WDPN32 PGTW 071500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 046// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 28.4N 131.2E INITIAL INTENSITY: 55 KTS GEOGRAPHIC REFERENCE: 292 NM SOUTH-SOUTHEAST OF SASEBO, JAPAN MOVEMENT PAST 6 HOURS: NORTHWARD AT 03 KTS SIGNIFICANT WAVE HEIGHT: 34 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED PROXYVIS SATELLITE IMAGERY DEPICTS DEEP CONVECTIVE BANDING WRAPPING INTO A BROAD, EXPOSED CENTER WITH MULTIPLE MESOVORTICES ROTATING CYCLONICALLY AROUND A DEFINED CENTROID. ANIMATED RADAR IMAGERY REVEALS CONVECTIVE BANDING WRAPPING INTO A BROAD, ILL-DEFINED CENTER. A 070847Z SMAP IMAGE SHOWS A LARGE, SYMMETRIC CORE OF WEAK WINDS, ABOUT 90 NM DIAMETER, WITH A REGION OF 55-60 KNOT WINDS (1- MINUTE AVERAGE) OVER THE EAST AND SOUTH QUADRANTS. DUE TO THE BROAD NATURE OF THE CENTER, THERE IS MEDIUM CONFIDENCE IN THE INITIAL POSITION. OVER THE PAST SIX HOURS, THE TRACK MOTION HAS REMAINED SLOW TOWARD THE NORTH. A 070917Z SSMIS 37 GHZ COLOR COMPOSITE IMAGE SUGGESTS SLIGHTLY IMPROVED CONVECTIVE STRUCTURE WITH BANDING WRAPPING INTO A DEFINED CENTER. ENVIRONMENTAL CONDITIONS HAVE IMPROVED WITH EXPANDING RADIAL OUTFLOW, LOW VERTICAL WIND SHEAR AND WARM SST (29C). HOWEVER, MID-LEVEL TO UPPER-LEVEL DRY AIR ENTRAINMENT IS LIKELY HINDERING DEVELOPMENT AT THIS TIME. THE INITIAL IS BASED ON THE RECENT SMAP DATA HEDGED CLOSER TO THE RJTD CURRENT INTENSITY ESTIMATE OF 55 KNOTS. A 070907Z RCM-2 SAR IMAGE INDICATES MAXIMUM WINDS OF 69 KNOTS BUT APPEARS TO BE TOO HIGH. INITIAL WIND RADII BASIS: SMAP DATA ADJUSTED WITH SURFACE OBSERVATIONS OVER THE RYUKYU ISLANDS. CURRENT STEERING MECHANISM: WEAK SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST AND NORTHEAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T3.5 - 55 KTS RCTP: T2.5 - 35 KTS KNES: T3.0 - 45 KTS CIMSS SATCON: 47 KTS AT 071034Z CIMSS ADT: 39 KTS AT 071140Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE RADIAL OTHER FACTORS: DRY AIR ENTRAINMENT ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 06W IS DRIFTING SLOWLY POLEWARD BASED ON A SERIES OF RECENT JMA RADAR FIXES AND IS FORECAST TO TRACK SLOWLY NORTHWARD TO NORTH-NORTHWESTWARD OVER THE NEXT 48 HOURS WHILE STEADILY INTENSIFYING TO 65-70 KNOTS NEAR SASEBO DUE TO IMPROVING, ROBUST POLEWARD OUTFLOW AND WARM SST VALUES. THE SYSTEM IS FORECAST TO GRADUALLY RE-MOISTEN, WHICH WILL ALSO AID IN THE REINTENSIFICATION PHASE. AFTER TAU 72, TS KHANUN WILL ACCELERATE OVER THE KOREAN PENINSULA AND BEGIN INTERACTING WITH THE LEADING EDGE OF A SUBTROPICAL SHORTWAVE TROUGH AND WEAK BAROCLINIC ZONE. DESPITE THE BAROCLINIC INFLUENCE, THE SYSTEM IS FORECAST TO DISSIPATE AS IT TRACKS INTO NORTH KOREA AND NORTHEAST CHINA. MODEL DISCUSSION: NUMERICAL GUIDANCE HAS SHIFTED FURTHER WEST OVER THE WESTERN KOREAN PENINSULA AND WEST SEA. CONSEQUENTLY, THE JTWC TRACK FORECAST WAS SHIFTED SLIGHTLY WEST OF THE PREVIOUS WARNING. DUE TO THE BROAD CENTER AND UNCERTAINTY IN THE INITIAL POSITION AND TRACK MOTION, THE JTWC TRACK FORECAST IS POSITIONED ALONG THE EASTERN EDGE OF THE AIDS ENVELOPE CLOSE TO THE ECMWF TRACK. SEVERAL MODELS INCLUDING GFS, UKMET AND NAVGEM TRACK THE SYSTEM NORTH-NORTHWESTWARD OVER THE WEST SEA INTO THE UPPER LEVEL WESTERLIES, WHICH APPEARS A LITTLE SUSPECT. HOWEVER, THE 070600Z GEFS AND EPS PROBABILISTIC GUIDANCE SHOWS INCREASING UNCERTAINTY WITH A LARGE SPREAD AFTER TAU 48. OVERALL, THERE IS MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST WITH THE 070000Z COAMPS-TC ENSEMBLE SHOWING AN 80 TO 100 PERCENT PROBABILITY OF MODERATE INTENSIFICATION THROUGH TAU 24 DECREASING TO 40 PERCENT PROBABILITY THROUGH TAU 48. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN