Severe thunderstorms expected to bring strong winds, hail and flash flooding across the Midwest and East Coast

Widespread thunderstorms are forecast to affect the northern United States beginning Sunday evening, bringing hail, strong wind gusts and heavy rain that could disrupt Monday commutes. The greatest risk is expected in the Great Lakes and Ohio Valley as the system skirts the edge of a heat dome over the Plains and moves through eastern Minnesota and northern Wisconsin.

AccuWeather meteorologist Brandon Buckingham said the storms could produce wind gusts of up to 85 miles per hour as they advance southeast into the Great Lakes region. > "Day-to-day thunderstorm activity can sometimes rely on where previous rounds of thunderstorms develop, which makes pinning down the exact location of the highest risk for severe weather difficult until just a matter of hours before storms form," he explained.

The same system earlier lashed Sioux Falls, South Dakota, with 80-mile-per-hour winds and gusts above 90 miles per hour, causing thousands of power outages. As the storms move east, officials expect additional tree damage, power outages, lightning and downpours through Monday afternoon and evening.

Travel along the Interstate 95 corridor from New York City to Raleigh, North Carolina, may be affected by damaging winds, hail and heavy rain. Prolonged rain along the northern edge of the system could produce flash-flooding from Buffalo to Boston through Tuesday evening, with the potential for further flooding in New England urban areas by Wednesday.

The National Weather Service also warned of hazardous heat across the central and southern United States, with afternoon temperatures in the upper 90s to low 100s and heat indices reaching 105-115 degrees in parts of the Rockies, Plains, Mississippi Valley and the South.