As with some past events, I had to put on my Sherlock Holmes hat with this one and do some sleuthing to figure out what exactly happened. The SPC has one tornado listed on August 3, 1963 and this is it: An F3 with a path length of 0.1 miles in Allegheny County, PA. There are several discrepancies that expand across our different sources.
At 1145 EST, a quick-hitting F3 hit parts of Montgomery County, PA. The official path is only 2 miles. The tornado paralleled Limerick Road on its western side and moved right over a housing development called “The Hamlet”. It was a newer development. Per Storm Data, “Of the 27 inhabited houses, 4 were leveled, 16 were damaged beyond repair, 1 under construction was destroyed and only 7 remained liveable. Damage in this development alone was $2 million.”
An F3 tornado hit portions of Westmoreland County, PA on July 11, 1976.
Per Thomas Grazulis in Significant Tornadoes: The tornado traveled 13 miles from near Delmont to Salem and Unit Townships, near the Latrobe-area hospital to Clover Hill, Oakville, and Darlington.
This tornado developed in Plains Township (Luzerne County) near Bald Mountain Road. It tracked a total of 12.52 miles (7.12 miles in Luzerne County and 5.40 miles in Lackawanna County).