|3.44mph from the W
A cold front will push south of the area today. High pressure will build over the area on Sunday, then move offshore Sunday night. A warm front will lift through the area Tuesday followed by a strong cold front Wednesday evening. Strong high pressure builds over the region during the second half of next week.
NEAR TERM /THROUGH TONIGHT/...
Shortwave low pressure continues to lift north and east through eastern PA this morning with its associated cold front sagging southward into central VA. Light shower activity continues to accompany this boundary mainly across northeast MD this morning. Elsewhere, dry conditions prevail with thickening cloud cover as an additional shortwave low pressure system approaches from the Ohio River Valley. This low pressure system will ride along the slow moving cold front into southwest and central VA this morning and into the afternoon hours. Accumulating snow is possible along the Alleghenies, portions of the Potomac Highlands, and central Blue Ridge/Shenandoah Valley. Hi-res deterministic/ensemble guidance continues to illustrate 1 to 3 inches of snow in these locations above 2500 feet with a worst case scenario of 3 to 6 inches especially along the highest ridges (i.e western Highland and Pendleton Counties as well as up around Wintergreen/Afton Mountain along the Blue Ridge). Some uncertainty remains in regards to overall accumulation due largely in part to the bulk of the snow falling within the max insolation period this afternoon into early evening 18-00z/1-7pm. For now, will hold off on any headlines given the uncertainty with a mention in the HWO. Headlines maybe needed though given the amount of QPF and intensity of any frontogenetic forcing/dynamical cooling as the low slides south and east. Either way, if you are traveling in these areas plan for slick road conditions as temperatures look to fall throughout the day and into tonight as additional CAA pours in. Elsewhere, dry conditions will prevail with a slight chance of rain mainly in areas south of I- 66/US-48 (Corridor H).
Dry conditions and clearing skies are expected later this afternoon across the PA/MD border sinking south toward I-66/US-50 this evening as high pressure builds in. Areas further south will likely hold onto the clouds a bit longer with clearing overnight. With low pressure and the associated front passing to the south and high pressure building in from the north and west, expect a tightened pressure gradient across the region. This will result in gusty north to northwesterly winds at 20 to 25 mph yielding wind chill values in the 20s over the mountains and 30s elsewhere across the region. High temperatures will also be much cooler compared to the last few days with highs in the mid to upper 40s (30s over the Alleghenies).
Skies clear out tonight with diminishing winds giving us a good radiational cooling setup. This will allow low temperatures to drop into the 20s for most of the area.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Dry conditions and more sunshine is expected with high pressure Sunday. High temperatures will climb into the upper 40s and low to mid 50s. High pressure slides offshore Sunday evening into Sunday night allowing for return flow back into the region. Some upslope precip is possible west of the Allegheny Front late Sunday night into Monday morning as a result. Low temperatures Sunday night will fall into the mid to upper 30s with increasing south to southwesterly flow.
South/southwesterly return flow continues around the departing high pressure off the Mid-Atlantic coast Monday into Monday night. Additional showers remain possible west of the Allegheny Front with most locations remaining dry as moisture steadily builds into the region. Clouds will begin to increase from the west ahead of an approaching frontal system late Monday and into Tuesday as the weather pattern turns active for the extended period. High temperatures Monday with increased south/southwesterly flow will push into the upper 50s and low to mid 60s. Overnight lows Monday night will fall Into the mid to upper 40s.
LONG TERM /TUESDAY THROUGH FRIDAY/...
A strengthening southerly flow ahead of a rapidly deepening area of low pressure tracking from the Midwest through the upper Great Lks and into northern Ontario will usher in milder temperatures during the middle portion of next week and bring the threat of showers. There is also a non-zero chance of t-storms Wed, but the risk is not great. It will turn breezy/windy Tue night into Wed in the pre-frontal air mass with winds gusting up to 40 mph (sub-advisory criteria), but at higher elevations, the winds could gust up to 50 mph specially over the most favored slopes of the Blue Ridge Mountains (i.e. Wintergreen). The front clears the area Wed evening with high pressure building over the region during the second half of the week.
Another system may bring more precipitation toward the end of next week, which may begin as mixed precip across the higher elevations with rain elsewhere.