MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (EIGHT) WARNING NR 001// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 08W (EIGHT), LOCATED APPROXIMATELY 451 NM EAST-SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 07 KNOTS (KTS) OVER THE PAST SIX HOURS. THE INITIAL POSITION, PLACED WITH LOW CONFIDENCE USING ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY WHICH SUGGESTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC), IS JUST NORTH OF SUSTAINED CONVECTIVE BANDING. THE EIR ALSO REVEALS LIMITED CONVECTIVE BANDING TO THE NORTH OF THE LLCC. THE INITIAL INTENSITY IS BASED ON A 301400Z METOP-C ASCAT IMAGE WHICH SHOWS 30 KT WINDS IN THE SOUTH, EAST, AND NORTH QUADRANTS (THE PASS MOSTLY MISSED THE WEST QUADRANT). DVORAK INTENSITY FIXES ARE T1.5 (25 KTS) AND BELOW. ENVIRONMENTAL CONDITIONS ARE SOMEWHAT FAVORABLE WITH GOOD EQUATORWARD OUTFLOW AND WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES, PARTIALLY OFFSET BY MARGINAL (15-20 KT) VERTICAL WIND SHEAR AND A WEAK UPPER LEVEL LOW RESULTING IN CONVERGENCE ALOFT JUST NORTH OF THE SYSTEM. TD 08W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST PHILOSOPHY. B. THROUGH TAU 72, TD 08W IS EXPECTED TO CONTINUE TRACKING ALONG THE PERIPHERY OF THE STR, PASS OVER THE LEIZHOU PENINSULA AROUND TAU 30, ENTER THE GULF OF TONKIN NEAR TAU 36, AND MAKE LANDFALL NEAR HANOI AROUND TAU 72. THE MARGINAL ENVIRONMENT IS EXPECTED TO LIMIT INTENSIFICATION TO 35 KTS AT TAU 12. HOWEVER, THERE IS A POSSIBILITY THE UPPER LEVEL LOW WILL WEAKEN AND ALLOW MORE INTENSIFICATION BEFORE LANDFALL. BY TAU 24, SIGNIFICANT LAND INTERACTION SHOULD INHIBIT INTENSIFICATION, BUT SMALL VARIATIONS IN THE ACTUAL TRACK COULD LEAD TO SIGNIFICANT DIFFERENCES IN THE INTENSITY. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 36. AFTER TAU 36, THE UKMET MODEL DEVIATES TO THE SOUTH FROM THE OTHER MEMBERS. FOR THIS PORTION OF THE FORECAST, THE JTWC TRACK FORECAST CLOSELY FOLLOWS CONSENSUS WITH LOW CONFIDENCE DUE PRIMARILY TO HIGH UNCERTAINTY IN THE INITIAL POSITION. C. AFTER TAU 72, TD 08W WILL CONTINUE INLAND AND DISSIPATE. THE JTWC TRACK FORECAST IS HEDGED NORTH OF CONSENSUS TO OFFSET THE SOUTHERN OUTLIER (UKMET) WITH LOW CONFIDENCE.// NNNN NNNN