A swath of severe storms cut power to more than 200,000 utility customers in the Midwest Wednesday before stormy conditions shifted into the Northeast. AccuWeather meteorologists warn that additional rounds of dangerous, disruptive, and damaging thunderstorms will affect the Midwest into this weekend.
The thunderstorms will erupt along the Northern rim of a massive heat dome that began to sprawl over much of the nation this week.
Hot weather will help to set the stage for the volatile weather, and highs will challenge or exceed the hottest temperatures set so far this season across more than a dozen states in the central United States into Saturday. Widespread highs in the 90s F are in store, with some locations approaching the 100-degree mark.
Most of the storms through Saturday will fire up along the leading edge of a push of much cooler air arriving from Canada. As this cooler slices Southward into the hot and humid air, towering clouds will develop and evolve into powerful thunderstorms.
Incidents of high winds, hail, torrential downpours, and frequent lightning strikes are likely. Because of the lightning strike risk, even outside of storms that turn severe, forecasters urge people to move indoors at the first rumble of thunder.
In a few of the strongest storms, wind gusts can reach hurricane force (74 mph) and topple trees. Hail large enough to dent vehicles, damage crops, and break windows is possible. Rainfall at the rate of 1-2 inches per hour can quickly flood city streets and low-lying rural roads. In a small number of cases, a tornado is also possible.
“Into Thursday night, the majority of the thunderstorm activity, including the potential for severe weather, will extend from the northern and central parts of Minnesota to the Upper Peninsula of Michigan, including over the waters of Lake Superior and northern Lake Michigan,” AccuWeather Senior Meteorologist Adam Douty said.
As cool Canadian air begins to push southward Friday, pockets of thunderstorms will erupt from southern South Dakota and central Nebraska to the Lower Peninsula of Michigan.
The storms may organize into complexes or perhaps into one or more solid lines as they turn severe and push through portions of the Interstate 80, 90, and 94 corridors. As the storms approach the airport hubs during the afternoon and evening hours, including the major cities of Chicago and Detroit, ground stops will be likely, and flight delays will mount.
“The zone which extends from northeastern Nebraska to southern Michigan and northern Ohio is at a moderate risk of severe weather on Friday afternoon and evening,” Douty said, adding that this will be the most likely zone to experience severe weather.
Within part of this same corridor, a long-lasting complex of severe thunderstorms packing wind gusts exceeding 58 mph occurred Wednesday. The complex moved along a 300-mile swath from near the southeastern shore of Lake Michigan to the southern shore of Lake Erie and may later be dubbed a derecho, pending investigation by the National Weather Service (NWS).
As the leading edge of cool air presses on, some severe thunderstorms may approach the I-70 corridor of Illinois, Indiana, and Ohio, as well as northwestern Pennsylvania and western New York Friday night.
On Saturday, daytime heating will again give thunderstorms a boost.
The Midwest portion of the severe weather threat Saturday will extend from parts of southern Indiana and northern Kentucky to central and southern Ohio and western West Virginia.
Farther to the east, storms will erupt and turn severe over portions of Pennsylvania, Maryland, Delaware, Virginia, New Jersey, Southeastern New York, and Southern New England. Residents and airline passengers in Pittsburgh and Cincinnati may have to deal with severe weather Saturday.
By Sunday, storms are likely to ignite and become locally severe farther south across portions of Southern Kentucky and Tennessee. Storms may also develop and become severe over portions of the central and Northern High Plains on the Western edge of the cool air.
In the wake of the cool front across much of the Midwest, temperatures will be shaved by 10-15 degrees. That will translate to highs in the 70s to near 80 across the Great Lakes region and the low to mid-80s in the Ohio Valley. Adding to the more comfortable conditions, humidity levels will be slashed substantially. Much lower nighttime temperatures are in store.
However, despite the push of cooler and less humid air coming this weekend, a familiar problem this season may return—wildfire smoke.
The Northwesterly flow in the wake of the cool front will scoop up smoke from distant wildfires in western Canada and sweep it southeastward across large portions of the Midwest this weekend to next week. Where the smoke reaches down to the ground, poor to unhealthy air quality levels are likely.
Produced in association with AccuWeather