Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 111900 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 300 PM EDT Fri Aug 11 2017 .SYNOPSIS...A cold front will move through the area Saturday evening and become stationary across the Carolinas early next week. Weak high pressure builds over the area Sunday and holds through the end of next week. && .NEAR TERM /THROUGH TONIGHT/...Strengthening srly flow has allowed warm front to advance north and allow for substantial breaks in the cloud cover. T-storms have developed over eastern WV and expect convective cvrg to increase through the remainder of the day and into the evening as air mass continues to destabilize. Main forcing appears to be advancing warm front. Can`t completely rule out a severe t-storm given 0-6km shear but CAPE values generally less than 1000 J/kg should keep that threat to a minimum. Flash flooding threat also appears low. Showers will likely linger well into the night across eastern areas but diminish across western areas. Areas of low clouds and/or fog can be expected overnight with stratus more common over northeast MD and fog more likely west of the Blue Ridge. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...Morning low clouds and fog will likely hinder sufficient destabilization for severe t-storms before cdfnt crosses the area late in the day or evening, but expect nmrs coverage of showers and t-storms especially east of I-95 and over southern MD. Greatest risk for flash flooding and severe wx appears over srn MD, the Chesapeake Bay and the Delmarva. Showers should move east and south of the area by Sat evening. && .LONG TERM /MONDAY THROUGH FRIDAY/... Uncertainty remains in place early next week with models diverging on the track of a wave of low pressure progged to move east along the stalled front to our south. The 0Z ECM continued to track it further north, moving across our region, while others such as the latest GFS and 0Z Canadian continue to allow high pressure to the north to build south and generally dominate. However, even with the drier solutions, an easterly flow may result in some clouds and perhaps some upslope showers in the mountains. Overall, however, temperatures will be near to perhaps a bit below normal early in the week. By Wednesday, high pressure dominates on most guidance including the ECM, with temperatures starting to warm a bit. By late Thursday and particularly Friday however, the high shifts off the coast and the next front is approaching, with a gradually increasing risk of showers and t-storms. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...Sct t-storms rest of today into the evening. Low clouds and/or fog expected tonight with MVFR/IFR cigs and vsbys. Another round of showers/t-storms expected again Sat with fropa. Depending on the strength of easterly flow and the path of a low pressure system moving eastward along the front stalled to the south, a period of sub VFR conditions may occur early next week due either to low clouds or rain. Uncertainty remains high, however. && .MARINE... Srly winds will continue to strengthen today into this evening with SCA conditions expected. Winds should diminish late tonight. T-storms Sat may require SMWs. Uncertainty exists regarding early next week on the strength of an easterly flow as a front remains south of the region and a wave of low pressure pushes east along it. However, at this time SCA conditions are not expected. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 9 PM EDT this evening for ANZ530- 531-536-538-539. Small Craft Advisory until 3 AM EDT Saturday for ANZ532>534- 537-540>543. && $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...RCM AVIATION...RCM/LFR MARINE...RCM/LFR is the U.S. government's official web portal to all federal, state and local government web resources and services.