The biggest severe storm threat so far this spring is underway across the Mississippi Valley, and is only poised to worsen as the weekend arrives.
Low pressure is quickly intensifying over the central and northern Plains, flinging warm air northward into the Mississippi Valley. At the same time, colder air is dropping southward along the back edge of the storm.
The result has been a powerful outbreak of severe thunderstorms, with wind gusts exceeding 70 mph across much of Missouri and Iowa. As the night progresses, the storms will continue their advance across the Mississippi while fresh storms percolate from the Mid-South to the Mississippi Delta.
Tornado Watches stretch from central Missouri and northern Arkansas to western Kentucky, western Tennessee, and much of Louisiana. Cities such as Memphis, Tenn., Paducah, Ky., Marion, Ill., Little Rock, Ark., and St. Louis and Columbia, Mo., are under these watches. An additional Tornado Watch has also been issued for southern Arkansas, northeastern Louisiana and west-central Mississippi, including Monroe, La., Pine Bluff, Ark., and Greenville, Miss. Severe Thunderstorm Watches extend along the periphery of the tornado alerts from southern Minnesota across most of Iowa and northern Illinois. This includes Des Moines, Iowa, and the Chicago metro area. An additional Severe Thunderstorm Watch has been issued for southern Wisconsin, including Madison.
The national Storm Prediction Center considers today to have a Moderate Risk for severe thunderstorms and tornadoes, the 2nd highest level on their 5-point scale. A very wide stretch of real estate from Iowa and Illinois to Mississippi is in this risk category. Here, wind gusts of 85 to 100 mph are possible along with golf ball sized hail and tornadoes.
Surrounding this zone of storminess in an Enhanced Risk and Slight Risk district, where wind gusts will still be expected to exceed 70 mph along with the threat of tornadoes. These areas extend from Madison and Milwaukee, Wis., to Cincinnati, Ohio, Nashville, Tenn., and Birmingham, Ala.
Wind has been the biggest aggressor so far today, with a report of 78 mph gusts near Tekamah, Neb., 74 mph at Jefferson City, Mo., Airport, and 71 mph in Grundy Center, Iowa. A stop sign blew off its post in 70 mph gusts in Williamsburg, Mo., while large trees are down across Springfield, Mo. Baseball-sized hail has been reported near Highlandville, Mo.
The severe thunderstorms aren’t the only hazard being presented by this storm system. A ribbon of snow has been falling across western Minnesota and eastern South Dakota, where Blizzard and Winter Storm Warnings are in place. Four to eight inches of snow will be blown by gusts up to 60 mph through Saturday afternoon, making travel impossible along the western Minnesota portion of Interstate 90.
On the other side of the storm, warm and dry air has been combining with the strong winds to produce extreme fire risk and several out-of-control wildfires in Oklahoma and western Texas. With winds that could gust as high as 70 to 80 mph overnight, be ready to evacuate if fire comes toward your neighborhood. The rest of the Plains, if not under a Red Flag Warning, have High Wind Warnings in place into Saturday.
Today is only the start of a multi-day severe weather outbreak poised to peak on Saturday. Another low pressure system will push its way across the Mid-South on Saturday, bringing the likelihood of tornadoes across Mississippi and Alabama.