(CNN) — About 80 million people in the south face the risk of extreme weather conditions from Friday to Saturday, with the threat of tornadoes, destructive winds and hail.
The area under threat of extreme conditions stretches from southeastern Texas through northwestern Florida on the Gulf Coast to lower Michigan. The greatest threat will be in parts of Arkansas, Louisiana, Mississippi and Alabama, which the National Weather Service’s (SPC) Storm Prediction Center rated a level 4 out of 5, “moderate risk.” This includes Jackson, in Mississippi, and Monroe, in Louisiana.
“Major strong storms, including widespread destructive winds, and at least some tornadoes are expected in parts of northeast Louisiana toward Mississippi, especially overnight,” Spc said.
The SPC also warned that some areas, especially those that were marked as “moderate risk”, could face winds with hurricane force, that is to say of at least 120 km / h.
The midnight and early morning hours will be the most worrying for these dangerous storms, but the threat will begin earlier.
During Friday daytime there will be rounds of showers and thunderstorms in the southeast, some of which could gain traction. Strong storm watches have already been issued for some of the storms from Friday morning. The main threats posed by these storms are hail and wind.
Towards the early afternoon there will be an increase in storm activity in the central area where extreme weather conditions are being monitored. This includes eastern Oklahoma, northeastern Texas, northern Louisiana, and much of Arkansas.
Threat of storms for Friday night
The SPC anticipates that multiple storm lines will form in this region. Therefore, although there could be storms as early as Friday afternoon, the risk will continue into the night.
Scattered storms further east are also forecast for Friday night in Mississippi, Alabama and Tennessee. Unfortunately, the worst of the storms could occur after sunset.
“While tornadoes are possible, it appears that blowouts will be the main concern,” said the National Weather Service office in Jackson, Mississippi. “With that said, there could be wind damage swaths that resemble EF-0 to EF-1 (tornado) damage, so people should take the threat of wind seriously,” he explained.
A significant severe weather event is expected to unfold across the region late this afternoon through tonight, as multiple rounds of severe storms are expected to impact the area. Damaging winds up to 80 mph, baseball size hail, and a few tornadoes are all possible. pic.twitter.com/fdra50MXNQ
– NWS Jackson MS (@NWSJacksonMS) April 9, 2021
The rest of the south could also deal with several rounds of strong storms. The weather will not improve until early Saturday morning west of the Mississippi River, while to the east of there stormy conditions will likely remain.
The threat shifts east on Saturday
The storm system that triggers this outbreak of anticipated extreme weather conditions will continue to move eastward, causing thunderstorms to move in that direction as well.
With many extreme weather configurations, heavy storms usually occur late in the day, but there could be persistent threatening storms late Friday night that continue through Saturday.
On Saturday, the area most at risk for extreme conditions will be from the Gulf Coast to northern Alabama and Georgia. This includes cities like Atlanta, New Orleans, Birmingham, and Mobile.
Tornadoes are possible, especially near the Gulf Coast. By that time, the storms are likely to have evolved into one line of storms rather than the multiple lines and supercell storms, which are the discrete spinning storms expected from Friday into the night.
By Saturday night the threat will begin to decrease. As the storms approach the east coast of Georgia and the Carolinas, they may dissipate as showers reach central Florida.
Rounds of storms could trigger flash floods
This storm system will draw a lot of moisture from the Gulf of Mexico, allowing heavy rains to fall from thunderstorms Friday through Saturday.
In some areas, especially around Mississippi, multiple strong storms are anticipated. There is a risk that for several hours more than 5 centimeters of rain will fall per hour.
The amount of rain will be variable, as it depends on the trajectory of the storms, but in general terms 2.5 to 5 cm of rain is forecast for much of the south. Mississippi, Alabama, and northwestern Florida are the areas most likely to have totals of 5 to nearly 13 cm of rainfall.
On Sunday there will be a period of drier weather, and on Tuesday there are chances of new rains.