030 FXUS62 KKEY 152018 AFDKEY Area Forecast Discussion National Weather Service Key West FL 318 PM EST Tue Jan 15 2019 .DISCUSSION...In the middle and upper levels(700-200 mb), latest available satellite imagery overlaid with model streamline analysis as of 200 pm, depict a mainly zonal/weakly anticyclonic middle and upper flow pattern across the entire CONUS, with low amplitude ridging more pronounced across the Southern half of the CONUS, including Florida, the Gulf of Mexico, as well as the Florida Keys. At the surface and in the lower to mid levels(Surface to 700 mb), latest available marine and land surface observations and analysis as of 200 pm, detail the center of an expansive east to west area of 1030 mb ridging located near the Arklatex region. .CURRENTLY...As of 200 pm, pesky thinly veiled stratocumulus continue to impact the Lower Florida Keys and surrounding Nearshore and Offshore Gulf waters to the north and west, as well as the Hawk Channel waters and the Florida Straits out 60 nm from Sombrero Key Light to 20 nm west of Dry Tortugas Light. Elsewhere some hi cloudiness has impacted the rest of the Keys and surrounding waters, with skies mostly sunny to partly cloudy. Temperatures across the islands are near 70 at Marathon and in the upper 60s in the Lower Keys. .SHORT TERM...Tonight thru Saturday, middle and upper mainly zonal pattern will continue across the Keys and surrounding waters as the center of the strongest ridging within an expansive east to west ridge gradually slides eastward. This ridge will reach off of the Georgia and Northern Florida Coast long about Friday evening, when slightly more moisture will enter into the boundary layer with gentle to light breezes and temperatures finally reaching near 80 degrees. Until that time however, gentle to moderate north to northeast breezes will originate off the cooler Peninsula, with some weak density surges with winds near 15 knots across the shallower waters at night given shallower cool air advection. High temperatures Wednesday will be near 70, with lower 70s Thursday, and middle 70s by Friday. Zones are split given the conduction of the coolest air to impact the Upper and Middle Keys tonight and tomorrow night, with 55 to 60 across the M/U Keys tonight and near 60 in the Lower Keys, and upper 50s across the M/U Keys tomorrow night and 60 to 65 in the Lower Keys. With more of a northeast trajectory by Thursday night, lows in the mid 60s will be near normal. Then on Friday winds veer more to between northeast and east, and for Friday night and Saturday, expect a weaker pressure pattern with winds backing a bit. Given a slight increase of moisture, a slight chance of showers, 10% to 20% is indicated for Friday Night and Saturday. More interestingly, given the increasing moisture and possibility of light northeast winds, the threat for low stratus/patchy fog again late at night and Saturday morning seems to be the bigger issue, but too far out to tell. && .LONG TERM...Saturday night thru Tuesday, including MARTIN LUTHER KING JR DAY, a more interesting pattern returns. Indications have been consistent that a larger trough will carve out along the eastern 1/3 of the CONUS. Given the latest available ensembles depiction of the amplitude of this next trough and available moisture ahead of the associated surface front, scattered showers will move across ahead of a strong frontal boundary very late Saturday night and early Sunday morning. Although we do not have thunder in the forecast prefrontal or frontally, this will likely need to be considered if consistency with the solutions continues. For now have 30% pops in the grids for the Sunday and Sunday evening. Models are honing in on later on Sunday as a 995 mb low moving thru the TN Valley swings a cold front rapidly eastward during later in the day Sunday and Sunday evening. A 1040 mb plus arctic surface high will move southeast from the Plains allowing for significant 1000-850 cold thickness advection behind the front. Given the depth of this cold air, still anticipate initially windy conditions Sunday through Monday even though Gulf waters are chilly upstream of the Keys. Hi and lo temperatures will be at least 7 to 10 degrees be below normal Monday per the ECMWF. Also a dearth of cold air stratocu will keep it mostly cloudy behind this next front. && .MARINE...Will still keep a SCEC for increasing winds across the Florida Straits tonight mainly for the first part of the night. Slightly higher breezes could impact the shallower Bay and Nearshore Gulf waters this evening but then the impact of decoupling will allow winds to come down later tonight. The next wind event seems more likely despite the time left in future as models have been consistent with the depth of the trough and strength of front and surface low pressure. As such SCA conditions will spread from west to east beginning Saturday night and overspreading all Keys waters by late in the day Sunday. && .AVIATION...MVFR cigs possible more probable aoa FL025-030 thru sunset, but with occasional VFR cigs at or above FL030 tonight. Brief cigs aoa fl030 possible at MTH, then becoming mostly clear after 24 or 01Z. Surface crosswinds will average from 340 degrees aoa 8 to 11 knots, becoming 360 to 010 degrees late. && .PRELIMINARY POINT TEMPS/POPS... Key West 61 70 61 73 / - - - - Marathon 59 70 61 74 / - - - - && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...Futterman Aviation/Nowcasts....Futterman Data Collection......BT Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest