164 FXUS61 KLWX 130141 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 941 PM EDT Mon Sep 12 2016 .SYNOPSIS... High pressure over eastern Pennsylvania and New Jersey will stall off the northern Mid-Atlantic coast tonight. A mainly dry cold front will cross the area Wednesday night. High pressure returns to the area through Friday before a cold front crosses the area this weekend. && .NEAR TERM /THROUGH TUESDAY/... Many places have decoupled this evening and temperatures are falling quickly into the 60s. Patchy fog is possible mainly across sheltered valleys and low lying areas. As of 8pm, 1024mb surface high is centered over the eastern seaboard from Norfolk VA to Cape Cod MA. This center will continue shifting east, stalling off the northern Mid- Atlantic coast tonight before drifting east Tuesday. SWly flow over the area tonight may allow some low level clouds overnight. Otherwise, dry into Wednesday. Light onshore flow through this evening, shifting south Tuesday morning. Minima tonight low 60s inland, upper 50s west of the Blue Ridge and mid 60s nearshore. Maxima Tuesday generally mid 80s with 850mb temps in the mid teens. Upper teens 850mb temps spread in late, perhaps allowing upper 80s to near 90F in valleys west of the Blue Ridge. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... Light moisture return makes for a warmer night (three or so degrees) Tuesday night compared to tonight. Dry Wednesday in advance of a cold front shifting east from the eastern Great Lakes. With surface high pressure off the SErn CONUS coast, westerly flow is expected in advance of the cold front. This downsloping flow will mix out and cause surface moisture to decrease while temperatures increase. This will continue to aide drying in the area. Max temps low to mid 90s with 850mb temps in the upper teens. Cold front crosses late Wednesday night with prefrontal convective activity dissipating on downsloping flow east of the Alleghenies. && .LONG TERM /THURSDAY THROUGH MONDAY/... A cold front will stall to our south and west Thursday while high pressure builds to our north over upstate New York. A northerly flow will usher in cooler and dry conditions across most locations. Still cannot ruled out an isolated shower or thunderstorm across the central Shenandoah Valley...but even here most areas will end up dry. A boundary will remain nearly stationary across the Allegheny Highlands south and east into North Carolina. High pressure will shift off the New England coast while a surface ridge extends south and west from the high into the Mid-Atlantic. This means more seasonable conditions along with sunshine for Friday across most areas. The high will continue to shift off the coast Saturday while a cold front moves through the Midwest. A southerly flow will develop in between these two systems and that will allow for the return of warmer and more humid conditions. A cold front will approach the area Saturday night before possibly passing through Sunday or Monday. Timing and location of the front remain uncertain this far out. Still looks like Sunday will be warm and humid with possible showers and thunderstorms. A few showers and thunderstorms are possible Monday...depending on exactly where the front is. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... VFR conditions prevail through Wednesday with the exception of valley/ground fog tonight. Light onshore flow through this evening becomes light Sly flow Tuesday morning. Wly flow Wednesday ahead of a dry cold front that crosses Wednesday night. A cold front will stall out to the south and west for Thursday and Friday. VFR conditions are expected during this time. && .MARINE... High pressure stalls along the northern Mid-Atlantic coast this evening, shifting east later Tuesday. Light onshore flow through this evening becoming Sly late tonight. Swly flow Tuesday becomes Wly Wednesday in advance of a cold front. All of this will be below SCA levels. Cold front crosses Wednesday with SCA likely from gusty NWly flow Wednesday night into Thursday. A cold front will stall to the south on Thursday. A small craft advisory may be needed for northerly winds during this time. High pressure will extend south toward the waters for Thursday night through Friday night before moving off the coast during the weekend. A return southerly flow is expected during the weekend. && .TIDES/COASTAL FLOODING... Anomalies have slowly risen to three quarters to a foot above normal on the western shore of the Chesapeake Bay this evening. Onshore flow will continue overnight and minor coastal flooding is expected at Annapolis. Elsewhere...water levels will be shy of flooding but will be monitored closely. Sensitive sites expected to reach action stages Tuesday and Tuesday night before the wind shifts west Wednesday. && .CLIMATE... Unseasonably hot weather will return to the area briefly on Wednesday. Here is a list of record daily high and warm low temperatures for September 14th. Washington DC area (Ronald Reagan National Airport, DCA) Record daily high temperature: 94 (1981, 1980 and 1915) Record daily high minimum temperature: 75 (2008 and 1961) Baltimore MD area (Baltimore-Washington International Thurgood Marshall Airport, BWI) Record daily high temperature: 94 (1931) Record daily high minimum temperature: 74 (1915) Dulles International Airport VA (IAD) Record daily high temperature: 95 (1998) Record daily high minimum temperature: 71 (2008) && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Coastal Flood Advisory until 6 AM EDT Tuesday for MDZ014. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...BAJ NEAR TERM...BAJ/HAS SHORT TERM...BAJ LONG TERM...BJL AVIATION...BAJ/BJL MARINE...BAJ/BJL TIDES/COASTAL FLOODING...HAS CLIMATE...DFH