WDPN31 PGTW 101500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (SARIKA) WARNING NR 07// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL STORM (TS) 05W (SARIKA), LOCATED APPROXIMATELY 160 NM EAST-SOUTHEAST OF HONG KONG, CHINA, HAS TRACKED NORTHWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY SHOWS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER 35NM TO THE NORTHEAST OF THE DEEP CONVECTION. THE INITIAL POSITION WAS BASED ON THE IR IMAGERY WITH HIGH CONFIDENCE. THE INITIAL INTENSITY WAS BASED ON A 996MB SHIP OBSERVATION 40 NM AWAY. ANIMATED WATER VAPOR IMAGERY SHOWS A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) LOCATED JUST NORTH OF THE SYSTEM IS CAUSING SUBSIDENCE ALOFT AND MODERATE NORTHEASTERLY VERTICAL WIND SHEAR (VWS) OF 25 TO 30 KNOTS. TS SARIKA IS CURRENTLY STEERING ALONG THE WESTERN PERIPHERY OF A LOW- TO MID- LEVEL SUBTROPICAL STEERING RIDGE. 3. FORECAST REASONING. A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TS 05W IS EXPECTED TO CONTINUE ROUNDING THE STEERING RIDGE AXIS BEFORE MAKING LANDFALL EAST OF HONG KONG, CHINA WITHIN THE NEXT 12 HOURS. DUE TO THE MODERATE VWS, TS 05W SHOULD MAINTAIN INTENSITY BEFORE LAND INTERACTION CAUSES THE SYSTEM TO RAPIDLY WEAKEN AND DISSIPATE BY TAU 36. AFTER LANDFALL, REMNANTS OF THE SYSTEM WILL TRACK TO THE NORTHEAST, AHEAD OF A TRANSITORY MID-LATITUDE SHORTWAVE TROUGH. THE AVAILABLE NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT. THEREFORE, THIS FORECAST REMAINS CONSISTENT WITH THE PREVIOUS JTWC FORECAST TRACK AND IS CLOSE TO MODEL CONSENSUS.// NNNN