Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
679 FXUS62 KKEY 011821 AFDKEY Area Forecast Discussion National Weather Service Key West FL 221 PM EDT Tue Jul 1 2025 ...New DISCUSSION, MARINE, AVIATION, PREV DISCUSSION... .AVIATION... (18Z TAFS) Issued at 214 PM EDT Tue Jul 1 2025 VFR conditions will prevail at both island terminals through 18z Wednesday afternoon. After a lull in scattered shower and isolated thunderstorm activity continuing through 00z, additional convective development is possible thereafter through around 06z. Confidence in timing and evolution is too low to include mention in the TAFs at this time, although this will continue to be reevaluated. Another wave of Saharan dust will likely limit additional convective activity after 06z through the rest of the TAF period. && .MARINE... Issued at 1142 AM EDT Tue Jul 1 2025 No watches, warnings, or advisories are in effect for Florida Keys coastal waters zones. From synopsis, broad low-level ridging will continue to rebuild over the North Atlantic and support gentle to moderate east to southeasterly breezes across Florida Keys coastal waters, veering to the southeast to south and modestly slackening throughout the week. An upper-level low north of the Bahamas will continue to move slowly northwestward towards the Florida east coast early this week, supporting slightly enhanced rain and thunder chances. Rain chances will briefly taper back mid-week before increasing again late this week due to a new weather disturbance sliding into the Southeast United States. && .PREV DISCUSSION... Issued at 1142 AM EDT Tue Jul 1 2025 CIMSS satellite-derived vorticity analysis places an expansive cyclonic upper-level gyre extending from the eastern Gulf eastward to well east of the Bahamas. This forcing for upper- level ventilation, combined with a moisture surge in the wake of a wave of Saharan dust, as well as copious outflow boundaries from the Mainland and Cuba supported scattered showers and isolated thunderstorms for last night`s overnight period through around sunrise. Convective available potential energy (CAPE) has since been exhausted, with recent GOES visible satellite trends highlighting mostly sunny skies across the Keys and the adjacent nearshore and offshore marine zones. Temperatures are finally rising into the upper 80s at this late morning hour. For this afternoon, coupled with the need for recharging of CAPE, southeast to south low- level steering flow will support some temporary moisture profile drying, with low rain and thunder chances expected. Thereafter, with the upper-level cyclonic flow still in the vicinity of the Florida Keys, we will need to watch for additional convection over the mainland to interact with any developing storms over Cuba to see if/when additional redevelopment occurs this evening and through at least the early overnight hours. Overall, this forecast reasoning is consistent with the inherited once-per-day full forecast package crafted overnight. No changes proposed. && .FORECAST... Issued at 505 AM EDT Tue Jul 1 2025 It has certainly been a tumultuous overnight across most of the Florida Keys. A slew of boundaries from all direction converged and collided across the Florida Keys and surrounding coastal waters. But even with all the activity that has occurred and remains ongoing, the Middle Keys have missed out on most of the precipitation. The Upper Keys picked up 1 to 3 inches, with the Lower Keys picking up a half to one inch thus far. The Middle Keys have seen at most around a tenth of an inch. There remains a healthy cluster still across the Straits of Florida but we are observing a noticeable downward trend on radar. Where it has rained, temperatures took a tumble down into the mid 70s, a nice reprieve from the milder lower 80s. Going forward today, most of our rain chances will be limited to this morning. As we go into the afternoon, a TUTT cell located off the east coast of Florida will continue a northward trek. As this feature pulls further away from the Keys, the low level steering flow will go more southerly. This coupled with relatively drier air pivoting around the periphery of a sprawling Atlantic Ridge, will provide lower rain chances this afternoon into the evening. Meanwhile, lurking along the entire Eastern Seaboard is a quasi- stalled trough and associated surface boundary that stretches into the northeastern Gulf. These features will very slowly slide southeast and across the Florida Peninsula through Saturday. Given the slow progression, it will take time for the Florida Keys to see much in the way of increased rain chances. As of right now, better rain chances return Friday, peaking Friday night into Saturday. Thereafter, a potent upper level shortwave diving southward will move into the base of this trough and strengthen into potentially a closed-off low. This will interact with the lingering surface boundary. That being said, there remains a lot of uncertainty as to what this interaction will ultimately produce. GFS has a surface low develop off the Georgia/Carolina coast, while the ECMWF has an inverted trough in the same region. Regardless, this poses no immediate threat to the Keys at this time. && .PRELIMINARY POINT TEMPS/POPS... Key West 91 82 90 81 / 60 30 20 10 Marathon 88 82 88 82 / 50 30 20 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 Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest