Forecast Discussion
Summary
SYNOPSIS
... Developing low pressure will introduce rain showers on Friday into early Saturday morning, with potential for embedded thunder on Friday and Friday night. Strong wind is possible by mid day Saturday ahead of a passing cold front, with coincident potential for severe thunderstorms.
NEAR TERM /THROUGH TONIGHT/... Warm and moist advection will allow for a steady increase in temperature in swly flow ahead of an approaching trough. Clouds will gradually thicken, with onset of rain showers around 9 or 10 am.
The chance for showers sticks around throughout the day as a coupled jet propagates eastward aloft. With the warmth in the lower boundary layer, some elevated instability may assist benign thunderstorm development Friday night. Broad jet ascent will move eastward by Saturday morning.
SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... Low pressure undergoing cyclolysis will propagate eastward toward the Ohio Valley on Friday morning. Gradient winds are likely ramp up by 8am, with widespread 40-50 mph gusts from the southwest are likely, with higher values possible in the ridges of WV and PA. This will especially be trust in northwest facing slopes, as wind will have a tunneling effect. Preliminary precipitation will move through early in the morning, followed by clearing and very productive warm advection.
Temperature will quickly climb into the mid-60s, with a strong jet association and cold air aloft. This sets the stage for a combination of buoyancy and upper level support. Severe thunderstorms are possible on Saturday afternoon as the cold front approaches from the northwest. Damaging wind, hail, and isolated tornadoes are all possible and have been addressed with a SPC Slight Risk.
Once the front passes on Saturday evening, a stark temperature drop, subsiding wind, and the possibility of brief snow showers nw of Pittsburgh will end the day.
LONG TERM /SUNDAY THROUGH THURSDAY/... Long range model ensembles indicate high pressure will develop over the region on Sunday, supported by the polar jet.
Shortwave passage on Tuesday may provide brief precipitation chance. Later in the week, a strong low pressure system is liable to develop in the Rockies and eventually move northeastward bringing rainfall chance.