Severe storms possible Thursday in Allegheny County

The Storm Prediction Center has upgraded the current severe weather outlook for Thursday evening to an enhanced risk.

The National Weather Service in Moon says the main reason for the upgrade is to include damaging winds. It says to expect the main line/broken discrete cells to begin entering northwestern Pennsylvania and eastern Ohio around 6 to 8 p.m.

Meteorologist David Shallenberger said the predicted path of the storm system has shifted and the worst of it will arrive some time after 8 p.m. Thursday, later than originally predicted.

“The strongest storms at this point will be west and northwest of the Pittsburgh area,” he said. “You’re still going to be looking at 60 mph winds. By the time it gets down into Southwestern Pennsylvania, it looks like more of a wind and heavy rain threat than a hale threat. The fact that it’s moving so fast, it’s more likely that any flooding threat is going to be few and far between.”

An "Enhance Risk" is rare in our region. On average, we only see 1-3 of them a year. Make sure to take this event seriously and have a way to get watches/warning in the next 6 to 12 hours. pic.twitter.com/4XVAuJVLAC

— NWS Pittsburgh (@NWSPittsburgh) July 20, 2023

The NWS’s outlook says storms capable of isolated tornadoes, flooding, hail and damaging wind gusts have the potential to form in Allegheny County and areas northwest of Pittsburgh. Heavy rainfall and localized flooding with stronger storms are possible between 8 p.m. and 2 a.m.

Meteorologist Shannon Hefferan described the outlook as a “heads-up” on potential conditions.

Though some areas of Southwestern Pennsylvania are not in the “yellow” region for “slight severe weather risk,” the threat could be relevant across the region, Hefferan noted.

“We look at models, and we look at the environment, and we see that we do have the potential to have severe storms,” she said. “The confidence is increasing that a few areas might experience severe storms.”

Forecasts from weather service predict partly sunny conditions Thursday during the day with a high near 85 and a low of about 66 overnight. There is an 80% chance of precipitation Thursday night in the Pittsburgh region, and rainfall amounts between a quarter and half of an inch are possible.

Julia Maruca is a Tribune-Review staff writer. You can reach Julia at jmaruca@triblive.com or via Twitter @marucajulia. Paul Guggenheimer is a Tribune-Review staff writer. You can contact Paul at pguggenheimer@triblive.com.