MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (MEARI) WARNING NR 07// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 26W (MEARI), LOCATED APPROXIMATELY 331 NM NORTH OF ULITHI, HAS TRACKED NORTHEASTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN ORGANIZING LOW-LEVEL CIRCULATION CENTER, WITH DEEP CONVECTIVE BANDING WRAPPING INTO THE SYSTEM ALONG THE NORTHERN AND SOUTHERN SEMICIRCLES. A 040549Z AMSU 89 GHZ IMAGE ALSO REVEALS TIGHTLY CURVED BANDING AND SUPPORTS THE CURRENT JTWC BEST TRACK POSITION WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 50 KNOTS REFLECTS THE IMPROVED NATURE OF THE SYSTEM AND IS SUPPORTED BY A DVORAK CURRENT INTENSITY OF T3.0 (45 TO 55 KNOTS) FROM PGTW AND KNES. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH DUAL-CHANNEL OUTFLOW AND LOW VERTICAL WIND SHEAR (VWS). THE SYSTEM IS TRACKING NORTHEASTWARD IN RESPONSE TO A WEAKNESS IN THE UPPER-LEVEL SUBTROPICAL RIDGE TO THE NORTH. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS MEARI IS EXPECTED TO TRACK GENERALLY NORTHEASTWARD OVER THE NEXT 48 HOURS AS IT TRANSITS THROUGH A WEAKNESS BETWEEN TWO STR FEATURES. AS THE SYSTEM APPROACHES THE STR AXIS, VWS WILL REMAIN LOW, AND POLEWARD OUTFLOW WILL BECOME ENHANCED LEADING TO STEADY INTENSIFICATION. A PEAK INTENSITY OF 85 KNOTS IS FORECAST TO OCCUR BY TAU 48. C. BY TAU 72, TS MEARI WILL BEGIN ACCELERATING NORTHEASTWARD IN RESPONSE TO A DEEPENING UPPER-LEVEL TROUGH TO THE NORTH. VWS WILL BECOME INCREASINGLY UNFAVORABLE AS THE SYSTEM BECOMES EMBEDDED WITHIN THE DEEP WESTERLY FLOW. RAPID WEAKENING OF THE SYSTEM WILL COMMENCE BETWEEN TAU 72 AND 96. EXTRATROPICAL TRANSITION OF TS MEARI WILL ALSO TAKE PLACE DURING THIS TIME AS IT ENTERS A PROMINENT BAROCLINIC ZONE. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT THROUGH THE ENTIRE FORECAST PERIOD LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN