The National Weather Service does a fine job of predicting weather, particularly severe weather. It does not create it. Every morning, I check www.spc.noaa.gov to see where thunderstorms may occur during the day.
In the "convective outlook" section, categorical, tornado, wind and hail risks are shown graphically. The categories of "thunderstorm" (general thunderstorms), "slight" (a slight risk of severe weather), "moderate" and "high" are used.
Pittsburgh was in the slight chance for convective weather events for the entire day on June 12, consistent with the weather we experienced, but initially a moderate chance area extended to the Ohio border near Pittsburgh. Although the forecast discussion did mention a derecho possibility, it also discussed what conditions would need to occur for it to happen. Thankfully, we were not subjected to it.
We should all be thankful for and proud of the National Weather Service and its local office. Our lives are considerably safer due to their efforts.