I'll gladly vouch for this -
When I was a kid, my father drove the turnpike a lot as he had work clients out in the Pittsburgh area. He would often comment how the weather would change drastically at times when exiting east or west out of some of the tunnels. That was my experience yesterday - from the time I left Pittsburgh until I reached the Blue Mountain tube the temp was between 32 and 37 for the entire route. Immediately after exiting east out of Blue Mountain, the temp spiked to the low to mid 40s with peaks of sun. (it was snowing/grauple entering the tunnel from the west) My son was like...what happened to the snow?