Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
531 FXUS62 KKEY 292011 AFDKEY Area Forecast Discussion National Weather Service Key West FL 311 PM EST Thu Jan 29 2026 ...New MARINE, AVIATION, PREV DISCUSSION... .KEY MESSAGES... -Rain chances will increase tonight and Friday. -A strong cold front will blast through the Florida Keys on Saturday, with a line of showers expected along and just ahead of the frontal passage. -Very cold and windy conditions are expected Saturday evening through at least Monday morning. A Wind Advisory and/or a Cold Weather Advisory may be required for portions or all of the Keys. && .MARINE... Issued at 311 PM EST Thu Jan 29 2026 Breezes across the coastal waters north of the island chain have substantially slackened to light to gentle. Meanwhile, moderate to occasionally fresh breezes persist across the Hawk Channel and Straits of Florida waters. Breezes will freshen slightly overnight into Friday. This will be due to a developing surface feature that will form along the Cuban coast and extend northeast into the Straits of Florida. In addition, better moisture will be able to pool northward across a larger portion of the Florida Keys and surrounding coast waters, increasing our rain chances. This feature is separate and independent from the next incoming cold front on Saturday. Confidence is very high that this front will be bring gale-force winds during the afternoon on Saturday and continuing into Sunday. Breezes will slacken Sunday evening through Monday, however, marine hazards are likely to continue. && .AVIATION... (18Z TAFS) Issued at 311 PM EST Thu Jan 29 2026 VFR conditions expected throughout most of the forecast period. A weak weather system will begin developing off the north coast of Cuba late tonight allowing for moisture to surge back north across the island terminals. Rain will likely move in close to midnight, or 05Z/Friday and linger through the morning, gradually dissipating from west to east. Confidence is not high enough at this point to include mentions of MVFR CIGs at this time. && .PREV DISCUSSION... Issued at 500 AM EST Thu Jan 29 2026 Synoptic-scale geopotential height analysis continues to depict a stubborn omega blocking pattern extending across the CONUS. A strong ridge continues to bridge over the western third of the United States, with a series of shortwave troughs pivoting to the west in the eastern North Pacific and over the Eastern Seaboard to the east of the ridge. Meanwhile, at the surface, a stationary front extends from the Yucatan northeastward to the central North Atlantic, with a sprawling area of high pressure over the Gulf States. The interaction of the high with the frontal boundary continues to support moderate to occasionally fresh northerly breezes across the Florida Keys at this early morning hour. Widespread mid-level cloud cover, in combination with the elevated winds, has limited the diurnal temperature signal for most island communities, with temperatures currently in the mid to upper 50s, only a few degrees cooler than the well below normal maxima observed Wedneday afternoon. For today through Friday, the aforementioned stationary front will slowly drift northward. Meanwhile, a weak area of low pressure may form along this front, drifting northeastward towards the Bahamas late tonight and Friday. Isentropic analysis on the 290K surface supports large-scale ascent at around 850 mb, with forecast soundings depicting ample boundary layer moisture and decent veering (warm advection). This seems to support a period of scattered light to moderate showers in the vicinity of the Florida Keys for these forecast periods, consistent with most available convective allowing model (CAM) guidance. Elected to nudge measurable rain chances to mid-level chance levels (30-40%) for tonight and Friday. Our attention then quickly turns to the weekend. Global ensemble mean and member fields are in fantastic agreement that a shortwave trough diving into the Mid-Atlantic will support rapid surface cyclogenesis off the Carolina Coast Saturday and Sunday. This is a textbook setup for an arctic invasion for the Florida Peninsula. All available numerical weather prediction and statistical guidance suggests temperatures plummeting Saturday evening through Monday into levels the Florida Keys have not seen since around 2010. The tight pressure gradient of the cyclone off the Carolinas interacting with building high pressure in the wake of the front will support very windy conditions. Coupled with the cool temperatures, rare Cold Weather Advisories may be required for portions or all of the Florida Keys Saturday night and Sunday night, with wind chills easily dipping into the 30s. As the large-scale synoptic pattern (at least temporarily) flattens by the middle to the latter part of next week, temperatures will slowly moderate closer to near-normal levels. && .PRELIMINARY POINT TEMPS/POPS... Key West 61 67 62 69 / 40 40 20 70 Marathon 61 68 60 67 / 40 50 20 60 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...LIW Aviation/Nowcasts....LIW Data Acquisition.....LIW Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest