WDXS31 PGTW 160300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING NR 027// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.8S 82.5E INITIAL INTENSITY: 135 KTS GEOGRAPHIC REFERENCE: 748 NM SOUTHEAST OF DIEGO GARCIA MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS SIGNIFICANT WAVE HEIGHT: 39 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A WELL DEFINED AND HIGHLY SYMMETRIC TROPICAL CYCLONE WITH A 7NM PINHOLE EYE. A 152222Z SSMIS 91GHZ MICROWAVE IMAGE DEPICTS A ROBUST AND WELL DEFINED EYE WALL WITH LIMITED CLOUD FEATURES EXTENDING OUTWARD FROM THE CENTRAL DENSE OVERCAST (CDO) INDICATIVE OF AN ANNULAR TC. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON EIR AND SSMIS IMAGERY. THE INITIAL INTENSITY OF 135 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AGENCY DVORAK CURRENT INTENSITY ESTIMATES ALL INDICATING T7.0. LESS CONFIDENCE IS PLACED IN AUTOMATED INTENSITY ESTIMATES SUCH AS CIMSS ADT AND SATCON WHICH HAVE RECENTLY REMAINED TOO LOW DESPITE PHYSICAL EVIDENCE (SCATTEROMETRY AND SAR) INDICATING MUCH HIGHER. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE SOUTH AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T7.0 - 140 KTS KNES: T7.0 - 140 KTS DEMS: T7.0 - 140 KTS CIMSS SATCON: 126 KTS AT 151943Z CIMSS ADT: 129 KTS AT 152100Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 10-15 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 11S IS FORECAST TO CONTINUE ITS WESTWARD MARCH AND BASED ON ITS ANNULAR CHARACTERISTICS, IT HAS DEMONSTRATED A PROCLIVITY FOR COCOONING ITSELF AND RESISTING THE SHEAR AND DRY ENVIRONMENT THAT SURROUNDS IT. THROUGH TAU 12, BASED ON THIS COCOONING AND OTHERWISE POSITIVE ENVIRONMENTAL CONDITIONS, (WARM SSTS AND GOOD DIVERGENCE ALOFT) FREDDY WILL LIKELY RETAIN MOST OF ITS CURRENT INTENSITY. AFTER TAU 12 THE SYSTEM WILL BEGIN TO SLOWLY WEAKEN AS IT CONTINUES WESTWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE SOUTH. AS THE STEERING RIDGE STRUGGLES TO BUILD WESTWARD, THE SYSTEM WILL GRADUALLY STEADY UP ON A WEST-SOUTHWESTWARD COURSE. IN THE EXTENDED TRACK, 11S IS FORECAST TO INCREASE SPEED AS THE RIDGE CONSOLIDATES AND REORIENTS, FORCING THE STILL TYPHOON STRENGTH SYSTEM TOWARDS MADAGASCAR. MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A BULK OF THE GUIDANCE FOLLOWING THE JTWC FORECAST TRACK WHILE COAMPS-TC (NVGM VERSION) SHOWS A MORE POLEWARD TRACK TOWARDS SOUTHERN MADAGASCAR. BASED ON THE 300NM SPREAD IN SOLUTIONS AT TAU 120, THE INITIAL TRACK FORECAST IS PLACED WITH HIGH CONFIDENCE WHILE THE EXTENDED TRACK FORECAST IS PLACED WITH MEDIUM CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE INDICATES THAT A BULK OF THE MODELS SHOW SLIGHT WEAKENING OR STAGNATION THROUGH TAU 12 AFTER WHICH GRADUAL DECLINE THROUGH THE FORECAST PERIOD WITH ALL MEMBERS INDICATING A TYPHOON STRENGTH TC AT TAU 120. FOR THIS REASON THE INITIAL INTENSITY FORECAST IS PLACED WITH MEDIUM CONFIDENCE WHILE THE EXTENDED INTENSITY FORECAST IS PLACED WITH LOW CONFIDENCE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN