An interesting severe weather potential is possible later today across parts of the eastern Corn Belt, mid-Mississippi River valley and the Ohio River valley. I’d expect to see more cold air funnel reports as we’ve had the past several days across parts of OK and KS, as well as the potential for low-topped convection in areas that are outlined for a slight risk by the SPC, per the Day 1 outlook graphic below (courtesy NOAA/NWS Storm Prediction Center).
The culprit here (see below) is a closed “cold core” low at 500 mb in the mid-levels of the atmosphere, which is creating a region of enhanced vorticity as it slowly gyrates eastward. Note the water vapor loop, where the low is very evident on this satellite imagery too (see http://climate.cod.edu/flanis/reg.php?loop=1&type=wv®ion=northcentral&numimages=48).
This doesn’t appear to be any sort of a widespread, appreciable severe weather threat. However, with mid-level temperatures AOB -25C, juxtaposed with a potential area of clearing, per a dry slot on visible satellite profiles, deceptively low CAPE profiles are progged to emerge over the region, fostering steep lapse rates with the cold air atop the more unstable surface conditions. The presence of strong vorticity and very cold air aloft, and instability at the surface, will tend to foster stretching in the boundary layer, which can facilitate the formation of cold air funnels, and even low-topped supercell tornadoes under the right conditions. If we look at a modified RUC sounding from SE Illinois (see below), there is a notable area of instability, along with steep lapse rates, though the ambient wind shear profile is not a classical one that fosters sickle-shaped hodographs. Though the environment is not a classic surface pattern that favors a synoptic setup typical of cold core tornado events, the MLCAPE (instability) via surface heating and steep lapse rates should promote some thunderstorms capable of large hail and some damaging downburst winds, though I wouldn’t be surprised to see cold air funnel reports today, along with, perhaps, a few tornado reports.
As noted in this reflectivity model below, some of the forecast models have been showing the development of convection across the warm sector later today (this image is from 21z/23). Interested parties may wish to stay tuned to later forecasts in the event that a watch or a warning is issued for your area later today.
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