Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 190801 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 401 AM EDT Mon Sep 19 2016 .SYNOPSIS...
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A weak front along the Appalachians will linger over the area into Tuesday. High pressure will build into the region for mid to late week. A cold front is expected to drop into the Mid Altantic this weekend bringing cooler temperatures by Sunday.
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&& .NEAR TERM /TODAY/...
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As of 3am, an upper level trough extends south from the Great Lakes to Louisiana. Broad southerly flow ahead of this trough is bringing low to mid 70 dewpoints into the area. The remnant low of Julia is off the SC coast. A notable area of heavy/repeating showers with isolated thunderstorms has progressed north from Srn VA to the tidal Potomac River. This will track across southern MD and produce locally 2-3 inches of rain through sunrise. 3-hour flash flood guidance there is 4.5 inches, so no flooding is expected. A secondary area of heavy rain has developed along a line over Ern PA and Nrn NJ. The Srn end of this line extends south to Frederick Co, MD. This area will also be monitored as cells continue to develop over the same area. Scattered heavy showers/thunderstorms will continue to lift north across the area with the main concentration through mid-morning. This is welcome rain, though it will be locally heavy and occur during the morning traffic rush. PWATS around 2 inches will continue to spread of the area. For the most part this will be welcome rain given the mainly dry month prior. The focus of heavy activity will shift east to the bay where it will remain into Tuesday. Temperatures suppressed today under clouds and rain. Maxima mid to upper 70s (not much higher than the dewpoint).
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&& .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
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High pressure builds over Wrn PA tonight with areas west of the Blue Ridge with valley fog developing in any clearing. North winds lower dewpoints into the 60s which the temperatures will follow, minima mid to upper 60s inland. Low pressure persists along the Carolina coast into Thursday. However, surface high pressure will shift south into the area with a return to dry conditions by Wednesday with a north wind. Dry and sunny conditions Wednesday through Friday would allow for above normal temperatures, generally mid 80s maxima.
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&& .LONG TERM /THURSDAY THROUGH SUNDAY/...
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Temperatures are expected to remain above normal for the latter part of the week with low precipitation chances as high pressure remains off the coast. A cold front is expected to sag into the Mid Atlantic during the weekend.
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&& .AVIATION /07Z MONDAY THROUGH FRIDAY/...
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IFR conds develop through the mid morning as increasing moisture lowers CIGs and intense rain has IFR vsbys. Rain generally shifts east of the DC metros by late afternoon. High pressure spreads in from the north Tuesday with VFR prevailing outside of morning fog. VFR conds prevail Wednesday high pressure builds into the area. VFR conditions expected Thursday and Friday.
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&& .MARINE...
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SCA continues until 6am for southerly channeling, expected to expire. NEly flow then through Tuesday generally 10 kt. High pressure builds in from eastern Great Lakes Tuesday and Wednesday with north winds. Winds expected to remain below SCA values Thursday and Friday.
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&& .TIDES/COASTAL FLOODING...
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Elevated water levels will persist through tonight. Minor coastal flooding is possible at sensitive sites for the morning high tide and more likely for this evening. Coastal flood headlines extended through the evening high tide. The northeast wind that develops today should bring down water levels enough into Tuesday to warrant an end to the headlines.
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&& .CLIMATE...
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Record high min reached at IAD Sunday.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...Coastal Flood Advisory until 2 AM EDT Tuesday for DCZ001. MD...Coastal Flood Advisory until 11 PM EDT this evening for MDZ014. Coastal Flood Advisory until 8 PM EDT this evening for MDZ017. VA...Coastal Flood Advisory until 2 AM EDT Tuesday for VAZ054. WV...None. MARINE...Small Craft Advisory until 6 AM EDT early this morning for ANZ531>534-537-539>541-543.
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&& $$ PRODUCTS...BAJ/WOODY!

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