... Low pressure will move toward the region Friday before passing through Friday night into Saturday. The low will move northeastward into New England during the second half of the weekend. High pressure returns Sunday and lingers into early next week.
NEAR TERM /THROUGH FRIDAY/...
Overrunning precip will start spreading across the central Shenandoah valley and the central Appalachians primarily after 12Z Fri. There is a non-zero (roughly 20-40%) chance that the precip at the northern edge may fall in the form of freezing rain where sfc temps may still be below freezing. At this time, will have a mention of ra/fzra across western Allegany, western Mineral, but no headlines given low confidence and low impact. Rain should slowly overspread across western VA during the daylight hours and across northeast MD Fri night.
SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... A large H5 low will continue to move through the Midwest, tracking northeastward towards NY state. Precipitation will begin to spread across the region, beginning mid AM Friday for southwestern portions of the CWA, before slowly progressing northeast into the metro areas Friday night. With strong dynamical forcing in place, a secondary low will develop late Friday night enhancing rainfall rates overnight. Expecting higher QPF amounts of near 2 inches mainly along the Blue Ridge due given stronger dynamical lift. Elsewhere, total QPF amounts will be near 1 inch. Rain will begin to tapper off from southwest to northeast Saturday AM before ending for the metros by late Saturday afternoon. Partial clearing ensues into Saturday night as the low exits the region. Strong westerly winds and colder air aloft will induce upslope snow along the western Allegheny Front into Sunday.
LONG TERM /SUNDAY THROUGH THURSDAY/... By Sunday low pressure, both surface and aloft, will be migrating toward New England. The forecast area will be experiencing northwest flow with scattered upslope snow showers Sunday and Sunday night... possibly extending into Monday. Winds will be on the gusty side as well, especially during the daytime hours when cold advection will have a better chance to mix to the surface.
Tuesday into Wednesday will be the lull when a ridge axis passes across the eastern CONUS. Thereafter, another transitory upper level closed low and surface reflection will approach at the end of the forecast period. Its too soon to get caught up in the details for this system.