A deep upper trough will advance out of the Midwest/Great Lakes
region into the Ohio Valley on Sunday, pushing a cold front through
the area through the day. Widespread rainfall as show below is expected by Sunday morning in advance and with the front.

Once that front swings through, temperatures will begin to quickly drop. By Sunday afternoon this will prompt a transition to mixed wintry precipitation during the afternoon hours, followed by changeover to all snow through the evening as temperatures fall into the lower 30s.

Snow/Snow Showers will continue through early Monday morning, with greatest accumulations expected along the I-80 corridor and across the ridges/higher elevations of the Allegheny Mtns.

Warm ground temperatures should initially limit accumulation, but
model soundings continue to show saturation with 3-4+ inches possible in some locations north of I-80.

Mesoscale models hint at the possibility of one or more narrow lake enhanced bands setting up which would/could further enhance snowfall totals farther south into the Beaver/Butler and perhaps even Metro PGH
areas. However there is a high uncertainty in these “streamers” occurring and if they do exactly where they may set up. As you can see below, the immediate metro area is not expected to see more than an 1.0 to 1.5 inches of snow at this moment within the immediate Pittsburgh metro area. I will watch for this throughout the event.

Models signal good potential for upslope snow during this same time
period for the ridges and higher elevations of Garrett/Preston/Tucker. At this time, at least 2-3 inches looks likely across portions of these areas, but would not rule out needing to bump these totals up slightly given forecast trends. Elsewhere across the region, generally an inch or less is expected.

Light snow showers will linger through Monday morning. Eventual clearing is expected during the afternoon hours, but temperatures will only warm into the 30s and 40s where melting will take place.

More updates throughout the day today and tomorrow as needed.

Happy Halloween!!