MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (ONE) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 01W (ONE), LOCATED APPROXIMATELY 234 NM SOUTHEAST OF MAJURO, MARSHALL ISLANDS, HAS TRACKED NORTH-NORTHWESTWARD AT 06 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A LARGE DEEP CONVECTIVE CELL OVER AN ENLARGED LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS BASED ON THE LARGE LLC IN THE EIR LOOP AND LINED UP WITH A NOTCH FEATURE IN THE 1638Z SSMIS MICROWAVE PASS WITH LOW CONFIDENCE. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON A PGTW DVORAK ESTIMATE OF T1.0/25KTS AND CONSISTENT WITH THE EIR SIGNATURE. THE ENVIRONMENT IS MARGINALLY FAVORABLE WITH LIGHT TO MODERATE (15-20 KT) VERTICAL WIND SHEAR (VWS), WEAK RADIAL OUTFLOW, AND WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE. THE CYCLONE IS TRACKING SLOWLY TOWARD A BREAK IN THE SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 01W WILL CONTINUE TRACKING SLOWLY NORTHWESTWARD TOWARD THE BREAK IN THE STR UNTIL TAU 36. AFTERWARD, THE STR WILL REBUILD AND ACCELERATE THE SYSTEM ON A WEST-NORTHWESTWARD TRAJECTORY. IMPROVED POLEWARD OUTFLOW WILL PROMOTE SLIGHT INTENSIFICATION TO 40 KNOTS BY TAU 72. C. AFTER TAU 72, TD 01W WILL CONTINUE ON A WEST-NORTHWESTWARD TRACK WITH LIMITED INTENSIFICATION UNDER MARGINALLY FAVORABLE ENVIRONMENTAL CONDITIONS, REACHING 45 KNOTS BY TAU 120. NUMERICAL GUIDANCE HAS COME TO BETTER AGREEMENT WITH SPREADING TO 250 NM TOWARD THE MID PORTION. HOWEVER, DUE TO THE FORMATIVE NATURE OF THE SYSTEM AND GIVEN THE LOW CONFIDENCE IN THE INITIAL POSITION, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN