Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
124 FXUS62 KKEY 080916 AFDKEY Area Forecast Discussion National Weather Service Key West FL 416 AM EST Mon Dec 8 2025 ...New DISCUSSION, MARINE, AVIATION... .KEY MESSAGES... -Showers and thunderstorms possible today and tonight ahead of a cold frontal passage tonight. -Southwesterly breezes are veering northwesterly ahead of the cold front. Expect light to gentle breezes to freshen to light to moderate -Breezes continue to veer to northeasterly by Tuesday morning -A cold front is expected to stall over the Florida Straits by mid week && .DISCUSSION... Issued at 416 AM EST Mon Dec 8 2025 The second Monday of December opened with a surprisingly active radar screen. A fast moving line of showers traveled south of the Dry Tortugas northeastward across the Keys. The Key West Airport ASOS measured gusts up to 31 knots with a third of an inch of rain, the first measurable precipitation in ten days. Lightning strikes were detected within this broad line of convection north and south of the island chain, though none of the marine stations measured wind gusts of the same intensity. This cluster was but the harbinger of more to come. KBYX radar highlights scattered convection south of the Dry Tortugas and showers entering the Gulf waters north of the Towers. Expect these clusters of activity to flare up more, because they are moving into a moisture-rich environment. CIMSS derived PWAT over the Florida Keys before sunrise was sampled at near 1.8 inches, above the 90th percentile for the day. What is causing this flare up in shower coverage? A stationary front that stalled across the Florida Peninsula finally began to move south after a couple of days. A high pressure system over the Great Plains began to migrate southeastward into the ArkLaTex region and force the boundary towards the Keys. While this front technically qualifies as a cold front, the fact it lingered over the Florida Peninsula means the dry air mass was heavily modified by Gulf moisture. That is not to say there will be no relief to the humidity; dew points are forecast to drop from the mid 70s to upper 60s post frontal passage. Today`s weather is forecast to be unsettled. Showers and isolated showers are expected to pulse up and down across the CWA ahead of the front. Southwesterly winds are expected to quickly rotate northwesterly. Gusts over 30 mph are possible ahead of the heaviest showers. Temperatures can still reach the lower 80s, but at least there will be some additional cloud coverage. Keep an eye on the radar today! .FORECAST... Uncertainty creeps back into the forecast rather quickly. Weather models indicate the front will stall once again across the Florida Straits tomorrow morning. The high pressure system pushing the front south will not be able to build very much, because a parade of clipper low pressure systems are sharpening a longwave trough established over the eastern CONUS. A lot of forecast questions exist because of this pattern. Exactly how much the high builds before it is forced east across the Deep South will determine breeze strength over the Gulf. Showers may be heavily convective over the Straits, which may allow the frontal moisture gradient to migrate closer to the Keys. Statistical models suggest another pattern change to Keys weather during the second half of the week. An arctic air mass is expected to surge into the upper CONUS late this week and allow a high pressure system to build over the Great Plains. This would help push another cold front across the Keys, but that could be ancillary to the threat of wind. In the situation the high extends deep towards the ArkLaTex region, there is a possibility of breezy to windy conditions next week. Check back later, because quite a bit can change in this kind of weather pattern! && .MARINE... Issued at 416 AM EST Mon Dec 8 2025 Gentle to moderate breezes will freshen to moderate and veer northeasterly tonight as a fractured front moves across the Florida Keys. Heaviest showers and thunderstorms are expected for the northern waters today and tonight, but the front may stall across the Straits of Florida. Expect greater shower coverage in the southern waters. Breezes will fluctuate between gentle and moderate during the week. && .AVIATION... (06Z TAFS) Issued at 416 AM EST Mon Dec 8 2025 VFR conditions are expected to largely prevail at the terminals through the TAF period, though both CIGs and visibility are likely to be briefly lowered at times, primarily towards MVFR and IFR categories, due to expected scattered showers throughout the day on Monday. While this activity is expected to continue into the evening, coverage will become more limited. In any case, specific timing on categorical changes will be left to amendments and refinements in later TAF issuances. Winds will veer from the southwest to northwest by sunset && .CLIMATE... On this day in 1986, the daily record rainfall of 6.66" was recorded at Key West. This is also the wettest day ever recorded in December at Key West. Rainfall records for Key West date back to 1871. && .PRELIMINARY POINT TEMPS/POPS... Key West 83 68 78 70 / 60 40 40 30 Marathon 82 70 77 71 / 50 40 40 40 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...AJP Aviation/Nowcasts....MC Data Acquisition.....MC Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest