Tropical Storm SINLAKU Advisory Sun Aug 02

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (SINLAKU) WARNING NR
004//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 04W (SINLAKU), LOCATED APPROXIMATELY 121 NM SOUTH
OF HANOI, VIETNAM, HAS TRACKED WESTWARD AT 07 KNOTS (KTS) OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A BROAD
LOW LEVEL CIRCULATION CENTER (LLCC) WITH FRAGMENTED DEEP CONVECTIVE
BANDING OVER THE WESTERN SEMICIRCLE. BASED ON THE MSI AND AN
EXTRAPOLATION OF A 012036Z GMI 89 GHZ MICROWAVE IMAGE SHOWING A BROAD
LLCC, THERE IS FAIR CONFIDENCE IN THE INITIAL POSITION. THE INITIAL
INTENSITY IS SET AT 35 KTS, SLIGHTLY HIGHER THAN A DVORAK CURRENT
INTENSITY ESTIMATE OF T2.0 (30 KTS) BY RJTD AND LOWER THAN A SUBJECTIVE
DVORAK INTENSITY ESTIMATE OF T2.9 (43 KTS). THE ENVIRONMENT REMAINS
MARGINALLY FAVORABLE WITH HIGH (>25 KTS) NORTHEASTERLY VERTICAL WIND
SHEAR (VWS) OFFSETTING THE WARM (>30 CELSIUS) SEA SURFACE TEMPERATURES
AND GOOD UPPER LEVEL OUTFLOW. TS 04W IS CURRENTLY TRACKING WESTWARD
ALONG THE PERIPHERY OF THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH.
3. FORECAST REASONING.
  A. NO CHANGE IN FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC
REASONING MESSAGE.
  B. TS 04W IS EXPECTED TO TRACK WEST-NORTHWESTWARD THROUGHOUT THE
FORECAST PERIOD, MAKING LANDFALL OVER VIETNAM PRIOR TO TAU 12. AS THE
SYSTEM TRANSITS OVER THE WARM WATERS OF THE GULF OF TONKIN, TS 04W IS
FORECAST TO WEAKEN DUE TO THE PERSISTENT NORTHEASTERLY VWS (25-30 KTS)
AND LAND INTERACTION. UPON LANDFALL, THE SYSTEM WILL STEADILY WEAKEN AS
IT TRACKS INLAND OVER MOUNTAINOUS TERRAIN. DISSIPATION IS ANTICIPATED BY
TAU 36, IF NOT SOONER. THERE IS GOOD CONFIDENCE IN THE JTWC TRACK
FORECAST WHICH IS PLACED NEAR THE MULTI-MODEL CONSENSUS.//
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