Tropical Storm SARIKA Advisory Wed Oct 19

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (SARIKA) WARNING NR
24//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 24W (SARIKA), LOCATED APPROXIMATELY 250 NM
EAST-SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT
9 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS SPIRAL BANDING WRAPPING INTO A DEFINED LOW
LEVEL CIRCULATION CENTER (LLCC), WITH SIGNS OF WEAKENING AS SARIKA
CROSSES OVER CENTRAL HAINAN ISLAND. THE INITIAL POSITION IS BASED ON
THE MSI AND FIXES FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THE
INITIAL INTENSITY IS ASSESSED AT 60 KNOTS BASED ON A CIMSS WIND
ANALYSIS AND ACCOUNTING FOR THE WEAKENING CONVECTIVE STRUCTURE DUE
TO LAND INTERACTION. UPPER-LEVEL ANALYSIS SHOWS GOOD RADIAL OUTFLOW
AHEAD OF AN APPROACHING SHORTWAVE TROUGH TO THE NORTHWEST, WITH LOW
(10 KNOTS) VERTICAL WIND SHEAR (VWS). CURRENTLY TS SARIKA IS
TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
   B. TS SARIKA WILL CONTINUE TO TRACK GENERALLY NORTHWESTWARD ALONG
THE STR OVER THE NEXT 12 HOURS, PRIOR TO FINAL LANDFALL. VWS WILL
INCREASE AS THE SHORTWAVE TROUGH PASSES, HOWEVER THE WEAKENING TREND
WILL BE PARTIALLY OFFSET BY GOOD OUTFLOW AND THE WARM 28 DEGREE
CELSIUS WATERS OF THE GULF OF TONKIN. AFTER LANDFALL, THE SYSTEM
WILL DISSIPATE DUE TO LAND EFFECTS AS SARIKA ROUNDS THE STR AND
TURNS TO THE NORTHEAST IN RESPONSE TO THE TROUGH. AVAILABLE MODEL
GUIDANCE IS IN GOOD AGREEMENT, LENDING HIGH CONFIDENCE TO THE JTWC
FORECAST TRACK.//
NNNN
NNNN