150 million brace for 'prolific' severe weather outbreak Friday amid multiday threat of long-track tornadoes

Fast Facts:

• An outbreak of severe storms is likely Friday afternoon and potentially into the overnight hours as a powerful storm system intensifies across the central U.S.
• These storms could bring significant tornadoes (EF-3+) as more intense storms form Saturday evening in the South.
• The final day of storms will slam the East Coast on Sunday from Florida to the Northeast.

A widespread and dangerous severe weather outbreak is expected to develop Friday and into the weekend as a powerful storm system unleashes its fury across the central and eastern U.S., impacting more than 150 million people. 

"Today may end up as one of the more prolific severe weather outbreaks in recent memory in the bi-state region," the National Weather Service in St. Louis wrote in a discussion Friday morning.

The FOX Forecast Center said that multiple days of potent thunderstorms could bring destructive winds, large hail and significant long-tracked tornado activity (EF-3 or higher).

The main action Friday will come in the form of a powerful squall line of storms which is expected to develop during the afternoon across Missouri and Iowa and charge east through the Mississippi Valley, the FOX Forecast Center said. 

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The highest risk for tornadoes is across 750 miles from Davenport, Iowa, to Jackson, Mississippi. The overall tornado threat is more than 1,000 miles long. The states with the most concern look to be centered in the mid-Mississippi Valley, including cities such as St. Louis, Missouri; Memphis, Tennessee; Paducah, Kentucky; and Little Rock, Arkansas.

Tornadoes, several of which could be strong, widespread damaging winds with gusts of 70-90 mph and scattered large hail up to baseball-sized will be possible, according to NOAA's Storm Prediction Center.

Multiple intense, long-tracked tornadoes possible Saturday

On Saturday, the powerful storm system will continue tracking east as a tornado outbreak is possible across the central Gulf Coast states and Deep South into the Tennessee Valley.

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The storms will develop along the Mississippi River and quickly move east from midday to the afternoon, according to the FOX Forecast Center. The line of supercells is then expected to swing through central and southern Mississippi into northern Alabama, central and east Tennessee and north Georgia. 

Cities such as New Orleans, Louisiana, and Birmingham, Alabama, are under a Level 4 out of 5 risk, indicating a high likelihood of supercell thunderstorms capable of producing tornadoes and damaging winds. 

Final day of storms likely to slam East Coast on Sunday

By Sunday, the storm will have traversed the entire U.S. with its eye now on the East Coast, including the Interstate 95 corridor. The threat of tornadoes will be confined to the Virginia coast and south into the Carolinas. Damaging wind gusts and large hail will be the main threats.

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Like on Friday and Saturday, plenty of wind shear will be present, allowing any singular storm to rotate and produce a tornado, according to the FOX Forecast Center.

North of the Delmarva into the Northeast, severe storms will also be possible.