Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 170219 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 919 PM EST Thu Feb 16 2017 .SYNOPSIS...
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High pressure will build in overhead tonight. A weak system will pass near the area Saturday night and Sunday. A backdoor cold front will be near the region on Monday followed by the return of high pressure.
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&& .NEAR TERM /THROUGH FRIDAY/...
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As of 9pm, 1020mb surface high is over the Gulf Coast with a 967mb surface low over the Magdalen Islands in the Canadian Maritimes. Clear and calming this evening as NW flow drops below 10 mph across the area except the western shore of the Bay and ridgelines. Dewpoints are in the low to mid teens with temperatures expected to quickly drop as locations decouple. After midnight, mid/high clouds spread across western areas of the forecast area as upper level energy moves through and warm air advection begins. Min temps low to mid 20s inland and near 30F nearshore; these may bottom out before sunrise depending on cloud cover. High pressure will be overhead to start the day Friday but will slide southward by the afternoon. Morning mid/high clouds will become less prevalent by the afternoon although with warm air advection regime, will likely still be some clouds around. Temperatures will be considerably milder with highs in the 40s/50s, coolest across northeast Maryland, warmest across central Virginia.
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&& .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
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A system will be pushing across the southern Plains Friday and Friday night, and move into the southeastern US by Saturday. Heights will build out ahead of this, leading to dry and mild conditions. Expecting partly-mostly sunny/clear skies with some increasing clouds by Saturday afternoon. Lows Friday night in the 30s will warm significantly into the 60s on Saturday. Some low 70s also possible across central VA. The system moving into the SE US will be in a decaying stage by Saturday night, so its effects will be relatively minor across our area, aside from the increased chances for a few showers. Lows Saturday night in the 40s.
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&& .LONG TERM /SUNDAY THROUGH THURSDAY/... High pressure will build into the region Sunday through Tuesday. Dry conditions and mild temperatures will evolve during this stretch of time, especially Sunday. Will have to monitor for potential backdoor cold front Monday which would keep temperatures a bit cooler for Monday/Tuesday, although still above normal for February. By Tuesday night, a cold front should sag across the region and then stall overhead Wednesday. There is a chance for rain showers Tuesday night and Wednesday in association with the front. Temperatures will remain mild to the south of the front and slightly cooler to the north of the front. The next low pressure system that could affect the region should develop along the tail-end of the stalled front Wednesday night. This low could meander northeastward over the Carolinas, bringing a chance for rain showers to the mid-Atlantic Wednesday night into Thursday. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/...
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VFR conditions prevail into Saturday night. Easing NW flow this evening becomes SWly Friday morning as high pressure passes. There is the potential for some sub-VFR conditions Saturday night with chances for some rain showers as a system pushes to the south of the area. Mostly VFR conditions Sunday through Tuesday. There is a low chance of sub-VFR conditions with potential backdoor cold front Monday into Tuesday. Winds northwest 5 to 10 knots Sunday through Monday. Winds becoming northeast around 5 knots Monday night and Tuesday.
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&& .MARINE...
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SCA continues for lower Tidal Potomac and MD Chesapeake Bay through the rest of the overnight. NW winds will continue to gradually subside overnight, however with air temperatures cooler than the waters, mixing of the lingering stronger winds aloft should still occur overnight Otherwise, mainly sub-SCA conditions expected Friday through Saturday night with developing south/southwesterly flow. No marine hazards Sunday through Tuesday. Winds northwest 10 to 15 knots Sunday through Monday. Winds becoming northerly around 10 knots.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 6 AM EST Friday for ANZ531>534-537- 539>541-543. Small Craft Advisory until 1 AM EST Friday for ANZ530-538-542.
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&& $$ SYNOPSIS...BAJ/MM NEAR TERM...BAJ/MM SHORT TERM...MM LONG TERM...KLW AVIATION...BAJ/MM/KLW MARINE...BAJ/MM/KLW

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