WDPN31 PGTW 091500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 11W (ELEVEN) WARNING NR 04// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 11W (ELEVEN), LOCATED APPROXIMATELY 671 NM EASTWARD OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS FORMATIVE DEEP CONVECTIVE BANDING SURROUNDING A SMALL, TIGHTLY COMPACT LOW-LEVEL CIRCULATION CENTER (LLCC). A 091048Z SSMIS MICROWAVE IMAGE REVEALS THE CONSOLIDATED STRUCTURE OF THE TIGHTLY WRAPPED LLCC WITH BANDING FEATURES WRAPPING TO THE CENTER. THE INITIAL POSITION IS BASED ON THE EIR ANIMATION WITH FAIR CONFIDENCE. THE INITIAL INTENSITY HAS BEEN INCREASED TO 30 KNOTS DUE TO THE IMPROVING STRUCTURE OF THE SYSTEM AS WELL AS FIXING AGENCY CURRENT INTENSITY ESTIMATES RANGING FROM 25 TO 40 KNOTS. UPPER-LEVEL ANALYSIS CONTINUES TO INDICATE A FAVORABLE ENVIRONMENT CHARACTERIZED BY WEAK (5 TO 10 KNOTS) VERTICAL WIND SHEAR AND STRONG RADIAL OUTFLOW. TD 11W IS CURRENTLY TRACKING WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE MID-LEVEL SUBTROPICAL STEERING RIDGE (STR). 3. FORECAST REASONING. A. THE INTENSITY FORECAST FROM TAU 36 TO TAU 120 HAS SUBSTANTIALLY DECREASED BY 10 TO 15 KNOTS AT EACH POSITION DUE TO AN OVERALL DECREASE IN OBJECTIVE AID INTENSITY GUIDANCE. B. TD 11W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWEST THROUGH THE NEXT 72 HOURS ALONG THE SOUTHERN PERIPHERY OF THE STR. FAVORABLE CONDITIONS OF LOW VWS, WARM SSTS, AND STRONG OUTFLOW ARE EXPECTED TO PERSIST THROUGH THE FORECAST PERIOD. THE SYSTEM IS FORECAST TO INTENSIFY TO 60 KNOTS BY TAU 48 AS IT APPROACHES LUZON. UPON MAKING LANDFALL WITH LUZON, TD 11W WILL EXPERIENCE A SLIGHT WEAKENING BEFORE IT REEMERGES IN THE SOUTH CHINA SEA (SCS), BUT IS EXPECTED TO RE-INTENSIFY TO 65 KNOTS BY TAU 72 AS IT CONTINUES TO TRACK WEST- NORTHWEST. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT THROUGH THIS PERIOD OF THE FORECAST WITH ONLY SLIGHT DIFFERENCES IN THE TRANSLATIONAL SPEED OF THE SYSTEM. THERE IS AN OVERALL HIGH CONFIDENCE IN THIS PORTION OF THE FORECAST TRACK. C. AFTER TAU 72, TD 11W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD ACROSS THE SCS. A PEAK INTENSITY OF 70 KNOTS IS EXPECTED BY TAU 96. THE SYSTEM IS THEN EXPECTED WEAKEN AS IT BEGINS TO ENCOUNTER LAND AND EVENTUALLY MAKES LANDFALL NEAR THE BORDER BETWEEN VIETNAM AND CHINA AT APPROXIMATELY TAU 120. THE DYNAMIC MODELS HAVE A SLIGHT SPREAD IN THIS PORTION OF THE FORECAST AS TD 11W APPROACHES SOUTHERN CHINA. THERE IS AN OVERALL HIGH CONFIDENCE IN THIS PORTION OF THE FORECAST TRACK.// NNNN