WDXS31 PGTW 111500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING NR 018// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.8S 103.0E INITIAL INTENSITY: 105 KTS GEOGRAPHIC REFERENCE: 775 NM NORTHWEST OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: WESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 40 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL CYCLONE (TC) 11S HAS RAPIDLY INTENSIFIED 35 KNOTS OVER THE PAST 24 HOURS FROM 70 KNOTS AT 101200Z TO THE CURRENT INTENSITY OF 105 KNOTS. THIS RECENT RI PHASE HAS OCCURRED DESPITE MODERATE TO HIGH (20 TO 25 KNOTS) EASTERLY VERTICAL WIND SHEAR (VWS) CLEARLY EVIDENT IN ANIMATED WATER VAPOR IMAGERY. SPECIFICALLY, TC 11S HAS MAINTAINED A COMPACT 90NM DIAMETER CORE, WHICH IS COCOONING AND ALLOWING THE SYSTEM TO FIGHT THIS EASTERLY VWS WITH IMPROVED OUTFLOW OVER THE EASTERN SEMICIRCLE. AS DEPICTED IN ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND AN 111206Z SSMIS 91GHZ MICROWAVE IMAGE, TC 11S HAS NOW FORMED A 10NM OBLONG EYE, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 105 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE PGTW AND KNES DVORAK INTENSITY ESTIMATES. UNFORTUNATELY, DUE TO COMMUNICATIONS ISSUES, ADT, AIDT, DMN AND OPEN-AIIR ESTIMATES STOPPED UPDATING AT ABOUT 111100Z WITH ADT RAW T NUMBERS AT 6.1 (ABOUT 115 KNOTS). INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE SOUTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.5 - 102 KTS KNES: T6.0 - 115 KTS CIMSS ADT: 90 KTS AT 110830Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 20-25 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 TRACK WESTWARD THROUGH THE FORECAST PERIOD ALONG THE NORTHERN PERIPHERY OF THE STR. THE SYSTEM SHOULD INTENSIFY SLIGHTLY TO 110 KNOTS, PERHAPS SLIGHTLY HIGHER, IN THE NEXT 12 HOURS. HOWEVER, VWS IS FORECAST TO MAINTAIN AT 20 TO 25 KNOTS THROUGH TAU 36 WHICH COULD HINDER DEVELOPMENT AND QUITE POSSIBLY WEAKEN THE COMPACT SYSTEM EARLIER THAN EXPECTED. REGARDLESS, A STEADY WEAKENING TREND IS EXPECTED AFTER TAU 12. REINTENSIFICATION IS EXPECTED IN THE LATER TAUS AS VWS RELAXES AGAIN BUT WITH A LOWER PEAK INTENSITY DUE TO COOLING SST VALUES (26-27C). MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH A 105NM SPREAD IN SOLUTIONS AT TAU 72 DIVERGING SLIGHTLY TO 135NM AT TAU 120 THEREFORE THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. DUE TO THE COMPACT NATURE OF THE SYSTEM AND ITS TENDENCY FOR LARGE FLUCTUATIONS IN INTENSITY, THERE IS MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST. RELIABLE INTENSITY GUIDANCE INDICATES A LARGE SPREAD THROUGH TAU 120. THE 110000Z COAMPS-TC ENSEMBLE INDICATES A 30 TO 40 PERCENT PROBABILITY OF RI OCCURRING FROM TAU 72 TO TAU 96, WHICH SUPPORTS THE REINTENSIFICATION PHASE IN THE JTWC INTENSITY FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN