The state should see some relief today thanks to a cold front set to move in last night from Ontario and Quebec. National Weather Service meteorologist Michael Cempa says the most recent heat wave was caused by something called a ‘Bermuda High.’ That’s when a high pressure system parks along the western Atlantic.
“And that kind of just keeps the flow of warm air from the southwest, from the southern states and the Gulf of Mexico," Cempa says. "So we get that warmer and more humid air just continually to flow in. And it looks like maybe we’ll see a break in that pattern, a little bit at least, for the next few days and into next week.”
The cold front should also calm down the recent spate of heavy thunderstorm activity. He says between Friday night and early yesterday morning, several lines of storms—called ‘Bow Echoes'--quickly worked their way across the state. While it’s normal to see those in New Hampshire a couple times a year, Cempa says it’s unusual to see several over just a few hours.