"The biggest threat to tornadoes will be across the Gulf Coast states of Mississippi and Alabama on Thursday," said CNN meteorologist Michael Guy.
The massive storm system will not leave the South peacefully either. It will enter the Ohio Valley region and then the East Coast, where on Thursday and Friday 100 million people are threatened with severe weather.
"Heavy thunderstorms can lead to violent gusts, a few tornadoes (possibly strong) and today great hail across the lower Mississippi valley through the central Gulf Coast region," said the National Weather Service's Storm Prediction Center on Thursday.
In Louisiana, the forecast is so dreadful that New Orleans City Hall and other local government agencies will be closed early Thursday, the mayor said. New Orleans is expected to be hit by the storm on Thursday afternoon and evening.
Where are those storms going?
This storm system will move towards the east coast by Friday, triggering tornadoes from the wind and hail Texas Panhandle damage to the coast of the Carolinas.
Early Friday morning it will pass through Georgia, until Friday afternoon through other Atlantic coastal states.
On Friday along the east coast, dangerous conditions will reign, spreading from the southern tip of Florida to Washington DC.
Who is the biggest risk? Friday?
The coastal areas of Carolinas and southeastern Virginia have the greatest potential for severe weather on Friday. This area is at an "increased risk," the Storm Prediction Center said, referring to the third level of severity on a scale of five.
Damaged winds and tornadoes could hit the Southeast and Central Atlantic states, especially within the "elevated" risk area.
The threat should decrease from Friday to Saturday during the night, as the storm-linked cold front eventually reaches the coast.