Area Forecast Discussion
Issued by NWS Sterling, VA

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318 FXUS61 KLWX 221829 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 229 PM EDT Sun Sep 22 2024 .SYNOPSIS...
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A frontal system will stall over the area into Monday. A strong front and area of low pressure over the Great Lakes and Upper Midwest will approach the area during the early to middle part of the week. High pressure will follow mid to late week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Latest satellite imagery shows abundant cloudcover across the region thanks to easterly flow and a backdoor cold front draped across the region. A few showers or areas of drizzle are possible along the backdoor front into the evening, but with diminishing forcing aloft expect coverage to be isolated to widely scattered. Some improvement in clouds diminishing is expected west of the Blue Ridge, with areas to the east in large remaining socked in the clouds with the easterly flow. Low temperatures tonight will drop into the upper 50s to mid 60s. A few showers, drizzle, or fog are still possible generally west of US-15 in the vicinity of the stalled front tonight.
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&& .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
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The forecast remains on track for Monday with little changes expected. Thus, expect lingering cloud cover for much of the area along with muted diurnal temperature spread. As another trough and area of low pressure/frontal system begin to approach from the OH Valley/Great Lakes by Monday afternoon, expect increasing rain chances from west to east. Greatest potential for rain likely arrives overnight Monday. Generally light QPF with this system with an overall quarter inch expected for most. This system will gradually push across the area Tuesday and Tuesday night with showers and a few thunderstorms likely.
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&& .LONG TERM /WEDNESDAY THROUGH SUNDAY/...
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A wavy frontal system will slowly move or stall across the area Wed- Thu bringing more showers and thunderstorms. It`s uncertain how far south this front can get given blocking ridge along the East Coast. There could also be some flood concerns given slow movement of this frontal system. At the end of the week, remnants of a tropical cyclone are expected to be pulled northward into the southern Mid-Atlantic and eventually get absorbed into a large upper low over the mid MS River valley. Lots of uncertainty at the end of next week, but not looking as wet as earlier in the week.
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&& .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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Primarily MVFR CIGS this afternoon which may gradually scattering out by this afternoon, perhaps a bit earlier at MTN as a backdoor front pushes through. Winds will be E/NE 5-10 kts through tonight. Onshore flow continues Monday into Tuesday with bouts of lower CIGs and patchy fog (especially overnight) possible at times. Showers and a few thunderstorms are possible late Monday afternoon through Tuesday night. Favoring more showers than thunderstorms at this juncture. Expect numerous to widespread showers Wed-Thu with a slow moving front. Flight restrictions seem likely at some point.
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&& .MARINE...
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Onshore flow is expected through Tuesday night. A few gusts of 15-20 kts are possible at times in the wake of a backdoor front, though most of the time should be sub-SCA. SCA conditions are possible Wednesday on SE winds.
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&& .TIDES/COASTAL FLOODING...
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A very prolonged period of onshore flow (east to southeast) will continue through much of the week. Minor coastal flooding is likely at high tide at all sensitive locations for the next few days. Coastal Flood Advisories are in effect for nearly the entire western shoreline of the Chesapeake Bay and tidal Potomac River, including Washington DC. A steady rise in anomalies is expected to produce Moderate flooding at Annapolis and Washington DC SW Waterfront/Alexandria through tonight. As a result, a Coastal Flood Warning remains in effect. Expect headlines to be extended for much of the upcoming week.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...Coastal Flood Warning until 5 AM EDT Tuesday for DCZ001. MD...Coastal Flood Warning until 5 AM EDT Tuesday for MDZ014. Coastal Flood Advisory until 5 AM EDT Tuesday for MDZ011- 016>018-508. VA...Coastal Flood Warning until 5 AM EDT Tuesday for VAZ054. Coastal Flood Advisory until 5 AM EDT Tuesday for VAZ057. WV...None. MARINE...None. && $$ SYNOPSIS...DHOF/CPB NEAR TERM...CPB SHORT TERM...CPB LONG TERM...LFR AVIATION...LFR/CPB MARINE...LFR/CPB TIDES/COASTAL FLOODING...LWX