Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
111 FXUS62 KKEY 161453 AFDKEY Area Forecast Discussion National Weather Service Key West FL 1053 AM EDT Fri Aug 16 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 1010 AM EDT Fri Aug 16 2024 The morning hours have been less quiet than previous mornings as the KBYX radar is currently detecting isolated to scattered thunderstorms across much of the forecast area. These thunderstorms have been almost stationary as low level flow has been very light, and this is reflected in surface observations that are currently showing variable winds at the surface near 5 mph. The 12Z sounding from this mornings balloon launch shows these light winds are persistent through the lower levels with a 0-10km mean wind speed of approximately 2 to 3 mph. This tells us that these storms should essentially put themselves out, but the resulting outflow boundaries will be worth keeping an eye on as they may continue to trigger new activity as the atmosphere continues to be worked over. The sounding also sampled approximately 2.00" of precipitable waters, which lines up with the CIMSS MIMIC PWAT product showing a swath of 2.00 to 2.25 inches. Both the sounding and satellite derived products show that the bulk of this moisture is in the lower and lower-middle levels, so we will see how much moisture we can work through this morning. The current forecast package has PoPs of 30 percent along the island chain for today, and there doesn`t seem to be much reason to stray from that, although the Upper Keys may see more of a 40 percent PoP day. The Heat Advisory is also going to continue until 7 PM EDT as planned, as most of the island chain is already seeing heat indices around 100F to 105F. Cloud cover from the activity this morning hasn`t increased enough to stave off the daytime heating, so we will see heat indices increase by a few degrees over the afternoon hours. && .MARINE... Issued at 1010 AM EDT Fri Aug 16 2024 There are no watches, warnings, or advisories in effect for the Florida Keys coastal waters. From synopsis, the duo of Hurricane Ernesto, located north of Puerto Rico and moving north, and a trough building over the Great Lakes will weaken the pressure gradient across the Florida Keys through the weekend. Generally light to gentle breezes will persist through Tuesday. Breezes will veer clockwise with a low possibility of numerous showers on Saturday. && .AVIATION... (15Z TAFS) Issued at 1010 AM EDT Fri Aug 16 2024 Earlier thunderstorms near MTH have weakened and drifted south. VFR should prevail otherwise through the TAF period. Shower coverage may become sparse enough later this morning to remove mention of VCSH, however VCSH or VCTS may be required later this afternoon and evening at both terminals as surface winds transition from light and variable to northeast 4 to 7 knots. && .CLIMATE... On this day in 1861, a Hurricane moved northwest through the Straits just southwest of the Lower Keys. && .PRELIMINARY POINT TEMPS/POPS... Key West 92 82 90 82 / 20 40 40 30 Marathon 91 81 90 81 / 30 40 40 30 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Heat Advisory until 7 PM EDT this evening for FLZ076>078. GM...None. && $$ Public/Marine/Fire...DP Aviation/Nowcasts....JR Data Acquisition.....JR/DP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest