Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
314 FXUS62 KKEY 210916 AFDKEY Area Forecast Discussion National Weather Service Key West FL 416 AM EST Wed Jan 21 2026 ...New DISCUSSION, MARINE, AVIATION... .KEY MESSAGES... -Windy to breezy conditions will persist until tonight -Warmer temperatures and increasing rain chances expected to return on Thursday. While the atmosphere will become drier on Friday, expect temperatures to remain above normal through the weekend. -The next frontal boundary could move across the Florida Keys early next week. && .DISCUSSION... Issued at 415 AM EST Wed Jan 21 2026 Early morning hours across portions of the Florida Keys were nearly cloud free based on GOES-East satellite observations. However, nighttime microphysics scans indicate low altitude winds are veering more east southeasterly, signaling muggier conditions and increased cloud cover are about to return to the Florida Keys. KBYX radar returns detect shallow showers across the Straits moving west to southwest, indicating moisture rich air is just on our doorstep. Mean layer advected precipitable water at 850 to 700 mb shows a plume of moisture trending towards southern Florida. At the same time, anemometers at the reef are measuring winds gusting to near 30 knots, so expect to once again wake up to windy conditions across the Keys. A broad high pressure system stretching from the DELMARVA region to the Carolinas is responsible for the aforementioned strong breezes. Weakening of this high and its movement towards the Atlantic are responsible for moisture lifting back into the Keys. Today, expect winds to gradually slacken across the island chain. Temperatures are returning to near normal values, but cloud cover should keep highs below 80 F. Those who enjoy milder weather can rejoice, but anyone who wanted the reprieve from humidity will need to wait until next week. .FORECAST... A series of clipper systems across the Great Lakes over the past few days weakened the high over the Carolinas, and the high will make its way out into the Atlantic by Thursday. The pressure gradient will weaken over the Keys, and breezy conditions are not expected for the end of the work week. Broad confluence in the low levels prompted a 30% chance of showers tonight and a slight chance on Thursday. Temperatures will remain above normal through the weekend. Highs in the lower 80s are possible on Saturday and Sunday. Dew points, sadly, may rebound to the lower 70s. Aloft, skies will dry out and shower chances are 10% at most through Monday. Elsewhere in the country, the forecast will be much more complicated. While the clipper lows weakened the Carolina high, they paved the way for a very sharp longwave trough to dig into the central United States. This low will phase together with a slow moving shortwave located over New Mexico tomorrow to Friday. Thus, the environment sets up for a very broad, very amplified winter storm stretching from Texas to the Carolinas. How exactly does this relate to Florida Keys weather? This winter storm will be able to form coastal lows, and statistical models suggest a coastal low could develop off the North Carolina outer bank. In this event, arctic air could be directed south towards the Keys. A cold front associated with this system is progged to move across the island chain sometime early next week. The most recent model guidance suggests frontal passage next Monday to Tuesday, but the timing and magnitude will change given newer data. Keep an eye on the forecast and to the north, because the upcoming winter system is going to be dramatic. && .MARINE... Issued at 415 AM EST Wed Jan 21 2026 A Small Craft Advisory remains in effect for all Florida Keys marine zones. From synopsis, a broad high pressure system located over the Carolinas will slowly weaken as it slides into the western Atlantic during the work week. Breezes will slacken as the pressure gradient diminishes, and gentle to moderate breezes are expected across the nearshore and offshore waters by Thursday. Weekend conditions are more uncertain because a sequence of strong low pressure systems over the southeastern United States. A col region could form over the Keys on Sunday and support light to gentle breezes, or the Keys could be stuck under gentle to moderate northwesterlies. && .AVIATION... (06Z TAFS) Issued at 415 AM EST Wed Jan 21 2026 There is increasing potential for MVFR ceilings at both island terminals this morning. Bases are expected to be between 2000 and 3000 ft. There will be a slight chance for showers, bringing with them spells of sub VFR visibility. Gentle to moderate northeasterly breezes early this morning are expected to become moderate to fresh after sunrise. && .PRELIMINARY POINT TEMPS/POPS... Key West 75 69 78 70 / 10 20 20 20 Marathon 75 69 78 68 / 10 30 30 20 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...Small Craft Advisory until 11 AM EST this morning for GMZ031>035- 042>044-052>055-072>075. && $$ Public/Marine/Fire...AJP Aviation/Nowcasts....11 Data Acquisition.....11 Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest