Forecasters are warning stormy weather could hit 63 million people in the central US as colliding air masses threaten strong winds and even tornadoes, Sky News reports. Missouri, southern Illinois and northern Arkansas are expected to bear the brunt, but the Storm Prediction Center has warned people throughout the Midwest to be prepared ahead of Wednesday.
The threatened area stretches north from San Antonio, Texas, to include cities including Chicago and Cincinnati. Bill Bunting, operations chief at the Storm Prediction Center, said: “It’s going to be a large area, depending on how much unstable air develops.”
He said the jet stream and disturbances in the upper-level atmosphere would help storms develop, but that moist air from the Gulf of Mexico moving into the Midwest could trigger more severe storms. “It’s not a given,” he added. “We have concerns about the amount of low-level moisture that will be in place.”
A series of cold fronts have pushed humid air well south, but if it returns on Tuesday and Wednesday it could trigger severe storms. Temperatures across the Midwest on Monday were a few degrees above normal, but could hit unseasonable high temperatures by Wednesday – 10 to 15 degrees above normal.
The National Oceanic and Atmospheric Administration (NOAA) said St Louis and Columbia, in Missouri, and Peoria and Decatur in Illinois are at “enhanced risk” of severe storms on Wednesday and Thursday. Memphis, Kansas City, Shreveport, Des Moines and Little Rock are at a “slight risk”.
In November 2013, eight people were killed in Illinois by tornadoes. So far in 2015, 10 people have been killed but no tornadoes have occurred since May.