MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 30W (PHANFONE) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 30W (PHANFONE), LOCATED APPROXIMATELY 914 NM EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST- NORTHWESTWARD AT 13 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM HAS BECOME MORE COMPACT WHILE MAINTAINING DEEP FLARING CENTRAL CONVECTION THAT REMAINS OFFSET NORTHWESTWARD OF THE LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLC IN THE EIR LOOP. THE INITIAL INTENSITY OF 35KTS IS BASED ON THE DVORAK ESTIMATES OF T2.5/35KTS FROM PGTW AND RJTD. ANALYSES INDICATE AN OVERALL FAVORABLE ENVIRONMENT WITH MODERATE (20KT) RELATIVE VERTICAL WIND SHEAR (VWS) THAT IS OFFSET BY ROBUST GOOD WESTWARD AND POLEWARD OUTFLOW AND VERY WARM (>30C) SST IN THE PHILIPPINE SEA. THE CYCLONE IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE LAST PROGNOSTIC REASONING MESSAGE. B. TS 30W WILL CONTINUE ON ITS CURRENT TRACK FOR THE DURATION OF THE FORECAST. THE FAVORABLE ENVIRONMENT WILL FUEL STEADY INTENSIFICATION REACHING TYPHOON STRENGTH BY TAU 36 BEFORE MAKING LANDFALL OVER THE ISLAND OF SAMAR, PHILIPPINES, AND DRAG ACROSS THE VISAYAN ISLANDS BEFORE EXITING INTO THE SOUTH CHINA SEA (SCS) PRIOR TO TAU 72. THE SYSTEM WILL CONTINUE TO GRADUALLY INTENSIFY, IMPEDED ONLY BY ISLAND INTERACTION, REACHING 70KTS BY TAU 72. C. AFTER TAU 72, TS PHANFONE WILL SLOW DOWN AND WEAKEN AS IT ENCOUNTERS INCREASING VWS AND RELATIVELY COOLER NORTHERLY DRY AIR IN THE SCS. BY TAU 120, THE SYSTEM WILL BE REDUCED TO 45KTS, ALBEIT WITH AN EXPANDING WIND FIELD ALONG THE NORTHERN FLANK DUE TO THE INCREASED GRADIENT WINDS. THE NUMERICAL MODELS REMAIN IN TIGHT AGREEMENT WITH MINIMAL SPREADING TO 200 NM BY TAU 120, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN