Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 191850 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 250 PM EDT Mon Jun 19 2017 .SYNOPSIS...
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A cold front will cross the area this afternoon into the evening. Expect widespread showers and thunderstorms with damaging winds and heavy rainfall to continue moving east. Weak high pressure will build over the area for the middle of the week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Severe thunderstorm watch until 8pm. Flash flood watch until 9pm for the Balt-Wash metro and 8pm west/south of the metro. As of 2pm, the cold front (based on wind direction) is still over WV. Prefrontal thunderstorms are now just east of the Blue Ridge with a second line over the southern Shenandoah Valley. We are issuing severe thunderstorm warnings for primarily wind though some cores are indicative of one inch hail. Flash flood warnings will continue to be issued where rain is anticipated to exceed the flash flood guidance. This activity will continue to slowly push east across the rest of the area through the early evening. Instability of 2000-3000 j/kg SBCAPE with 30 to 40 kt effective shear and PWATs around 2 inches should allow isolated to scattered severe activity. End time for severe looking to be 8pm for southern MD. Will cancel the severe and flash flood watches as it pushes east and the threat ends. Wind shifts west behind the front with drying conditions, but will ease overnight. Min temps upper 60s inland to low 70s urban/east of I-95.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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An upper trough persists north of the area Tuesday into Thursday. Weak surface high pressure will build over the area with dry conditions and near normal temperatures.
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&& .LONG TERM /THURSDAY THROUGH MONDAY/...
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Low pressure over the Gulf will move ashore late in the week/perhaps Wednesday night. Moisture from that will combine with a cold front approaching from the NW over the Mid-Atlantic Thursday night into Saturday. The cold front may not cross the area until Saturday night or Sunday.
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&& .AVIATION /19Z MONDAY THROUGH SATURDAY/...
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IFR conds in heavy thunderstorms across the DC metros through 22Z. Following showers continue until around 00Z. Main threats are heavy rain and damaging winds. Should be enough mixing overnight to keep fog away. West winds increase with gusts around 20 kt through Tuesday. High pressure persists Wednesday into Thursday. Tropical moisture looks to return ahead of a cold front Friday into Saturday.
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&& .MARINE...
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Heavy thunderstorms move across the waters late this afternoon into the evening hours ahead of a cold front. Winds gusting 30 to 50 knots are expected with heavy rain and hail also possible. West winds gust around 20 knots Tuesday with an SCA likely as high pressure builds from the west. Next cold front Friday into Saturday.
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&& .HYDROLOGY...
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Heavy thunderstorms will continue to cause localized flooding and flash flooding into this evening. A flash flood watch is in effect. Since there were dry conditions going into this, large stem flooding is not expected.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...Flash Flood Watch until 9 PM EDT this evening for DCZ001. MD...Flash Flood Watch until 8 PM EDT this evening for MDZ004. Flash Flood Watch until 9 PM EDT this evening for MDZ005-006- 011-013-014-503>508. VA...Flash Flood Watch until 8 PM EDT this evening for VAZ036>040- 050-051-055-056-501-502-505. Flash Flood Watch until 9 PM EDT this evening for VAZ052>054- 506. WV...None. MARINE...Small Craft Advisory until 6 AM EDT Tuesday for ANZ532>534-537- 540-541-543. Small Craft Advisory until 9 PM EDT this evening for ANZ530- 531-535-536-538-539-542.
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&& $$ SYNOPSIS...BAJ NEAR TERM...BAJ SHORT TERM...BAJ LONG TERM...BAJ AVIATION...BAJ MARINE...BAJ HYDROLOGY...BAJ

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