Over 100 tornadoes reported from last week's outbreak as renewed severe weather threat looms

The twisters have killed at least 31 people across six states and left more than 150 injured.

A massive tornado outbreak that struck more than a dozen states in the Mississippi, Tennessee and Ohio valleys last Friday and Saturday has now reached over 100 confirmed twisters, according to a FOX Weather analysis of National Weather Service storm surveys.

And the number may continue to climb as NWS storm-survey teams still work to complete investigations over dozens of tornado-damaged areas.

The twisters have killed at least 31 people across six states and left more than 150 injured.

Image 1 of 12

ARKANSAS, USA - APRIL 1: Residents clean up after the devastating tornadoes in Little Rock, Arkansas, United States on April 1, 2023. Governor Sarah Huckabee Sanders surveyed damaged areas. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 2 of 12

ARKANSAS, USA - APRIL 1: A view of damage as residents clean up after the devastating tornadoes in Little Rock, Arkansas, United States on April 1, 2023. Governor Sarah Huckabee Sanders surveyed damaged areas. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 3 of 12

ARKANSAS, USA - APRIL 1: A view of damage as residents clean up after the devastating tornadoes in Little Rock, Arkansas, United States on April 1, 2023. Governor Sarah Huckabee Sanders surveyed damaged areas. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 4 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: An inside view of a house after the tornado covering a path of dozens of miles in length caused severe damage in Little Rock, Arkansas, United States on April 02, 2023. Tornadoes that ravaged the US have killed at least 26 people, injuring dozens across southern and midwestern parts of the country, according to officials on Sunday. Houses and workplaces were heavily damaged and thousands were left without power in regions hit by tornadoes and storms. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 5 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: A view of the area after the tornado covering a path of dozens of miles in length caused severe damage in Little Rock, Arkansas, United States on April 02, 2023. Tornadoes that ravaged the US have killed at least 26 people, injuring dozens across southern and midwestern parts of the country, according to officials on Sunday. Houses and workplaces were heavily damaged and thousands were left without power in regions hit by tornadoes and storms. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 6 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: A view of the area after the tornado covering a path of dozens of miles in length caused severe damage in Little Rock, Arkansas, United States on April 02, 2023. Tornadoes that ravaged the US have killed at least 26 people, injuring dozens across southern and midwestern parts of the country, according to officials on Sunday. Houses and workplaces were heavily damaged and thousands were left without power in regions hit by tornadoes and storms. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 7 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: An inside view of a house after the tornado covering a path of dozens of miles in length caused severe damage in Little Rock, Arkansas, United States on April 02, 2023. Tornadoes that ravaged the US have killed at least 26 people, injuring dozens across southern and midwestern parts of the country, according to officials on Sunday. Houses and workplaces were heavily damaged and thousands were left without power in regions hit by tornadoes and storms. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 8 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: A view of the area after the tornado covering a path of dozens of miles in length caused severe damage in Little Rock, Arkansas, United States on April 02, 2023. Tornadoes that ravaged the US have killed at least 26 people, injuring dozens across southern and midwestern parts of the country, according to officials on Sunday. Houses and workplaces were heavily damaged and thousands were left without power in regions hit by tornadoes and storms. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 9 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: The tornado covering a path of dozens of miles in length causes severe damage in Little Rock, Arkansas, United States on April 02, 2023. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 10 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: The tornado covering a path of dozens of miles in length causes severe damage in Little Rock, Arkansas, United States on April 02, 2023. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 11 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: The tornado covering a path of dozens of miles in length causes severe damage in Little Rock, Arkansas, United States on April 02, 2023. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

Image 12 of 12

LITTLE ROCK, AR, UNITED STATES - APRIL 02: A view of the area after the tornado covering a path of dozens of miles in length caused severe damage in Little Rock, Arkansas, United States on April 02, 2023. Tornadoes that ravaged the US have killed at least 26 people, injuring dozens across southern and midwestern parts of the country, according to officials on Sunday. Houses and workplaces were heavily damaged and thousands were left without power in regions hit by tornadoes and storms. (Photo by Peter Zay/Anadolu Agency via Getty Images) ( )

HOW ARE TORNADOES RATED? THE ENHANCED FUJITA SCALE EXPLAINED

So far, one tornado has been designated as an EF-4 on the Enhanced Fujita Scale – a twister that tore through Keokuk County in Iowa, packing a peak gust of 170 mph and leaving three people injured.

There have been 10 tornadoes rated at an EF-3 so far, including deadly tornadoes that hit Little Rock, Arkansas, Wynne County, Arkansas, Jasper and Crawford counties in Illinois, Sullivan County in Indiana and the Covington and Hornsby/Mount Pleasant areas in Tennessee. Some of those tornadoes may still be upgraded to higher ratings as more data comes in.

HOW METEOROLOGISTS DETERMINE IF A TORNADO IS TO BLAME FOR STORM DAMAGE

NWS storm survey teams found 27 tornadoes reaching EF-2 status, 39 EF-1s and 20 EF-0s. There are six confirmed tornadoes that have yet to be classified.

Same area hit by Friday tornado outbreak under threat of strong tornadoes again

The grim milestone comes as that same region is under threat of another severe weather and possible tornado outbreak again Tuesday night and into Wednesday morning.

A large area of severe thunderstorms is expected to develop from Tuesday afternoon through the overnight hours in a swath extending from southeastern Minnesota, southern WisconsinIowa, Illinois and western Indiana southward to portions of MissouriArkansas, eastern Oklahoma and eastern Texas.

These storms will pose threats of destructive wind gusts, large hail and tornadoes, some of which could be long-track, EF-2 or stronger tornadoes.

NOAA's Storm Prediction Center has rated two areas in their level 4 of 5 severe weather threat for Tuesday night into Wednesday morning, including Springfield, Missouri, a large swath of northwestern Arkansas and much of eastern Iowa, including Cedar Rapids, Davenport and Iowa City.

The severe weather threat spreads east into Wednesday, covering much of the Great Lakes and Ohio and Tennessee valleys.