Area Forecast Discussion
Issued by NWS Sterling, VA

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463 FXUS61 KLWX 190749 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 349 AM EDT Fri Aug 19 2016 .SYNOPSIS...Weak high pressure builds in through Saturday with a cold front crossing the area Sunday evening. High pressure returns for the first half of next week. && .NEAR TERM /THROUGH TONIGHT/...Mid-high level clouds continue to stream into the Mid-Atlantic region early this morning due to westerly flow aloft. A shortwave trough will approach the region from the TN valley today. Iso-sct showers and an isolated thunderstorm are possible mainly across the VA highlands and Shenandoah Valley where forcing and instability is higher. As the disturbance tracks eastward into this evening a few showers and thunderstorms may pop-up south and east of the Washington DC metro. Rainfall amts will be light in any activity. Mostly sunny conditions will allow temps to reach the low 90s east of the Blue Ridge today...mid to upper 80s elsewhere. && .SHORT TERM /SATURDAY THROUGH SUNDAY/...Similar conditions on Saturday as westerly flow aloft continues. Iso- sct showers and an isolated thunderstorm are possible Saturday afternoon mainly across the higher elevations. Activity should diminish into the evening. Warm conditions continue Saturday but may be a deg or two cooler than today due to more cloud cover. Temps will still reach U80S/L90s east of the Blue Ridge. Attention shifts to a cold front that will move into the Ohio Valley Saturday night. This system is associated with a deep upper level trough that will swing across the Great Lakes and New England Sunday. The cold front will move through the Mid-Atlantic during the day Sunday. Strong moisture advection is expected ahead of the front and showers and sct thunderstorms are expected. The wind field will increase Sunday afternoon and a few thunderstorms may become strong to severe however coverage seems isolated at this time. The risk is greater across NY/PA. The bigger threat will be heavy rain on Sunday. Widespread amounts of a half inch in 6 hours are probable east of the Blue Ridge Sunday afternoon. Greater amts of near an inch are possible along the I-95 corridor. Locations closer to the better forcing such as northeast MD including the City of Baltimore may see some flash flooding Sunday afternoon and into the evening. Training storms capable of flooding are possible in this synoptic set-up. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...Cdfnt clears the fcst area by 03Z Mon with showers ending. Dry wx most of next week as ridge builds over the area sfc and aloft. Temps below normal early next week then gradually warm up. High pressure begins to weaken at the end of next week with moisture returning to the area with showers possible over the higher terrain next Fri Aug 26. By the end of next week, we`ll be also paying attention to the tropics as all of the GEFS members show a tropical cyclone north of Puerto Rico on a track WNW to the east of the Bahamas. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... VFR conditions expected through the next 36 hours. Isolated showers and thunderstorms are possible in the afternoon hours today and Saturday mainly at CHO- MRB. Sub-vfr conditions are possible in activity. A cold front will cross the terminals Sunday and widespread showers are expected. Flight restrictions are expected and TSRA causing gusty winds are also possible Sun afternoon. Showers end by 03Z Mon as cdfnt sweeps through the area. NW winds Sun night and Mon as high pressure builds from the west. VFR all of next week under high pressure. && .MARINE...Sub-SCA conditions on all the waters through Saturday. An isolated shower or thunderstorm is possible each afternoon which could bring gustier winds. No marine hazards expected Sunday through Sunday night. Winds south becoming southwest around 10 knots. Small craft advisory conditions are likely Sun night through Mon night as winds shift to the NW behind cold front. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...LFR NEAR TERM...HAS SHORT TERM...HAS LONG TERM...LFR AVIATION...HAS/LFR MARINE...HAS/LFR

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