From NWS Sterling:
Warm advection envelops the region Saturday night as the storm
presently along the West Coast gathers Gulf Moisture and sends
it our way. With cold air mass in place, precip likely begins as
snow region-wide by late Saturday night. Temps stay a little
milder with the clouds, with lows in the 20s.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A potent upper level low will move east along the Ohio Valley
Sunday and Sunday night, prior to moving into the mid-Atlantic
region Monday. As it reaches our CWA, the development and
intensification of a coastal low is expected. Helping in feeding
this rapid development will be additional upper level energy
that will move inside a deepening trough of low pressure across
the eastern third of the U.S. The deepening trough and energy
that will be intensifying the coastal low will perhaps slow its
forward eastward progress early next week. A cold wedge east of
the Appalachians will set up the atmosphere in which a large
part of our CWA should see, at least, some accumulating snowfall
late Saturday night through Monday. The slow forward progress
could allow for some places to see a continual snowfall or
perhaps some constant bands of light snow.