Connecticut Light & Power reported about 20,000 customers, mostly in the southwestern part of the state, had lost electricity as of about 8 p.m. on Tuesday.
Meanwhile, the National Weather Service has issued a tornado watch until 11 p.m. for Litchfield, Fairfield and New Haven counties.
Forecasters also warn that wind gusts up to 60 mph and one to three inches of rain are possible. They say the rain could cause localized flooding.
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