It’s been a very warm February across the Midwest so far and that’s not going to change much as we end the month. Both today and tomorrow, many locations across the region will see temperature anomalies 25-35° above average! This will set the stage for many locations to break their daily maximum temperature records from the Southern Plains to the Upper Midwest.
However, the greater concern will be the threat of severe weather emerging across portions of the Ohio Valley and the Great Lakes region tomorrow. An area of low pressure will move across the Ohio Valley/Great Lakes area Tuesday into Wednesday. An unseasonably warm, moist air mass will accompany this system making for a strong warm front setting up across northern Indiana, northeastern Illinois, into Michigan Tuesday late afternoon into the evening. The Storm Prediction Center has issued a Slight Risk for severe weather for portions of the region that includes the threat of damaging winds, very large hail, and tornadoes.
A strong cold front will be in place as well further west across portions of Iowa, Illinois, and Missouri where a sharp temperature gradient will exist. Air temperatures will drop up to 35° in less than 200 miles!
We will also see a feature present that we often do not see in the Midwest, especially east of the Mississippi River- a dry line. This is a boundary where warm, moist air and warm, dry air meet. This will develop across portions of Illinois into Indiana and Missouri tomorrow afternoon and evening.
Strong low to upper-level winds will be in place as well. A west-southwest 500mb jet at around 50-70 knots and an 850mb jet from the southwest at 50-70 knots (increasing into the evening) will arrive tomorrow afternoon. This is while a south-southwest wind occurs at the surface. Not only will this promote strong speed shear (winds increasing with height) but also strong directional shear (winds turning with height). This allows storms that do form to begin to rotate, you can see the wind directions plotted on the map below.
In the warm sector of the storm, instability is forecast to build through the day. This will be one of the last ingredients needed to allow storms to form and become strong to severe. Hi-resolution data suggests CAPE values of 1000-2000 J/Kg are possible, more than enough to generate explosive thunderstorm development late afternoon into the evening.
While severe weather will be possible across Illinois, Indiana, southern Wisconsin, Michigan, and northwestern Ohio, the greatest threat looks to be in northeastern Illinois, southern Michigan, and northern Indiana. This is where thunderstorms look to develop late afternoon into the evening, initially either along the warm front or perhaps closer to the low-pressure center along the dryline feature. This will also serve as the focus for the greatest tornado threat as storms there will run into greater areas of wind shear, thanks to the warm front.
Keep in mind that severe weather is complex, and any small change in the timing of surface or upper-level features, cloud coverage, instability, or other variables can have a dramatic impact on the forecast. Make sure to follow us on Twitter, Facebook, Instagram, & LinkedIn for the latest information!
Thermodynamic Solutions (“TDS Weather”) provides professional weather consulting services to a variety of industries including: professional and minor league sports, snow removal and landscaping, golf courses and turf management, colleges and universities, and hospital networks. With nearly two decades of living and forecasting in the Ohio Valley region, our meteorologists provide custom, reliable forecasts that help clients SAVE and MAKE money in their daily operations. Our services include commercial and agricultural forecasting in the short and long ranges, lightning alerts and on-site hazardous weather monitoring, 24/7 on-call decision support services, forensic weather reporting, and more! For weather consulting inquiries, please contact us at info@tdsweather.com.