MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 28W (TWENTYEIGHT) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 28W (TWENTYEIGHT), LOCATED APPROXIMATELY 488 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS A SYSTEM WITH DEEP CONVECTION SHEARED TO THE WEST OF AN ALMOST FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE WITH NO MICROWAVE IMAGERY OR ASCAT PASSES TO ASSIST IN PLACING THE LLCC. THE INITIAL INTENSITY OF 30 KNOTS IS BASED ON THE DVORAK INTENSITY ESTIMATES OF T1.5-2.5 (25-35 KNOTS) FROM PGTW, RJTD, AND KNES. ANALYSIS INDICATES AN OVERALL FAVORABLE ENVIRONMENT WITH WARM (29 DEGREES CELSIUS) SEA SURFACE TEMPERATURES, STRONG POLEWARD OUTFLOW AND LOW (10-15 KNOT) VERTICAL WIND SHEAR. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 27W WILL CONTINUE TO TRACK NORTHWESTWARD AS IT GRADUALLY DEVELOPS ALONG THE SOUTHWEST PERIPHERY OF THE AFOREMENTIONED STR. THE OVERALL FAVORABLE ENVIRONMENT WILL FUEL INTENSIFICATION TO A PEAK OF 55 KNOTS AT TAU 36. TD 27W IS EXPECTED TO PASS BETWEEN TAIWAN AND LUZON AT TAU 72 AS STRONG (30-35 KNOTS) SHEAR IMPEDES FURTHER DEVELOPMENT. THE FORECAST TRACK HAS BEEN MOVED NORTH OF THE PREVIOUS JTWC TRACK AS MODEL GUIDANCE HAS STARTED TAKING A MORE NORTHERLY TRACK WITH THE EXCEPTION OF JGSM. THERE IS OVERALL FAIR CONFIDENCE IN THIS PORTION OF THE FORECAST WITH A GUIDANCE SPREAD OF 250NM AT TAU 48. C. AFTER TAU 72, TD 27W WILL CONTINUE TRACKING NORTHWESTWARD AS IT BEGINS TO DISSIPATE NORTH OF LUZON. INCREASING VWS (40-50 KNOTS) WILL BEGIN TO ERODE THE SYSTEM WITH DISSIPATION EXPECTED AT TAU 96. NUMERICAL MODELS ARE IN VERY BROAD AGREEMENT WITH THE DIRECTION OF TRACK WITH NAVGEM AS THE EXTREME NORTHERLY OUTLIER AND JGSM AS THE EXTREME SOUTHERLY OUTLIER. AT TAU 96 THE DISTANCE BETWEEN THE TWO EXTREMES IS 600 NM LENDING POOR CONFIDENCE TO THE LATTER PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN