Outlook:
Severe storms are expected across southern Iowa into northern portions of Missouri and Illinois during the late afternoon and evening hours. The main risks with these storms will be very large hail, destructive wind gusts, and perhaps a couple of tornadoes if the ingredients align. For detailed information on timing, impacts, and more, refer below.
Overall Forecast:
In the upper levels of the atmosphere, a fast upper-level jet streak will become centered across parts of the Upper Midwest/Great Lakes by Thursday afternoon. This will coincide with a series of embedded shortwave impulses moving eastward. A surface cyclone should move into Quebec, with an attached cold front likely centered from southern Wisconsin to the Kansas/Nebraska border by the late afternoon. A plume of large to extreme buoyancy is expected to develop amid very steep mid-level lapse rates and a corridor of enhanced boundary-layer moisture ahead of the impinging front.
Across Southern Iowa into Northern Portions of Missouri & Illinois:
At the same time, strong effective mid/low-level shear amid west-northwest flow will support an elongated hodograph. This, combined with very strong instability, should yield initial splitting supercells capable of producing very large hail. The orientation of the shear vector, semi- to nearly parallel to the front, should lead to upscale growth by early evening, especially in the western extent where effective bulk shear is relatively weaker. Given the significant downward instability, there will be potential for intense wind gusts of 75-95 mph possible. These storms will eventually subside into Thursday night as they move into a less unstable airmass.
Coverage Details:
Storms are expected to form immediately as destabilization occurs around late afternoon across southern portions of Iowa, moving south southeastward into northeastern Missouri over time. More storms will develop into the evening across Illinois and portions of Indiana. The highest concentration of storms will be across Illinois through Iowa and into northern Missouri, where destructive wind gusts will be a significant risk.
Main Risk: very large hail, destructive damaging winds, isolated tornadoes and CG (cloud to ground) lightning.
Stay tuned for more updates.
Sina⚡⚡
With over a decade of experience in forecasting severe thunderstorms, this individual is a seasoned forecaster and developer. Their expertise in severe weather forecasting and computer science is entirely self-taught, complemented by a foundation in Atmospheric Science from UNCO and an IT background from WGU. They have dedicated their efforts to developing innovative tools that enhance the accuracy of analyzing large hail and tornadoes. As a significant contributor and partner at National Weather Force Innovations LLC, they have played a crucial role in providing accurate and timely information. Additionally, they have been instrumental in developing tools and organizing projects that focus on accuracy and performance, ensuring those affected are well-informed.