1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 14W (DOLPHIN), LOCATED APPROXIMATELY 551 NM SOUTH-SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS PERSISTENT SYMMETRIC CONVECTION ABOUT THE CORE OF THE SYSTEM WITH FLARING HOT TOWERS CYCLING NEAR THE CENTER AND SHEARING OFF TO THE NORTHEAST, LEADING TO A SOMEWHAT ELONGATED CONVECTIVE MASS. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON LATE RECEIPT OF A 220013Z METOP-B ASCAT PASS WHICH CAUGHT THE CENTER ON THE EDGE OF SWATH, WITH THE COINCIDENT AMSU-B 89 GHZ MICROWAVE IMAGERY PROVIDING ADDITIONAL SUPPORT FOR THE HIGH CONFIDENCE POSITION. THE INITIAL INTENSITY IS ASSESSED AT 50 KNOTS WITH HIGH CONFIDENCE BASED ON A DVORAK CURRENT INTENSITY ESTIMATE OF T3.0 FROM PGTW AND RJTD, SUPPORTED BY AN ADVANCED DVORAK TECHNIQUE (ADT) CURRENT INTENSITY ESTIMATE OF 3.3 (53 KNOTS), A SATELLITE CONSENSUS ESTIMATE OF 47 KNOTS, AND THE AFOREMENTIONED ASCAT PASS, WHICH SHOWED A SINGLE 50 KNOT WIND BARB TO THE SOUTHEAST OF THE CENTER, EMBEDDED IN A LARGE AREA OF 45-50 KNOT WINDS. TS DOLPHIN CONTINUES TO EXHIBIT BOTH TROPICAL AND SUBTROPICAL CHARACTERISTICS. THE THERMAL STRUCTURE REMAINS TROPICAL WITH A FIRMLY ENTRENCHED WARM CORE ANOMALY IN THE MID- LEVELS AND THE CONVECTIVE SIGNATURE HAS BECOME MORE SYMMETRIC OVER THE PAST SIX HOURS. HOWEVER, THE WIND STRUCTURE AND VORTICITY STRUCTURE IS ASYMMETRIC. THE SYSTEM REMAINS IN A MARGINALLY FAVORABLE ENVIRONMENT, WITH ROBUST POLEWARD OUTFLOW, STILL TAPPING INTO THE DIVERGENT UPPER-LEVEL TROUGH THAT HAS NOW MOVED NORTHEAST OF THE SYSTEM, WITH MODERATE EQUATORWARD OUTFLOW IN PLACE ON THE EASTERN SIDE OF THE CIRCULATION. UPPER-LEVEL WESTERLIES BEHIND THE TROUGH ARE PRODUCING SOME PRESSURE ON THE WEST SIDE, IMPINGING OUTFLOW IN THIS QUADRANT. THE VWS REMAINS LOW AT 10-15 KTS AND SSTS REMAIN VERY WARM (29-30 DEG C), SERVING TO OFFSET THE CONVERGENCE ON THE WESTERN SIDE AND ALLOWING FOR SOME INTENSIFICATION OVER THE PAST SIX HOURS. THE SYSTEM IS CURRENTLY MOVING NORTHWARD IN A COL AREA BETWEEN A WEAK STR POSITIONED TO THE EAST AND A SECOND STRONGER STR LOCATED TO THE WEST, WITH THE EASTERN STR BEGINNING TO BECOME THE DOMINATE STEERING MECHANISM. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS DOLPHIN WILL CONTINUE TRACKING NORTHWARD THROUGH TAU 12 ALONG THE WESTERN PERIPHERY OF THE BUILDING STR TO THE EAST, AND AFTER ROUNDING THE RIDGE AXIS BETWEEN TAUS 12 AND 24, ACCELERATE ON A NORTHEASTWARD TRACK THROUGH THE END OF THE FORECAST PERIOD. OVER THE NEXT 12 TO 24 HOURS, THE SYSTEM IS WILL CONTINUE TO TAKE ON MORE SUBTROPICAL CHARACTERISTICS, BECOMING FULLY SUBTROPICAL BY TAU 24 AS IT MOVES OVER COOLER WATER, EXPERIENCES INCREASING VWS AND BEGINS TO ENTRAIN COOLER AND DRIER AIR. BY TAU 36 THE SYSTEM WILL BECOME MORE CLOSELY ASSOCIATED WITH THE POLAR FRONT JET, EXPERIENCE INCREASING VWS AND BEGIN TO DEVELOP FRONTAL CHARACTERISTICS, TRANSITIONING TO A FULLY EXTRATROPICAL SYSTEM BY TAU 48 SOUTH OF HONSHU. UPPER LEVEL MASS CONVERGENCE FROM THE WEST, COMBINED WITH A DECREASE IN THE POLEWARD OUTFLOW AS THE TROUGH MOVES OUT OF THE AREA, WILL COMBINE TO KEEP THE INTENSITY STEADY AT 50 KNOTS FOR THE NEXT 12 HOURS. THEREAFTER, THEY SYSTEM WILL AGAIN TAP INTO THE DIVERGENT QUADRANT OF THE 200 MB JET OVER HONSHU, INCREASING THE POLEWARD OUTFLOW, WHICH WILL OFFSET COOLER WATERS AND INCREASING VWS, LEADING TO A SHORT PERIOD OF INTENSIFICATION THROUGH TAU 48. THEREAFTER, THE SYSTEM WILL STEADILY WEAKEN AS IT MOVES RAPIDLY OFF THE NORTHEAST AS A STRONG EXTRATROPICAL SYSTEM. UPON APPROACH TO THE KANTO PLAIN TS 14W IS EXPECTED TO BE A 40 TO 45 KT EXTRATROPICAL LOW. NUMERICAL MODEL SOLUTIONS ARE IN MODERATE AGREEMENT THROUGH TAU 48, WITH A 105 NM SPREAD BETWEEN THE ECMWF AND NAVGEM OUTLIERS AT TAU 48. CROSS TRACK SPREAD DRASTICALLY INCREASES BY TAU 72 AS SOME TRACKERS BEGIN TO LOSE THE VORTEX OR JUMP TO A DEVELOPING LOW IN THE SEA OF JAPAN, LEADING TO A 350 NM SPREAD AT TAU 72. HOWEVER THE MAJORITY OF THE TRACKERS ARE MORE TIGHTLY PACKED NEAR THE JTWC TRACK. THE JTWC FORECAST TRACK IS PLACED ALONG THE EASTERN/SOUTHERN SIDE OF THE TRACKER ENVELOPE THROUGH TAU 36 AND NEAR THE MULTI-MODEL CONSENSUS THEREAFTER. BASED ON THE TIGHT GROUPINGS IN THE MODEL TRACKERS, THERE IS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN