Overview
Strong thunderstorms formed in the high-shear environment that was present as the remnants of once-Category-Five Hurricane Katrina (loop) passed through Pennsylvania.

A few tornadoes formed as supercell thunderstorms moved through the Great Valley and Lower Susquehanna Valley just after midnight on the 31st. Sporadic wind damage occurred in other areas as well. Read a more scientific explanation of these storms.

Text Reports of Damage
Summary of the preliminary storm damage reports (LSRCTP)
24 hour precipitation reports from observers
(compiled from reports received in real time during the event).
Public Information Statements on the surveyed tornado damage.

Damage Location Maps

Storm Relative Motion Image (from KLWX (Sterling, VA) radar) around the time tornado was on the ground in Adams County:
Click on a damage track to view a close-up map of that area.

Damage path of F1 tornado that occurred in Northern Lycoming County later that night:
 

Precipitation

Rainfall Total (Multi-Sensor Precip Estimate from MARFC) for 48 hours (top panel) and
2-Day Total Cooperative Observer Precipitation reports (bottom panel).
Both images show the same period 7:00 am August 30 to 7:00 am September 1.