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Show Area Forecast Discussion - Key West, FL (Florida Keys) Selection: |
| #1242558 (Received by flhurricane at: 5:03 AM 23.Aug.2025) AFDKEY Area Forecast Discussion National Weather Service Key West FL 501 AM EDT Sat Aug 23 2025 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 500 AM EDT Sat Aug 23 2025 It has been a generally calm night once again until recently. KBYX radar was not detecting anything on radar until around 2am. After 2am, an isolated thunderstorm developed across the nearshore waters to the north of the Island Chain. This cell put out quite a bit of lightning for a time and has now since waned around 330 am early this morning. In addition, a few isolated showers developed across the Straits of Florida in the past hour (230-330 am) and these are still ongoing. GOES East Nighttime Microphysics imagery shows mostly clear conditions across the Keys with any cumulonimbus clouds and cumulus congestus associated with the shower and thunderstorm activity. It remains quite warm yet again early this morning as we are in the droves of summer now down here in the Keys compared to what has been an actually quite pleasant summer to this point. Temperatures along the Island Chain are mostly in the mid 80s with dew points in the mid to upper 70s. However, across the Upper Keys and Big Pine Key, temperatures are still in the upper 70s. These are also the areas where showers and thunderstorms moved through last evening. Mean layer ridging remains in place across the Keys with the center of this ridge located over the western tip of Cuba to the Yucatan Channel. As a result, marine platforms surrounding the Keys are observing mainly variable breezes of 5 knots or less and Island Chain communities observing 5 mph or less. .FORECAST... The main weather feature for the next several days will be a weak subtropical high settling in the vicinity of the Keys. Moisture continues to remain quite plentiful yet again for today with GOES East Total Precipitable Water (TPW) products showing PWAT values of 1.8 to 2.0 inches across the Keys. Due to slightly higher moisture, PoPs were increased from 20% --> 30% for today. Slightly drier air moves back in for tonight through early next week resulting in 20% PoP being maintained (Tonight through Tuesday night). The only real triggers 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 a reverse cloud line for one more time today as the pattern remains quite stagnant and winds remain light out of the southwest. This remains a favorable pattern for cloud lines and waterspouts for at least one more day. It should also be noted that PoPs might be a bit too low for Sunday and Monday and could change in subsequent updates. Some of the hi- res model guidance is showing quite a bit of thunderstorm activity across the Gulf not too far to our north and northwest. There is the potential for some of this activity to drift southward towards the Keys but right now it most likely looks to remain over the offshore SE Gulf waters. The highest chances of rain remain over the offshore Gulf waters and across the central to southern Florida mainland for the next few days. Outside of the rain chances, the summertime heat and humidity will be the name of the game with daytime highs in the lower to potentially mid 90s in some locations with overnight lows in the lower to mid 80s. Heat index values will consistently be between 105 to 108 degrees with some isolated locations reaching 110-112 degrees as dew points remain in the mid to upper 70s. Lastly, model guidance is beginning to show an uptick in moisture for the middle to latter half of next week. The timing still remains uncertain at this time but we advertise 30% Pops for now. However, it should be noted that these may go up as we get closer and continue to fine tune the forecast once we get a better handle on the moisture. Stay tuned! && .MARINE... Issued at 500 AM EDT Sat Aug 23 2025 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, a weak subtropical high pressure ridge will remain over the Keys through early next week. This will result in generally light breezes, occasionally becoming light to gentle as well as variable at times. && .AVIATION... (06Z TAFS) Issued at 500 AM EDT Sat Aug 23 2025 VFR conditions will prevail at EYW and MTH in the pre-dawn and early morning hours for the 06Z TAF period. Near surface winds will remain light and variable, but will favor a southwesterly direction. A cloud line near MTH is possible tomorrow afternoon to evening, and will leave mention of VCSH or VCTS to later amendments. && .PRELIMINARY POINT TEMPS/POPS... Key West 91 84 91 84 / 30 10 10 10 Marathon 93 83 93 83 / 30 20 20 20 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ |
