Torrential Downpours, Flash Flooding Possible Sunday: MA Weather Alert

MASSACHUSETTS — A round of heavy rain and thunderstorms could bring flooding to parts of Massachusetts Sunday, with the National Weather Service warning of potentially torrential downpours from late Saturday night through Sunday afternoon.

A Flood Watch is in effect for portions of southeastern Massachusetts, including Cape Cod and islands and parts of Bristol and Plymouth counties. The NWS says showers and a few embedded thunderstorms could produce narrow bands of extremely heavy rain.

Widespread rainfall amounts are expected to range from about 0.50 to 2 inches and the NWS warns that narrow bands of torrential rainfall could produce 2 to 4 inches of rain in as little as three hours. While forecasters say it remains uncertain exactly where those bands will develop, the potential exists for localized flash flooding, particularly in vulnerable urban and poor-drainage areas, according to the National Weather Service.

A flood watch, which will take effect Sunday morning and run into the afternoon, includes portions of Bristol, Plymouth and Barnstable counties, along with Dukes and Nantucket counties. Communities including New Bedford, Fall River, Taunton, Plymouth, Falmouth, Provincetown, Chatham, Nantucket and Vineyard Haven are among those included in the affected region.

The Boston area and portions of Norfolk and Worcester counties are also facing the potential for heavy rain and flooding Sunday.

Residents should be prepared for rapidly changing conditions, particularly if a heavy rain band stalls over one location. The NWS warns that excessive runoff could cause flooding along rivers, creeks, streams and other low-lying and flood-prone locations.

The National Weather Service is urging residents to monitor the weather Sunday and prepared is a flood warning is issued. Drivers should use extra caution Sunday, particularly during the heaviest downpours, since roads can flood quickly in urban and poor-drainage areas, according to NWS.

Weather officials are also reminding residents not to drive through a flooded roadway — they should instead turn around and find another route.

The weather is expected to improve Monday, with lingering showers ending early before a generally drier and more seasonable stretch develops.