MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FOURTEEN) WARNING NR 07// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 14W (FOURTEEN), LOCATED APPROXIMATELY 1601 NM SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED WESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A FULLY-EXPOSED, WELL-DEFINED LOW-LEVEL CIRCULATION CENTER WITH LIMITED DEEP CONVECTION SHEARED OVER THE EASTERN SEMICIRCLE, WHICH SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE. A 030632Z MHS 89GHZ MICROWAVE IMAGE INDICATES TIGHTLY-CURVED SHALLOW BANDING WRAPPING INTO THE CENTER WITH AN ISOLATED AREA OF DEEP CONVECTION OVER THE SOUTHEAST QUADRANT. UPPER-LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH LOW TO MODERATE (15 TO 20 KNOTS) WESTERLY VERTICAL WIND SHEAR AND FAIR POLEWARD OUTFLOW ASSOCIATED WITH A TUTT CELL POSITIONED TO THE NORTH-NORTHWEST. TS 14W IS TRACKING WESTWARD WHILE UNDER THE INFLUENCE OF A SUBTROPICAL RIDGE (STR), LOCATED TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THE AFOREMENTIONED STR WILL REMAIN THE PRIMARY STEERING FEATURE THROUGH TAU 72 AS TS 14W BEGINS TO TRACK WEST-NORTHWESTWARD. SEA SURFACE TEMPERATURES WILL REMAIN FAVORABLE ALONG THE TRACK. UPPER LEVEL OUTFLOW AND VERTICAL WIND SHEAR WILL GRADUALLY IMPROVE AND ALLOW TS 14W TO SLOWLY INCREASE IN INTENSITY, REACHING 70 KNOTS BY TAU 72. DYNAMIC MODEL GUIDANCE IS IN FAIR AGREEMENT WITH A SPREAD OF 120 NM AT TAU 72. THEREFORE, THERE IS MODERATE CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. C. BEYOND TAU 72, THE STR WILL SHIFT EASTWARD AND ALLOW TS 14W TO BEGIN TO TRACK MORE NORTHWESTWARD. FAVORABLE SEA SURFACE TEMPERATURES (29 TO 30 DEGREES CELSIUS), FAVORABLE VERTICAL WIND SHEAR AND AN ENHANCED POLEWARD OUTFLOW CHANNEL WILL ALLOW TS 14W TO INCREASE TO AN INTENSITY OF 90 KNOTS BY TAU 120. DYNAMIC MODEL GUIDANCE IS IN FAIR AGREEMENT WITH A SPREAD OF 150 NM AT TAU 120. THE JTWC FORECAST TRACK REMAINS SLIGHTLY TO THE WEST OF THE MULTI-MODEL CONSENSUS, FAVORING THE ECMWF TRACK. OVERALL, THERE IS MODERATE CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN