569 FXUS62 KKEY 172006 AFDKEY Area Forecast Discussion National Weather Service Key West FL 306 PM EST Sat Dec 17 2022 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 300 PM EST Sat Dec 17 2022 GOES-16 satellite imagery is detecting mostly cloudy skies across the island chain, with temperatures in the upper 70s. It remains quite muggy to the senses, with dew points in the lower 70s. The evolution of KBYX Doppler radar returns today has been quite similar to the evolution of yesterday, with the main convective activity limited to the Straits of Florida. No major change to the overall thinking for the forecast for the first few periods. The stalled frontal boundary over the Straits of Florida will continue to work its way back northward this evening. This will result in continued veering (warm advection, large- scale forcing for ascent) throughout the evening and overnight hours. CAM guidance agrees with this evolution, with showers and thunderstorms likely proliferating in the western waters around midnight, before eventually pushing across the island chain overnight. Have elected to continue advertising likely PoPs (around 60%). A second frontal boundary currently draped over the Florida Panhandle will finally push this primary frontal boundary south of the Florida Keys tomorrow afternoon. This will promote a brief period of drying through Monday night, as high pressure builds across the Southeast. Deterministic and ensemble global guidance then pegs the next feature of interest as a shortwave trough promoting surface cyclogenesis over the Gulf coast. Indications are this trough will dive southeastward towards central Florida Tuesday through Tuesday night. Forecast soundings highlight a window of great veering, with storm-relative helicity values above impressive 150 m2/s2 levels. Have decided to introduce thunder to the forecast for these periods, and this will continue to be monitored for potential stronger impacts. There appears little in the way of cool advection in the wake of this feature. Winds will quickly veer from the northeast, to southeast, to southwest late in the week. This will be in the response to what appears will be a powerful upper-level trough and associated cold front pushing through the East Coast Friday and Friday night. As is typical this time of year, there is quite a bit of model spread and respective uncertainty with regards to how strong the cold advection is behind this front. However, all indications point towards below average temperatures for Christmas Eve and Christmas Day for the Florida Keys. Current forecast calls for lows 55 to 60 Friday night, with highs in the upper 60s for Christmas Eve. It should be noted that this forecast is on the upper 50th percentile (warm) side of guidance, and should model trends continue, this may need to bumped further downwards. && .MARINE... Issued at 300 PM EST Sat Dec 17 2022 There are no watches, warnings, or advisories currently in effect for the coastal waters of the Florida Keys. From synopsis, a surface front stalled south of the island chain will lift back northward overnight tonight. Light to gentle southeasterly breezes will veer to the southwest overnight. A reinforcing secondary front will push through the Florida Keys on Sunday. High pressure will build across the Southeast in the wake of the front, resulting in freshening north to northeast breezes Sunday afternoon through Monday. High pressure will weaken on Tuesday, as a disturbance in the Gulf of Mexico pushes towards the Florida Peninsula. Winds will then quickly veer from the northeast, to the southeast, and then eventually southwest ahead of a potentially much stronger cold front by the end of the week. && .AVIATION... (18Z TAFS) Issued at 300 PM EST Sat Dec 17 2022 Showers will likely steer clear from both terminals until later this evening. Have introduced VCSH at 04z for EYW and 05z for MTH. Sub-VFR conditions are likely withing passing showers and thunderstorms. EYW could see some light rain over the next few hours as a cluster of decaying showers to the southwest of Key West moves to the northeast. There is a chance that after tomorrow's cold frontal passage for MVFR CIGS around mid-morning, however, confidence was too low to include at this time. Surface winds will rapidly shift clockwise ahead of an approaching front, with winds being southeast this afternoon at 6 to 10 knots, becoming southwest to west overnight. The veering will continue through tomorrow morning, and winds will be northwest to north at 4 to 7 knots. && .CLIMATE... On this day in 2006, the daily record rainfall at both Key West (1.07") and Marathon (2.24") was recorded. Rainfall records in Key West date back to 1871, and 1950 in Marathon. && .PRELIMINARY POINT TEMPS/POPS... Key West 79 72 79 69 / 40 60 30 20 Marathon 80 72 79 69 / 40 60 30 20 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...BT Aviation/Nowcasts....NB Data Acquisition.....DR Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest