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| #219108 (Received by flhurricane at: 4:46 AM 28.Sep.2008) TCDAT1 HURRICANE KYLE DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112008 500 AM EDT SUN SEP 28 2008 KYLE EMERGED FROM THE SATELLITE ECLIPSE PERIOD LOOKING RATHER UGLY FROM A CONVECTION PERSPECTIVE. HOWEVER...THERE IS ENOUGH CONVECTION NEAR AND NORTH OF THE CENTER ALONG WITH SUPPORTIVE RECON WIND DATA TO KEEP THE CYCLONE DESIGNATED AS A HURRICANE. THE HIGHEST 700 MB FLIGHT-LEVEL WIND SPEED MEASURED IN THE NORTHEAST QUADRANT WAS 80 KT AND THE MAXIMUM SFMR SURFACE WIND SPEED OBSERVED WAS 61 KT. HOWEVER...THESE TWO WIND SPEED VALUES WERE NOT ANYWHERE CLOSE TO HAVING BEEN OBSERVED IN THE SAME GENERAL LOCATION. DROPSONDE WIND PROFILES ALSO INDICATE THAT THERE IS CONSIDERABLE NORTHEASTWARD TILT BETWEEN THE SURFACE AND FLIGHT-LEVEL CENTERS. THE TWO CENTER DROPS REVEALED LIGHT WINDS AT FLIGHT-LEVEL WITH UP TO 52 KT AT THE SURFACE ALONG WITH A PRESSURE VALUE OF 1001 MB. USING A 1 MB PER 10 KT REDUCTION FACTOR YIELDS A CENTRAL PRESSURE OF APPROXIMATELY 996 MB. ALTHOUGH THE 80-KT FLIGHT-LEVEL WIND WOULD NORMALLY RESULT IN A SURFACE WIND ESTIMATE OF 73 KT...THE SEVERELY TILTED STRUCTURE AND DEGRADED CONVECTIVE PATTERN HAS INSTEAD COMPELLED ME TO USE A BLEND OF THE FLIGHT-LEVEL AND PEAK SFMR WIND SPEEDS TO ESTIMATE THE MAXIMUM SURFACE WIND SPEED TO BE 65 KT. HOWEVER...THIS VALUE COULD BE ADJUSTED IN THE POST-STORM ANALYSIS. THE INITIAL MOTION ESTIMATE IS 010/21 KT. RECON FIX DATA SHOWS THAT KYLE REMAINS ON TRACK. WATER VAPOR SATELLITE IMAGERY INDICATES KYLE HAS BEEN CAPTURED BY AN EAST-WEST ORIENTED SHORTWAVE TROUGH AND IS BEING LIFTED NORTHWARD BY DEEP-LAYER SOUTHERLY FLOW BETWEEN A LARGE RIDGE TO THE EAST AND A BROAD TROUGH TO THE WEST SITUATED OVER THE EASTERN UNITED STATES. THE NHC MODEL GUIDANCE REMAINS TIGHTLY CLUSTERED ON A NORTH-NORTHEASTWARD TRACK TOWARD THE GULF OR MAINE AND BAY OF FUNDY AS KYLE IS EXPECTED TO ROUND THE NORTHWEST PERIPHERY OF THE LARGE-SCALE RIDGE. THEREFORE...THE CURRENT FORECAST TRACK IS JUST AN UPDATE OF THE PREVIOUS ADVISORY TRACK. POST-ECLIPSE SATELLITE IMAGES INDICATE THAT KYLE IS BECOMING CONVECTIVELY CHALLENGED DUE TO INCREASING SOUTHWESTERLY VERTICAL WIND SHEAR. KYLE IS ALSO ABOUT 6-9 HOURS AWAY FROM REACHING MUCH COOLER WATERS THAT NORTH OF THE GULFSTREAM THAT IS POSITIONED ALONG 40N LATITUDE. THESE NEGATIVE FACTORS SHOULD RESULT IN GRADUAL WEAKENING OF THE CYCLONE...AND IT IS POSSIBLE THAT THE LOW- AND UPPER-LEVEL CIRCULATIONS COULD DECOUPLE BEFORE KYLE REACHES ANY LAND AREAS IN ABOUT 24 HOURS. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND FOLLOWS THE DOWNWARD TREND PREDICTED BY THE SHIPS...GFDL...HWRF INTENSITY MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 28/0900Z 38.4N 69.1W 65 KT 12HR VT 28/1800Z 41.5N 68.2W 60 KT 24HR VT 29/0600Z 45.2N 66.5W 55 KT...BECOMING EXTRATROPICAL 36HR VT 29/1800Z 48.0N 64.9W 40 KT...EXTRATROPICAL INLAND 48HR VT 30/0600Z 49.5N 64.1W 35 KT...EXTRATROPICAL INLAND 72HR VT 01/0600Z 50.8N 63.3W 30 KT...EXTRATROPICAL INLAND 96HR VT 02/0600Z...ABSORBED BY FRONTAL SYSTEM $$ FORECASTER STEWART |
