MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (SIX) WARNING NR 002// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 06W (SIX), LOCATED APPROXIMATELY 264 NM EAST- SOUTHEAST OF CHICHI JIMA, HAS TRACKED WESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON RECENT MICROWAVE SATELLITE IMAGERY, INCLUDING A 091813Z SSMIS 91 GHZ IMAGE, AND A 091750Z PGTW SATELLITE FIX. THE INTENSITY OF 45 KNOTS IS CONSISTENT WITH A BYU HIGH RESOLUTION ANALYSIS OF A 091133Z ASCAT PASS, AND FURTHER SUPPORTED BY CURRENT LOW-LEVEL BANDING STRUCTURE EVIDENT IN RECENT MICROWAVE SATELLITE IMAGERY INCLUDING THE AFOREMENTIONED SSMIS IMAGE. TS 06W IS TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL STEERING RIDGE (STR) TO THE NORTH. THE SYSTEM IS PASSING OVER WARM WATER (29-30C) IN AN AREA OF MODERATE VERTICAL WIND SHEAR (15-20 KTS). UPPER LEVEL OUTFLOW TOWARD TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELLS TO THE WEST AND SOUTHEAST IS SUPPORTING SYSTEM DEVELOPMENT. 3. FORECAST REASONING. A. FORECAST INTENSITIES HAVE INCREASED FROM THE PREVIOUS WARNING AND THE FORECAST PERIOD HAS BEEN EXTENDED TO 96 HOURS. B. TS 06W WILL CONTINUE TRACKING WESTWARD ALONG THE SOUTHERN EDGE OF THE STR. THE ENVIRONMENT WILL BECOME UNFAVORABLE AS STRONG EASTERLY FLOW ALOFT DEVELOPS OVER THE CIRCULATION, INCREASING VERTICAL WIND SHEAR, OVER THE NEXT 24 TO 36 HOURS. DESPITE THE INCREASING 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 72. C. TS 06W IS EXPECTED TO FINALLY SUCCUMB TO INCREASING VWS AND DISSIPATE BY TAU 96, TURNING SOUTHWESTWARD WITH LOWER-LEVEL FLOW. NUMERICAL MODEL SOLUTIONS ARE IN TIGHT AGREEMENT, LENDING HIGH CONFIDENCE TO THE OVERALL JTWC FORECAST TRACK.// NNNN NNNN