Area Forecast Discussion
Issued by NWS Key West, FL
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Issued by NWS Key West, FL
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-- Discussion containing changed information from previous version are highlighted. --114 FXUS62 KKEY 191843 AFDKEY Area Forecast Discussion National Weather Service Key West FL 243 PM EDT Wed Jun 19 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION...-- Changed Discussion --Issued at 230 PM EDT Wed Jun 19 2024 Scattered showers and isolated thunderstorms continue to dot the Florida Keys island chain as well as the adjacent nearshore and offshore coastal waters. Surface wind observations suggest the zone of the greatest confluence was confined to the Lower and Middle Keys today. Remote sensing- derived rainfall estimates support this evaluation, general rainfall amounts between 0.1-0.75" across island communities here, with totals generally less than 0.1" in the Upper Keys. Outside of any passing showers, skies are generally partly cloudy across the Florida Keys, with temperatures in the upper 80s to near 90F. Satellite-derived vorticity analysis shows a well-defined tropical upper-tropospheric trough (TUTT) cell pinching off in the vicinity of the Florida Keys. Meanwhile, a tropical wave currently north of the Lesser Antilles continues to progress towards the west to northwest. Finally, at the surface, a strong area of high pressure east of New England continues to interact with newly formed Tropical Storm Alberto in the Bay of Campeche. For tonight through Saturday, the aforementioned TUTT cell will reside in the vicinity of the Florida Keys. Meanwhile, the tropical wave will approach Northern Florida. These features, combined with waves of deep moisture originating from the periphery of a stubborn Central American Gyre near the Yucatan, will result in well above measurable rain chances. While there will likely be dry spells mixed in, including one predicted for much of tonight`s overnight hours by most recent CAM guidance, a wet and thundery overall pattern appears to be a good bet. It is tempting to go to elevated thunder chances for some of this period as well, given the upper-level support for large-scale ascent and deep moisture evident in forecast soundings, but have elected to punt for this forecast cycle, given the overall lack of thunder observed thus far today. Most ensemble global guidance suggests the aforementioned gyre will gradually weaken late in the weekend into early next week. This should gradually lead to a decline in tropical moisture. Expansive high pressure building across the North Atlantic will slowly drop measurable rain chances back down closer to normal for next week, with convection limited to any moisture undulations pushing in from the gentle southeasterlies.-- End Changed Discussion --&& .MARINE...-- Changed Discussion --Issued at 230 PM EDT Wed Jun 19 2024 A Small Craft Advisory remains in effect for all Florida Keys marine zones, including the Florida Bay, Bayside and Gulfside, southeastern Gulf of Mexico, Hawk Channel, and the Straits of Florida. From synopsis, strong surface high pressure centered off the New England coast working in tandem with falling pressures over the Yucatan Peninsula and the Bay of Campeche will result in moderate to fresh breezes this afternoon through late week. A weak area of low pressure will begin to develop later this afternoon a few hundred miles north of the central Bahamas and move towards the Southeast U.S. coastline. This will lead to slackening east to southeast breezes for Friday through the weekend.-- End Changed Discussion --&& .AVIATION...-- Changed Discussion --(18Z TAFS) Issued at 230 PM EDT Wed Jun 19 2024 VFR conditions will prevail at both EYW and MTH through the TAF period. Shower activity will wax and wane so TEMPOs will be included if impacts to the airport are expected. Near surface winds are easterly at near 15 knots with gusts at times of up to 25 knots.-- End Changed Discussion --&& .PRELIMINARY POINT TEMPS/POPS...-- Changed Discussion --Key West 80 88 80 89 / 40 50 50 50 Marathon 80 88 81 89 / 40 50 50 50-- End Changed Discussion --&& .KEY WATCHES/WARNINGS/ADVISORIES...-- Changed Discussion --FL...None. GM...Small Craft Advisory until 5 AM EDT Thursday for GMZ031>035- 042>044-052>055-072>075.-- End Changed Discussion --&& $$ Public/Marine/Fire...BT Aviation/Nowcasts....AP Data Acquisition.....DR Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest