Severe thunderstorm risk to stretch from Midwest to Northeast

• Thunderstorms will rumble from the Ohio Valley to the Northeast on Tuesday before becoming more confined to the East by Wednesday.

• In the wake of the storms, much cooler and less humid air will move into the Midwest, Great Lakes and Northeast.

• The cold front responsible for the storms and cooler air will stall in the Southeast late this week.

The likelihood of thunderstorms, some packing severe weather, will expand from the Ohio Valley to the Northeast on Tuesday, before departing from west to east from Wednesday to Thursday. The storms will be locally damaging and disruptive, AccuWeather meteorologists warn.

Storms erupted Monday afternoon across Iowa before charging across Illinois, Indiana and Michigan generating over 300 storm reports and leaving behind a swath of power outages. As the system rolled through Chicago a wind gust of 75 mph was reported at the O'Hare airport.

As AccuWeather meteorologists mentioned last week for the particular weather pattern, there was the potential for a long-lived severe thunderstorm complex packing high wind gusts. This complex covered a distance of more than 400 miles, generating hundreds of reports of consistent high winds or wind damage incidents, which qualifies as a derecho by the National Weather Service definition.

Cooler and drier air will arrive in the wake of the cold front Tuesday, finally ending the threat of thunderstorms across the Midwest. However, the hot and humid air and the east-advancing cold front will continue the severe thunderstorm risk farther to the south and east.

"The strongest storms will be from southern Illinois to southeastern Ohio, where storms will be capable of producing flooding downpours, damaging wind gusts and hail," outlined AccuWeather Senior Meteorologist Tyler Roys.

Another pocket with more extensive coverage of severe weather will exist over much of New York on Tuesday. In this zone, there can also be an isolated tornado or two.

Outside of these zones, there will still be some risk of severe weather.

Regarding the heat, the exact timing of thunderstorms will impact high temperatures. Roys mentioned that places like St. Louis, Pittsburgh and Scranton, Pennsylvania, and Albany, New York, may run a bit lower than forecast if any thunderstorms occur in those locations before the late afternoon.

The Midwest will catch a break by Wednesday as the cold front moves to the East Coast.

"The cold front moving into a very hot and very muggy air mass in the northern Tennessee Valley and into the Northeast and mid-Atlantic will lead to explosive thunderstorm development," explained Roys.

AccuWeather experts are honing in on a zone from southern Maine to northern Virginia for the highest potential for severe weather at midweek. A large zone outside of that, stretching as far west as eastern Oklahoma and as far south as South Carolina, will have some risk for severe weather Wednesday.

"This time, the big cities from Washington, D.C., to Boston are likely to have storms during the afternoon commute or in the early evening hours, snarling travel for those driving home," said Roys.

In the wake of the front, widespread lower humidity and temperatures below the historical average will grace the Midwest, Great Lakes and interior Northeast Wednesday into Thursday. Just how far the front advances will affect the degree of air mass change along the East coast. Even there, cooler and less humid air should arrive by Thursday night and Friday.

"It may take an extra day [Thursday] for showers and thunderstorms to depart coastal areas of New England and the mid-Atlantic, as the front's forward speed may slow down," AccuWeather Senior Meteorologist Alex Sosnowski said, "This may delay the humidity drop until Thursday evening for these same areas."

As is typical in the summer, the cold front will eventually slow down and stall as it moves into the Southeast. This will set up a zone of potential downpours. This could cause instances of flooding, but much of the region is also in a drought. Therefore, the rain will largely be beneficial in the grand scheme of things.

The risk of severe thunderstorms will be lower late this week, but locally gusty storms are possible from Georgia through the Carolinas on Thursday. AccuWeather meteorologists will continue to monitor this potential throughout the week, but the main hazard is likely to be heavy rain.