... Scattered showers during the day will change over to snow this evening. Lake enhanced snow showers should linger near I-80 Sunday into Monday with northwest flow.
NEAR TERM /THROUGH TONIGHT/...
Scattered showers will continue the remainder of the day as shortwaves rotate around an upper low passing north of the region.
A changeover to a rain/snow mix is likely over the course of the afternoon with continued cold advection aloft. Precipitation is expected to change to all snow tonight, however, accumulation will be minimal as moisture depth is too shallow to extend into the DGZ. Overnight lows will be slightly below freezing on average across the region.
SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
Broken record forecast looks likely Sunday and through the first part of the week w/ an overcast sky, temperature ranging from the mid 20s to mid 30s, and scattered snow showers.
The large scale trough responsible for this weekend's wet weather will progress northeast on Sunday. Multiple shortwave trough axes will cross the CWA Sunday and Monday within broad cyclonic flow aloft, leading to an ebb-and-flow of showers. The near-surface temperature will likely be too warm to support snow in the lower elevations (e.g. towns/neighborhoods along the Ohio) during the daylight hours, so have included a mix in the gridded forecast. Regardless, QPF looks to be quite minimal, so no snowfall accumulation is anticipated outside of the I-80 corridor and the Allegheny Front, where 1-2 inches are possible through the duration of the period.
LONG TERM /WEDNESDAY THROUGH FRIDAY/... Seasonable weather continues into mid-week as surface high pressure takes hold. Both the GFS and ECM have an upper-level shortwave trough crossing Wednesday night, but a lack of moisture will keep conditions dry. Primarily dry conditions will continue through the end of the work week w/ a slight warming trend resulting in Friday being the warmest day.
Attention then turns towards next weekend. GFS has been consistent with phasing a northern stream shortwave with a system across the northern Gulf, then moving it along the spine of the Appalachians. The ECMWF, however, keeps the gulf low suppressed south of the Appalachians, resulting in a prolonged dry forecast for the Pittsburgh forecast area.