Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
240 FXUS62 KKEY 300834 AFDKEY Area Forecast Discussion National Weather Service Key West FL 434 AM EDT Thu Jul 30 2026 ...New DISCUSSION, MARINE, AVIATION... .KEY MESSAGES... - A reverse cloud line is possible this afternoon. Any developing cloud line will tend to favor waterspout development. - Light to gentle southwest to west breezes expected today becoming mainly light breezes tonight. Seas around 1 foot across much of the Keys coastal waters, except SE Gulf: 1-2 ft. && .DISCUSSION... Issued at 433 AM EDT Thu Jul 30 2026 CIMSS products show mean layer ridging in place across much of the western North Atlantic with a trough just off the Eastern Seaboard. The Keys remain on the western periphery of the aforementioned mean layer ridge. Marine observations platforms surrounding the Island Chain are observing southwest to west breezes of 5 to 10 knots. KBYX radar has not detected any shower activity overnight as drier air compared to last several days has moved into the region. GOES 19 Nighttime Microphysics imagery shows mostly clear skies across the Keys with mainly low level cumulus, though, there are some high level clouds stretching from the SE Gulf into South Florida. Temperatures along the Island Chain are in the lower to mid 80s and dew points are in the mid to upper 70s. .FORECAST... The western periphery of the Atlantic ridge will continue to extend west into the Keys for today. This will result in mainly southwesterly flow, though, much weaker than previous days. Expect mostly light to gentle southwest breezes today becoming light tonight. While a generally quiet day is on tap for today, a reverse cloud line is possible in the vicinity of the Island Chain. We do have drier air in place, therefore, the cloud line may struggle a bit. However, if it does develop, any cloud line will tend to favor waterspout development. Outside of the cloud line development, the heat will be the main concern with highs in the lower 90s combined with dew points in the mid to upper 70s. This will lead to heat index values pushing close to 108 degrees. Overnight lows also won`t provide much relief in the lower to mid 80s. The ridge over the Atlantic will retreat slightly for Friday through the first half of the weekend. This will place the Keys into a col region resulting in a potential period of light and variable breezes. Moisture undulations will continue to rotate around the ridge resulting in slight rain and thunder chances. Also, expect continued typical summertime heat and humidity with highs in the lower 90s and overnight lows in the lower to mid 80s. As we head into Saturday night and the second half of the weekend, the high will regain some control across the region resulting in breezes freshening out of the southeast. Moisture will increase slightly compared to previous days, though, still mostly remain slight chances. However, there is a possibility these become chance PoPs due to the increased moisture. It just depends on how much more it increases across the area. Temperatures will be slightly cooler with highs near 90 degrees and overnight lows in the lower 80s. There are signals for a potentially more active pattern to move the Keys for the early to middle part of next week. Numerical model guidance is beginning to signal a Tropical Upper Tropospheric Trough (TUTT) cell lumbering into the Keys or nearby. Other model guidance just shows an increase in moisture with an uptick in rain chances. However, if the prior solution occurs, the potential exists for feistier showers and thunderstorms as well as more widespread. This would also come with some upper level support as well. Right now, it is too far out to tell exactly the details of what may occur. However, the one trend being picked up on is for an increase in cloud cover, slightly cooler temperatures, and increased rain chances through the period. The details for when and how much, intensity of any activity remains all but highly uncertain. Check back for updates as we continue to fine tune the forecast. && .MARINE... Issued at 433 AM EDT Thu Jul 30 2026 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, the western periphery of an Atlantic surface ridge will continue to slide westward across the Florida Keys coastal waters. This will result in a weak nebulous flow today through tonight resulting in light to gentle breezes. A col region will set up for Friday into the first part of the weekend, resulting in a potential period of light and variable breezes. As high pressure strengthens in the North Atlantic, southeast breezes will freshen by the second half of the weekend and into early next week. && .AVIATION... (06Z TAFS) Issued at 433 AM EDT Thu Jul 30 2026 VFR conditions are expected to persist at both EYW and MTH terminals through the TAF period. Near surface winds will remain mainly southwesterly till this evening before becoming light and variable. A reverse cloud line remains possible again for today. A few showers or even a thunderstorm are possible along this cloud line. Due to average confidence on this cloud line developing this afternoon, VCSH was included for Marathon where any activity looks most likely. && .CLIMATE... On this day on 2009, the daily record warm low temperature of 86F was recorded in Key West. Temperature records for Key West date back to 1872. On this day in 2017, the daily record warm low temperature of 85F was recorded in Marathon. Temperature records for Marathon date back to 1951. && .PRELIMINARY POINT TEMPS/POPS... Key West 91 84 91 84 / 10 0 10 0 Marathon 91 83 90 83 / 10 0 10 0 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...MJV Aviation/Nowcasts....MJV Data Acquisition.....MJV Visit us on the web at weather.gov/key Follow us on Facebook and X at: www.facebook.com/nwskeywest www.x.com/nwskeywest