WDPN31 PGTW 041500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (GONI) WARNING NR 031// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 22W (GONI), LOCATED APPROXIMATELY 269 NM EAST- SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP, SYMMETRIC FLARING CONVECTION SHEARED TO THE NORTHWEST. THE INITIAL POSITION IS ASSESSED WITH MODERATE CONFIDENCE BASED ON AN EXTRAPOLATION OF A WEAK LLCC EVIDENT IN A 041048Z SSMIS 37 GHZ MICROWAVE IMAGE, AS THE LLCC IS NOT READILY EVIDENT IN THE LOW-RESOLUTION INFRARED IMAGERY. THE INITIAL INTENSITY REMAINS SET AT 35 KNOTS WITH MODERATE CONFIDENCE HEDGED SLIGHTLY LOWER THAN THE PGTW T3.0 (45 KNOTS) TOWARDS THE RJTD ESTIMATE OF T2.5, AND THE RAW ADT ESTIMATE OF T2.4. THE ENVIRONMENT REMAINS MARGINAL, THOUGH THE IMPRESSIVE FLARE UP IN CONVECTION OVER THE PAST COUPLE OF HOURS INDICATES THE DIVERGENT NATURE OF THE WESTWARD OUTFLOW, BUT SHEAR REMAINS MODERATE (15-20 KNOTS), AS CONFIRMED BY THE CONVECTIVE BLOOM SHEARED OFF TO THE NORTHWEST. SSTS REMAIN WARM (27-28 DEG CELSIUS) BUT WILL DECREASE CLOSER TO THE COAST. THE SYSTEM IS TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYER STR TO THE NORTH. 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 WESTWARD, TRACKING ALONG THE SOUTHERN PERIPHERY OF THE STR. TS 22W IS FORECAST TO MAKE LANDFALL BY TAU 36 ALONG THE SOUTH CENTRAL COAST OF VIETNAM, AND WILL CONTINUE TO TRACK SOUTHWESTWARD TOWARDS CAMBODIA. NO CHANGE IS FORECAST IN THE INTENSITY THROUGH LANDFALL, WITH THE SYSTEM MAKING LANDFALL AS A WEAK TROPICAL STORM, BEFORE DISSIPATING OVER RUGGED TERRAIN. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH LANDFALL, WITH INCREASING SPREAD THEREAFTER AS THE MODELS LOSE THE LOW LEVEL VORTEX WITH THE EXCEPTION OF NAVGEM, WHICH CONTINUES TO TRACK THE SYSTEM UNREALISTICALLY POLEWARD AND THE GFS, WHICH NOW TRACKS THE SYSTEM STRAIGHT SOUTHWEST THROUGH TAU 72. THE JTWC FORECAST LIES JUST SOUTH OF THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.// NNNN