Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 171424 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1024 AM EDT Tue Sep 17 2019 .SYNOPSIS... A cold front to our south will push into the southeastern U.S. through tonight as Canadian high pressure builds to our north. This high will dominate over the Northeast and Mid-Atlantic region for the balance of the work week, promoting dry conditions and cooler temperatures. The high will settle to our south this weekend. && .NEAR TERM /THROUGH TONIGHT/... Latest surface analysis depicts a cold front across southern VA as northeasterly breezes and cloudy skies dominate across the CWA. Widely scattered showers are moving across portions of southern MD and adjacent Northern Neck of VA, tracking off to the southeast as winds turn out of the NNW above 5kft. Clouds will be slow to erode today as winds remain out of the east northeast, with temperatures topping out in the middle 70s to lower 80s. Will carry a chance for showers across central VA into early this afternoon, with drier air working into the region late this afternoon and evening. This drier air was evident with this mornings 12z IAD sounding above 700mb. Conditions will stay dry overnight as skies clear and winds slacken. This will promote patchy fog in the sheltered valleys and rural areas toward daybreak. Temperatures overnight will be much cooler than previous days, dropping into the low to middle 50s to near 60 degrees in the city centers. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... High pressure will remain in control through the period. Dry conditions with light northeast winds, becoming more variable as the high pressure settles overhead. Dry conditions and cool temperatures in the 70s during the day, followed by temperatures in the 50s at night. && .LONG TERM /FRIDAY THROUGH MONDAY/... Surface high pressure will slowly ease off the coast through the extended portion of the forecast, as ridging remains in place aloft. This setup will promote a warming trend as well as increases in humidity (dewpoints rising from upper 40s/lower 50s to above 60). But the forecast will remain rain-free until perhaps Monday, when an approaching cold front could perhaps support shower (thunderstorm?) activity. PoPs (20-30%) will be focused on the Potomac Highlands at this time. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... Light northeasterly breezes today at the terminals today in the wake of a frontal passage. MVFR CIGs will improve to VFR this afternoon as drier air works into the area. One exception will be CHO where MVFR CIGs likely hold on until late this afternoon with a passing shower or two possible. VFR conditions expected the remainder of the work week as high pressure dominates to our north and winds remain light and easterly through Thursday before turning out of the south Thursday night and Friday. && .MARINE... SCA conditions continue across the main stem of the Bay and lower tidal Potomac into this afternoon in the wake of the frontal passage, slackening toward evening. SCA conditions likely linger for portions of the lower Bay/Potomac waters tonight and into Wednesday. Thereafter, high pressure will build over the waters through weeks end with lighter winds and sub SCA conditions expected. && .TIDES/COASTAL FLOODING... Onshore flow through through Thursday will promote higher than normal tidal anomalies, resulting in the threat for minor tidal flooding. Currently, no active advisories in place but that will change over the next couple of days as anomalies continue to increase. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until noon EDT today for ANZ531>533- 538>542. Small Craft Advisory until 6 AM EDT Wednesday for ANZ534-537- 543. && $$ SYNOPSIS...BKF NEAR TERM...MM/BKF SHORT TERM...KLW LONG TERM...HTS AVIATION...BKF/HTS/KLW MARINE...BKF/HTS/KLW TIDES/COASTAL FLOODING...BKF

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