WDPN31 PGTW 201500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (EIGHT) WARNING NR 01// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 08W (EIGHT), LOCATED APPROXIMATELY 178 NM EAST-SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS DEEPENED CENTRAL CONVECTION OBSCURING A DEVELOPING LOW-LEVEL CIRCULATION CENTER. THE CURRENT POSITION IS BASED ON THE EIR LOOP, 201127Z SSMIS MICROWAVE IMAGE AND PGTW SATELLITE FIX WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN OVERALL ASSESSMENT OF DVORAK INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES AND THE CURRENT STRUCTURE. UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM IS LOCATED IN AN AREA OF MARGINAL (20 KNOT) VERTICAL WIND SHEAR AND GOOD DIFFLUENT OUTFLOW. TD 08W IS CURRENTLY TRACKING SLOWLY WESTWARD UNDER THE STEERING INFLUENCE OF AN EXTENSION OF A STR LOCATED TO THE EAST. 3. FORECAST REASONING. A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST PHILOSOPHY. B. TD 08W WILL CONTINUE TO TRACK SLOWLY WESTWARD TO NORTHWESTWARD IN THE SHORT TERM DUE TO THE STEERING STR. BY TAU 24, THE STR IS FORECAST TO WEAKEN AND MOVE EAST, ALLOWING THE SYSTEM TO SHIFT POLEWARD. MARGINAL CONDITIONS WILL PERSIST, CAUSING A MODEST INTENSIFICATION THROUGHOUT THE FORECAST PERIOD. THE SYSTEM IS EXPECTED TO FURTHER WEAKEN AS IT APPROACHES HAINAN ISLAND. C. TD 08W IS FORECAST TO MAKE LAND FALL NEAR MAOMING, CHINA AFTER TAU 72 AND IS EXPECTED TO DISSIPATE BY THE END OF THE FORECAST PERIOD. AVAILABLE MODEL GUIDANCE IS OVERALL IN GOOD AGREEMENT DEPICTING A NORTHWARD TRACK; HOWEVER, DUE TO SIGNIFICANT DIFFERENCES IN TRACK SPEEDS AMONG AVAILABLE TRACKERS, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN