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#52840 (Received by flhurricane at: 5:03 PM 21.Oct.2005) TCDAT4 HURRICANE WILMA DISCUSSION NUMBER 26 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT FRI OCT 21 2005 THE EYE OF WILMA HAS BEEN GRADUALLY CONTRACTING DURING THE DAY... WITH THE EYE DIAMETER DOWN TO 25 N MI COMPARED TO 30 N MI THIS MORNING. CONCENTRIC EYEWALLS REMAIN AT RADII OF ABOUT 20 AND 40 N MI... WITH FLIGHT LEVEL WIND DATA INDICATING THAT THE OUTER EYEWALL CONTAINS THE STRONGEST WINDS. SEVERAL EYEWALL DROPSONDES HAVE MEASURED SURFACE WINDS IN THE 110-130 KT RANGE. ONE SUCH SONDE MEASUREMENT MIGHT NOT BE REPRESENTATIVE OF SUSTAINED SURFACE WINDS... BUT A SEQUENCE OF THEM PROBABLY PROVIDES A REASONABLE ESTIMATED OF THE INTENSITY... WHICH IS ESTIMATED TO BE IN THE MIDDLE OF THIS RANGE AT 120 KT. THE ADVISORY INTENSITY IS ALSO SUPPORTED BY 18Z DVORAK INTENSITY ESTIMATES THAT ARE UNANIMOUSLY T6.5/127 KT. WILMA IS MOVING SLOWLY NORTHWESTWARD... NEARLY ALONG THE PREVIOUS ADVISORY TRACK WITH A SLIGHTLY WOBBLY MOTION OF 320 DEGREES AT 4 KT. THE CENTER OF THE EYE IS CROSSING THE NORTHEASTERN END OF THE ISLAND OF COZUMEL AT THIS HOUR... BUT DUE TO THE SLOW MOTION IT WILL PROBABLY TAKE A FEW MORE HOURS FOR THE EYE TO CROSS THE NORTHEASTERN COAST OF THE YUCATAN PENINSULA. NEARLY ALL OF THE DYNAMICAL MODELS FORECAST WILMA TO CONTINUE MOVING INLAND AND PROCEED RATHER SLOWLY DURING THE NEXT COUPLE OF DAYS. THE NEW OFFICIAL FORECAST ANTICIPATES WILMA COULD SPEND ABOUT 24 HOURS OVER LAND... WHICH WILL PROBABLY LEAD TO MORE WEAKENING THAN HAS PREVIOUSLY BEEN FORECAST. OBVIOUSLY THIS WILL INCREASE THE DURATION OF DESTRUCTIVE WINDS AND HEAVY RAINS OVER YUCATAN. IT SEEMS PROBABLE THAT WILMA WILL STILL EMERGE NORTH OF THE PENINSULA AS A HURRICANE IN ABOUT 36 HOURS... ALTHOUGH SOME OF THE MODELS SUGGEST IT COULD LINGER FOR LONGER THAN THAT. WHEN IT DOES REACH THE GULF OF MEXICO... CONDITIONS APPEAR TO BE CONDUCIVE FOR A LITTLE RESTRENGTHENING IN THE SHORT TERM. WHEN WILMA MOVES FARTHER NORTHEASTWARD AND WIND SHEAR INCREASES... A WEAKENING TREND IS EXPECTED PRIOR TO PASSAGE OVER FLORIDA. THE OFFICIAL FORECAST OF THE INTENSITY AS WILMA APPROACHES FLORIDA IS LESS THAN IN THE PREVIOUS ADVISORY... PRIMARILY DUE TO THE WEAKENING EXPECTED OVER YUCATAN. THE MODELS ARE IN REMARKABLE AGREEMENT... AT LEAST FOR NOW... REGARDING WHERE WILMA WILL PASS OVER FLORIDA... ALTHOUGH THEY COULD OF COURSE ALL BE WRONG TO SOME DEGREE GIVEN THE 3-4 DAY LEAD TIME. SIGNIFICANT DISAGREEMENT REMAINS IN THE TIMING OF THE IMPACT ON FLORIDA... SO THE WHILE THE CONFIDENCE IN THE OFFICIAL FORECAST HAS INCREASED A LITTLE WITH RESPECT TO WHERE WILMA WILL EVENTUALLY GO... THE UNCERTAINTY IN THE TIMING REMAINS LARGE. FORECASTER KNABB FORECAST POSITIONS AND MAX WINDS INITIAL 21/2100Z 20.6N 86.9W 120 KT 12HR VT 22/0600Z 20.9N 87.3W 100 KT...INLAND 24HR VT 22/1800Z 21.2N 87.5W 80 KT...INLAND 36HR VT 23/0600Z 21.8N 87.4W 80 KT 48HR VT 23/1800Z 22.7N 86.5W 90 KT 72HR VT 24/1800Z 25.5N 82.5W 80 KT 96HR VT 25/1800Z 32.0N 75.0W 60 KT 120HR VT 26/1800Z 42.0N 62.9W 55 KT...EXTRATROPICAL |