12:15 PM | *Shower/thunderstorm threat later today/early tonight…”clipper” system can produce some snow late Sunday night/early Monday*
Unseasonably mild conditions today across the Mid-Atlantic region ahead of a strong cold front which will usher in much colder air for the weekend. As the front arrives later today, the threat for showers will increase and there can be a few strong thunderstorms mixed in; especially, along of and to the east of the I-95 corridor. After a cold, dry weekend, a fast-moving “clipper” system will drop southeastward and into the Mid-Atlantic region late Sunday night/early Monday and it can produce some snow in the region extending from DC-to-southern NJ on the south side to southern PA on the north side including the Philly area – perhaps even small accumulations in some areas.
Frontal passage late today/early tonight
A strong cold front is approaching the I-95 corridor from the west today and it has resulted in windy and unseasonably mild conditions in DC, Philly and NYC. Showers passed through some spots early today, but the remainder of the morning and mid-day has been primarily rain-free. As the front arrives later today, the chance for showers will increase with the best chance between 3 and 9 PM and there can be some strong thunderstorm activity; especially, in the region from I-95 to the coast. Temperatures have climbed to the 70’s in many areas along the I-95 corridor and SW winds have gusted to 30 mph or so. The best chance for showers and storms will come later in the afternoon and continue into the evening as the thermal boundary zone provides some lifting action in the atmosphere creating instability.
Once the front passes through the I-95 corridor, low-level winds will shift from SW-to-NW and usher in much colder air in the overnight hours – and make no mistake about it – this is a cold air mass headed this way. The winds will remain quite strong on Saturday and continue to be evident on Saturday night and, despite plenty of sunshine during the day, temperatures will stay below-normal for mid-March and noticeably colder than today.
Clipper late Sunday night/early Monday
After a dry and quite cold day on Sunday for mid-March, a “clipper” system will drop southeastward and arrive in the Mid-Atlantic region late Sunday night. This system will be supported by a pretty decent wave of energy in the upper atmosphere and it can result in some snow or snow shower activity late Sunday night/early Monday in the region extending from DC on the south side to southern PA on the north side and eastward to the southern NJ coastline. This system can even result in some small snow accumulations from the northern suburbs of DC to southern PA (including Philly) and we’ll have to watch for any sudden intensification as it approaches the east coast which could potentially result in some steadier snow across the Delmarva Peninsula, southern NJ and perhaps even back into SE PA on Monday morning.