Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
510 FXUS62 KKEY 281737 AFDKEY Area Forecast Discussion National Weather Service Key West FL 137 PM EDT Fri Aug 28 2026 ...New MARINE, AVIATION, PREV DISCUSSION... .KEY MESSAGES... - Chance of showers and thunderstorms expected today and tonight. - Mainly light to gentle east to southeast breezes will continue into the weekend, though occasional periods of moderate breezes will occur, especially south of the Island Chain. && .MARINE... Issued at 125 PM EDT Fri Aug 28 2026 Shower and thunderstorm coverage has generally diminished across the Florida Keys coastal waters early this afternoon, but a zone of isolated activity has developed along a boundary north of the Lower Keys in the southeastern Gulf. Locally hazardous winds and seas are expected in the vicinity of this thunderstorm activity. Current marine observations indicate the forecast is on track with generally light to gentle south-southeasterly breezes. Breezes will take on more of an easterly heading by this evening. From synopsis, the western periphery of an Atlantic high is expected to maintain control of the Keys for the next several days. This will continue to promote peaking and lulling east to southeast breezes. Breezes will peak in the evening through early morning hours and lull in the afternoons. In addition, the southeasterly flow will also keep deep moisture in place across the region with daily chances of showers and thunderstorms. && .AVIATION... (18Z TAFS) Issued at 125 PM EDT Fri Aug 28 2026 Convection has develop along an outflow boundary north of KEYW, but activity is moving further away from the terminal. Potential for additional development in the wake of this activity is low, so mention of precip was removed from the TAFs for the remainder of the day. Therefore, aviation impacts are not expected with VFR conditions set to continue. High moisture content will support isolated to scattered storms again tomorrow morning, especially in the eastern part of the area, and a PROB30 was included from 10-14Z at KMTH. The western periphery of the Atlantic high remains extended across the area, promoting southeast to easterly sfc winds of 5 to 8 kts. && .PREV DISCUSSION... Issued at 437 AM EDT Fri Aug 28 2026 CIMSS products continues to show the split ridge pattern that has dominated for much of the past week remaining in place. The main changes have been intensity with the ridge just south of the Four Corners region which is stronger than it was this time yesterday. The other ridge remains over the Atlantic just southwest of the Azores. In between the two ridges, mean layer troughing remains across much of the eastern United States, though, this trough has dug a bit further south into the Gulf early this morning. At the surface, the western periphery of the Atlantic ridge nudges into the Keys. Marine observation platforms surrounding the Island Chain are recording east to southeast breezes of 5 to 10 knots as a result. GOES 19 Total Precipitable Water (TPW) products shows estimated PWATs of 1.8 to 2 inches in place throughout the Keys. One would think this would be enough to muster up a bunch of showers and thunderstorms. KBYX radar has only detected a couple baby showers and a tiny thunderstorm earlier in the Florida Bay which lasted all but 5 minutes, though between 3-4am, we noticed activity starting to increase, especially over the marine area. Temperatures along the Island Chain are in the mid 80s and dew points are in the mid to upper 70s. .FORECAST... The forecast for today is tricky to say the least. Multiple CAMS- Convective Allowing Mesoscale System models show quite the ramp up in activity shortly after daybreak, especially in the vicinity of the Upper Keys. Any activity that forms, if they do, are anticipated to move southwest to west through the Keys with the threat ending by the early afternoon. Nearly all the guidance shows a shower/storm free late afternoon through evening and into the overnight hours. However, with that said, a shower or storm or two still cannot be completely ruled out. Due to the nature of the past few days, rain chances have been nudged down across the board for today and tonight with 30% for today and 20% tonight. Guidance suggests this pattern once again showing more moisture and even some added upper level support as we head through the weekend. Therefore, the rain chances return to 40% for Saturday and Saturday night with 50% for Sunday. Granted with the way this pattern has been playing out, adjustments to the rain chances are plausible. Outside of the moisture, east to southeast breezes will continue to be on a peaking and lulling regime. Peak breezes will continue to be during the evening and overnight with lulls during the afternoons as the western periphery of the Atlantic high maintains control. Daytime highs near 90 degrees with overnight lows in the lower to mid 80s. Global and numerical model guidance suggests this pattern remaining into the middle of next week with elevated rain chances continuing and breezes peaking and lulling through the period. However, rain chances will be subject to change as we have seen in recent days. A complicated pattern to say the least especially since we have all this moisture in place but it has been a struggle at times to keep showers and thunderstorms ongoing. Also, September is 4 days away and also the time when average rain chances peak (35%). Therefore, daily showers and thunderstorms are perfectly normal for this time of the year. TROPICS: The National Hurricane Center (NHC) is continuing advisories on Tropical Storm Dolly across the Central Tropical Atlantic and this system does not pose a threat to the Florida Keys. && .PRELIMINARY POINT TEMPS/POPS... Key West 83 91 83 90 / 10 30 40 50 Marathon 83 90 83 90 / 20 40 40 50 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...MJV/DM Aviation/Nowcasts....DM Data Acquisition.....DM Visit us on the web at weather.gov/key Follow us on Facebook and X at: www.facebook.com/nwskeywest www.x.com/nwskeywest