MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (MARIA) WARNING NR 11// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 23W (MARIA), LOCATED APPROXIMATELY 205 NM NORTH- NORTHEAST OF IWO TO, JAPAN, HAS TRACKED NORTHEASTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON RECENT INFRARED SATELLITE FIXES FROM PGTW AND RJTD AND A 161627Z AMSU-B PASS. THE INTENSITY OF 55 KNOTS IS CONSISTENT WITH AN AVERAGE OF DVORAK CURRENT INTENSITY ESTIMATES FROM MULTIPLE REPORTING AGENCIES. THE CONVECTIVE STRUCTURE OF TS 23W HAS BECOME LESS ORGANIZED OVER THE PAST SIX HOURS. RECENT ANIMATED INFRARED SATELLITE IMAGERY SHOWS CONVECTION BEGINNING TO SHEAR EASTWARD FROM THE LOW LEVEL CIRCULATION CENTER (LLCC) DUE TO INCREASING WESTERLY FLOW ALOFT ASSOCIATED WITH A SUBTROPICAL JET STREAM. THE SYSTEM IS TRACKING ALONG THE NORTHWESTERN PERIPHERY OF A SUBTROPICAL STEERING RIDGE. 3. FORECAST REASONING. A. THE FORECAST PHILOSOPHY HAS CHANGED FROM THE PREVIOUS WARNING. TS 23W IS NOW EXPECTED TO DISSIPATE BELOW THE WARNING THRESHOLD INTENSITY OF 25 KNOTS. THEREFORE, THE CURRENT WARNING CALLS FOR DISSIPATION VICE EXTRATROPICAL TRANSITION. B. TS 23W WILL CONTINUE TRACKING ALONG THE NORTHERN PERIPHERY OF THE CURRENT STEERING RIDGE THROUGHOUT THE FORECAST PERIOD. STRONG WESTERLY FLOW ALOFT WILL DRIVE STEADY WEAKENING, RESULTING IN DISSIPATION BY TAU 72. THE NUMERICAL MODEL TRACK GUIDANCE IS IN FAIR AGREEMENT, WITH EACH DEPICTING A SLIGHTLY DIFFERENT ORIENTATION TO THE STEERING FLOW ALONG THE NORTHERN PORTION OF THE SUBTROPICAL RIDGE. THE CURRENT FORECAST LIES CLOSE TO THE MULTI-MODEL CONSENSUS. THERE IS STILL A VERY SMALL PROBABILITY THAT TS 23W WILL TRACK EQUATORWARD ALONG THE EASTERN PORTION OF THE STEERING RIDGE AFTER TAU 72. HOWEVER, THE SYSTEM IS EXPECTED TO BE VERY WEAK AT THAT POINT AND IS NOT LIKELY TO REGENERATE.// NNNN NNNN