Close to 30 million people may be at risk for severe thunderstorms over the central United States as a volatile weather pattern unfolds into Saturday, and AccuWeather meteorologists say some of the storms will be capable of spawning isolated tornadoes from late Friday into Saturday.
The main severe weather threat will arise as a storm system, which will unleash snow in the Rockies, emerge from the region and track northeastward across the Plains and then the Upper Midwest.
Storm clouds appear over a home near Meers, Okla., Tuesday, April 26, 2016. (Robert MacDonald via AP)
The first strong storms in the pattern will ramp up during Thursday night over portions of eastern Kansas to central Missouri.
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Areas from near Wichita, Kansas, to the suburbs south of Kansas City, Missouri, and the suburbs west of St. Louis could be in for a noisy night with pounding rain, vivid lightning, loud thunder and the potential for up to quarter- and half-dollar-sized hail.
A few communities in southeastern Kansas and south-central Missouri may also experience strong wind gusts. However, the storms Thursday night are not likely to be the most intense of the multiple-day severe weather outbreak.
The storm threat is forecast to expand over a more broad area of the Mississippi Valley from late Friday through Saturday evening and most likely include a few tornadoes.
In addition to the large hail and tornado threat, strong straight-line wind gusts with an AccuWeather Local StormMax™ of 70 mph can occur. Winds this strong can break large tree limbs and knock over poorly-rooted or diseased trees. Sporadic power outages are possible in addition to the risk of falling trees.
Flash flooding is another significant concern with the storms. Even though many of the storms will be fast-moving and last less than an hour, some areas, such as the Ohio Valley and central Plains, can experience repeating storms that bring excessive rainfall.
“From late Friday afternoon to Friday evening, severe storms are expected to erupt from eastern Oklahoma, southeastern Kansas and northwestern Missouri,” AccuWeather Lead Storm-Warning Meteorologist Brian Knopick said.
There is also the potential for thunderstorms to become severe over portions of central Illinois and Indiana during Friday.
During Friday night, the risk of severe weather is forecast to extend from the central parts of Illinois and Indiana southwestward to near the tri-state region of Arkansas, Oklahoma and Texas. It is possible severe storms extend southward into portions of north-central and northeastern Texas as well.
The severe weather risk will continue on Saturday. During the daytime, the severe weather threat may extend as far to the north as central Iowa and southern Wisconsin and as far to the south as northeastern Texas and northwestern Louisiana. Large metro areas of Chicago, St. Louis, Davenport, Iowa, and Little Rock, Arkansas, are among the areas at risk.
“Storms from northern Missouri and southern Iowa to central Illinois may have the greatest potential for tornadoes on Saturday, but this threat area may lift northward later in the day and early in the evening,” Knopick said.
“Farther south along the cold front, a more common threat is likely to be damaging winds and hail during Saturday,” he added.
As Saturday evening progresses, storms are forecast to advance across Indiana, the western parts of Kentucky and Tennessee, southeastern Arkansas and the northwestern parts of Mississippi and Louisiana. People in Indianapolis; Louisville, Kentucky; Memphis, Tennessee; Tupelo, Mississippi; and Shreveport, Louisiana; may be at risk for rapidly changing severe weather conditions.
From later Saturday night to Sunday, the setup for severe weather will likely become less defined and the storms are forecast to diminish in intensity. However, there can still be heavy, gusty and locally severe storms from southeastern Michigan, southern Ontario and western New York state to northern Georgia, central Alabama and central Mississippi.
“Since a significant number of the storms, including a tornado risk, will exist for at time after dark Friday and Saturday, this outbreak could be especially dangerous,” AccuWeather Meteorologist Brandon Buckingham said.
The severe weather threat comes at a time when worry about and precautions for COVID-19 increase across the nation. Experts urge people to check whether their community shelters will be open amid coronavirus restrictions ahead of time, so alternate plans can be made as needed.
AccuWeather Meteorologist Tom Bedard, a volunteer firefighter and EMT who regularly works with emergency management officials, said residents who own a tornado shelter should clean the shelter out immediately and make sure they are stocked with blankets, helmets and backpacks with some clothes, necessities and first aid equipment.
For those without a shelter, he recommended communicating with friends and neighbors for sheltering possibilities well before warnings are issued and heading to a safe place ahead of the storms.
If you can’t make it to a shelter or a family or friend’s residence, AccuWeather Meteorologist and Emergency Preparedness Specialist Becky DePodwin said residents should take cover in a bathroom with no exterior walls, a stairwell or a basement.
Temporary triage and testing centers have been set up outdoors in some communities amid the pandemic. These shelters could be at significant risk to these operations should severe weather roll in.
The strengthening storm from the Rockies will pull warm air that has been building over the Deep South since the start of this week northward due to the circulation around the system. At the same time, moisture will surge northward from the Gulf of Mexico, as a sweep of dry air pushes eastward from the southern High Plains.
A strong jet stream overhead will create what is known as strong wind shear, or changing wind speed or direction with altitude, over the lower Plains and Mississippi Valley. It is as these conditions come together that thunderstorms will erupt and become severe.
Not long after the severe weather risk diminishes during the latter part of the weekend, a new round of severe thunderstorms and flash flooding may arise early next week over the South Central states.
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