B5.2 The Historic Heavy Rainfall and Flooding Events of 7-8 September 2011 across the Mid-Atlantic and Northeastern States

The combined effects of Tropical Storm Lee and Hurricane Katia resulted in excessive rainfall across Maryland, Pennsylvania, and New York State on 7-8 September, 2011. Lee's plume of moisture spread northward across the Eastern United States from 5-8 September, while its remnant circulation slowly decayed. Although heavy rainfall affected a wide region, it became particularly concentrated on 7-8 September. Further analyses revealed a complicated pattern and moisture contributions from multiple sources, including distant Hurricane Katia. Given the infusion of moisture from Katia, and the influence of this system on the overall large-scale pattern, this case is considered to be a Predecessor Rainfall Event (PRE).