WDPN31 PGTW 030300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (GONI) WARNING NR 025// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 22W (GONI), LOCATED APPROXIMATELY 417 NM EAST OF DA NANG, VIETNAM, HAS TRACKED WEST-SOUTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH FLARING CONVECTION JUST NORTHWEST OF THE CENTER. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED NATURE OF THE LLCC. THE INITIAL INTENSITY OF 35KTS IS BASED ON A DVORAK ESTIMATE OF T2.5/35KTS FROM PGTW, KNES AND RJTD, HEDGING JUST BELOW AN ADT OF 39KTS AT 022340Z. ENVIRONMENTAL ANALYSIS INDICATES A MARGINAL ENVIRONMENT FOR FURTHER DEVELOPMENT WITH MODERATE (15-25 KTS) VERTICAL WIND SHEAR (VWS) PARTIALLY OFFSET BY DECENT WESTWARD OUTFLOW AND WARM (28C) SEA SURFACE TEMPERATURE (SST). THE SYSTEM IS TRACKING THROUGH THE SOUTH CHINA SEA STEERED BY A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHWEST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 22W WILL CONTINUE TO TRACK WEST-SOUTHWESTWARD THROUGH TAU 72, MAKING LANDFALL IN VIETNAM AROUND TAU 68. THE ENVIRONMENT WILL REMAIN MARGINAL WITH MODERATE VWS PERSISTING AND MINIMAL UPPER LEVEL OUTFLOW EXPECTED TO INHIBIT ANY FURTHER INTENSIFICATION. THE VWS, COOLING SST, AND INTERACTION WITH THE LAND AS IT NEARS VIETNAM WILL GRADUALLY WEAKEN THE SYSTEM AFTER TAU 36 LEADING TO DISSIPATION OVER VIETNAM BY TAU 72. NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A GRADUAL AND EVEN SPREAD TO 200NM BY TAU 72, LENDING FAIR CONFIDENCE TO THE JTWC FORECAST TRACK. THERE IS A DISTINCT POSSIBILITY THAT TS 22W WILL DISSIPATE OVER WATER PRIOR TO LANDFALL DUE TO MODERATE VWS AND COOLING SST OVERCOMING THE MINIMAL OUTFLOW.// NNNN