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#52547 (Received by flhurricane at: 11:11 PM 19.Oct.2005) TCDAT4 HURRICANE WILMA DISCUSSION NUMBER 19 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT WED OCT 19 2005 EARLIER REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT WILMA HAD A CENTRAL PRESSURE OF 892 MB INSIDE THE 4 N MI WIDE EYE...ALONG WITH 700 MB FLIGHT-LEVEL WINDS OF 140-150 KT. SINCE THAT TIME...SATELLITE IMAGERY SHOWS THAT THE EYE HAS BECOME CLOUD-FILLED. ADDITIONALLY...A 00Z SSM/I OVERPASS SHOWS THAT THE INNER EYEWALL HAS WEAKENED AS A 40 N MI WIDE OUTER EYEWALL BECOMES BETTER DEFINED. BASED ON THIS...THE INITIAL INTENSITY IS DECREASED TO 135 KT. THE NEXT AIRCRAFT IS SCHEDULED TO INVESTIGATE WILMA AROUND 05Z-06Z. THE INITIAL MOTION IS A VERY WOBBLY 300/7. IN THE SHORT TERM...A LOW/MID-LEVEL RIDGE NORTH OF WILMA SHOULD STEER THE HURRICANE ON A GENERALLY NORTHWESTWARD TRACK TOWARD THE YUCATAN PENINSULA. AFTER 24-36 HR...THE RIDGE SHOULD WEAKEN AS A SHORTWAVE TROUGH MOVES THROUGH THE EASTERN UNITED STATES...FOLLOWED BY THE DEVELOPMENT OF A POWERFUL DEEP-LAYER TROUGH OVER THE EASTERN U. S.. THE FIRST SHORTWAVE SHOULD ALLOW WILMA TO TURN NORTHWARD...WHILE THE STRONGER TROUGH SHOULD EVENTUALLY RECURVE THE STORM INTO THE WESTERLIES. THE LATEST RUNS OF THE GFDL AND GFS HAVE RETURNED TO THEIR EARLIER NO-STALL RECURVATURE SCENARIO...THUS INCREASING THE AGREEMENT BETWEEN THE MODELS THROUGH 72-96 HR. HOWEVER...THE ENTIRE SUITE OF GUIDANCE IS SLOWER FOR THE FIRST 96 HR THAN THE EARLIER RUNS. THE NEW FORECAST TRACK IS SHIFTED A LITTLE TO THE LEFT FOR THE FIRST 48 HR...THEN IS SLOWER THAN THE PREVIOUS FORECAST FROM 48-96 HR. HOWEVER...EVEN THIS SLOWER FORECAST IS FASTER THAN THE GUIDANCE. IT SHOULD ALSO BE NOTED THAT THE TRACK IS ALONG THE RIGHT SIDE OF THE GUIDANCE ENVELOPE...A LITTLE TO THE RIGHT OF THE MODEL CONSENSUS. WILMA SHOULD UNDERGO AN EYEWALL REPLACEMENT CYCLE DURING THE NEXT 12-24 HR. THE FIRST 36 HR OF THE INTENSITY FORECAST IS BASED ON THE PREMISE THAT WILMA WILL RE-INTENSIFY WHEN THE CYCLE IS OVER. THERE IS A CHANCE WILMA COULD WEAKEN MORE THAN CURRENTLY FORECAST BEFORE THE EYEWALL CYCLE ENDS. THE SHIPS MODEL IS FORECASTING A SIGNIFICANT INCREASE IN VERTICAL SHEAR ONCE WILMA REACHES THE THE GULF OF MEXICO. THAT COMBINED WITH COOLER SEA SURFACE TEMPERATURES SHOULD CAUSE A GRADUAL WEAKENING. THAT BEING SAID...WILMA IS STILL EXPECTED TO REACH FLORIDA AS A MAJOR HURRICANE. AFTER PASSAGE OVER FLORIDA...WILMA SHOULD CONTINUE TO WEAKEN DUE TO SHEAR AND EVEN COOLER WATER. THERE ARE TWO POSSIBILITIES THAT COULD MAKE LARGE DIFFERENCES IN THE INTENSITY OF WILMA. THE FIRST IS THE POSSIBILITY OF LANDFALL OVER YUCATAN OR THE INTERACTION WITH THE PENINSULA IN THE FORECAST CLOSE APPROACH. A LANDFALL WOULD RESULT IN A WEAKER STORM...WHILE INTERACTION COULD WEAKEN THE SYSTEM MORE THAN CURRENTLY FORECAST. THE SECOND IS POSSIBLE EXTRATROPICAL TRANSITION AND PHASING WITH THE DEEP TROUGH AFTER 96 HR. SHOULD THIS HAPPEN...WILMA COULD BECOME A POWERFUL STORM EITHER OVER THE WESTERN ATLANTIC OR THE NORTHEASTERN U. S.. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 20/0300Z 18.1N 84.3W 135 KT 12HR VT 20/1200Z 18.8N 85.2W 135 KT 24HR VT 21/0000Z 19.8N 86.0W 145 KT 36HR VT 21/1200Z 20.8N 86.5W 145 KT 48HR VT 22/0000Z 21.8N 86.6W 125 KT 72HR VT 23/0000Z 24.0N 84.5W 110 KT 96HR VT 24/0000Z 27.0N 80.0W 80 KT 120HR VT 25/0000Z 38.0N 70.5W 65 KT |