This study spans the atmospheric and hydrologic sciences by analyzing the large-scale atmospheric precursors to flood events in central Pennsylvania, using historical streamflow and atmospheric circulation data. USGS streamflow data from sites in central PA will be analyzed and correlated with indices representing atmospheric variability based on NCEP-NCAR reanalysis data. The analysis will include time scales from daily to decadal and will cover the period from 1950-2002. A particular focus will be the relationship between the frequency of flood events and longer-term atmospheric variability such as the Arctic Oscillation. The role of flow controls (levees, dams, etc.) in long term streamflow data records will also be discussed.