... High pressure will keep the region dry through Saturday morning. A series of shortwaves will return rain to the Ohio River Valley over the weekend.
NEAR TERM /THROUGH TONIGHT/... AM Update... 12z PIT observation indicates substantial subsidence occurring through the atmospheric column. This will support beautiful weather today, before increasing clouds this afternoon and no real warm reinforcement cap the high temperature likely just below 50 degrees.
Previous Discussion: Building high pressure will maintain dry weather today. Warm advection and insolation will support temps above the climatological average.
An incoming shortwave will return rain to the area late tonight. With weak ascent expected everywhere, with the exception of portions of the ridges, precip may not reach the ground until midnight due to lingering dry air. In eastern Tucker, freezing rain is expected to occur this evening and overnight due to cold air damming as a result of sely flow, and warmer swly flow aloft.
SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... Warm, moist advection and weak ascent will continue to keep rain in the region through Saturday evening. A period of ridging in eastern Ohio may create a break in precip Saturday night. Overall, less than a quarter of an inch of rain is expected through this forecast period.
Note, ongoing snowmelt and temps at or above normal, with the expected additional precip may continue to increase the flow of creeks/streams/rivers in isolated areas...especially near the ridges.
LONG TERM /SUNDAY THROUGH THURSDAY/... A new quick moving shortwave will return rain to the region early Sunday morning. Unfortunately with this next round of precip heavier amounts are anticipated with increased frontogenesis prompting stronger ascent. Hi-Res models show PWATS above 1.00 inches south of Pittsburgh and isolated thunder may occur in northern West Virginia if shallow instability prevails. At the moment, an additional 1.00 to 1.50 inches of rain may fall south of Pittsburgh Sunday into Monday. As mentioned above, ongoing snow melt is expected to continue in the ridges of WV/PA. An additional inch of precipitation will likely create quick rises across the banks of some rivers/creeks and will need to be monitored closely.
Building high pressure and colder conditions will bring an end to an active weather period Monday through Tuesday. Warm, moist advection under SW flow will return temperatures above the climatological norm Wednesday and last into the weekend.