WDPN31 PGTW 260300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (SON-TINH) WARNING NR 10// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 24W (SON-TINH), LOCATED APPROXIMATELY 500 NM EAST OF HUE, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES CONTINUED IMPROVING DEEP CENTRAL CONVECTION WRAPPING INTO A DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH STRONG FORMATIVE BANDING OVER THE NORTHERN PERIPHERY. A PARTIAL 252240 SSMIS 91 GHZ AND A 252249Z CORIOLIS 37 GHZ MICROWAVE IMAGES REVEAL OVERALL IMPROVING STORM STRUCTURE CONSISTENT WITH A STRENGTHENING STORM. THE INITIAL POSITION IS BASED ON THE MSI AND MICROWAVE IMAGES WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 55 KNOTS BASED ON THE IMPROVING STORM STRUCTURE AND CONGRUENT DVORAK ESTIMATES FROM PGTW AND KNES. ANIMATED WATER VAPOR IMAGERY DEPICTS GOOD RADIAL OUTFLOW WITH A POLEWARD BIAS WHICH BEING ENHANCED BY THE WESTERLIES TO THE NORTH AND A TUTT CELL LOCATED TO THE EAST. TS 24W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL STEERING RIDGE TO THE NORTH. 3. FORECAST REASONING. A. TS 24W IS NOW FORECASTED TO INTENSIFY AT A HIGHER RATE DUE TO OVERALL IMPROVING STRUCTURE AND FAVORABLE ENVIRONMENTAL CONDITIONS THROUGH OUT THE FORECAST. B. TS 24W IS FORECAST TO TRACK WEST-NORTHWESTWARD THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE DEEP SUBTROPICAL RIDGE POSITIONED TO THE NORTH. TS 24W WILL INTENSIFY TO A PEAK OF 85 KNOTS BY TAU 36 AND MAINTAIN THAT STRENGTH THROUGH TAU 48 AS IT ENTERS THE GULF OF TONKIN DUE TO THE FAVORABLE ENVIRONMENTAL CONDITIONS OF WEAK VERTICAL WIND SHEAR, GOOD OUTFLOW AND WARM SEA SURFACE TEMPERATURES. TS 24W SHOULD MAKE LANDFALL INTO NORTHERN VIETNAM SHORTLY AFTER TAU 48 AND BEGIN TO WEAKEN DUE TO THE FRICTIONAL EFFECTS OF LAND. C. IN THE EXTENDED TAUS, TS 24W IS EXPECTED TO DISSIPATE AS IT SLOWS AND ENCOUNTERS THE MOUNTAINOUS TERRAIN OF NORTHERN VIETNAM. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT AND IS CONSISTENT WITH PREVIOUS FORECAST. THERE IS HIGH CONFIDENCE IN THE OVERALL FORECAST TRACK DUE TO THE WELL UNDERSTOOD ENVIRONMENT.// NNNN