Area Forecast Discussion
Issued by NWS Sterling, VA

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305 FXUS61 KLWX 010800 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 400 AM EDT Fri Jul 1 2016 .SYNOPSIS... High pressure over Bermuda will continue to bring warm and moist air to the region today ahead of an upper level trough shifting east from the Midwest. A cold front will push southeast through the area this evening, with high pressure then building from the west through Saturday night. High pressure will shift east from the area Sunday. Low pressure will pass through the region Monday into Tuesday while a stationary front persists near the region through Wednesday. && .NEAR TERM /THROUGH TONIGHT/... As of 3am, an upper trough axis is apparent in water vapor imagery over the upper Midwest with a few leading thunderstorm clusters stretching from MI to AR. This wave will shift east today with most of the energy focused well north of the central Mid-Atlantic. In fact, low pressure develops over Quebec this afternoon in advance of the upper trough as it becomes negatively tilted. However, the southern extent of the trough axis extends south of the Mason-Dixon line, providing forcing to this area which is seeing moisture advection from the Bermuda high. As a result, there is a slight risk for severe thunderstorms over the eastern half of the LWX CWA. Severe threat: 2000 j/kg SBCAPE and 30 to 35 kt shear, particularly north, combined with forcing in the peak heating will result in strong to severe supercell thunderstorms. West flow will support a surface trough in the lee of the Blue Ridge with the focus of severe weather there. One limiting factor is available sunshine. A small cluster of thunderstorms over southern VA after 3am will spread clouds across the SErn portion of the CWA through the mid-morning hours. This may set up differential heating boundaries. Main threats are large hail and damaging wind with tall and moderately fat CAPE. The presence of boundaries and possible splitting supercells in the nearly straight line hodographs could allow isolated tornadoes. Max temps in the upper 80s, 90F possible where sun shines longest. The wave passes through this evening with activity shunting southeast of the MD part of the Chesapeake Bay by midnight. NW flow overspreads the area overnight with dry air advection and min temps low to mid 60s inland, near 70f nearshore/urban. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... High pressure builds in from the west Saturday through Saturday night and shifts east across the area Sunday. Meanwhile the surface trough lingers near the NC/VA border. Some associated Ely flow may allow some showers Saturday night and Sunday. Otherwise, dry and below normal temperatures expected. Sunday night, low pressure approaches with a chance that the associated activity reaches the Allegheny Front by sunrise Monday. && .LONG TERM /MONDAY THROUGH THURSDAY/... High pressure will be situated over the Great Lakes/Northeast while a stationary boundary is stretched from the Mid-West to the Mid- Atlantic region through much of the long term. Low pressure is expected to move along this boundary Monday into Tuesday resulting in unsettled conditions. There is uncertainty as to the track of the low across the region Monday into Tuesday. Models have shifted further north with their moisture fields and therefore showers and thunderstorms are becoming more likely. Low pressure should deepen as it moves eastward off the east coast Tuesday however the stationary front will be around the Mid-Atlantic into Wednesday. Unsettled conditions are possible through next Wednesday. Temperatures should be near normal next week. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... VFR conditions prevail through mid-morning under the influence of a Bermuda high. Mix of mid and high clouds through the morning with a cluster of thunderstorms currently over Srn VA staying SE of the DC metros. Cold front crosses the area late this evening with strong to severe thunderstorms across the DC metros in the afternoon/early evening. Damaging winds and large hail are the main threats. High pressure builds tonight with NWly flow 10 to 15 kt. VFR then through Sunday under high pressure. Sub-vfr conditions possible Monday-Tuesday of next week. SHRA/TSRA are possible during this time. && .MARINE... Cluster of thunderstorms currently over Srn VA may impact the Srn MD waters in the mid-morning hours. Cold front crosses around midnight with leading strong to severe thunderstorms across the Bay late this afternoon through the evening. Hazardous weather for a summer Friday evening for sure. NWly flow tonight looks to remain just below SCA levels will need to monitor that. High pressure builds through Saturday night, crossing Sunday with a switch to Sly flow. Southerly winds are expected Monday-Tuesday and SCA are possible on the waters during this time.&& .TIDES/COASTAL FLOODING... Tidal anomalies are running about a half foot above normal this morning. Water levels will stay below flood stage however will reach action stage at sensitive locations at Annapolis, Alexandria and DC SW/Waterfront. The next high tide will be the lower of the two and no flooding is expected. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...BAJ/HAS NEAR TERM...BAJ SHORT TERM...BAJ LONG TERM...HAS AVIATION...BAJ/HAS MARINE...BAJ/HAS TIDES/COASTAL FLOODING...HAS

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