Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
381 FXUS62 KKEY 171905 AFDKEY Area Forecast Discussion National Weather Service Key West FL 305 PM EDT Sun Aug 17 2025 ...New AVIATION... .AVIATION... (18Z TAFS) Issued at 305 PM EDT Sun Aug 17 2025 VFR conditions will prevail at both EYW and MTH for the rest of today and into tonight. Cloud line formation has been limited due to drier air settling in aloft and while a stray shower or two is still possible near either terminal, VCSH is not mentioned at this time. Near surface winds will continue to be light and broadly out of the southeast, becoming east to southeast later tonight. && .PREVIOUS DISCUSSION... Issued at 1111 AM EDT Sun Aug 17 2025 It has been a fairly normal start to this mid August day across the Florida Keys. KBYX radar has recorded widely scattered but shallow nocturnal showers bubbling along boundaries stretched across the Deep Gulf waters and Straits of Florida. A few of these were able to briefly cross over the island chain. MRMS 6 hour QPE notes that nothing more than half an inch was estimated to fall over land. GOES-19 visibile imagery currently depicts a handful of showers still in the Gulf and Straits off the Middle and Lower Keys, but a notable gap is observed in the eastern Straits and southernmost edges of our waters. Another interesting detail is a cloud line forming just west of the Upper Keys with less cloud cover observed over the Lower and Middle Keys than yesterday around this time. This has allowed temperatures to reach relatively the same point as yesterday if not a touch higher than the upper 80s to near 90 range. Light east to southeast breezes prevail along the Reef. Today has the potential to develop another round of cloud lines across the island chain. There is already one ongoing along the Upper Keys, but only a few showers are starting to develop in it. This morning`s KKEY sounding looks to mostly give a green light for this forecast. The pocket of low to mid level dry air is mostly mixed out, though a small inversion still exists around 700 mb where it started. Otherwise, there is plenty of instability along with light low leveling winds and decent amount of low level moisture. While this profile looks good on paper, there are a few factors that may hinder convective development. CIMMS MIMIC Layer TPW notes a mass of drier air already present in the eastern Straits of Florida where convective development has been mostly ceased. Meanwhile, a weakly anticyclonic flow observed in the Straits via GOES-19 also looks to be pulling in some Cuban shadow from the south with drier air approaching the island chain from now two directions. It seems like it will be somewhat of a race between the cloud lines forming and dry air intruding, but as such we will hold onto chance PoPs expecting at least some cloud line development this afternoon along with possibly more nocturnal convection tonight. && .FORECAST... Issued at 408 AM EDT Sun Aug 17 2025 Looking ahead, the western Atlantic subtropical ridge will remain firmly in place through at least the early parts of this week, providing light to gentle breezes that will be occasionally variable. With minimal support aloft, convection across the Keys will remain limited or isolated in coverage when it occurs. Farther east, Hurricane Erin will track northward over the open Atlantic and remain well outside our forecast area. Even so, modest moisture from the systems western side could slightly elevate rain chances around midweek, though no direct impacts are expected. For now, it seems dry continental air from the northwesterly winds will keep showers at bay. Stay tuned for any updates. && .MARINE... Issued at 305 PM EDT Sun Aug 17 2025 No watches, warnings, or advisories are currently in effect for the coastal waters of the Florida Keys. From synopsis, a broad ridge stretching from the North Atlantic westward across the Florida Peninsula will result in light to gentle easterly breezes across the Keys coastal waters through early this week. As Hurricane Erin approaches and passes by The Bahamas and away from the Keys, breezes will veer to the north and freshen before gradually backing to the south by the end of the week. && .PRELIMINARY POINT TEMPS/POPS... Key West 82 92 82 92 / 40 30 30 30 Marathon 83 91 82 91 / 30 30 30 30 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...JAM Aviation/Nowcasts....JAM 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