Heavy rain may fall on a deep primed snowpack leading to the melt increasing. Flows in rivers may increase quickly and reach critical levels. * WHAT...Flooding caused by excessive rainfall is possible. * WHERE...Portions of central and western New York, including the following counties, in central New York, Northern Cayuga. In western New York, Allegany, Cattaraugus, Chautauqua, Genesee, Livingston, Monroe, Niagara, Northern Erie, Ontario, Orleans, Southern Erie, Wayne and Wyoming. * WHEN...From Tuesday morning through Wednesday evening. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS... - Multiple rounds of showers and embedded thunderstorms are expected between tonight and Tuesday night which may result in several inches of rainfall over a 2 to 3 day period. Excess runoff from this rainfall may cause area waterways to reach or exceed bankfull stage. General flooding away from area waterways will also be possible during this timeframe, especially in typical low-lying and poor drainage areas. - http://www.weather.gov/safety/flood