WDPN32 PGTW 010300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 07W (TRASES) WARNING NR 001// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 32.6N 127.0E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 199 NM SOUTH OF KUNSAN AB MOVEMENT PAST 6 HOURS: NORTHWARD AT 20 KTS SIGNIFICANT WAVE HEIGHT: 10 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY-EXPOSED, WELL-DEFINED LOW-LEVEL CIRCULATION WITH DEEP CONVECTION DISPLACED ABOUT 45-50NM TO THE SOUTH. MSI ALSO INDICATES THE TWO SYSTEMS ARE BEGINNING TO INTERACT WITH THE OUTER LOW-LEVEL BANDING (NORTHWEST OF CHEJU-DO) BEGINNING TO CONVERGE AND FRAGMENT. THE TRACK MOTION OF BOTH SYSTEMS IS ALSO ALTERED WITH TD 06W NOW QUASI-STATIONARY WHILE TD 07W IS ACCELERATING NORTH-NORTHWESTWARD ALONG THE SOUTHEASTERN PERIPHERY OF TD 06W. ENVIRONMENTAL CONDITIONS ARE MARGINAL WITH CONVERGENT FLOW NORTH OF 07W LIMITING POLEWARD OUTFLOW AND INTERACTION WITH LAND OFFSET SOMEWHAT BY MODERATE EQUATORWARD OUTFLOW, WHICH IS SUSTAINING SOME DISORGANIZED DEEP CONVECTION OVER THE SOUTHERN SEMICIRCLE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON MSI. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON WIND DATA FROM BUOY 22187 (33.1N 127.0E), WHICH REPORTED 25-33 KNOTS AS THE CENTER PASSED ABOUT 10-15 NM WEST FROM 010000Z TO 010100Z. ADDITIONALLY, RECENT ASCAT INDICATED 20 KNOT WINDS OVER THE WESTERN SEMICIRCLE AND A LARGE SWATH OF 30-35 KNOT WINDS OVER THE EASTERN SEMICIRCLE. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: PRIMARY STEERING MECHANISM IS THE LOW- LEVEL SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST BUT ALSO INFLUENCED BY BINARY INTERACTION WITH TD 06W AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T1.5 - 25 KTS FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 5-10 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE EQUATORWARD OTHER FACTORS: INTERACTION WITH LAND AND BINARY INTERACTION ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TD 07W IS UNDERGOING BINARY INTERACTION WITH TD 06W, WHICH IS LOCATED ABOUT 190NM WEST-NORTHWEST OF TD 07W'S 010200Z POSITION. THE TWO SYSTEMS ARE EQUAL IN INTENSITY AND ARE FAIRLY COMPACT SYSTEMS, HOWEVER, TD 06W HAS MAINTAINED A STRONGER, MORE DOMINANT PRESSURE FIELD. THEREFORE, TD 07W IS FORECAST TO TRACK ALONG THE SOUTHEASTERN AND EASTERN PERIPHERY OF TD 06W THROUGH TAU 12 THEN TURN POLEWARD AS IT GETS ABSORBED AND DISSIPATES WITHIN THE EASTERN PERIPHERY OF TD 06W. INTERACTION WITH LAND WILL ALSO SERVE TO SIGNIFICANTLY WEAKEN THE SYSTEM AS IT TRACKS ACROSS CHEJU-DO AND SOUTHWEST SOUTH KOREA. DUE TO THESE FACTAORS, TD 07W IS FORECAST TO WEAKEN QUICKLY WITH DISSIPATION BETWEEN TAU 12 AND TAU 24. MODEL DISCUSSION: DESPITE THE COMPLEX INTERACTION WITH TD 06W, THE NUMERICAL GUIDANCE IS IN FAIR AGREEMENT INDICATING A NORTH-NORTHWESTWARD TO NORTHWARD TRACK THROUGH TAU 24. THE 311800Z ECMWF ENSEMBLE (EPS) ALSO INDICATES A SIMILAR SPREAD OF SOLUTIONS, THEREFORE, THERE IS MEDIUM OVERALL CONFIDENCE IN THE JTWC TRACK FORECAST. THE INTENSITY FORECAST IS FAIRLY STRAIGHT-FORWARD WITH PEAK INTENSITY LIMITED, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC INTENSITY FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM INTENSITY 0 - 72 HR: HIGH// NNNN