Timing, Location of Ohio Valley, PA Storms

When residents of Pennsylvania woke up this morning, they saw a couple of scary graphics that probably made them want to pull the covers back up over their heads:

But what does this really mean? Should you fear deadly tornadoes on the way to lunch this morning if you live in Pittsburgh? No. Because of the timing of this outbreak, it's overhyped for eastern Ohio and western Pennsylvania -- at least for today. These forecasts are for 8 AM Friday to 8 AM Saturday and it'll be closer to the latter time before Pennsylvanians will see any action. So what will happen?

First things first, there are storms in progress this morning, and despite how horrible they look on radar, only flood advisories are in effect right now (9:30 AM). Here's the current radar and advisories from MapSpace.

But these storms are not associated with the actual outbreak itself that will affect western Pennsylvania, and the cluster of storms in Ohio is moving southeast, affecting Pennsylvanians with light rain at best. The "real outbreak" won't happen until much later today, in fact there may be no rain in the state until after dark. Here's what the hi-res 4-KM WRF model (from our Pro site) says the radar will look like between 4 PM today and 8 AM Saturday:

As you can see, it believes that a line of storms will break out from Detroit through Fort Wayne around 21Z (4 PM Central Time) and move into western Pennsylvania by 03Z (11 PM Eastern). At the same time, a second line of storms will form in the same place as the first, propagating into western Pennsylvania overnight but weakening and breaking up, then finally passing by the big cities by 11 AM Saturday. Given that the SPC's risk starting at 8 AM tomorrow only has Pennsylvania in the "General" thunderstorm risk, they probably won't be too severe.

But of course, that's just a model guess of how things will play out. The severe weather experts at The SPC [JessePedia] are being more vague about timing and placement. They say in their Public Statement"FROM PARTS OF IOWA AND MISSOURI EAST INTO MUCH OF THE OHIO VALLEY AND CENTRAL APPALACHIANS. AS DAYTIME HEATING FURTHER DESTABILIZES THE REGION... NUMEROUS STRONG TO SEVERE THUNDERSTORMS WILL FORM WITHIN THE AXIS"

This makes it sound like we could see more pop-up storms this afternoon, possibly even in Pennsylvania, something that the model is not predicting. Could that happen? Absolutely, the guys at the SPC know what they are talking about; we'll just have to wait and see.

How can you keep up with the progression of the outbreak this evening? Once the storms start, the front page of AccuWeather.com will contain a special video with our severe experts, showing the radar and talking about where the storms will move. I may check in, especially if these storms get close to PA, but I'd advise you to keep an eye on AccuWeather.com for 24/7 severe weather coverage as these storms move through.