Thunderstorms Lash New England After Rare Risk of Tornadoes

Parts of New England and the Northeast faced the rare threat of possible tornadoes on Sunday as severe thunderstorms marched across the region, forecasters said.

The National Weather Service issued a tornado watch early Sunday afternoon for Massachusetts, Vermont, New Hampshire, northern Connecticut, northeastern New York and western Maine.

More than eight million people were covered by the watch, which signals that conditions could lead to severe storms or tornadoes. The watch expired on Sunday evening after no tornadoes were reported, according to the National Weather Service.

Parts of Vermont, New Hampshire, Connecticut, New York and Maine also faced severe thunderstorm warnings on Sunday evening. The Weather Service reported hail and uprooted trees in several states.

In New Jersey, where the threat of severe thunderstorms expired at 11 p.m., the National Weather Service warned of likely wind gusts of up to 70 miles per hour on Sunday evening.

The Weather Service office in Albany, N.Y., had warned of an enhanced risk of severe thunderstorms on Sunday afternoon and evening. An enhanced risk “corresponds to the potential for more persistent” and intense storms, placing it at the third level of a five-level scale for the risk of severe weather.

Strong to severe thunderstorms were also expected to affect western and central Massachusetts and possibly spawn tornadoes, according to the Boston office of the Weather Service. A tornado warning was issued for a swath of northern Connecticut including Hartford.

The Weather Service office in Burlington, Vt., said on Sunday that parts of the state could see intense storms with damaging winds, large hail and possible tornadoes.

A combination of factors on Sunday were contributing to the tornado risk, including the heat that has been baking the region, said Bill Deger, a senior meteorologist with AccuWeather.

“We have the hot humid air moving into the Northeast,” he said, adding that a cold front was also moving from the west, approaching New England from upstate New York. He said the other factor was that “wind direction is changing with height in the atmosphere, which increases the chance of thunderstorms to spawn tornadoes.”

Citing a database maintained by Iowa State University, Mr. Deger said that the enhanced tornado threat on Sunday was the highest in New England in six years.

While people typically think of the Plains or the South as tornado hot spots, they do happen in New England, Mr. Deger said.

He noted that this type of tornado risk “comes around once or twice each year for interior New England.”

Last summer, an EF 0 tornado, which is rated as a weak tornado with winds of 65 to 85 miles per hour that causes minor damage, struck Vermont, Mr. Frank said.

“We don’t get these setups too often,’’ he said. “They do happen.”

Alexandra E. Petri and Yan Zhuang contributed reporting.