WDPN32 PGTW 100900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (VAMCO) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 25W (VAMCO), LOCATED APPROXIMATELY 413 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE SHOWS A CONSOLIDATING SYSTEM THAT HAS OVERALL IMPROVED AS EVIDENCED BY A DEEPENED CENTRAL CONVECTION AND RAIN BANDS THAT HAVE WRAPPED TIGHTER INTO A PARTIALLY EXPOSED LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON RAGGED BUT DEFINED LLC FEATURES IN THE 100420Z AMSR2 AND 100525 ATMS MICROWAVE IMAGES. THE INITIAL INTENSITY OF 40KTS IS AVERAGED FROM THE ADT ESTIMATE OF T3.0/45KTS AND PGTW/RJTD DVORAK ESTIMATES OF T2.5/35KTS AND REFLECTS THE SLIGHT IMPROVEMENT. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM REMAINS IN A FAVORABLE AREA FOR INTENSIFICATION WITH LOW (5-10KT) VERTICAL WIND SHEAR (VWS) AND STRONG RADIAL OUTFLOW ASSOCIATED WITH A POINT SOURCE DIRECTLY OVERHEAD. ADDITIONALLY, SEA SURFACE TEMPERATURES (SST) IN THE PHILIPPINE SEA REMAIN WARM AT 29- 30 CELSIUS. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 25W WILL CONTINUE ON ITS WEST-NORTHWESTWARD TRACK TOWARD THE PHILIPPINES, PASSING JUST TO THE NORTH OF CATANDUANES ISLAND AROUND TAU 24 THEN BRUSH THE COAST OF CAMARINES NORTE BEFORE MAKING LANDFALL OVER THE PROVINCE OF RIZAL SHORTLY AFTER TAU 36. AFTERWARD, IT WILL DRAG ACROSS THE NATIONAL CAPITAL REGION JUST SOUTH OF MANILA BEFORE EXITING INTO THE SOUTH CHINA SEA (SCS) AROUND TAU 42. THE FAVORABLE ENVIRONMENT WILL FUEL A GRADUAL THEN RAPID INTENSIFICATION TO 90KTS BY TAU 36, JUST BEFORE LANDFALL. AFTERWARD, LAND INTERACTION WILL ERODE THE SYSTEM DOWN TO 70KTS AS IT EXITS INTO THE WARM SCS WHERE IT WILL RE-CONSOLIDATE AND STRENGTHEN SLIGHTLY TO 75KTS BY TAU 72. NUMERICAL MODELS ARE IN TIGHT AGREEMENT, LENDING HIGH CONFIDENCE TO THIS PORTION OF THE JTWC TRACK FORECAST. C. AFTER TAU 72, TS VAMCO WILL CONTINUE TO TRACK GENERALLY WEST- NORTHWESTWARD UNDER THE SAME STR, MAKING LANDFALL OVER CENTRAL VIETNAM NEAR DANANG JUST BEFORE TAU 120. AS THE SYSTEM TRACKS FURTHER WEST IN THE SCS, DECREASING SST AND SIGNIFICANTLY LOWER OCEAN HEAT CONTENT WILL WEAKEN THE SYSTEM DOWN TO 50KTS BY TAU 120. NUMERICAL MODELS GRADUALLY SPREAD TO OVER 250NM BY TAU 12O WITH AFUM AND UEMN AS NOTABLE RIGHT-OF-TRACK OUTLIERS, UNREALISTICALLY DRIVING THE VORTEX INTO THE STR. THE EXTENDED PORTION OF THE JTWC TRACK FORECAST IS LAID WITH FAIR CONFIDENCE JUST TO THE LEFT OF THE MODEL CONSENSUS TO OFFSET THE RIGHT OUTLIERS.// NNNN