MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (SIX) WARNING NR 004// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 06W (SIX), LOCATED APPROXIMATELY 232 NM EAST-NORTHEAST OF IWO TO, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH ASSOCIATED CONVECTION SHEARED OVER THE WESTERN SEMICIRCLE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN THE MSI AND THE LOW LEVEL CIRCULATION FEATURE PRESENT IN A 100634Z SSMIS 91GHZ IMAGE. THE INITIAL INTENSITY IS PLACED WITH HIGH CONFIDENCE BASED ON MULTIAGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T1.5 (25 KTS, RJTD) AND T2.0 (30 KTS, PGTW), A 100610Z ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY ESTIMATE OF T2.5 (35 KTS) AND A 100540Z SATCON INTENSITY ESTIMATE OF 39 KTS. TS 06W IS TRACKING WESTWARD THROUGH A MARGINAL ENVIRONMENT FOR DEVELOPMENT WITH MODERATE TO STRONG (20-25 KTS) VERTICAL WIND SHEAR (VWS) OFFSET BY VERY WARM (30-31 CELSIUS) SEA SURFACE TEMPERATURES (SST). INCREASING EASTERLY VWS HAS SHEARED THE ASSOCIATED CONVECTION TO THE WEST AND LEFT THE LLCC FULLY EXPOSED. UPPER LEVEL SUPPORT ASSOCIATED WITH A NARROW TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) TO THE WEST, HOWEVER, IS HELPING TO SUSTAIN THE SYSTEM IN THE PRESENCE OF THE INCREASING VWS. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 06W WILL CONTINUE TRACKING GENERALLY WESTWARD ALONG THE SOUTHERN EDGE OF THE STR THROUGHOUT THE 96 HOUR FORECAST. THE ENVIRONMENT WILL BECOME INCREASINGLY UNFAVORABLE AS VERTICAL WIND SHEAR INDUCED BY STRONG EASTERLY FLOW ALOFT PERSISTS. DESPITE THE PERSISTENT SHEAR, PASSAGE OVER WARM WATER AND A FAVORABLE OUTFLOW PATTERN IN THE NEAR-TERM SHOULD ALLOW THE SYSTEM TO REMAIN INTACT AS A WEAK TROPICAL STORM OR TROPICAL DEPRESSION THROUGH TAU 48 AND BY TAU 72 WILL BEGIN TO DISSIPATE OVER WATER. C. TS 06W IS EXPECTED TO WEAKEN TO 20 KTS BY TAU 96 DUE TO THE HOSTILE SHEAR ENVIRONMENT AND DISSIPATE OVER WATER AT THAT TIME. NUMERICAL MODEL SOLUTIONS REMAIN IN TIGHT AGREEMENT WITH MINIMAL SPREAD IN SOLUTIONS THROUGH THE ENTIRE FORECAST PERIOD. THE TIGHT AGREEMENT OF MODEL SOLUTIONS LENDS HIGH CONFIDENCE TO THE OVERALL 96 HOUR JTWC FORECAST TRACK.// NNNN NNNN