... Low pressure will move from the Great Lakes into New England overnight. The low will exit across northern New England Sunday, followed by an area of Arctic high pressure for much of next week. Low pressure may approach toward the end of next week.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Surface analysis at 9pm indicates low pressure entering southern Ontario with a cold front extending southwest of it across Pennsylvania and West Virginia. Regional radar mosaic paints a well defined band of precipitation along it. The cold front will cross the region overnight.
Based on the current radar depiction believe that some showers will persist across the area coincident with the frontal passage, and have adjusted PoP forecast accordingly. However temperatures appear to have warmed enough ahead of fropa to preclude a change over to snow showers (Elkins WV currently 50 degrees, Petersburg WV 49 degrees) so have removed that from forecast. However, upslope showers will transition to snow showers along the Allegany Front once cold air does arrive with minor accumulations (an inch or so) by dawn. East of the mountains, the arrival of cold air should be delayed just enough, and accompanied by enough wind, to preclude a widespread refreeze situation. (Across the ridge tops, these winds may reach 35-40 kt.)
SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... The region will actually be comparatively mild on Sunday thanks to downslope flow and a mediocre air mass behind the initial front. Temps in many areas will be warmer than they've been for the last couple of days, with 40s expected along I-95. The wind will keep it feeling chilly, however. A reinforcing cold front will cross the area Sunday night, with colder air pushing southward behind it for Monday. Upslope snow showers will continue during this time, but not expecting anything significant to cross the Allegany Front. Lows Sunday and Monday nights will be in the 20s and teens, with Monday being a touch colder than Sunday. Highs Monday will be in the 30s overall.
LONG TERM /TUESDAY THROUGH SATURDAY/... The long term period will feature an extended stretch of dry conditions, with temperatures gradually moderating from below normal, to near normal.
We'll start off on Tuesday with large scale troughing in the east, and a shortwave departing off to our south. An expansive area of high pressure will be centered over the Mississippi Valley, providing us with northwesterly winds at the surface. Sunny skies are expected, along with highs in the 30s.
The high will shift overhead Tuesday night, creating an ideal setup for efficient radiational cooling. This will lead to a cold night, with temperatures dropping into the teens for many. The surface high will remain overhead Wednesday into Thursday, as ridging aloft builds in. With the vertically stacked area of high pressure in control, conditions will remain dry. Temperatures will moderate slightly each day, with highs in the upper 30s to low 40s on Wednesday and mid-upper 40s on Thursday.
Moving into the latter portions of the upcoming week, a potent trough will dig over the center of the country, eventually leading to the formation of an area of low pressure over the Ohio Valley. The vast majority of deterministic and ensemble solutions keep precipitation associated with this system off to our west during the day on Friday, but precipitation may work in Friday Night. There's a non-zero chance that the precipitation could be wintry in nature, but currently that looks like an unlikely scenario.