The Flash Flood Warning is in effect until 9:30 p.m. Tuesday.
At 6:30 p.m., Doppler Radar indicated thunderstorms producing rainfall rates of 1 to 2 inches per hour were moving into the area.
Up to 2 inches of rain have already fallen Tuesday in parts of the county.
Flash Flooding is expected to begin shortly, the National Weather Service warns.
Residents are warned to move to move to higher ground and to avoid roads that are covered with water. Most flood deaths occur in vehicles — turn around, don't drown, the weather service warns.
The line of strong thunderstorms is bring torrential rainfall, the weather service said. The storms are moving east at 15 mph from northern Westchester County.
Wind gusts of up to 50 mph are possible.
The storms are expected to pass through Danbury, Ridgefield, Wilton, Bridgeport and Stamford as well as surrounding towns and cities.
The heavy rainfall will cause localized flooding. Do not drive through flooded roadways.
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