Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 231401 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1001 AM EDT Wed May 23 2018 .SYNOPSIS... A cold front will push south through the area this afternoon. High pressure will build eastward from the Great Lakes tonight, eventually moving offshore by Friday. Moisture will increase ahead of a low pressure system over the weekend into early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 930am, a cold front stretches from the central Chesapeake Bay, to the south of Washington D.C., just north of Fredericksburg, Virginia, and southwest into the central Shenandoah Valley. This cold front will continue to move southeast across our CWA the remainder of the day today. With ample sunshine across the southern one- third of our CWA, including southern Maryland, dewpoint temperatures in the middle to upper 60s, and the cold front progressing southeastward, we are anticipating a couple of scattered showers and perhaps a thunderstorm or two this afternoon. It seems the best time frame for this activity to develop is between Noon and 4 pm, although we can`t rule something developing a little before and a little after this window. The area of interest would be the central Shenandoah Valley, across the Virginia Piedmont, and into southern Maryland. High temperatures will be in the lower to mid 80s for most locations. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... The center of surface high pressure will be located over the Great Lakes tonight, moving overhead by Thursday evening, then off the Mid-Atlantic coast Friday. With ridging building aloft as well, a respite from the recent unsettled weather will extend through the end of the work week. Temperatures will be a little above normal, with highs in the lower to mid 80s, and low temperatures in the 50s to lower 60s. Some moisture will begin to advance northward in the return flow on the back side of the high by late Friday and Friday night. Most of this advection will be focused on the Ohio Valley, and while it`s not impossible a few showers could develop over the Appalachians, have kept the forecast dry through Friday night for now. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Southerly flow will continue advecting moist and warm air over our region on Saturday as a Bermuda High is settled over the North Atlantic. Temperatures will be between the low and the mid 80s on Saturday with possible showers and thunderstorms in the afternoon due to diurnal heating. A low pressure system will be moving north from the Gulf coast and along the southeastern states Sunday into Monday as Bermuda high continues settled east of us. Winds will be turning more easterly as moist air continues to be advected Sunday and Monday with additional showers and thunderstorms. A boundary will approach the area on Tuesday and settle over us into Wednesday. This may trigger more showers and thunderstorms both days. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... A cold front will push southeastward the remainder of today. Winds have become northwest at all terminals, except for CHO terminal, where the front has not passed yet. We could encounter a shower or thunderstorm near the CHO terminal during the early to middle afternoon hours; elsewhere, dry conditions and VFR conditions are expected at the other terminals. High pressure will then build across the area through Friday. VFR conditions and light winds are expected through the period. VFR conditions likely Saturday with possible afternoon showers and thunderstorms which may decrease the CIGS. Sunday and Monday looks wetter with additional moisture over us, therefore more showers and thunderstorms possible. && .MARINE... A cold front will push south across the waters of the Potomac and Chesapeake Bay the rest of today. Winds will become northwesterly behind the front. Peak winds will be around 15 kt through the day, with a low probability for a few higher gusts. High pressure will build across the waters tonight and Thursday before moving offshore on Friday with light winds. Some of the wider waters of the Bay may come close to SCA criteria Friday night as southerly flow increases on the back side of the high. Winds are expected to remain below SCA criteria from Saturday into Monday, not anticipating an advisory for this period. && .TIDES/COASTAL FLOODING... Tidal anomalies will continue to decrease this afternoon as northwesterly winds develop behind a cold front. However, water levels remain more elevated around DC given some freshwater input, with the current high tide barely coming in below flood stage. This situation may repeat itself during the morning high tides the next couple days. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...ADS/KLW NEAR TERM...KLW SHORT TERM...ADS/KLW LONG TERM...IMR AVIATION...IMR/KLW MARINE...IMR/KLW TIDES/COASTAL FLOODING...ADS/KLW is the U.S. government's official web portal to all federal, state and local government web resources and services.