Combined, these systems are set to deliver heavy rain to millions across most of the country east of the Mississippi River, as well as a severe weather threat to parts of the central US and Deep South, while the potential for flash flooding develops across the Tennessee Valley on Friday.

Meanwhile, a potential weekend washout looms for most of the mid-Atlantic and Northeast, as rain reaches the region Friday.

Downpours spread across parts of Oklahoma, Missouri, and Kansas on Thursday morning.

This first system will then sprint through the Midwest throughout the day, and a widespread area of rain will cover Chicagoland in Illinois, Wisconsin, and Indiana, and reach into parts of the Ohio Valley in the evening.

As this first storm lifts into the Midwest on Thursday afternoon, a round of thunderstorms will be possible across the Mississippi River Valley from St. Louis to Oklahoma City and as far south as Monroe, Louisiana.

Damaging wind gusts are the main threat, but brief tornadoes could form if storms are able to cluster together in a fast-moving line.

A cold front associated with the first storm will move into the Deep South on Friday, sparking the potential for the most significant severe weather threat this week.

NOAA’s Storm Prediction Center has issued a Level 2 out of 5 risk of severe thunderstorms for an area covering more than 8 million people across the Lower Mississippi and Tennessee valleys, including parts of west Tennessee, Arkansas, Mississippi, Alabama, and Louisiana.

Morning Report delivers the latest news, videos, photos and more.

Please provide a valid email.

By clicking above you agree to the Terms of Use and Privacy Policy.

Never miss a story.

This covers Memphis, Tennessee, Jackson, Mississippi, and Baton Rouge, Louisiana. These storms could be capable of generating damaging wind gusts, hail, and possibly tornadoes.

Never miss a story.

On Friday, the second cross-country will develop once again in the Four Corners and move out of the southern Rockies, bringing another round of rain to many of the same places as the first storm in the Midwest, and in the Mississippi and Tennessee valleys.

NOAA’s Weather Prediction Center has issued a Level 2 out of 4 threat of flash flooding for middle Tennessee, Mississippi, and northern Alabama through Saturday, where more than 2 to 3 inches of rain is expected, with localized pockets of up to 5 inches possible.

Rain from the first storm will arrive in the Northeast and New England, including Washington, DC, Philadelphia, New York City, and Boston Friday morning.

Rain is expected to linger across the Southeast Saturday morning as the second storm shifts into the Great Lakes region by the afternoon.

Showers and thunderstorms are expected across much of the Northeast and New England coasts through Saturday.

Conditions are expected to improve by late Sunday, with most areas drying out by Monday.