The National Weather Service has extended its warning about thick fog until Tuesday afternoon.
The dense fog advisory was issued at 3:30 a.m., and initially was to remain in effect until 9 a.m. It was extended to 11 a.m. and, later, until 1 p.m., the service said.
The advisory means visibility at times will be less than a quarter of a mile during a 3-hour period. It covers northeast Connecticut — including the Hartford area — in addition to parts of Massachusetts and Rhode Island.
“Dense fog will result in hazardous travel for motorists into mid morning,” the Taunton, Mass.-based service said. “Drive with extra caution and leave plenty of space between the vehicle in front of you.”
Middlesex, New Haven and Fairfield counties also had fog advisories in effect, according to the weather service in New York.
In addition to fog, drivers also should watch for rain showers, and possibly a thunderstorm, Tuesday, the weather service said.