MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (SIX) WARNING NR 1// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 06W (SIX), LOCATED APPROXIMATELY 350 NM EAST-NORTHEAST OF IWO TO, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A COMPACT, SYMMETRIC SYSTEM OF DEEP CONVECTION OBSCURING A LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE LOW LEVEL CIRCULATION (LLC) FEATURE PRESENT IN A 091136Z AMSU COMPOSITE IMAGE. THE INITIAL INTENSITY OF 35KTS IS PLACED WITH HIGH CONFIDENCE BASED ON A PARTIAL 091137Z ASCAT-B IMAGE DEPICTING 35 KTS WINDS ALONG THE EASTERN PERIPHERY OF THE LLC AND HEDGED ABOVE A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T1.5 (25 KTS) BASED ON THE SCATTEROMETRY DATA. TS 06W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) AND THROUGH AN UNFAVORABLE ENVIRONMENT FOR CONTINUED DEVELOPMENT WITH MODERATE (15-20) KTS) VERTICAL WIND SHEAR (VWS) AND WEAK UPPER LEVEL OUTFLOW OFFSET BY WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES. 3. FORECAST REASONING. A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE AND SETS THE FORECAST PHILOSOPHY. B. TS 06W IS FORECAST TO CONTINUE TRACKING WESTWARD ALONG THE SOUTHERN EDGE OF THE STR. THE ENVIRONMENT WILL BECOME INCREASINGLY UNFAVORABLE DUE TO THE ROBUST EASTERLY FLOW ALOFT, LEADING TO A RISE IN VWS TO 25 KTS BY TAU 12 AND 30 KTS BY TAU 48. DESPITE THE CONTINUED WARM (29-30 CELSIUS) SSTS DURING THIS TIME, THE SYSTEM IS FORECAST TO WEAKEN TO 30 KTS BY TAU 12 AND 25 KTS BY TAU 24. CONTINUED HIGH (25-30 KTS) VWS AT TAU 36 WILL CAUSE THE SYSTEM TO BEGIN DISSIPATION OVER WATER AND LEAD TO DISSIPATION OVER WATER BY TAU 72 AFTER WEAKENING TO 20 KTS. NUMERICAL MODEL SOLUTIONS ARE IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE OVERALL JTWC FORECAST TRACK.// NNNN NNNN