By late morning or mid-day on Friday, floor low strain will possible be situated over Ohio and precipitation might get away from central Virginia and the DC metro area northward into central PA. By later within the afternoon, precipitation is more likely to push eastward into jap PA, New Jersey and New York Metropolis. The preliminary precipitation might be rain or a mixture of rain and snow when it arrives within the speedy metro areas, and snow is feasible throughout a number of the northern and western suburbs. By later within the night, the preliminary floor low strain system over Ohio will start to weaken and a secondary low will kind off the Mid-Atlantic shoreline and develop into the principle participant. In reality, this western Atlantic low will intensify fairly quickly from late Friday evening into early Saturday and this strengthening will permit for colder air to wrap round from northwest-to-southeast.
In consequence, any rain that also remains to be falling can change to snow late Friday into early Saturday throughout jap PA, New Jersey, NYC and probably as far south because the suburbs of DC. Accumulations of up to some inches are on the desk late Friday evening into early Saturday in all of those areas with the very best probabilities to the north and west of the massive cities. There might be lingering snow or snow showers on Saturday morning earlier than the system pulls away to the open waters of the western Atlantic.
One last word on the primary system…if there are to be any surprises, it will come early Saturday whereas the floor low is quickly intensifying over the western Atlantic. There will likely be an inverted trough (aka Norlun Trough) extending again to the west or northwest from the middle of the low to the Mid-Atlantic area and this will likely act to pull the system nearer to the coast which might improve precipitation (snow) quantities on Saturday morning in some areas equivalent to New Jersey, NYC and jap PA.