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 rain and snowmelt is possible. * WHERE...A portion of central New York, including the following counties, Jefferson, Lewis and Oswego. * 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. This rain combined with snowmelt from the higher elevations of the Tug Hill and Western Adirondacks may cause area waterways to reach or exceed bankfull stage, especially on the Black River and those that drain into the Black River basin. - http://www.weather.gov/safety/flood