745 FXUS62 KKEY 160909 AFDKEY Area Forecast Discussion National Weather Service Key West FL 409 AM EST Tue Feb 16 2021 .DISCUSSION... .CURRENTLY... Under partly cloudy skies and light south winds, temperatures are averaging in the mid 70s along the island chain. Meanwhile, local radars are detecting an area of scattered showers on the outer waters of Mainland Monroe, with only isolated showers elsewhere. On our marine district, winds are south to southwest at 10 to 15 knots. && .SHORT TERM...(Today through Thursday night) A deep full-latitudinal long wave trough extending from the Upper Great Plains southward into the extreme Southeast Gulf of Mexico early this morning will lift northeastward, resulting in most of the mid and upper level ascent remaining well north of our area. However, a modest low level confluent flow combined with an abundance of moisture will prompt a brief spell of well above normal rain chances today, with moisture and low level convergence becomes negligible later tonight. For Wednesday through Thursday night, a deep western Atlantic anticyclone will build westward and over our region, resulting in 5 to 10 percent rain chances beginning Wednesday. The main temperature challenge will be over the Lower Keys this afternoon with the shallow cool front passing through. Given considerable low level stratus and gusty north winds, temperatures of around 80 degrees may fall into the mid to upper 70s during this afternoon with temperatures averaging in the lower to mid 80s elsewhere. Temperatures will return to well above normal with an increasing southeast flow Wednesday through Thursday night. && .LONG TERM...(Friday through Monday) Another progressive long wave trough accompanied by a well pronounced cold front will plow through the Southeast United States and Florida Peninsula Friday night, with much cooler and drier air to filter into our area beginning Saturday. With that, the best chance for an episode or two of rainfall will be with the aforementioned boundary, with little if any measurable rainfall expected for the balance of this time frame. Well above normal temperatures Friday will become about 5 degrees below normal Friday night through Saturday night, before moderating quickly thereafter. && .MARINE... A shallow cool front in the extreme Southeast Gulf of Mexico will limp southeastward and clear at least the western half of our marine district, before becoming stationary on our far eastern waters late this afternoon and early evening. With that, a Small Craft Should Exercise Caution for increasing winds will be inserted for the western half of our coastal water this afternoon and early evening. Beyond that, the boundary will lift northwestward and into the Southeast Gulf of Mexico and the Florida Peninsula on Wednesday. Thereafter, a strong cold front is expected to pass through our entire marine district late Friday, with strong northerly breezes to follow through at least Saturday night. && .AVIATION... Scattered showers and a possible thunderstorm are expected to affect the Florida Keys this morning and early afternoon ahead of a cold front, with the main core likely moving through between 14Z and 19Z. These squalls are expected to produce MVFR conditions, although the ceilings may drop to IFR in the late morning and early afternoon. The weather will dry out behind the cold front this afternoon. Winds S-SW near 10 knots, becoming NW-N at 10 to 15 knots with occasional gusts near 20 knots this afternoon. && .CLIMATE... In 1991, the daily record low temperature of 53 degrees was recorded in Key West. Temperature records date back to 1872. && .PRELIMINARY POINT TEMPS/POPS... Key West 79 71 81 75 / 70 30 10 10 Marathon 81 72 83 75 / 60 30 10 - && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...APA Aviation/Nowcasts....SDR Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest