Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
336 FXUS62 KKEY 030851 AFDKEY Area Forecast Discussion National Weather Service Key West FL 451 AM EDT Wed Sep 3 2025 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 450 AM EDT Wed Sep 3 2025 Convection has already started to develop around the Keys and its coastal waters this morning with wet weather on tap for the next few days. For the last few hours, scattered showers with some embedded thunderstorms were percolating in the western Straits of Florida south of the Dry Tortugas and Lower Keys. While individual cells were not very impressive, a few were able to build up to throw some lightning bolts. More recently, KAMX radar detected a new cluster of convection pulsing in the nearshore waters of the Upper and Middle Keys showing that the atmospheric profile is still unstable and juiced even in the wee hours of the morning. All overnight activity has been moving east at 10 to 15 knots or so following the same direction as the gentle to moderate westerly flow observed across the Reef. Meanwhile on land, temperatures have fallen to the expected lows in the lower 80s and hold strong to moist dewpoints in the upper 70s. This wet weather pattern has been in place across the Keys for several days now and that does not look to change anytime soon. A stationary front finds itself parked over south Florida and the Florida Keys this morning with a broad associated surface low analyzed somewhere north of The Bahamas. Mid to upper level troughing across eastern CONUS along with this surface low will continue to promote westerly breezes across much of our vertical wind profile similar to what was recorded in yesterday evening`s 00z KKEY balloon sounding. Looking at the Gulf in CIMSS MIMIC TPW, high PW values indicating robust moisture are found not only over our area, but also upstream in the Gulf waters. This will help keep PW values close to if not breaching the 90th percentile over the next few days or so. Warm temperatures promoting seasonal instability with a high reserve of moisture advecting over a synoptic boundary is a slam dunk for high rain chances along with a Marginal Risk (level 1 of 4) for excessive rainfall (via the Weather Prediction Center) throughout the short term. Unfortunately, this pattern will linger around into the end of the week resulting in multiple days in an environment capable of producing potentially heavy, flooding rains at times. The wind forecast is a little more murky as the future location of the broad surface low is somewhat uncertain. Recent guidance has it opening up into a broad trough as it shifts northeast throughout today, thus resulting in a somewhat lighter flow than previous runs. That being said, a moderate to fresh westerly surge will still be in the cards on the daily depending on the allowance of daytime heating on mainland and behavior of the low. We look to finally break free of this pattern Saturday as the mid to upper level troughing and the surface low exit to the northeast. This will allow weak ridging to slide back into the area with winds gradually flipping back around to a closer to normal southeasterly wind direction. While the big players for heavy rainfall will be out of the picture, another undulation of moisture looks to settle in from the east keeping rain chances just above normal into next week. && .MARINE... Issued at 450 AM EDT Wed Sep 3 2025 No watches, warnings, or advisories are currently in effect for the coastal waters of the Florida Keys. From synopsis, a broad surface low along a stationary front stretching from the Gulf eastward to the Florida Peninsula will maintain west to northwest winds across the Keys marine zones tonight. The front will remain rooted in place through the next few days, while the low meanders northeast into the western North Atlantic promoting southwest to west breezes throughout the week. Abundant moisture will promote above normal rain and thunder chances through the end of the work week. && .AVIATION... (06Z TAFS) Issued at 450 AM EDT Wed Sep 3 2025 TAFs continue to reflect a prolonged period of VCSH due to shower activity gradually increasing this morning, and remaining in place virtually all day to some degree. Recent trends suggest that the next opportunity for reduced flight categories may be later this afternoon. Will hold off on TEMPO groups for this package due to the uncertainty related to timing and the degree of impact. Future TAF amendments will ultimately be needed. Outside of any activity, surface winds will generally be out of the west at near 10 knots. && .CLIMATE... On this day in Keys weather history in 2007, the daily record high temperature of 95F was recorded in Key West. This is also tied for the warmest temperature ever recorded in September. Temperature records for Key West date back to 1872. && .PRELIMINARY POINT TEMPS/POPS... Key West 91 79 91 80 / 80 80 80 70 Marathon 90 79 89 80 / 80 80 80 80 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...JAM Aviation/Nowcasts....DP/MC Data Acquisition.....JAM Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest