The National Weather Service’s Storm Prediction Center issued a series of severe thunderstorm watches across the Northeast on Thursday, placing millions of holiday travelers on alert. A watch covering all of Maine and New Hampshire is in force until 6 p.m. Eastern, while a second watch, effective until 10 p.m., extends southward to include Connecticut, Massachusetts, Rhode Island, southern New York—including New York City—northern New Jersey and northeast Pennsylvania. Forecasters said the atmosphere is primed for scattered but potentially dangerous storms capable of producing wind gusts up to 60 mph, half-dollar-sized hail, torrential rain and frequent lightning. The Storm Prediction Center assigned the region a Level 2 out of 5 risk, indicating conditions are favorable for pockets of severe weather as cells flare from mid-afternoon into the evening. Thunderstorms are expected to form after temperatures climb into the upper 80s and low 90 °F, with the most active window projected between 2 p.m. and 10 p.m. EDT. A fast-moving line of storms could coincide with the evening rush, raising the potential for travel disruptions on one of the busiest get-away days of the summer. Meteorologists expect the front to clear the coast Thursday night, ushering in drier air and mostly sunny skies for the Fourth of July. Comfortable conditions should persist into Saturday before heat and humidity build back into the 90 °F range late in the holiday weekend.