Area Forecast Discussion
Issued by NWS Sterling, VA

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160 FXUS61 KLWX 110800 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 400 AM EDT Fri Aug 11 2017 .SYNOPSIS... High pressure has moved offshore. A warm front will lift north towards the region today. A cold front will approach the region from the northwest Saturday, then stall south of the area Sunday. A wave of low pressure may move along the stalled front early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 3am, a 1013mb surface low pressure is centered over northern Lake Michigan with the associated cold front stretching southwest from WI to IA and 1023mb surface high pressure over the Jersey shore. The Great Lakes low will drift east through Saturday with the cold front crossing the central Mid-Atlantic Saturday night. Just a few showers in the area through sunrise with a diurnal increase in showers and thunderstorms over the area as moist southwesterly low level flow persists. Dewpoints are currently in the mid 60s, but will increase to around 70F through midday. MLCAPE around 500 j/kg this afternoon allows up to scattered coverage of thunderstorms. Theta-E ridge generally west of I-95 where categorical PoPs are. Thick clouds make for max temps in the low 80s for all lower elevations today. Nocturnal decrease in precip is slowed by continued moist southwesterly flow. Min temps upper 60s inland to around 70F nearshore. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Cold front approaches Saturday warranting categorical PoPs across much of the area. MLCAPE up to 1000 j/kg with chances for thunder across the area. Dewpoints low 70s make for a much more humid day than today. Latest consensus of GFS/NAM/ECMWF is for the cold front to cross the area Saturday night and cutoff PoPs by midnight. Cold front persists south of the area through Sunday night with PoPs removed accordingly through this time. && .LONG TERM /MONDAY THROUGH THURSDAY/... We will be into the mid part of August during the extended part of this forecast. The high heat remains at bay for next week - 80s for high temperatures all week. The upper level air flow will be in a general zonal pattern. A short wave is expected to push through the northeastern US Tuesday night. This will give Tuesday/into the overnight hours the best potential time for precipitation, although 30-40 PoP is all that can be warranted for now. Wednesday/Thursday look dry as weak ridging moves over the Mid Atlantic. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... Rain with embedded scattered thunderstorms today and Saturday across the DC metros before a cold front crosses Saturday night. Tranquil/VFR behind the cold front Sunday. VFR conditions expected Monday. There will be a potential for degraded ceilings Tuesday. && .MARINE... South flow generally 15 knots today and Saturday ahead of a cold front that crosses Saturday night. Will need to look out for SCA NWly gusts Saturday night into Sunday. Winds are expected to remain below SCA values Monday. Showers/thunderstorms possible Tuesday. && .EQUIPMENT... LWX 88D went down around 1030 pm. As there was no threat of hazardous weather it was determined that El Techs would wait until this morning to look at it. .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ PRODUCTS...BAJ/WOODY!

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