Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
388 FXUS62 KKEY 191834 AFDKEY Area Forecast Discussion National Weather Service Key West FL 234 PM EDT Wed Aug 19 2026 ...New DISCUSSION, AVIATION... .KEY MESSAGES... - A swath of Saharan dust will remain across the Keys this afternoon and evening, maintaining rain-free conditions. - Rain chances will slowly increase by late week into the weekend, as dust concentrations decrease. - Warm and muggy conditions will continue throughout the work week, with light and often variable breezes. && .AVIATION... (18Z TAFS) Issued at 233 PM EDT Wed Aug 19 2026 VFR conditions will prevail at both island terminals through 18z Thursday afternoon. Light northwest to north winds will become variable overnight, continuing through Thursday. Although an isolated shower cannot be ruled out on any forming broken island cloud line, chances are far too low to include mention in the TAFs at this time. && .PREV DISCUSSION... Issued at 306 AM EDT Wed Aug 19 2026 Regarding the synoptic picture, surface analysis shows high pressure across the Gulf with its axis bisecting the Florida straits and this will yield a low-level NW flow across the Florida Keys today. Meanwhile, weak cyclonic flow aloft will gradually become established in the northeastern Gulf as a weak upper level low slowly develops throughout the day. While the KEY CWA should be far enough removed from the upper low to take advantage of any forcing for ascent, enhanced moisture associated with this feature will cause a sharp moisture gradient across the mainland with PWATs in excess of 2 inches across much of north/central FL compared to the exceptionally dry values across the Keys. However, the proximity of the upper low coupled with the low-level northerly flow will finally start to moisten atmospheric conditions across the Keys, which could favor some shower activity developing by this evening depending on the evolution of outflow boundaries originating from seabreeze convection across SEFL later today. Highest rain chances this evening will generally be north of the Island Chain and across the Bay/Gulf side waters where slight PoPs are in place. A slight decrease in boundary layer flow on Thursday could then introduce cloud line development as a possibility and with much less dust to contend with, there are some signals for precip activity but PWATs will still be quite below the daily mean values for this time of the year. The aforementioned upper low in the northeastern Gulf will weaken late week and into the weekend as longwave troughing gradually amplifies across the eastern US. This trough will push a frontal boundary into the northern Gulf Coast and Southeast US late weekend and into early next week. As this occurs, a more familiar pattern develops locally as Atlantic high pressure at the surface brings a more southeasterly flow regime back to the Florida Keys by late weekend and into next week. Should this pattern materialize, it is possible that daily PoPs may finally return to normal climatological levels, though this may take until next week to fully develop as another wave of Saharan Dust could push through the region this weekend but dust concentrations shouldn`t be quite as extreme as what has been recently observed. Either way, an eventual end to this incredible mid August dry stretch is within sight but there remains no signals for any substantial rains at this time. && .MARINE... Issued at 1146 AM EDT Wed Aug 19 2026 A ridge axis draped across the Florida Keys will maintain a mostly variable wind pattern through the remainder of the week with wind speeds mainly less than 10 knots. However, brief surges in wind speeds are possible in the evening hours with breezes occasionally approaching 15 to 20 knots near the Upper Keys. Exercise cautionary conditions may be periodically required for waters adjacent to the Upper Keys. A broad swath of Saharan air blanketing the area will maintain rain-free conditions today, but rain chances will slowly increase into late week as moisture slowly recovers. By the weekend, a light and variable flow pattern should persist on Saturday before winds gradually increase and become more southeasterly by late weekend and into next week. && .PRELIMINARY POINT TEMPS/POPS... Key West 92 83 92 82 / 0 10 0 10 Marathon 91 83 90 83 / 0 20 0 10 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...BT Aviation/Nowcasts....BT Data Acquisition.....BT Visit us on the web at weather.gov/key Follow us on Facebook and X at: www.facebook.com/nwskeywest www.x.com/nwskeywest