Event Summary

A low pressure system moved northeast along the mid-Atlantic coast and produced widespread heavy rain across the New York City metropolitan area and Long Island beginning late Thursday night March 29th and ending by Friday evening March 30th. The low developed over the southeast states Thursday afternoon, and moved northeast to a position near Washington D.C. by early Friday morning. The low then continued moving northeast, passing across eastern Long Island early Friday afternoon and off the New England coast by late Friday night. Strong "overrunning" of warm, moist air over a pre-existing colder air mass, combined with a strong easterly wind flow of moisture-laden air off the Atlantic Ocean, produced very heavy rainfall across New York City and Long Island during the daytime hours on Friday. Two to three inches of rain were common across much of southeast New York, with some localized amounts up to four inches, particularly across portions of Nassau and Suffolk counties. This created widespread urban and highway flooding during the Friday morning commute, which continued into the early afternoon hours. The rain finally tapered to showers later Friday afternoon, and ended by Friday night as the low departed off the New England coast. Here are some storm total rainfall amounts: For Bronx County: 2.90 inches. For New York County (Manhattan): 2.37 inches at Central Park. For Kings County (Brooklyn): 2.70 inches at Gravesend. For Queens County: 1.99 inches at La Guardia Airport, to 2.41 inches at John F. Kennedy International Airport.