It will begin to turn colder Sunday and really cold Monday. Then, the focus of our attention on Tuesday will be turning to a low pressure system that will intensify near the Carolina Coast and ride northward. It could bring wet, perhaps accumulating snow on Tuesday into Tuesday night. Arctic high pressure will quickly slide to the east of the region later on Monday into Monday night as a strong upper level disturbance digs into the Ohio Valley and Southeast. Light snow associated with the disturbance will enter western Pennsylvania early Tuesday morning. In all likelihood, the snow will have a difficult spreading eastward, especially early Tuesday morning, as a battle between dry air and moister air occurs at the low levels of the atmosphere. Thus, there is a chance that while the radar will show an advancing area of snow from southwest to northeast across the Mid-Atlantic during the mid-morning hours Tuesday, it will actually be “virga” or precipitation that is drying up before it reaches the ground.
Anytime from the mid-morning on (say around 8 a.m. on Tuesday) is likely fair game for snow. Above freezing late morning/afternoon temperatures should prevent snow, especially since it will be light, from accumulating on paved surfaces, however, some slick spots may develop. Due to the above freezing temperatures, the snow may mix with rain, especially Tuesday afternoon. As the day turns to night, the energy from the initial disturbance will transfer to a newly forming low off the Atlantic Coast. This should solidify the “shield of snow,” however most of it will be east of I-95.