WDXS31 PGTW 130300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING NR 021// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 15.1S 96.8E INITIAL INTENSITY: 100 KTS GEOGRAPHIC REFERENCE: 163 NM SOUTH OF COCOS ISLAND, AUSTRALIA MOVEMENT PAST 6 HOURS: WESTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: 46 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A COMPACT AND INTENSE SYSTEM WITH A SYMMETRICAL CENTRAL DENSE OVERCAST THAT IS OFFSET WESTWARD BUT HAS MAINTAINED OVERALL CONVECTIVE STRUCTURE AND A PINHOLE EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE IN THE MSI LOOP. THE INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON CLOSELY CLUSTERED AND ESTIMATED AGENCY DVORAK FIXES AND REFLECTS THE 12-HR SUSTAINED INTENSITY. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH MODERATE VWS OFFSET BY WARM SST AND STRONG RADIAL OUTFLOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE SOUTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.5 - 102 KTS KNES: T6.0 - 115 KTS DEMS: T5.5 - 102 KTS CIMSS SATCON: 104 KTS AT 121858Z CIMSS ADT: 90 KTS AT 122340Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 15-20 KTS SST: 27-28 CELSIUS OUTFLOW: STRONG WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC FREDDY WILL CONTINUE ON A GENERALLY WESTWARD TRACK UNDER THE STEERING STR. THE ENVIRONMENT WILL BECOME LESS FAVORABLE WITH THE INCURSION OF DRY AIR IN THE MID-LEVELS IN ADDITION TO INCREASING VWS THAT WILL CAUSE A GRADUAL WEAKENING TO 80KTS BY TAU 48. AFTERWARD, THE DIMINISHING DRY AIR AND INCREASING POLEWARD OUTFLOW WILL FUEL ANOTHER RE-INTENSIFICATION PHASE, ALBEIT MORE GRADUAL, TO 110KTS BY TAU 96 BEFORE ANOTHER WEAKENING PHASE FOLLOWS. MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH AN EVEN AND GRADUAL SPREADING TO 152NM BY TAU 120, LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. THE INTENSITY FORECAST IS ONLY AT MEDIUM CONFIDENCE FOR THE DURATION OF THE FORECAST DUE TO THE UP-AND-DOWN INTENSITY CHANGES. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN