000 FXUS62 KKEY 191952 AFDKEY Area Forecast Discussion National Weather Service Key West FL 252 PM EST Tue Feb 19 2019 .DISCUSSION...In the middle and upper levels(700-200 mb), latest available satellite imagery overlaid with model streamline analysis as of 200 pm depicts a deepening middle and upper longwave pattern over the Western CONUS, with a sharpening full latitudinal trough axis that now extends from NE MT south to near El Paso. Conversely and downstream of that, record value 500 mb height rises and building subsidence is in place across the length of the MS Valley to the Eastern CONUS, is in association with a burgeoning massive mid and upper ridge centered a couple hundred miles north of San Juan, PR. South Florida and the Keys lie beneath the western expanse of the deep and very warm anticyclone. At the surface and in the lower to middle levels,(Surface to 700 mb), latest available land and marine surface observations and analysis as of 200 pm, show the an expansive anticyclone with its near 1040 mb plus center located from Madison, WI east to Akron, OH. Well to the south of that, a weakening frontal boundary is analyzed across Central Florida from low pressure in the NW Atlantic. .CURRENTLY...As of 200 pm, skies are sunny across the islands and adjoining waters. Temperatures have reached the middle 80s again with the exception of 88 degrees recorded at MTH airport. C-man stations along the Florida Reef are recording east to southeast winds near 15 knots and gusty, and island platforms are 10 to 15 mph and gusty. .SHORT TERM...Tonight thru Thursday Night, expect record mid-level heights, with 590-595 decameter heights at 500 mb continuing across South Florida and the Keys thru this time. 1035-1040 mb surface ridging will reach New York State this evening, moving slowly into the NW Atlantic as still a 1035 mb high by Wednesday Night. Then 1025 mb surface ridging will elongate to across the Florida Peninsula from the West Central Atlantic during Thursday, then weakening slightly Thursday Night. As a result, will continue to see well above normal high and low temperatures in the mid 80s with lows in the mid to upper 70s thru the period. Just have a dime pop in the grids thru the period with the exception of the Thursday day period when time heights indicate a little more moisture available at that time, so just have a 20 pop for that period alone. PWAT averages 1.25 inches except 1.25 to 1.50 during Thursday morning. && .LONG TERM...Friday thru Tuesday, middle and upper heights only fall from the lower 590s, maybe back to 588 dm by Monday and Tuesday. The surface ridge across Florida on Thursday night, slowly loosens during Friday thru Saturday Night, with the Keys in a weak pressure pattern Sunday thru Monday. High temperatures will continue above normal in the mid 80s with low temperatures in the mid 70s with higher dewpoints and humidity. Will continue to maintain a dime pop in the grids, and although this is above normal in mid to late Feb, its actually below normal compared with the guidance 12 hour pops. && .MARINE...SCA are now in effect until at least Wed afternoon across GMZ033-034-042>044-052>055-072>075 with SCEC across the shallower waters which have warmed appreciably. SCEC conditions expected Wed Night and Thursday likely for GMZ033-034-042>044-052>055-072>075 as well. SCEC and SCA not expected thereafter, with great boating conditions this upcoming weekend. && .AVIATION...VFR conditions will prevail at the EYW and MTH island terminals the rest of this afternoon and tonight. Expect only FEW-SCT cumulus and stratocumulus between 1500 and 2500 feet. ESE winds of 8 to 13 knots with occasional gusts to 18 knots will continue. && .PRELIMINARY POINT TEMPS/POPS... Key West 77 83 77 83 / 10 10 20 20 Marathon 78 87 78 87 / 10 10 20 20 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...Small Craft Advisory until 5 PM EST Wednesday for GMZ033-034- 042>044-052>055-072>075. && $$ Public/Marine/Fire...Futterman Aviation/Nowcasts....Jacobson 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