Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
902 FXUS61 KLWX 210213 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 913 PM EST Thu Nov 20 2025 .SYNOPSIS... Cloudy and dry conditions look to continue through tonight with weak wedging high pressure nearby. Rain chances return Friday into early Saturday as an area of low pressure and series of fronts cross the region. High pressure briefly builds back into the area Sunday and Monday. Another wave of low pressure and front look to cross the area Tuesday into the middle part of next week. && .NEAR TERM /THROUGH FRIDAY/... Clouds will thicken overnight as low pressure approaches from the Ohio Valley. Winds become south and southeast through the evening. This may help scrub out some of the low level cloud cover east of the Alleghenies with increasing mid and high level cloud cover expected through the the evening/overnight hours. Patchy fog is possible again late tonight given increased low level moisture across the region. As of 02Z, the areas with the lowest visibilities due to fog are eastern facing slopes in the Alleghenies. Have contemplated an SPS to handle this, but VSBYs hovering around a half of mile in these locations. Will continue to monitor. Elsewhere, confidence is low due to increased cloud cover although areas north of I-66/US-50 could see a few breaks leading to greater fog development. Otherwise, dry conditions will prevail with scattered rain showers moving into the western mountains and Shenandoah Valley at or around daybreak Friday morning. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... Wedging high pressure will gradually buckle Friday morning as a warm front lifts toward the Mid-Atlantic region. The warm front will lead to some overrunning light rain shower activity, mainly west of the Blue Ridge prior to daybreak Friday before spreading north and east Friday afternoon. Rain shower activity looks to be light and scattered across the area. Temperatures will also warm despite the shower activity and added cloud cover with highs pushing into the mid 50s and low 60s. Mountain locations will also warm into the low 50s making this an all rain event. Low pressure will approach the area from the mid-Mississippi and Ohio River Valleys late Friday afternoon and evening before crossing overhead Friday night. The associated cold front with this system will cross the area Saturday morning into Saturday midday. Some uncertainty still remains in the overall timing and placement of these features given the split flow jetstream pattern. The northern stream remains much more amplified compared to the southern jetstream which will likely inhibit the push of cold air advection behind the front as the mean upper level trough advances east across eastern Canada. Either way the area looks to see another round of widespread beneficial rainfall Friday night into Saturday mid- morning. Rainfall amounts of a tenth to a quarter of an inch can be expected with locally heavier totals across the higher terrain. This should help quell fire weather concerns for another few days with additional rain chances by the middle part of next week (see Long Term). Low Temperatures Friday night will hold steady in the mid 40s to low 50s with highs Saturday back into the mid 50s and low 60s. Some clearing may take place late Saturday afternoon and evening as the cold front pushes east of the area. Cold air advection appears weak with north to northwest flow (gusting 15-25 mph) in the wake of the boundary. The colder air does not look to catch up until Saturday night with lightening northerly winds and clearing skies across the area. Lows Saturday night will fall into the upper 20s and low 30s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... In the wake of Saturday`s cold front, slightly cooler temperatures are expected Sunday, with highs only in the mid 50s (mid to upper 40s in the mountains). A brief period of upper-level ridging will build over the region on Monday. Expect slightly warmer temperatures as a result, with continued dry conditions. This will continue for the first half of the day on Tuesday. However, a strong upper trough begins to take shape over the central CONUS during this time as well. The details beyond this point become a bit murky, as there are several pieces of upper-level energy to keep track of. Generally speaking though, this trough moves toward the Northeast through the middle portion of the week. There are hints at a powerful frontal system developing and pushing through, but timing is very uncertain. There also may be a system ahead of the main front around Tuesday. However, guidance is still very split on how the upper-level pattern actually evolves at this time. High temperatures will be in the 50s and 60s each day with highest elevations staying in the upper 40s. Overnight low temperatures drop into the 30s and 40s each night. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Cloudy skies continue tonight with rain shower activity moving into locations west of KMRB/KCHO by daybreak Friday. Some fog is also possible in areas that see breaks within the clouds. Highest confidence for this would be north of KIAD and KDCA although uncertainty remains with added cloud cover. Winds shift to the south Friday as a warm front slowly lifts through. Some sub-VFR conditions are possible in lower CIGs and -RA at times. Low pressure and its cold front will follow Friday night into Saturday with increasing potential for lower CIGs and VSBYs due to more widespread rain through early Saturday morning. VFR is expected to return by late Saturday afternoon as the cold front moves away and drier air moves in. VFR conditions are expected on Sunday and Monday with light southwest winds on Sunday before turning light and variable on Monday under high pressure. && .MARINE... Sub-SCA Level winds are expected through Friday morning. Winds will remain light and variable this afternoon while switching to the southeast at less than 10 kts. Southerly winds are expected Friday as a warm front slowly lifts across the waters. The front will bring a few light scattered showers to the waterways late Friday morning into Friday afternoon. More widespread rain shower activity holds off until Friday evening and night as an area of low pressure and cold front cross the region. Winds may increase out of the south (leading to channeling) for a short time window ahead of the low pressure system late Friday, then increase a bit more readily in the wake of the cold front Saturday. SCAs are possible late Friday through Saturday before winds become lighter under building high pressure Saturday night. Southwest winds around 10 knots are expected on Sunday before turning more variable in direction on Monday under high pressure. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...EST NEAR TERM...CPB/EST SHORT TERM...EST LONG TERM...CJL AVIATION...CJL/CPB/EST MARINE...DHOF/CJL/CPB/EST