Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
444 FXUS62 KKEY 211855 AFDKEY Area Forecast Discussion National Weather Service Key West FL 255 PM EDT Fri Jun 21 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 226 PM EDT Fri Jun 21 2024 Shower and thunderstorm activity has largely struggled thus far today. This is despite broad cyclonic flow in the mid- and upper- levels, no discernible convective cap, and deep, tropical tropospheric profile sampled by the 12z sounding at KEY this morning. We are admittedly a bit puzzled by the lack of convective development, given this environment. GOES-16 visible satellite imagery is highlighting partly to mostly cloudy skies across the Florida Keys island chain and the adjacent nearshore and offshore coastal waters, with only a few widely scattered showers and isolated thunderstorms being detected by KBYX Doppler radar. Land- based surface observations are reporting temperatures generally in the upper 80s across the Keys. For tonight through much of the weekend, the synoptic-scale environment will remain largely unaltered. The only ingredient seeming to be lacking thus far is a trigger to get this convection going. At this time, given the largely supportive environment for convection, it seems prudent to retain middle of the road measurable rain chances for the weekend. With deep tropospheric moisture, nearly every shower that does form will have the potential to morph into a thunderstorm as well. The main question remains when the aforementioned trigger fires. All convective allowing model (CAM) guidance has struggled with this key ingredient, with many different run-to-run and model-to-model solutions. As a monsoonal low in the vicinity of the Bay of Campeche finally weakens late in the weekend, high pressure will slowly build across the North Atlantic and through the Florida Peninsula. This will finally setup a typical summertime pattern for the Florida Keys, with convection limited to either moisture undulations in the east to southeasterlies or diurnally-driven island cloud line formation on days with lighter steering flow. Temperatures this weekend will remain at or below average due to bouts of rainfall and elevated cloud cover, and these temperatures will slowly moderate to at near or just above normal levels for next week. && .MARINE... Issued at 226 PM EDT Fri Jun 21 2024 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, interaction among low pressure off the east coast of Florida, high pressure centered north of Bermuda, and broad low pressure in the vicinity of the Yucatan Peninsula will result in gentle to moderate east to southeast breezes over the next few days. Moisture pulled into our area via the low to the west will result in waves of unsettled weather this weekend. High pressure building over the North Atlantic early next week will result in light to gentle southeast to south breezes and a return to near- normal rain and thunder chances. && .AVIATION... (18Z TAFS) Issued at 226 PM EDT Fri Jun 21 2024 VFR conditions will prevail at both EYW and MTH through the TAF period. Shower activity could return later this evening, but confidence in any impacts is low, so only VCSH is included for the time being. Near surface winds are easterly at near 10 knots. && .PRELIMINARY POINT TEMPS/POPS... Key West 81 89 80 89 / 50 50 50 50 Marathon 80 90 80 90 / 50 50 50 50 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...BT/AJP 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