Tropical Storm KAI-TAK Advisory Qui, 21-12

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 32W (KAI-TAK)
WARNING NR 30//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 32W (KAI-TAK), LOCATED APPROXIMATELY 286 NM
SOUTH-SOUTHEAST OF HO CHI MINH CITY, VI, HAS TRACKED WEST-
SOUTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS PERSISTENT DEEP
CONVECTION DISPLACED INTO THE WESTERN SEMI-CIRCLE OF A RAGGED,
PARTLY EXPOSED LOW-LEVEL CIRCULATION. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON ANALYSIS OF THE MUTLI-SPECTRAL LOOP
AND IS SUPPORTED BY A 210213Z 89GHZ AMSU MICROWAVE IMAGE. THE
MICROWAVE IMAGE ALSO CONFIRMS THE DISPLACEMENT OF THE DEEP
CONVECTION TO THE WEST WITH THE STRONGEST CONVECTION IN THE
NORTHWEST QUADRANT. THE INITIAL INTENSITY OF 30 KNOTS IS BASED ON
MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T2.0 (30 KTS) BY
BOTH PGTW AND RJTD. SUPPORTED BY SURFACE OBSERVATIONS. UPPER-LEVEL
ANALYSIS REVEALS THAT CONDITIONS REMAIN MARGINALLY FAVORABLE WITH
MODERATE (15-20 KNOTS) VERTICAL WIND SHEAR AND WEAK DIFFLUENCE
ALOFT. SEA SURFACE TEMPERATURES ALONG THE TRACK ARE MARGINALLY
FAVORABLE AT 26-27 DEGREES CELSIUS. TD 32W IS TRACKING ALONG THE
SOUTHERN EXTENT OF THE SUBTROPICAL STEERING RIDGE LOCATED TO THE
NORTH AND IN-STREAM WITH THE NORTHEASTERLY WIND SURGE IN THE SOUTH
CHINA SEA.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY SINCE
THE LAST PROGNOSTIC REASONING MESSAGE.
   B. TD 32W WILL CONTINUE TO TRACK WEST-SOUTHWESTWARD FOR THE
DURATION OF THE FORECAST PERIOD. THE SYSTEM WILL MAINTAIN THE
INITIAL INTENSITY OF 30 KNOTS THROUGH TAU 12 DUE TO MARGINALLY
FAVORABLE ENVIRONMENTAL CONDITIONS. AFTER TAU 12, INCREASING
VERTICAL WIND SHEAR AND DISSIPATION OF THE NORTHEASTERLY COLD SURGE
WILL BEGIN TO GRADUALLY WEAKEN THE SYSTEM. THE SYSTEM IS FORECAST TO
COMPLETELY DISSIPATE OVER WATER BY TAU 36. AVAILABLE DYNAMIC MODEL
GUIDANCE IS IN STRONG AGREEMENT LENDING HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK.//
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