Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 260349 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1049 PM EST Sun Feb 25 2018 .SYNOPSIS... A cold front will cross the region overnight. That will push our recent airmass with clouds, showers, and fog to our south. High pressure with mild temperatures will move over the area for the early and middle work week. Our next area of low pressure will slide east over the region between Thursday and Friday. && .NEAR TERM /THROUGH MONDAY/... Cold front is ever so slowly crossing the area from northwest to southeast, with a gradual drying out of the atmosphere as it does so. Where the front has yet to clear, patchy fog has developed as low clouds have finally broken up. As the front pushes southeast, the fog should clear as winds pick up from the northwest. However, this is looking delayed until after 1AM in the metro and perhaps as late as 3 or 4 AM, so have issued dense fog advisory in anticipating of the fog getting denser until the front arrives. Clouds will remain until slowly breaking down from NW to SE tomorrow during the day. A weak low scurrying along the front to our south will temporarily swing some showers back north towards our southern tier across central VA and S MD. At this point, expecting they will stay just to the south of the metro. Did increase POPS across central VA, however, as guidance is in firmer agreement regarding rain returning to the southern Shenandoah Valley and CHO area. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... The weak wave of low pressure will slide eastward off the coast late Monday. After that, mild high pressure moves across the region. That having been said, enough dry air and radiational cooling should occur Monday night for many rural areas to reach freezing for the first time in a week or so. Tuesday will turn out mild again with plenty of sun. The next system will start to approach Tuesday night, with increasing clouds and most places staying above freezing. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... A high pressure system will be moving away from our area on Wednesday over Atlantic waters. Return flow will settle over our area with high temperatures reaching the 50s and low 60s. Mid level energy and a lifting warm front may cause showers on Wednesday into Wednesday night. A low pressure system will develop over the Midwest Wednesday night into Thursday which will bring a very moist air mass over our region. Precipitation associated to this system could begin early on Thursday. The low will then push a cold front over us Thursday night into Friday, as it lingers and intensifies offshore. Precipitation could last into early Saturday. Expecting rain to be dominant p- type...but upslope snow showers in the mountains are expected late Friday into Saturday as high pressure builds over our area and remains into Sunday. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... Forecast has been highly problematic this evening with low clouds breaking much later than anticipated earlier, and then earlier than anticipated for the 0Z package. In fact, BWI recently lost them but had them return. In addition, because there has been little wind, those places that have lost the low clouds have tended to see fog develop. However, with the cold front slowly but surely pushing southeastward, expect cigs to break and fog to lift in the next few hours, with VFR later tonight thru Tue as high pressure moves in. Periods of sub-VFR conditions possible Wednesday with scattered showers over our area. A more substantial period of sub-VFR is expected Thu into Friday as low pressure moves through the area. && .MARINE... Other than some lingering marine fog tonight, no marine concerns through midweek with high pressure moving over the waters. Winds will remain below SCA criteria Wednesday and into Thursday night. Winds will likely increase enough for advisories Friday as low pressure intensifies offshore. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Dense Fog Advisory until 5 AM EST Monday for DCZ001. MD...Dense Fog Advisory until 5 AM EST Monday for MDZ011-013-014- 016>018-503>506-508. VA...Dense Fog Advisory until 5 AM EST Monday for VAZ030-031- 052>055-057-501-502-505-506. WV...None. MARINE...None. && $$ SYNOPSIS...CS/RCM NEAR TERM...CS/RCM SHORT TERM...CS/RCM LONG TERM...IMR AVIATION...CS/IMR/RCM MARINE...CS/IMR/RCM

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