A man walks through the rain in Sayville on Jan....

A man walks through the rain in Sayville on Jan. 17, 2010. Credit: Newsday File / Ed Betz

Heavy rain forecast for Monday is putting the region at risk for flooding, the National Weather Service said.

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Between 2 and 2 ½ inches of rain could drench New York City and Long Island, meteorologist Matthew Tauber said. Some parts of Long Island could see more, he said.

There is a flash-flood watch for Nassau and Suffolk from Sunday at 10 p.m. until Monday at 4 p.m. A gale watch is in effect for the Long Island Sound and Great South Bay from Sunday night through Monday afternoon. Boaters and mariners will notice sustained winds of at least 35 mph and up to 49 mph.

Meteorologists issue flash-flood warnings when conditions put an area at risk for flooding in a short period of time because of heavy rainfall.

Temperatures are expected to be in the 50s on Monday.

The weather is being caused by a storm system moving out of the mid-Mississippi Valley, Tauber said.

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NewsdayTV's Doug Geed takes you to a few special places 'Out East' Credit: Newsday Staff

Out East Show: Shrine of Our Lady of the Island, Browder's Birds & Sheep Shearing, and Bennett Shellfish in Montauk NewsdayTV's Doug Geed takes you to a few special places 'Out East'

NewsdayTV's Doug Geed takes you to a few special places 'Out East' Credit: Newsday Staff

Out East Show: Shrine of Our Lady of the Island, Browder's Birds & Sheep Shearing, and Bennett Shellfish in Montauk NewsdayTV's Doug Geed takes you to a few special places 'Out East'

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