MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (SON-TINH) WARNING NR 05// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 24W (SON-TINH), LOCATED APPROXIMATELY 215 NM SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) SHOWS A LARGE SYSTEM WITH IMPROVED DEEP CONVECTIVE BANDING, WRAPPING AROUND A LOW LEVEL CIRCULATION CENTER (LLCC) WITH BUILDING CENTRAL CONVECTION. THE INITIAL POSITION IS BASED ON THE EIR ANIMATION AND SATELLITE FIXES FROM RJTD AND PGTW, WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS BASED ON CONGRUENT DVORAK ESTIMATES FROM ALL AGENCIES. UPPER LEVEL ANALYSIS INDICATES A POINT SOURCE ANTICYCLONE IS OVER THE SYSTEM AND IS PROVIDING GOOD RADIAL OUTFLOW. A MID-LATITUDE TROUGH TO THE NORTH AND A TROPICAL UPPER TROPOSPHERIC TROUGH TO THE EAST HAVE BEEN AMPLIFYING THE POLEWARD AND EASTWARD PORTIONS OF THE RADIAL OUTFLOW. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. INTENSITY HAS BEEN INCREASED DUE TO TS 24W IS NO LONGER EXPECTED TO ENCOUNTER THE COLD DRY AIR FROM THE NORTHEASTERLY FLOW. B. TS 24W IS EXPECTED TO BE STEERED BY THE STR THROUGHOUT ITS LIFESPAN, TRACKING OUT THE CENTRAL ISLANDS OF THE PHILIPPINES INTO THE SOUTH CHINA SEA (SCS) BY TAU 24. AFTER TAU 24, TS 24W WILL CONTINUE ON NORTH-NORTHWEST TRACK, STEADILY INTENSIFYING AS IT REMAINS IN A FAVORABLE ENVIRONMENT OF HIGH (28-30 DEGREES CELSIUS) SEA SURFACE TEMPERATURES AND FAVORABLE UPPER LEVEL SUPPORT. DYNAMIC MODELS REMAIN IN VERY TIGHT AGREEMENT, LEADING TO HIGH FORECAST CONFIDENCE. C. AFTER TAU 72, TS 24W WILL MAKE LANDFALL ALONG THE NORTHERN COAST OF VIETNAM, JUST SOUTH OF HANOI. AFTER LANDFALL, TS 24W WILL DISSIPATE AS IT SLOWS IN TRANSLATIONAL SPEED AND ENCOUNTERS THE FRICTIONAL EFFECTS OF LAND. DUE TO THE WELL UNDERSTOOD STEERING ENVIRONMENT AND TIGHT MODEL AGREEMENT, THERE IS HIGH CONFIDENCE IN THE TRACK FORECAST.// NNNN NNNN