WDPN31 PGTW 050300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (GONI) WARNING NR 033// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 22W (GONI), LOCATED APPROXIMATELY 241 NM EAST-SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST- SOUTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH ASSOCIATED CONVECTION SHEARED 57 NM TO THE NORTHWEST. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE FULLY EXPOSED LLCC IN THE EIR LOOP AS WELL AS THE LOW LEVEL BANDING EVIDENT IN A TIMELY 042324Z SSMIS 37 GHZ IMAGE. THE INITIAL INTENSITY OF 40 KTS IS PLACED WITH FAIR CONFIDENCE BETWEEN MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T3.0 (45 KTS, PGTW) AND T2.5 (35 KTS, RJTD) AND HEDGED SLIGHTLY BELOW A 042256Z CIMSS SATELLITE CONSENSUS INTENSITY ESTIMATE OF 43 KTS. THE SYSTEM HAS CONTINUED TO TRACK WESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH AND THROUGH A MARGINAL ENVIRONMENT WITH MODERATE (15-20 KTS) VERTICAL WIND SHEAR (VWS) OFFSET SLIGHTLY BY THE DIVERGENT WESTWARD OUTFLOW ALOFT AND WARM (26-27 CELSIUS) SEA SURFACE TEMPERATURES. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THERE IS NO SIGNIFICANT CHANGE EXPECTED IN THE OVERALL FORECAST AS THE SYSTEM WILL CONTINUE TO TRACK GENERALLY WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR THROUGH THE ENTIRE FORECAST PERIOD WITH A SLIGHT WEST-SOUTHWESTWARD TRACK CHANGE AFTER TAU 24. DUE TO THE MODERATE VERTICAL WIND SHEAR OVER THE NEXT 48 HOURS, TS GONI WILL CONTINUE TO WEAKEN TO 30 KTS BY TAU 24 AT WHICH TIME IT WILL MAKE LANDFALL ALONG THE SOUTH CENTRAL COAST OF VIETNAM. THE SYSTEM WILL THEN BEGIN THE AFOREMENTIONED WEST-SOUTHWESTWARD TRACK TOWARDS CAMBODIA. INTERACTION WITH THE UNDERLYING TERRAIN WILL LEAD TO FURTHER WEAKENING TO 30 KTS BY TAU 36 AND LEAD TO FULL DISSIPATION OVER LAND BY TAU 48. DYNAMIC MODEL GUIDANCE IS IN FAIR AGREEMENT WITH A SPREAD IN SOLUTIONS OF 100 NM AT LANDFALL WHICH INCREASES TO 160 NM BY TAU 48. THIS FAIR AGREEMENT IN THE NUMERICAL MODEL TRACK GUIDANCE LENDS OVERALL FAIR CONFIDENCE IN THE JTWC FORECAST TRACK WHICH LIES JUST SOUTH OF THE MULTI-MODEL CONSENSUS.// NNNN