WDXS32 PGTW 220300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 16S (ELEANOR) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.3S 59.1E INITIAL INTENSITY: 55 KTS GEOGRAPHIC REFERENCE: 112 NM EAST-NORTHEAST OF PORT LOUIS, MAURITIUS MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 17 KTS SIGNIFICANT WAVE HEIGHT: 25 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL CYCLONE (TC) 16S (ELEANOR) TRACKING SOUTH-SOUTHWESTWARD AT 17KTS WITH MODERATE RADIAL OUTFLOW AND SMALL AMOUNTS OF STRIATED OUTFLOW WEAKLY EXTENDING TO THE SOUTHEAST. DEEP CONVECTION BRIEFLY DEVELOPED INTO A VERY SYMMETRICAL CENTRAL DENSE OVERCAST (CDO) BUT CLOUD TOPS HAVE SUBSEQUENTLY WARMED AND DECREASED IN AREAL COVERAGE. THE SEA SURFACE TEMPERATURES (SST) ARE FAVORABLE BETWEEN 28-29C, HOWEVER OUTFLOW IS MODERATE IN THE UPPER LEVELS DUE TO NORTHEASTERLY VWS RANGING FROM 15-20KTS. DRY AIR FROM THE SOUTHEAST IS ALSO BEGINNING TO WRAP AROUND THE NORTHERN SEMICIRCLE OF THE STORM. TC 16S IS BEING STEERED SOUTH-SOUTHWESTWARD ON THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE EAST. THE INITIAL POSITION WAS ASSESSED WITH MEDIUM CONFIDENCE BASED ON RADAR IMAGERY FROM MAURITIUS DEPICTING A LOWER LEVEL CIRCULATION CENTER (LLCC) AND AN EXTRAPOLATED 22325Z SSMIS 37GHZ IMAGE SHOWING A MICROWAVE EYE-LIKE STRUCTURE. THE INITIAL INTENSITY WAS ASSESSED WITH MEDIUM CONFIDENCE USING PERSISTENCE AND THE SUBJECTIVE AND OBJECTIVE FIXES LISTED BELOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF AN STR TO THE EAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS KNES: T3.5 - 55 KTS FMEE: T3.5 - 55 KTS FIMP: T4.0 - 65 KTS CIMSS SATCON: 48 KTS AT 220030Z CIMSS ADT: 57 KTS AT 220030Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM 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: THROUGH TAU 12, TC 16S IS FORECAST TO TRACK SOUTH-SOUTHWEST AS IT CONTINUES TO RIDE THE WESTERN PERIPHERY OF AN STR TO THE EAST BEFORE TRACKING ON A MORE SOUTHERLY ROUTE ALONG THE RIDGE THROUGH TAU 24. AROUND TAU 48, A DEEP MID-LATITUDE TROUGH MOVES IN FROM THE WEST, INDUCING SIGNIFICANT VERTICAL WIND SHEAR OF 25-30KTS, WHICH WILL SHEAR APART TC 16S, MARKING THE ONSET OF RAPID WEAKENING. AS THE SYSTEM WEAKENS, THE VORTEX WILL SHALLOW OUT, RESULTING IN THE LOWER-LEVEL FLOW BECOMING THE DOMINANT STEERING MECHANISM AND A TRACK TO THE WEST-NORTHWEST THROUGH THE END OF THE FORECAST PERIOD. THE SYSTEM IS ANTICIPATED TO INTENSIFY THROUGH TAU 12 AND PEAK AT APPROXIMATELY 65KTS AS UPPER-LEVEL POLEWARD OUTFLOW INTO A 120 KNOT JET MAX TO THE SOUTH OFFSETS STEADILY INCREASING VWS. BEYOND TAU 24, VERTICAL WIND SHEAR IS EXPECTED TO SIGNIFICANTLY INCREASE TO A STRONG 25-30KTS AND ENCOURAGE DRY AIR ENTRAINMENT AS THE SYSTEM STEADILY DRIES AND WEAKENS TO 45KTS BY TAU 48 AND REACH FULL DISSIPATION OF 30KTS AT TAU 96. MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT THAT TC 16S WILL TRAVEL SOUTH-SOUTHWESTWARD THROUGH TAU 24, WITH A CROSS-TRACK ERROR OF ONLY APPROXIMATELY 100NM THROUGH THE ENTIRE FORECAST PERIOD. THE TRACK CONTINUES TO AGREE THROUGH TAU 36-48 EXPECTING A WEST-NORTHWESTERLY TRACK THROUGH THE END OF THE FORECAST PERIOD. JTWC INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT THE SYSTEM WILL PEAK BETWEEN 60-65KTS BY TAU 12 BEFORE CONTINUING TO DISSIPATION THROUGH THE END OF THE FORECAST PERIOD. THE ONLY STANDOUT MEMBER WAS THE JTWC SHIPS (GFS) MEMBER WHICH REMAINS JUST ABOVE 35KTS THROUGH TAU 120. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN