Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 210056 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 856 PM EDT Mon Mar 20 2017 .SYNOPSIS... A weak cold front will cross the region tonight. A stronger cold front will cross the area Tuesday night. High pressure will return Wednesday through Thursday night. A warm front will cross the region Friday. Low pressure may affect the area Sunday. && .NEAR TERM /THROUGH TONIGHT/...
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As of 8pm, a broad upper trough is north of the Great Lakes with low pressure over the Texas panhandle and an associated warm front extending east to Kentucky. A weakening MCS is moving southeast from Ohio to eastern Kentucky. This precipitation looks to graze the far SWrn zones (Highland to Nelson Counties) with isolated thunder until midnight. A vort lobe associated with the MCS will shift across the area after midnight which may should allow some showers to develop across middle and lower sections of the CWA including southern Washington DC suburbs. Min temps generally around 40F with low 40s near the Bay (water temps are low 40s).
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Area will be in northwest flow on Tuesday. The downsloping will keep it dry, although its looking quite cloudy (we will be in the baroclinic zone). A stronger cold front will cross late Tuesday night. The thermal packing will be aloft (clearly evident at 850 mb), so anticipate the front will be marked more by a surge of wind. Precipitation continues to be pressed south; have trimmed PoPs once again. There still will be a chase between exiting moisture and approaching cold air, but with PoPs very low, this should be a non-factor. Wednesday and Wednesday night will largely be marked by cold advection. This will be the coldest part of the upcoming week. Entire area easily will be in the 20s by late Wednesday night. && .LONG TERM /THURSDAY THROUGH MONDAY/... An area of high pressure will be overhead Thursday and Thursday night. Dry air and chilly temperatures are expected across the region. This high pressure will move to the coast Friday and Friday night to allow for a return flow and milder air to develop for the mid- Atlantic. A cold front will sag across the Eastern Great Lakes Saturday before stalling across our region Saturday night. A chance for rain showers will develop during this period. A storm system will develop along the west end of this stalled front on Sunday, keeping the chance for rain showers in the region. The storm system will move east along the front toward the East Coast. The chance for rain showers linger throughout Sunday night. More rain showers could develop along an associated cold front that should also stall across our region on Monday. Temperatures will be more seasonable. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/...
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VFR generally prevails through the rest of the week. A weak low will move east across the area overnight with brief MVFR cigs/vsbys possible. Low clouds will be persistent Tuesday. Believe ceilings will be low-end VFR. Higher based MVFR within reason. A secondary cold front will be crossing Tuesday night, before the Wednesday morning push. Gusts to 25 kt will mark the frontal passage. VFR/northwest flow gusting up to 30 knots on Wednesday, with decreasing winds through the end of the week.
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&& .MARINE...
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Light winds through midday Tuesday. The direction will be variable through Tuesday morning, with northwest flow then prevailing. A NWly surge will cross the Bay Region with a subarctic cold front late Tuesday night through Wednesday night. Gales possible around sunrise Wednesday. SCA in effect midnight Tuesday night through Wednesday and expected to continue through Wednesday night. High pressure moves overhead Thursday with southerly flow Friday and Saturday ahead of the next cold front Sunday night.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from midnight Tuesday night to 6 PM EDT Wednesday for ANZ530>543.
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&& $$ SYNOPSIS...BAJ NEAR TERM...BAJ/HTS SHORT TERM...ADS/HTS LONG TERM...KLW AVIATION...BAJ/HTS/KLW MARINE...BAJ/HTS/KLW

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