Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
734 FXUS62 KKEY 130838 AFDKEY Area Forecast Discussion National Weather Service Key West FL 438 AM EDT Sun Jul 13 2025 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 437 AM EDT Sun Jul 13 2025 It has been a generally calm night across the Florida Keys. KBYX radar is not detecting any shower activity currently, though, earlier in the night, it did detect some showers over the eastern Straits of Florida. GOES East Nighttime Microphysics imagery shows mostly clear skies across the Keys for the time being with the only clouds of note being some low level cumulus. Temperatures along the Island Chain are in the lower to mid 80s with dew points in the upper 70s. Big Pine Key has actually dipped to 79 degrees as a result of some radiational cooling that has taken effect overnight. High pressure over the Atlantic extends its western periphery westward through Florida and into the western Gulf. This is resulting in marine platforms around the Keys observing east to southeast breezes of 5 to 10 knots and Island Chain communities observing 5 to 10 mph. .FORECAST... High pressure remains in control of the Florida Keys weather through tonight. GOES East Total Precipitable Water (TPW) products shows PWAT values ranging from 1.75 inches to 1.95 inches throughout the area. Therefore, even though we have high pressure largely in control, there is plenty of moisture throughout the area. This can lead to the threat for some showers and even thunderstorms at any point in time. Therefore, above normal rain chances remain in place for today and tonight with 40% and 50% respectively. Any activity today is largely expected to form off any residual boundaries or mesoscale processes. For tonight, showers and thunderstorms that form on the mainland are expected to drift southward potentially impacting parts of the Island Chain, especially the Upper Keys. Any storms will be capable of producing gusty winds, frequent lightning, and heavy downpours. Monday through Wednesday, the focus will mainly be on the 20% area for tropical development within the next 7 days that the NHC- National Hurricane Center has highlighted across the northern Gulf. At most, a weak area of low pressure is expected to slowly meander southward from off the Georgia coastline and then retrograde back to the west through mid week. As a result, bouts of showers and thunderstorms are expected to be initiated each day as the system slowly moves through the area. Most of the activity the Keys could see may initially form on the mainland and then drift southward through the Keys. Any storms will be capable of producing strong gusty winds, locally heavy rainfall, and frequent lightning. Due to this, the forecast has been drastically changed from previous packages. There is now a 60% chance for rain from Monday through Tuesday with 50% for Tuesday night and Wednesday. Thunder has also been increased from slight chance to chance as confidence increases for a much wetter and stormier period for the early to middle part of the week. The Weather Prediction Center (WPC) has the Keys highlighted in a slight risk (Level 2 out of 4) for the Monday through Tuesday time period. A more typical summer time pattern returns for mid to late week and into the first half of the weekend. High pressure over the Atlantic builds into Florida bringing a return to the east to southeasterlies and moisture undulations around the western periphery of the high. As a result, expect decreasing rain chances with 40% for Wednesday night before rain chances return to around normal for the remainder of the extended which is near 30%. && .MARINE... Issued at 437 AM EDT Sun Jul 13 2025 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, high pressure remains in control across much of the Florida Keys through tonight. This will result in east to southeast breezes early this morning becoming variable. Weak low pressure tries to develop in the vicinity of Florida heading through the first half of the week. Initially, the Keys will be on the southern fringe in a col region resulting in mainly variable breezes through Monday night. As the weak low pressure area shifts to the west and high pressure builds in behind, breezes will freshen becoming southeast to south at first, before becoming east to southeast for mid to late week. Also, expect increasing coverage of showers and thunderstorms for the early to middle part of the week. && .AVIATION... (06Z TAFS) Issued at 437 AM EDT Sun Jul 13 2025 VFR conditions are expected to prevail at EYW and MTH through the TAF period. Some passing showers and thunderstorms are possible, which would likely result in brief periods of MVFR conditions. Timing and coverage of any showers that do approach the terminals will be addressed via TAF amendment as needed. Winds will remain from the southeast at 5 to 10 knots into this afternoon, then slacken and become variable. Higher gusts will be possible with passing shower and thunderstorm activity. && .CLIMATE... On this day in 2023, the daily record high temperature of 99F was recorded at Marathon. This is also tied for the warmest temperature ever recorded for the month of July, or any month, for the Marathon area. The daily record warm low temperature of 86F was also recorded at Marathon in 2023. Temperature records for Marathon date back to 1950. && .PRELIMINARY POINT TEMPS/POPS... Key West 91 81 90 79 / 20 30 50 60 Marathon 89 80 88 78 / 40 50 60 70 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...MJV Aviation/Nowcasts....MC Data Acquisition.....MC Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest