Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
500 FXUS62 KKEY 031828 AFDKEY Area Forecast Discussion National Weather Service Key West FL 228 PM EDT Wed Sep 3 2025 ...New DISCUSSION, MARINE, AVIATION, PREV DISCUSSION... .AVIATION... (18Z TAFS) Issued at 228 PM EDT Wed Sep 3 2025 EYW and MTH TAFs will be dominated by VCSH for the 18Z period. Waves of VCSH with an occasional VCTS or TSRA will require frequent updates for MVFR to IFR VIS. Outside of showers, CIGs are limited to MVFR to VFR. Winds outside of showers are forecast to shift southwesterly but remain near 10 knots. A lull in VCSH is forecast overnight with shower coverage increasing once more before sunrise. Stay tuned for additional amendments. && .PREV DISCUSSION... Issued at 1009 AM EDT Wed Sep 3 2025 Drenched would be an apt word to describe the environment around the Florida Keys. The broad environmental pattern that directed deep layers of moist tropical water across the Florida Keys shows no signs of stopping. The morning KKEY radiosonde sampled a PWAT of 2.46", a new daily record. Westerly winds are directing untapped Gulf moisture and heat across the Gulf and Caribbean into a synoptic near-stationary boundary across Southern Florida. The Weather Prediction Center put the Florida Keys under a Marginal Risk (level 1 of 4) for excessive rainfall today. Considering the KKEY rain gauge sampled almost an inch of rain yesterday, makes perfect sense. Outside of showers, which is a bit of a rarity today, breezes are rather persistent gentle to moderate westerlies. Copious amounts of moisture and cloud cover will keep temperatures below normal for the rest of the afternoon. Shower activity is expected to diminish tonight following this afternoon`s bouts of rainfall. However, the overall environmental pattern is not forecast to break until Saturday, so expect yet more rounds of showers tomorrow. && .DISCUSSION... Issued at 450 AM EDT Wed Sep 3 2025 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 1009 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. && .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 79 91 80 91 / 80 80 70 70 Marathon 79 89 80 89 / 80 80 80 80 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...AJP Aviation/Nowcasts....AJP Data Acquisition.....AP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest