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Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
874 FXUS62 KKEY 120908 AFDKEY Area Forecast Discussion National Weather Service Key West FL 508 AM EDT Mon Aug 12 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 505 AM EDT Mon Aug 12 2024 It seems like another repeat of yesterday across the Florida Keys this morning. A spattering of showers is percolating and drifting west through the Straits of Florida and nearshore waters of the island chain. Despite modest coverage noted on KBYX radar, most convection has kept clear of land leaving current temperatures once again in the mid 80s and dewpoints in the upper 70s. A persisting Atlantic low level ridge across the Florida Peninsula continues to promote gentle easterly breezes along the Reef. Not much change in sensible weather is on tap for today. The main headline is once again the issuance of a Heat Advisory for the Keys from later this morning into the evening hours. Forecast highs in the lower 90s paired with dewpoints in the upper 70s will result in heat index values up to 110 degrees. The good news is that there is enough moisture in the air for a few showers to possibly cross the island chain today bringing some relief to the heat. However a lack of organized lift will leave their coverage scattered at best, with PoPs remaining near normal for this time of year. Tonight, a Saharan Air Layer (SAL) plume will slide over our area from the east. This airmass is currently observed over the Bahamas via CIMSS MIMIC TPW. Model soundings for later tonight and into tomorrow morning show a stark drying of the lower to mid levels as this feature crosses through. As a result, PoPs have been lowered to a slight chance for tonight and to a lower end chance for Tuesday as the moisture plume behind it no longer seems as potent as in previous guidance. In the extended forecast, a deep layer trough will establish itself along the East Coast by the middle of the week. As this trough slides south down the Eastern Seaboard, the Atlantic ridge over mainland Florida will recede east. This will result in lighter and more variable winds across our CWA by Thursday evening. Northerly winds will then take over as PTC 5 passes far to the east of Florida this weekend. && .MARINE... Issued at 505 AM EDT Mon Aug 12 2024 No watches, warnings, or advisories are in effect for the Florida Keys coastal waters. From synopsis, an Atlantic ridge axis planted north of the Keys coastal waters will promote gentle to moderate easterly breezes through the early part of this week. Breezes will then slacken and veer to the northwest by Thursday night as a trough dips south along the Eastern Seaboard. As a result, breezes will then become more chaotic by Friday as the ridge axis fractures over Florida. A tropical disturbance to the east of the Bahamas will move north towards Bermuda Friday and Friday night. && .AVIATION... (06Z TAFS) Issued at 505 AM EDT Mon Aug 12 2024 Isolated showers dotting the forecast area may near both terminals through the mid to late morning, so have maintained VCSH. Later this afternoon/evening, a much drier airmass will lead to minimal shower coverage. Surface winds will be from the east to southeast at 5 to 10 knots. && .CLIMATE... On this day in 1926, the daily record low temperature of 71F and the daily record rainfall of 2.59" were both recorded in Key West. Temperature records date back to 1872 and rainfall records date back to 1871. && .PRELIMINARY POINT TEMPS/POPS... Key West 92 83 92 84 / 30 20 30 30 Marathon 92 84 93 84 / 30 20 30 30 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Heat Advisory from 10 AM this morning to 7 PM EDT this evening for FLZ076>078. GM...None. && $$ Public/Marine/Fire...JAM Aviation/Nowcasts....NB Data Acquisition.....NB Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest