE TO THE NORTHEAST SURGE FLOW. THE
WIND SURGE WILL ALSO EXPAND THE 35-KNOT WIND RADII. DISSIPATION IS
ANTICIPATED AFTER TAU 120 AS THE SYSTEM BECOMES EMBEDDED WITHIN THE
STRONG NORTHEAST FLOW. DYNAMIC MODEL TRACKERS REMAIN IN EXCEPTIONALLY
TIGHT AGREEMENT, HOWEVER, THERE ARE SOME DIFFERENCES IN THE SPEED OF
ADVANCE. OVERALL, THERE IS FAIR CONFIDENCE IN THE JTWC TRACK
FORECAST.//
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