MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 17W (PEIPAH) WARNING NR 06// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 17W (PEIPAH), LOCATED APPROXIMATELY 301 NM SOUTHEAST OF IWO TO, HAS TRACKED NORTHWESTWARD AT 23 KNOTS (KTS) OVER THE PAST SIX HOURS. THE FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) IN ANIMATED MULTISPECTRAL SATELLITE IMAGERY PROVIDES HIGH CONFIDENCE IN THE INITIAL POSITION. A PARTIAL 152256Z METOP-A ASCAT PASS JUST MISSED THE LLCC BUT IT DOES SHOW 30 KT WINDS TO THE EAST OF THE LLCC. THE INITIAL INTENSITY OF 30 KTS IS BASED ON THE ASCAT PASS AND MULTI-AGENCY DVORAK ESTIMATES OF T1.5 (25 KTS). THE ENVIRONMENT IS HOSTILE, DESPITE STRONG EQUATORWARD OUTFLOW AND WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE (SST), DUE TO HIGH (35-40 KT) VERTICAL WIND SHEAR. TD 17W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A NORTH-SOUTH ORIENTED SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. FOR THE DURATION OF THE FORECAST, TD 17W WILL TRACK NORTH- NORTHWESTWARD ALONG THE PERIPHERY OF THE STR. THE HOSTILE ENVIRONMENT WILL CAUSE DISSIPATION BETWEEN TAU 24 AND 36. THE FORECAST TRACK CLOSELY FOLLOWS THE CONSENSUS WITH FAIR CONFIDENCE BASED ON DECENT AGREEMENT IN THE MODEL GUIDANCE.// NNNN NNNN