WDPN32 PGTW 102100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (VAMCO) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 25W (VAMCO), LOCATED APPROXIMATELY 284 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM HAS FURTHER CONSOLIDATED OVER THE PAST 6 HOURS WITH CURVED RAIN BANDS CONTINUING TO WRAP TIGHTER INTO AN OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED UPON BANDING FEATURES IN THE EIR LOOP AS WELL AS IN THE 101708Z ATMS 88.2GHZ IMAGE. AGENCIES REPORT DVORAK CURRENT INTENSITY ESTIMATES OF T3.0/45KTS FROM PGTW, AND T3.5/55KTS FROM KNES, AND RJTD. THE INITIAL INTENSITY IS HEDGED SLIGHTLY HIGHER THAN THESE INTENSITY ESTIMATES BASED ON A 101706Z CIMSS SATELLITE CONSENSUS INTENSITY ESTIMATE OF 62KTS. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM REMAINS IN A FAVORABLE AREA WITH LOW (05-10KT) 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 AND FAVORABLE AT 29-30C. 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. AS THE STR BUILDS IN THE NEAR TERM, TS 25W WILL TRACK ON A MORE WESTWARD TRAJECTORY TOWARD THE PHILIPPINES, PASSING JUST TO THE NORTH OF POLILLO ISLAND AND LAMON BAY BEFORE MAKING LANDFALL OVER THE PROVINCE OF BULACAN AROUND TAU 24. THE ENVIRONMENT WILL REMAIN HIGHLY FAVORABLE AND FUEL A RAPID INTENSIFICATION TO 85KTS BY THIS TIME. SHORTLY AFTER TAU 24, THE SYSTEM WILL MAKE LANDFALL ALONG THE EASTERN COAST OF LUZON. AFTERWARD, LAND INTERACTION WILL ERODE THE SYSTEM DOWN TO 65KTS BY TAU 36. AS TS VAMCO EXITS INTO THE WARM SCS IT WILL THEN RE-CONSOLIDATE AND STRENGTHEN TO 75KTS THROUGH TAU 72. NUMERICAL MODELS ARE IN TIGHT AGREEMENT DURING THIS INITIAL PERIOD OF THE FORECAST AND THUS LEND HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. C. AFTER TAU 72, TS VAMCO WILL TRACK WEST-NORTHWESTWARD AS THE STR IS WEAKENED BY AN APPROACHING MIDLATITUDE TROUGH. DURING THIS TIME, THE SYSTEM IS FORECAST TO WEAKEN STEADILY DUE TO INCREASING VWS AND COOLING SST TO 60 KTS BY TAU 96. THEREAFTER, THE SYSTEM WILL MAKE LANDFALL ALONG THE COAST OF CENTRAL VIETNAM WHEREUPON THE RUGGED TERRAIN WILL RAPIDLY ERODE THE SYSTEM DOWN TO 35KTS BY TAU 120. NUMERICAL MODELS SPREAD INCREASES FROM 260NM SPREAD AT TAU 96 TO OVER 520NM AT TAU 120. THIS INCREASING SPREAD IN NUMERICAL MODEL SOLUTIONS LENDS OVERALL POOR CONFIDENCE IN THIS FINAL PORTION OF THE JTWC FORECAST TRACK WITH IS PLACED NEAR THE MULTI-MODEL CONSENSUS.// NNNN