Tropical Storm CHOI-WAN Advisory Per, 03.06.

SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (CHOI-WAN)
WARNING NR 017//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 04W (CHOI-WAN), LOCATED APPROXIMATELY 72
NM WEST-NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT
14 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY (EIR) SHOWS TD 04W (CHOI-WAN) BECOMING SLIGHTLY
DISORGANIZED IN THE EASTERN PERIPHERY DUE TO INTERACTION WITH THE
PHILIPPINES WITH DEEP CONVECTION TO THE NORTHWEST AND SOUTH OF THE
LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED
WITH FAIR CONFIDENCE BASED ON LOW CLOUD TRACING IN THE EIR LOOP AND
SHORE-BASED WEATHER OBSERVATIONS FROM MANILLA AND SUBIC BAY. THE
INITIAL INTENSITY OF 30KTS IS SET WITH FAIR CONFIDENCE BASED ON THE
AFOREMENTIONED OBSERVATIONS AND AN OVERALL ASSESSMENT OF DVORAK
ESTIMATES OF T2.0/30KTS (PGTW), T2.7/39KTS (ADT), AND SATELLITE
CONSENSUS (SATCON) OF 44 KTS. TD 04W (CHOI-WAN) IS IN A MARGINAL
ENVIRONMENT WITH GOOD WESTWARD AND EQUATORWARD OUTFLOW AND VERY WARM
(30-31C) SEA SURFACE TEMPERATURES (SST), OFFSET BY MARGINAL (15-
20KTS) VERTICAL WIND SHEAR. THE CYCLONE IS TRACKING ALONG THE
SOUTHWEST PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE EAST-
NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 04W WILL CONTINUE TO TRACK NORTH-NORTHWESTWARD OVER THE
NEXT 24 HOURS UNDER THE STEERING INFLUENCE OF THE STR. THE SYSTEM IS
FORECAST TO INTENSIFY TO 35KTS UNDER THE AFOREMENTIONED MARGINAL
CONDITIONS AS IT APPROACHES THE RIDGE AXIS. BY TAU 36, TD 04W (CHOI-
WAN) WILL BEGIN RAPIDLY DISSIPATING DUE TO LACK OF UPPER LEVEL
SUPPORT AND UNFAVORABLE VWS DUE TO CONSISTENT EASTERLY FLOW FROM
ANTI-CYCLONIC FEATURE LOCATED OVER SOUTHERN CHINA. BY TAU 48, THE
SYSTEM WILL BECOME FULLY DISSIPATED. THE FORECAST TRACK IS LAID IN
GOOD AGREEMENT WITH MODEL CONSENSUS FOR THE FIRST 24 HOURS. AFTER
TAU 24, THE FORECAST TRACK IS MORE TO THE RIGHT OF FORECAST
CONSENSUS TO OFFSET NAVGEM BEING THE EXTREME LEFT OUTLIER WITH A
NORTH-NORTHEASTWARD TRACK TOWARD THE WESTERN PORTION OF TAIWAN.//
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