WDPN31 PGTW 291500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 21W (SINLAKU) WARNING 
NR 14//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
  TROPICAL STORM (TS) 21W (SINLAKU), LOCATED APPROXIMATELY 199 NM
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT
08 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE 
IMAGERY DEPICTS A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION CENTER 
(LLCC) WITH DEEP CONVECTIVE BANDING DISPLACED OVER THE WESTERN SEMI-
CIRCLE OF THE LLCC. A 290907Z SSMIS 91 GHZ IMAGE DEPICTS DEEP 
CONVECTIVE BANDING OVER THE WESTERN QUADRANT WITH TIGHTLY-WRAPPED 
SHALLOW BANDING ELSEWHERE, WRAPPING INTO A WELL-DEFINED CENTER. 
OVERALL, THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION. THE 
INITIAL INTENSITY OF 50 KNOTS IS BASED ON DVORAK INTENSITY ESTIMATES 
RANGING FROM 45 TO 55 KNOTS. UPPER-LEVEL ANALYSIS INDICATES MODERATE 
(15 KNOTS) EASTERLY VERTICAL WIND SHEAR OFFSET BY DIFFLUENT FLOW. TS 
SINLAKU IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF THE 
SUBTROPICAL RIDGE. 
3. FORECAST REASONING.
   A. NO CHANGE TO FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC 
REASONING MESSAGE.
   B. TS SINLAKU IS FORECAST TO TRACK WESTWARD THROUGH THE FORECAST 
PERIOD AND WILL MAKE LANDFALL NEAR TAU 06 THEN TRACK INLAND, 
DISSIPATING RAPIDLY. THE DYNAMIC MODELS ARE IN TIGHT AGREEMENT, 
THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST.//
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