Tropical Storm TORAJI Advisory 11月17日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 32W (TORAJI)
WARNING NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 32W (TORAJI), LOCATED APPROXIMATELY 254
NM EAST OF HO CHI MINH CITY, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD
AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS A LARGE CLUSTER OF PERSISTENT DEEP
CONVECTION OVER THE NORTHWEST QUADRANT OF AN EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC). A 171038Z SSMIS 37GHZ COLOR COMPOSITE
IMAGE INDICATES TIGHTLY-CURVED BANDING OVER THE NORTHERN SEMICIRCLE
WRAPPING INTO THE WESTERN QUADRANT OF THE SYSTEM WITH A MORE DEFINED
LLCC, WHICH SUPPORTS THE CURRENT POSITION WITH GOOD CONFIDENCE.
UPPER-LEVEL ANALYSIS INDICATES MODERATE TO STRONG (20 TO 25 KNOTS)
VERTICAL WIND SHEAR OFFSET BY A VIGOROUS POLEWARD OUTFLOW CHANNEL
AND STRONG DIFFLUENCE ALOFT. THE CURRENT INTENSITY IS ASSESSED AT 30
KNOTS BASED ON A RJTD DVORAK ESTIMATE OF T2.0 (30 KNOTS). RECENT
SHIP OBSERVATIONS OVER THE NORTHERN SEMICIRCLE CONTINUE TO SHOW 30
TO 35 KNOT WINDS ASSOCIATED WITH THE AFOREMENTIONED DEEP CONVECTIVE
BANDING. TD 32W IS CURRENTLY TRACKING WEST-NORTHWESTWARD UNDER THE
STEERING INFLUENCE OF A LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING MESSAGE AND SETS THE
FORECAST PHILOSOPHY.
   B. TD 32W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD
THROUGH TAU 12 TOWARD A BREAK IN THE STR, WHICH SEPARATES THE
EASTERN AND WESTERN SUBTROPICAL RIDGES. AFTER TAU 12, TD 32W WILL
TRACK UNDER THE WESTERN STR, WHICH WILL PRODUCE A WEST-SOUTHWESTWARD
TRACK THROUGH TAU 48. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT,
THEREFORE, THERE IS LOW CONFIDENCE (HIGH UNCERTAINTY) IN THE EXACT
FORECAST TRACK. TD 32W IS FORECAST TO INTENSIFY TO TROPICAL STORM
STRENGTH BY TAU 12 BUT IS EXPECTED TO WEAKEN SLIGHTLY AS IT
APPROACHES THE SOUTHEASTERN COAST OF VIETNAM AND MAKES LANDFALL NEAR
TAU 24. AFTER TAU 24, TD 32W WILL WEAKEN DUE TO INCREASED FRICTIONAL
EFFECTS OVER LAND WITH DISSIPATION EXPECTED BY TAU 48. THE REMNANTS
OF THE SYSTEM MAY REGENERATE OVER THE GULF OF THAILAND AFTER TAU
48.//
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