Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
588 FXUS62 KKEY 220834 AFDKEY Area Forecast Discussion National Weather Service Key West FL 434 AM EDT Fri Aug 22 2025 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 430 AM EDT Fri Aug 22 2025 It has been another quiet night across the Florida Keys. KBYX radar is detecting only a few showers and even an isolated thunderstorm across the westernmost Straits of Florida and the offshore Gulf waters, including the Dry Tortugas. In addition, there was one lonely shower that developed just to the east of the 18 mile stretch near the Upper Keys which has been dissipating over the course of the past hour. GOES East Nighttime Microphysics imagery shows mostly clear conditions throughout the Keys outside of the stratocumulus and cumulus congestus associated with the aforementioned showers. Looking more closely there appears to be a cloud line of cumulus north of the Island Chain that was slowly migrating northward. This could potentially be the foci for new shower development later this morning. It also remains very warm as we continue to move into late August. Temperatures along the Island Chain are in the lower to mid 80s with dew points in the mid to upper 70s. The cool spot is the Big Pine Key RAWS which is currently down to 77 degrees due to some radiational cooling and some rain from a thunderstorm last evening. CIMSS data shows a deep mean layer ridge across the central North Atlantic to the southwest of the Azores Islands. A piece of this ridge is extending off to the west towards the Bahamas and Florida as it builds in behind Hurricane Erin. Hurricane Erin continues racing northeastward south of the Canadian Maritimes and will not be a threat to any land masses. Due to this, marine platforms surrounding the Keys are observing south to southwest breezes to 5 to 10 knots and Island Chain communities observing 5 to 10 mph. .FORECAST... Hurricane Erin is now moving away from the United States coastline as it continues to race off to the northeast south of the Canadian Maritimes over the next few days. Other than that, the main weather feature for the next several days to week will be a weak subtropical high continuing to build into the Keys today and then settling over the weekend into early next week. Moisture continues to remain quite plentiful again for today with GOES East Total Precipitable Water (TPW) products showing PWAT values of 1.7 to 2.0 inches across the Keys. Therefore, 20% PoP was maintained. However, the only real trigger we have to get any shower or thunderstorm activity are leftover mesoscale boundaries and other latent heat fluxes. In addition, there remains the potential for reverse cloud lines at least today and again on Saturday as the pattern remains quite stagnant and winds remain light out of the southwest. This is typically a good pattern for cloud lines and waterspouts. We will keep an eye on this closely over the next couple days. Weak ridging remains dominant through the extended period resulting in 20% PoPs through around mid week before a slight increase in moisture is anticipated which will raise PoPs back to chances at 30%. Otherwise, the summertime heat and humidity will be the name of the game going forward with daytime highs in the lower 90s and overnight lows in the lower to potentially mid 80s. Heat index values will be consistently between 105 to 108 degrees each day. && .MARINE... Issued at 430 AM EDT Fri Aug 22 2025 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, Hurricane Erin continues to race off into the North Atlantic south of the Canadian Maritimes. A weak subtropical high pressure ridge will continue to build into the Keys today before settling over the Keys over the weekend continuing into early next week. This will result in generally light breezes, occasionally becoming light to gentle breezes as well as becoming variable at times. && .COASTAL FLOOD.. A Coastal Flood Statement remains in effect for the Upper Florida Keys. Tides are running almost a foot above predicted. As a result, minor saltwater flooding of low elevation streets and lots is likely. Some storm drains will overflow, and some seawalls and docks will be overtopped. Boaters can expect less clearance under fixed bridges. Motorists should remember that persistent puddles around the times of high tide are almost certain to contain a mix of saltwater. && .AVIATION... (06Z TAFS) Issued at 430 AM EDT Fri Aug 22 2025 VFR conditions will prevail at EYW and MTH for the 06Z TAF period. Near surface winds remain southwesterly near 5 knots, and winds are expected to become variable by sunset. Showers and thunderstorms are not included in the current TAFs, but light southwesterly winds suggests a possible reverse cloud line near MTH. In the event a cloud line forms, expect MVFR to IFR CIGs from nearby SHRA. && .CLIMATE... On this day in Keys weather history, in 1889, the daily record cold high temperature of 81F was recorded. This is also tied for the coldest high temperature ever recorded in August. Temperature records for Key West date back to 1872. OF NOTE In 1852, a Hurricane moved northwest through the straits south of the Lower Keys. The eye passed over the Dry Tortugas with maximum sustained winds of 105 mph. Rough waves damaged ships throughout the Florida Keys and ships in the Florida Straits recorded hurricane-force winds. && .PRELIMINARY POINT TEMPS/POPS... Key West 91 84 91 84 / 10 20 20 10 Marathon 93 84 93 83 / 20 20 20 20 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...MJV Aviation/Nowcasts....AJP 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