Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
197 FXUS62 KKEY 051902 AFDKEY Area Forecast Discussion National Weather Service Key West FL 302 PM EDT Wed Jun 5 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 300 PM EDT Wed Jun 5 2024 The Florida Keys remain encamped in a weak pressure gradient regime, with east to southeast surface flow owed to a surface high located southwest of Bermuda in the western North Atlantic. The 12z morning balloon sounding at KEY sampled a well- mixed, moist layer up to around 950 mb. The sounding also sampled a series of weak capping inversions owed to the continued weak presence of a mid- level ridge extending from the Gulf of Mexico eastward to the Florida Peninsula. These capping inversions along with the weak steering flow has limited convection today across the Keys and the adjacent nearshore and offshore coastal waters. GOES-16 visible satellite imagery is currently detecting ample sunshine across the island chain, allowing temperatures to creep up to near 90F. Combined with dewpoints in the mid 70s, feels like temperatures are hovering around 100F yet again this afternoon. For overnight tonight through Thursday, the status quo will continue. With the lack of any strong steering and upper-level support for large-scale ascent, any shower or thunderstorm activity will be limited to mesoscale in nature, with boundary layer collisions and possible afternoon cloudline development. Given that coverage is struggling even over the diurnally-favored South Florida Mainland so far this afternoon, elected to lower rain chances to slight levels (around 20%) for the overnight period through Thursday. A positively tilted, weak shortwave trough is progged to dive southeastward, pushing across northern Florida Thursday afternoon through Friday night. This should help weaken the aforementioned cap, allowing for a slight better chance for measurable rainfall across the forecast area. However, moisture appears to be the limiting factor in any more widespread, long convective events for this period. Latest ensemble mean guidance suggests the mid-level ridge over the Gulf will build back across Florida in the wake of the trough, warranting lower rain and thunder chances for the weekend. Forecast confidence for the early to middle part of next week remains unusually low. Another positively tilted trough is progged to pivot across the Southeast early next week. Meanwhile, a climatologically-consistent Central American Gyre is expected to intensify in the vicinity of the Yucatan Peninsula, which may result in potential surface cyclogenesis somewhere in the western Caribbean. Regardless of development of this system, the aforementioned trough should still drive moisture northward towards the Keys for the early to middle of next week along with freshened southerly flow. As is often the case for this setup, there will likely be a strong moisture gradient (with associated rain chances) based on where the gyre ultimately sets up. An extended period of above normal rain and thunder chances are advertised for Monday through Wednesday for now, with adjustments expected over the next several forecast cycles. Cloud cover should keep temperatures in check for this extended period, only reaching the upper 80s during the daytime hours for these periods. && .MARINE... Issued at 300 PM EDT Wed Jun 5 2024 No watches, warnings, or advisories are in effect for Florida Keys coastal waters zones. From synopsis, a weak area of high pressure centered southwest of Bermuda will slowly slide eastward in the North Atlantic, resulting in light to gentle east to southeast breezes through Thursday night. Winds may freshen out of the south late this weekend into early next week, as pressures fall in the northwestern Caribbean Sea. && .AVIATION... (18Z TAFS) Issued at 300 PM EDT Wed Jun 5 2024 VFR conditions will prevail at both EYW and MTH through the TAF period. Although a cloudline is attempting to form over the Lower Keys, at this time no precipitation is expected for EYW. Near surface winds will be east to southeast at 5 to 10 knots. && .CLIMATE... On this day in 1985, Key West measured a record high temperature of 93F. On the same day, Marathon measured a record high temperature of 96F. Temperature records for Key West and Marathon date back to 1872 and 1950, respectively. && .PRELIMINARY POINT TEMPS/POPS... Key West 90 82 90 82 / 10 20 20 30 Marathon 90 83 90 81 / 20 20 20 30 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...BT/JR Aviation/Nowcasts....AP Data Acquisition.....AP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest