Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
117 FXUS62 KKEY 180243 AFDKEY Area Forecast Discussion National Weather Service Key West FL 1043 PM EDT Tue Sep 17 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 1043 PM EDT Tue Sep 17 2024 After quite a dreary day across the Florida Keys, the evening provided clearing skies and mostly rain-free conditions. This is likely due to the atmosphere being thoroughly worked over after the earlier convection. There is still a little pouch of drier air in the lower-levels, sampled by this evening`s sounding. This indicates that the atmosphere still has not fully recovered. This weather pattern can be attributed to a few synoptic features including a stationary decayed frontal boundary across Central Florida and a deepening low across the Southeast. Surface flow has been negligible as the lower-level ridge resides roughly across the Keys. The lack of flow may have also contributed to the meager shower development across our forecast area over the past few hours. Tonight`s forecast remains a question. How long will the atmosphere need to recover? Will there be enough of a forcing mechanism to spark widespread shower development as we saw this morning? Based on this evening`s sounding and the current lack of convection, have decided to drop PoPs to the high end chance category (50%). With that being said, we have a few ingredients in place (CAPE, moisture aloft), so if the dry air in the lower- levels can mix out and the atmosphere to recover, all that is needed is a little bit of lift to spur on convection. Temperatures will drop a few degrees into the lower 80s outside of any rain- cooled locations and winds will shift to the east overnight. && .MARINE... Issued at 1043 PM EDT Tue Sep 17 2024 Light and generally variable breezes will continue through the remainder of the week. Expect higher winds and seas in and around thunderstorms. Northerly swell generated by a low near the Eastern Seaboard will linger through Wednesday. This disturbance will meander southeast to southward this weekend and into early next week and deepen as it interacts with an upper level trough. Unpredictability in the movement of this trough means confidence in the extended forecast is very low. A Coastal Flood Advisory remains in effect for the Upper Keys, and a Coastal Flood Statement remains in effect for the Middle and Lower Keys. Boaters can expect less clearance under fixed bridges. && .AVIATION... (00Z TAFS) Issued at 1043 PM EDT Tue Sep 17 2024 VFR conditions will prevail overnight at both island terminals. The exact timing of the redevelopment of showers and thunderstorms across the forecast area is somewhat uncertain, so have included VCSH in for both terminals by 06Z, although this may be a little early. Another wet morning is expected, so short-term amendments and TEMPOs are possible. Outside of any convection, winds will be generally from the east to southeast at 4 to 7 knots. && .CLIMATE... On this day in 2023, the daily record high temperature of 97F was recorded. This is also tied for the warmest temperature ever recorded in the month of September for the Marathon area. Temperature records date back to 1950. && .PRELIMINARY POINT TEMPS/POPS... Key West 82 91 82 91 / 60 60 40 40 Marathon 82 91 82 91 / 60 60 40 40 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until 5 PM EDT Wednesday for FLZ076. GM...None. && $$ Public/Marine/Fire...NB Aviation/Nowcasts....NB Data Acquisition.....MJV Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest