An East Coast winter storm precipitation climatology

AbstractUsing a previously compiled climatology of East Coast winter storms (ECWS), an ECWS precipitation climatology was developed for the eastern United States from 1951–1952 to 2005–2006, using an automated procedure. Non‐ECWS precipitation that may have occurred during ECWS events was excluded through the development of a decision process based on knowledge of the characteristics of extratropical storms and aided by ECWS case study analyses. The main components used by this decision process were the location of precipitation and pressure gradients, and the presence of additional cyclones, not meeting the ECWS criteria. A sensitivity analysis of the ECWS precipitation climatology was conducted, which considered the change in the climatology if non‐ECWS precipitation was not excluded by the decision process. The highest average percentages of snowfall from ECWS occur in the Middle Atlantic and southern New England regions. These heavily populated metropolitan areas typically receive 45% of snowfall from ECWS. The highest average percentages of annual precipitation from ECWS are generally 20–25% and are located along the East Coast from Virginia northward to Maine. For the metropolitan centres of the Northeast, and for northern New England, El Niño years seem to indicate above average precipitation and snowfall amounts from ECWS, as well as an above average overall percentage of precipitation and snowfall from ECWS. Copyright © 2010 Royal Meteorological Society