WDPN31 PGTW 261500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (NOCK-TEN)// WARNING NR 10// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL STORM (TS) 10W (NOCK-TEN), LOCATED APPROXIMATELY 110 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED DEPTH AROUND ITS CENTRAL CONVECTION EVEN AS IT BRUSHED THE SOUTHERN PROVINCES OF LUZON. THE INITIAL POSITION IS BASED ON THE ABOVE ANIMATION AND TRIANGULATED FROM NEARBY OBSERVATIONS INCLUDING ONE FROM DAET, CAMARINES NORTE, JUST 23 NM TO THE SOUTHEAST. THE INITIAL INTENSITY IS SUPPORTED BY SAME OBSERVATIONS AND BY DVORAK ESTIMATES FROM PGTW, KNES, AND RJTD RANGING FROM 30 TO 40 KNOTS. UPPER LEVEL ANALYSIS INDICATES THE STORM IS NOW JUST OVER FIVE DEGREES TO THE SOUTHWEST OF A TROPICAL UPPER TROPOSPHERIC TROUGH CELL THAT HAS BEGUN TO PROVIDE A POLEWARD OUTFLOW CHANNEL. ADDITIONALLY, A NEAR-EQUATORIAL TROUGH TO THE SOUTHEAST IS ALSO ENHANCING EQUATORWARD OUTFLOW. THESE DYNAMICS ARE EVIDENT ON WATER VAPOR SATELLITE ANIMATION. VERTICAL WIND SHEAR (VWS) VALUES HAVE SLOWED TO 05-10 KNOTS. TS 10W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE ANCHORED TO THE EAST OF JAPAN. B. TS 10W IS EXPECTED TO CONTINUE ALONG THE AFOREMENTIONED TRACK AS IT MAKES LANDFALL NEAR LEGASPI CITY, THEN DRAGS OVER ROUGH TERRAIN JUST NORTH OF MANILA, BEFORE EXITING INTO THE SOUTH CHINA SEA BEFORE TAU 24. THE SYSTEM WILL GRADUALLY REINTENSIFY OVER WARM WATERS AND LIGHT VWS UNTIL IT APPROACHES HAINAN BEFORE TAU 72. C. TS NOCK-TEN WILL MAKE A SECONDARY LANDFALL - THIS TIME OVER HAINAN SHORTLY AFTER TAU 72. IT WILL WEAKEN TO A TROPICAL DEPRESSION WHEN IT EMERGES IN THE GULF OF TONKIN BY TAU 96. THE SYSTEM WILL MOMENTARILY INTENSIFY OVER THE GULF BEFORE MAKING A THIRD AND FINAL LANDFALL JUST SOUTH OF HANOI, VIETNAM. THE AVAILABLE NUMERICAL GUIDANCE IS IN TIGHT AGREEMENT WITH THE SOLE EXCEPTION OF NOGAPS THAT IS ERRONEOUSLY DEFLECTING THE VORTEX NORTHWESTWARD AFTER TAU 48. THIS TRACK FORECAST IS SLIGHTLY SLOWER AND TO THE SOUTH OF CONSENSUS.// NNNN