MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (MITAG) WARNING NR 023// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 19W (MITAG), LOCATED APPROXIMATELY 57 NM EAST-SOUTHEAST OF KUNSAN AB, HAS TRACKED NORTHEASTWARD AT 18 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY REVEALS A BROAD, ILL-DEFINED LOW LEVEL CIRCULATION CENTER WITH CONVECTION PRIMARILY ISOLATED TO THE NORTHEAST, INDICATING EXTRATROPICAL TRANSITION (ETT) HAS COMMENCED. THE EIR LOOP, RADAR IMAGERY, AND SURFACE OBSERVATIONS PROVIDE FAIR CONFIDENCE IN THE INITIAL POSITION. THE INITIAL INTENSITY OF 40 KNOTS IS CONSISTENT WITH SURROUNDING SURFACE OBSERVATIONS WHERE MOST OF THE STRONG WIND SPEED REPORTS ARE FROM STATIONS THAT ARE OVER 60 NM FROM THE CENTER. THE MID-LATITUDE JET IS PROVIDING A STRONG POLEWARD OUTFLOW CHANNEL; HOWEVER, STRONG (30-40 KT) VERTICAL WIND SHEAR AND LAND INTERACTION MAKE THE ENVIRONMENT UNFAVORABLE. TS 19W IS TRACKING INTO THE MID-LATITUDE WESTERLIES ON THE NORTHWEST SIDE OF THE SUBTROPICAL RIDGE (STR) THAT HAS GUIDED IT SINCE FORMATION. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. OVER THE NEXT 12 HOURS, TS 19W WILL SHIFT ONTO A MORE WEST-NORTHWESTWARD TRACK AS IT MOVES DEEPER INTO THE MID-LATITUDE WESTERLIES. ETT SHOULD COMPLETE AROUND TAU 24. THE 48 HOUR FORECAST FOLLOWS THE REMNANT CIRCULATION UNTIL IT PASSES OVER JAPAN INTO THE PACIFIC OCEAN. FOR THE DURATION OF THE FORECAST, THE INTENSITY IS EXPECTED TO REMAIN RELATIVELY CONSTANT ALTHOUGH THE WIND FIELD WILL BECOME MORE EXPANSIVE AS THE SYSTEM COMPLETES ETT. WITH THE EXCEPTION OF NAVGEM AND GFS TO THE SOUTH AND JGSM TO THE NORTH, TRACK AGREEMENT AMONG THE MODELS IS STRONG. BASED ON THE OUTLIERS, CONFIDENCE IN THE JTWC TRACK FORECAST IS ASSESSED AS FAIR.// NNNN NNNN