High pressure will continue to settle to the south early today. Clipper system will bring the threat for some light snow late today into early Monday. Cold front passes late Monday into Tuesday, bringing another round of potential snow for portions of the area. Arctic high pressure will settle overhead for the middle portion of the week.
NEAR TERM /THROUGH TONIGHT/...
Morning temperatures will be in the teens and 20s across the Mid- Atlantic region to start. Increasing clouds have already begun to build into the region ahead of an anticipated clipper system that will impact portions of the area later today into early Monday morning. Latest expected ratios across portions of the Allegheny Front with this system are still on the order of close to 15:1 across Garrett and Grant counties later today. 2 to 4 inches of snow is looking increasingly likely with the event. Stronger vorticity signatures in the runs within the past day or so have become increasingly present just east of the mountains, particularly over north-central MD for a few hours later this evening. This could be the scene of a local maxima for any snow that may moves closer to the metropolitan areas.
Synoptically speaking, high pressure will remain situated off to the south with southwesterly flow allowing for an increase (slightly) in temperatures for the day. Trough axis will migrate through the area later today and into the evening hours. Best chance of seeing any snowfall continues to be mainly north of I-66 and west of the metropolitan areas. In terms of the higher accumulating areas of the Allegheny Front, there does exist an opportunity for heavy snow to fall with coinciding stronger winds at the higher elevations. This, along with falling pavement temperatures and isolated pockets of instability may initiate periods for snow squalls to develop. Some localized heavy streamers may be possible across portions of I-81/I- 70/I-68 for a few hours during the best forcing times within this event. Will continue to monitor the likelihood for this to occur early in the day and make any adjustments to headlines as needed. Nonetheless, a Winter Weather Advisory is in effect this afternoon for Garrett and western Grant counties through early Monday morning.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Beyond early Monday morning behind the initial clipper system will be a brief return of high pressure overhead, allowing for drying conditions across the north and western portions of the area along with temperatures to remain chilly. A quick wash/rinse/repeat scenario for later Monday night as another clipper system will drop ESE towards the Mid-Atlantic region. Better forcing appears north of the Mason-Dixon into portions of PA, but, nonetheless, an associated cold front will likely bring a period of snow showers for the Allegheny Front, more than likely less accumulations than the previous clipper system with less forcing for the area. Snow should stay fairly confined to the higher elevation along the Allegheny Front with warmer temperatures expected further east limiting the threat for wintry precipitation coincided with bigger dewpoint depressions likely for those areas.
As this cold front evolves and migrates further east, expect a mostly cold rain event for areas east of the mountains, though guidance has flipped back and forth on this solution so this will be something to monitor as we head into the work week. By sunset Tuesday, expect drying conditions to prevail.
LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Very cold Wed under strong CAA and 25 mph winds with highs not likely getting out of the mid 20s east of the Blue Ridge. Wind chill values will be in the teens all day and below zero in the mountains. Strong Canadian high pressure builds overhead Wed night leading to a very cold night. Could see lows dropping as low as they did yesterday (Saturday) morning or perhaps a few degs lower.
A significant shortwave drops through the Great Lks Thu-Fri with global models continuing to indicate strong cyclogenesis offshore of the Mid-Atlantic coast next weekend. 24-hr model trends have shown sfc development occurring farther north and offshore limiting any precip potential over our area with only gale conditions over the waters the most likely impact at this time.
For snow lovers, it appears one more last chance for a winter storm to begin next month before EPO and NAO all switch positive and upper level pattern flips.