This was a very interesting storm. The storm fired up in the heat and instability over Western Pennsylvania during the late afternoon of July 10th, 2006. It showed very strong cyclonic rotation as it passed to the south of Emlenton, PA (along I-80), knocking down trees in Brady's Bend, PA (Armstrong Co).
The storm then began to split as it moved eastward. The left-half of the split-cell moved northeastward into Elk County, PA, and the entire cell was rotating anti-cyclonically (clockwise) - which is unusual.
The Southern/Right-moving/cyclonically-rotating half of the cell moved into Indiana County and fell apart, as it moved into an area cooled-off by it's own shadow and anvil-rain.
The Northern/Left-moving/anti-cyclonically rotating cell had rotation so strong and deep, that it prompted Severe Thunderstorm Warnings for Elk and Cameron Counties. Little if any damage was reported in those areas, as the cell crossed through the very sparsely-populated State Forest land over the north-central mountains.
However, as the storm cell continued to move to the east-northeast, the storm's rotation changed back to mainly cyclonic (counter-clockwise) rotation, and eventually made damage in Mansfield, PA (Tioga County), and downstream in Athens, PA (Bradford Co) and on toward Binghamton, NY.
Preliminary Damage Reports from this storm cell in Text format