Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 260757 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 357 AM EDT Sun Mar 26 2017 .SYNOPSIS... A cold front is dropping into the Mid Atlantic and will stall over the area today. This will move back to the north as a warm front Monday. Another cold front will cross the area late Tuesday. High pressure will build over the region Thursday. && .NEAR TERM /TODAY/... As of 3am, a 1036mb surface high pressure is centered over north- central Quebec, 1027mb surface high pressure is centered over Bermuda, and 1008mb surface low pressure is centered near the border of IA/MO/IL. The low is weakening/filling under an upper trough over eastern Canada. The Canadian high pressure will shift southeast across Maine through today. Influence of the Canadian high is already felt with a backdoor cold front moving through the area. It has pushed through KCBE, KOKV, and KEZF in the past hour (and KLWX radar depicts the front moving from Fauquier to Culpeper County). South of this front is southerly flow and warmer air from the Bermuda high. The front is expected to cross all of the CWA today except maybe southern Nelson County. Mid-level clouds currently across the area will thicken, lower and eventually produce rain and drizzle. The 00Z GFS depicts drizzle across the area before sunrise. Cloud ceilings are starting to lower on the Eastern Shore with light showers developing south of Atlantic City over the past hour. Maintained a forecast of patchy drizzle starting at 10am east from the Blue Ridge. PoPs remain low given the shallow saturated layer. However, the occluded front from the Midwest low crosses the western half of the CWA this afternoon, so likely rain is out there through this evening. Whether the occluded front will be enough to break the CAD wedge tonight remains a key question. 00Z consensus shifts the wind to the south across the area tonight. However, models often erode CAD wedges too quickly, particularly overnight. So, there is low confidence in temperatures Monday particularly in NErn zones/in the Baltimore metro where low clouds may hold on well into the day. Where wind does shift south, temperatures Monday look to rise well into 70s. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... A second low currently along the CO/NM border will reach the Midwest late Monday before tracking across the northern Mid-Atlantic Tuesday per 00Z ECMWF/GFS. Continued moist southwesterly flow warrants high chance PoPs with slight chance for thunder for the LWX CWA Monday. Better chance for thunderstorms looks to be Tuesday on the south side of the low crossing the region. The cold front trailing this low enters the area Tuesday night bringing in a brief stretch of quiet weather under high pressure. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... The first part of the forecast will be dominated by an induced upper ridge over the Mid Atlantic in-between low pressure east of Nova Scotia and a developing low across the central US. The middle part of the week will be dry. Highs Wednesday in the 60s. Lows Wednesday night 35-40. Thursday should see quite a bit of sunshine with highs in the lower 60s. Conditions will deteriorate Thursday night as the aforementioned low tracks into Missouri to near Lake Erie Friday. The attendant warm front will hang south of the Mid Atlantic through Friday. This will bring cooler temperatures to the region, cloudy skies, and likely PoPs. Low pressure may develop along the Virginia coast Friday night keeping the forecast area on the cloudy and wet side through Saturday. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... Onshore flow across the area generally 10 to 15 knots through tonight. Drizzle and IFR conds expected to develop through the daylight hours today with ceilings slow to lift tonight. Southwesterly flow from low pressure to the west/north Monday and Tuesday brings rain showers and thunderstorms to the DC metros with the better thunder threat Tuesday afternoon. VFR conditions Wedensday and Thursday. Clouds will thicken Thursday nght. && .MARINE... Onshore flow 15 to 20 knots continues through tonight before shifting south Monday. Generally sub-SCA SWly flow prevails Monday and Tuesday with thunder chances Tuesday. Cold front crosses the area Tuesday night with SCA likely across the area in NWly flow. High pressure will build into the waters for midweek. No problems expected on the waters Wednesday/Thursday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 9 PM EDT this evening for ANZ530>532-535-538>540. Small Craft Advisory until 9 PM EDT this evening for ANZ533- 536-541-542. && $$ PRODUCTS...BAJ/WOODY! is the U.S. government's official web portal to all federal, state and local government web resources and services.