Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 170801 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 401 AM EDT Mon Apr 17 2017 .SYNOPSIS...
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A cold front will cross the area this morning. High pressure builds over the area tonight through early Wednesday. The next cold front will cross the area Thursday night. High pressure builds over New England for the weekend.
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&& .NEAR TERM /TODAY/...
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As of 3am, a 1001mb surface low is over Nova Scotia with a surface trough/cold front extending southwest across the Mid-Atlantic. High pressure is also centered just south of Bermuda. These two features are bringing the southerly flow and decent moisture advection to the area. However, westerly low level flow (southerly at the surface under and inversion) is causing showers to dissipate as they shift east across the central Appalachians. The actual front is approaching the MD/PA border from the north and will be the focus of activity today. Preferred diurnal window allows isolated thunder threat south of DC, though this depends on the pace of the front. The cold front shifts south of the area tonight with Canadian high pressure spilling south along the Mid-Atlantic. Cool with min temps in the 40s inland and mid 50s near the water (water temps are upper 50s to low 60s.
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&& .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
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A surface high pressure ridge shifts east across the area Tuesday. An onshore flow limits temperatures, so mid to upper 60s east of I- 95 and low 70s in interior locales. Low pressure weakens as it shifts east from the northern Great Lakes Wednesday enhancing southerly flow over the Mid-Atlantic. Little in the way of forcing, so will lower PoPs Wednesday from likelies over most of the area to chance.
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&& .LONG TERM /THURSDAY THROUGH SUNDAY/...
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Low pressure is expected to track across PA Thursday. This will place the Mid Atlantic on the warm side of the fronts. This in turn will allow temperatures to climb to around 80. This will be the more unstable side of the front as well, and showers and thunderstorms will be possible. At this time coverage seems like it will be scattered at best. Severe threat looks low as well. The low is expected to push off the NJ coast Friday morning and an associated cold front will sink into the Mid Atlantic. Showers will be possible overnight into early Friday morning, then diminishing by afternoon. Lows Thursday night in the upper 50s, highs Friday 70-75. High pressure over New England will nose down into the region Friday night. After seeing high minimum temperatures records broken on Sunday Friday night will feel downright chilly with lows in the 40s, possibly upper 30 in some spots. The upcoming weekend looks on the cool side as the high to the north and low pressure moving into the Ohio Valley create a cold air damming situation for the forecast area. Convective chances will be nil. Sunday looks to have chances for rain though - cloudy and cool with periods of light rain summarizes how things look six days out.
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&& .AVIATION /07Z MONDAY THROUGH FRIDAY/...
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A weak cold front shifts south across the area today. Lightning from associated thunderstorms looks to be limited south of DC this afternoon depending on the pace of the front. MVFR possible in showers/thunderstorms. High pressure/vfr tonight and Tuesday. Southerly flow then through Wednesday. Thursday and Friday look primarily to be VFR. The will be a possibility for showers and isolated thunderstorms Thursday but it is too far out/confidence too low to say there would be any prolongued period of sub-VFR conditions.
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&& .MARINE...
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Southwesterly flow 10 to 15 kt persists ahead of a cold front that will slowly move south of the area by late tonight. NWly flow also around 10 to 15 knot behind the cold front, no SCA as of this time. Flow shifts southerly tonight as high pressure shifts east. Southerly flow prevails then through Wednesday with low pressure persisting over the northern Mid-Atlantic. SCA possible Thursday.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ PRODUCTS...BAJ/WOODY!

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