WDPS31 PGTW 030300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 15P (JUDY) WARNING NR 017// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 25.5S 177.0E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 451 NM SOUTH OF SUVA, FIJI MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 36 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: AS THE SYSTEM CONTINUES TO BE BATTERED BY DRY AIR FROM THE WEST, ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A NEAR FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). WITH LIMITED MICROWAVE DATA, THANKFULLY A 022151Z ASCAT-B SCATTEROMETRY PASS CAME TO THE RESCUE. THIS ASCAT-B PASS INDICATES THE SYSTEM STILL POSSESSES A LARGELY SYMMETRIC AND ROBUST WIND FIELD WITH A BULK OF THE HIGHEST WINDS EXCLUSIVELY TO THE NORTHEAST OF THE LLCC. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON MSI AND ASCAT-B IMAGERY. THE INITIAL INTENSITY OF 75 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON PGTW AND KNES DVORAK INTENSITY ESTIMATES INDICATING 65-77 KTS. DVORAK INTENSITY ESTIMATES HISTORICALLY WEAKEN SYSTEMS TOO FAST WHICH IS WHY THE JTWC INITIAL INTENSITY IS PLACED ON THE HIGHER END OF THIS SPECTRUM WITH MEDIUM CONFIDENCE. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS KNES: T4.5 - 77 KTS CIMSS ADT: 57 KTS AT 022330Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 30+ KTS SST: 26-27 CELSIUS OUTFLOW: STRONG EASTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 15P (JUDY) IS FORECAST TO CONTINUE TRACKING EAST-SOUTHEASTWARD UNDER THE STEERING INFLUENCE OF THE STR. 15P WILL CONTINUE TO WEAKEN IN A UNFAVORABLE ENVIRONMENT CHARACTERIZED BY HIGH VERTICAL WIND SHEAR, INCREASING DRY AIR ENTRAINMENT AND COOLING SEA SURFACE TEMPERATURES, WHICH WILL GRADUALLY ERODE THE SYSTEM DOWN TO 60KTS BY TAU 12. THE SURPRISINGLY SYMMETRIC AND ROBUST LOW LEVEL WIND FIELD, 850MB VORTICITY SIGNATURE AND MOISTURE STRUCTURE ARE THE PRIMARY TROPICAL CHARACTERISTICS THAT 15P IS DISPLAYING AT THIS TIME. OVER THE NEXT 12 HOURS, THESE FACTORS WILL BEGIN TO FALTER, HERALDING ITS INEVITABLE SUBTROPICAL TRANSITION (STT). BY TAU 24, NOW DEVOID OF ANY TROPICAL CHARACTERISTICS AND EMBEDDED IN THE SUBTROPICAL JET, TC 15P WILL TRANSFORM INTO A SUBTROPICAL LOW WITH AN EXPANDING WIND FIELD. MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT, WITH A 73NM SPREAD IN SOLUTIONS AT TAU 24. FOR THIS REASON THE JTWC TRACK FORECAST IS PLACED WITH HIGH CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD AGREEMENT WITH ALL MEMBERS WEAKENING THE SYSTEM THROUGH THE FORECAST PERIOD. FOR THIS REASON THE JTWC INTENSITY FORECAST IS ALSO PLACED WITH HIGH CONFIDENCE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH INTENSITY 0 - 72 HR: HIGH// NNNN