March 19, 2020

A Widespread Threat For Severe Weather Will Cover The Central U.S. On Thursday Evening



A widespread risk for severe weather will develop across much of the central United States on Tuesday as warm, humid air surges northward behind a warm front. Several rounds of severe thunderstorms will develop through Thursday night, bringing the risk for damaging winds, tornadoes, and large hail. The greatest tornado risk appears centered on the Mississippi and Ohio Rivers.

Today's severe weather threat looks like the first large-scale severe weather threat of the season, with a slight risk extending from Waco to Milwaukee, Grand Island to Columbus, and everywhere in between. The Storm Prediction Center issued two separate enhanced risk areas for Thursday evening; one covers the threat near the center of the low-pressure system across portions of Iowa, Missouri, and Nebraska, while the other covers the threat for severe storms between central Arkansas and southern Indiana.

Source: Tropical Tidbits



You can see the basic setup by glancing at a map of dew points this afternoon. There's a beautiful low-pressure system centered right over the Colorado/Kansas border this afternoon—look at the moisture swirling around its center!—with a series of warm fronts extending from there all the way east to the Delmarva Peninsula. This swath of warm and humid air will fuel the development of thunderstorms this afternoon and evening, and strong wind shear through the atmosphere will allow many of the storms to grow severe. The warm front will serve as a focus for the tornado threat across Iowa, Missouri, and Nebraska, while a low-level jet will drive this evening's tornado risk in the Mid-South and Ohio Valley.



A 10% risk for tornadoes exists across both of the enhanced risk zones, with slightly lower threats radiating out from there. That doesn't sound like much, of course, but when you consider there's typically about a 0.1% to 0.2% risk for a tornado within 25 miles of any location across today's risk areas on an average March 19, today's 10% risk should make everyone's ears perk up and pay attention to the radar.

Damaging winds are likely in any of the thunderstorms that form today. Don't sleep on the damage that can result from 60+ MPH wind gusts. It's important to take severe thunderstorm warnings seriously, as well. Flowers and leaves are developing on the trees now, which can act like little sails by catching the wind and adding stress to limbs and trunks.

Any of today's severe thunderstorms could produce large hail (the size of quarters or larger), but there's a risk for "significant" large hail—the size of golf balls or larger—across the enhanced risk in IA/MO/NE.

Nighttime tornadoes are exceptionally dangerous because people are tuned-out, asleep, or they can't fight their urge to look outside and visualize the threat before they take action. As always, make sure wireless emergency alerts are activated on your phone before you tune-out or go to bed tonight. Given the advanced radar technology available to meteorologists today, you can trust that you're at risk if your location goes under a warning.


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I graduated from the University of South Alabama in 2014 with a degree in political science and a minor in meteorology. I ran Gawker's The Vane for two years and I've contributed to Mental Floss, Forbes, Popular Science, and the Washington Post's Capital Weather Gang. I also teamed up with Outdoor Life to write a book called The Extreme Weather Survival Manual, which came out in October 2015.

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