>temperature inversions

Bingo! and the most famous inversion event happened in Western Pennsylvania south of Pittsburgh in Denora.

https://pabook.libraries.psu.edu/literary-cultural-heritage-map-pa/feature-articles/cloud-silver-lining-killer-smog-donora-1948

Inversions are definitely a thing in the Southeast of the state. I used to commute through Lancaster and Lebanon counties along 322 and on still winter days, you would see the smoke from farms burning trash rise up undisturbed vertically to a point and then spread out horizontally as if it was trapped by a giant pane of glass.