A weak upper level ridge wil work its way across the eastern Great
Lakes Saturday night. In the meantime, a shortwave trough over the
western Great Lakes will deepen Saturday night and Sunday as it
eventually passes by to the northeast of the region. Its associated
surface low will pass east across southern Ontario, where it will
drag its surface cold front across the region Sunday. All the while,
another shortwave will traverse the southern jet stream across the
Southeastern states, where it will nurture its own surface low. This
southern low will ride north along the East Coast Sunday and Monday.
Overall, the region will see some general light snowfall across the
region on Sunday with the passage of the cold front. The
aforementioned low tracking up the east coast Sunday will primarily
stay far enough east off the coast to cause snow east of the area.
Though wrap around moisture, much cooler temperatures aloft (around -
18/-19C), and now westerly winds across the region Sunday night,
will allow for some lake effect to set up east of both lakes. Lake
effect snow will then last through Monday.