A prolonged threat of flash flooding, gusty winds and hail pose a risk to those in the Midwest, as strong storms could continue to hit the area this weekend.

       On Friday night into early Saturday morning, storms swept across parts of the Upper Midwest, bringing wind gusts up to 80 mph and reports of downed trees and power lines.

       These storms are still continuing Saturday, with 14 million people over portions of South Dakota, southern Wisconsin, northern Illinois, northwestern Indiana, far eastern Iowa and southeastern Minnesota remaining under a slight risk for severe storms through Saturday evening. These storms will be capable of producing damaging winds, large hail and a couple tornadoes.

       Nearly 12 million people across portions of southeastern Wisconsin and northern Illinois are under a Severe Thunderstorm Watch until 7 p.m. local time on Saturday. Wind gusts could reach up to 70 mph and scattered hail the size of 1.5 inches in diameter is also possible.

       A persistent flash flood threat will come with these storms on Saturday and Sunday, with a Flood Watch in effect for parts of southern Wisconsin, including the Milwaukee area, through Sunday morning.

       These storms will begin during the late afternoon east of the Rockies on Saturday, before moving east into South Dakota and nearby areas. Rapid City, South Dakota, should see these storms at approximately 6 p.m. local time on Saturday, whereas other areas nearby, including Aberdeen, South Dakota, and Bismarck, North Dakota, will witness the storms before 11:59 p.m. on Saturday.

       After moving east, the storms will reinvigorate on Sunday, continuing the elevated flash flood risk for parts of Minnesota and Wisconsin.

       This comes after a strong storm dumped 5 inches to a foot of rain in the Milwaukee, Wisconsin, area last week, flooding basements of homes, toppling trees and leaving numerous drivers stranded on flooded roads.

       Along with a flash flooding threat, more than 56 million Americans across 15 states in the Midwest and South are under heat alerts this weekend, with dangerously warm heat indices -- what the temperature feels like with humidity -- ranging from 105 degrees in the Central Plains to 112 in Florida.

       Temperatures in the South are close or slightly above what is normal for this time of year, but the excessive humidity makes it dangerous for the body, as it needs to exert itself more to cool down.

       The Northeast will see seasonably warm temperatures throughout the weekend, but less humid conditions, keeping heat indices below 100 degrees across the region.

       A cold front will push through early next week to bring a drop in temperatures and will also keep Hurricane Erin -- now a Category 5 storm -- out to sea.

       ABC News' Shawnie Caslin Martucci contibuted to this report.