Severe storms that could bring tornadoes and flooding threaten more than 30 million people in the US.

Watch this drone brave tornado-like winds 1:02

(CNN) --

Severe storms with tornadoes and damaging winds will move across the southern United States, from eastern Texas and eastern Oklahoma to Alabama, Monday and Tuesday.

Some of these tornadoes could be strong, EF2 (strong) scale or higher.

The Enhanced Fujita Scale or simply EF is used in the United States to classify the force of a tornado according to the damage they cause.

The scale, based on the strength of tornadoes, ranges from EF-0 to EF-5, according to the Storm Prediction Center of the National Office of Oceanic and Atmospheric Administration, NOAA.

The winter storm on the north-central Plains will pull moisture from the Gulf of Mexico north to the south, where temperatures are more than 6 degrees Celsius above normal for this time of year.

This will create the right conditions for severe storms to develop.

More than 30 million people are at risk from severe storms this Monday through Tuesday morning from eastern Texas east to western Tennessee and north to Missouri.

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(Credit: Hector Amezcua/AP)

Authorities issued a tornado risk level of 3 out of 5 for parts of eastern Texas, eastern Oklahoma, northwestern Louisiana, most of Arkansas, and a small portion of eastern Tennessee and thus eastern Missouri, Memphis, Shreveport, Little Rock, and Tyler, Texas are included in this region.

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Tornadoes and scattered damaging winds will be the primary hazards from these storms.

Some of the tornadoes could be strong: damage level EF2 or more.

Thunderstorms are expected to start early this Monday afternoon, although the severe potential in this round of storms remains somewhat uncertain.

A second line of thunderstorms is expected to develop Monday night and has the greatest potential to produce tornadoes and damaging winds.

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The storms will move east through Tuesday, threatening more than 25 million people from Louisiana east to Georgia and north to Kentucky.

A risk level of 3 out of 5 has been issued for parts of eastern Louisiana, southern Mississippi, and southern and central Alabama, including Baton Rouge, and Montgomery.

Damaging winds seem the most likely threat and tornadoes (some strong) are not out of the question.

Accompanying heavy storms will be heavy rain bringing a threat of flooding.

Flood advisories are posted for about 5 million people from East Texas northeast to far western Kentucky.

Widespread rain is expected bringing 2 to 3 inches of water, much of which will fall in a short period of time.

This will lead to possible flash flooding.

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