(11:00AM - 3/24/21) A storm system will move through the region Thursday into Friday, bringing a severe t'storm threat to the southern half of the state and windy conditions to Northeast, Eastern and Southern Illinois.
A storm system will move from the Plains tonight, through the Ohio Valley on Thursday, and into the Great Lakes by Friday morning. The northern side of a larger and more significant severe t'storm risk to the south will reach into the southern half of the state, with a severe t'storm threat expected Thursday afternoon through Thursday evening. Additionally, a period of windy conditions are expected across Northeast, Eastern and Southern Illinois, Thursday afternoon through Friday morning.
Areas of rain and t'storms will spread across the southern half of the state Thursday morning, as a warm front lifts towards and into Southern Illinois. In the wake of this early activity and with the warm front in the vicinity, a lower end environment will develop. This low end environment will feature low instability, modest moisture and great shear. Additional areas of scattered showers and t'storms that develop along a cold front across Missouri and Arkansas during the afternoon, will spread across the southern half of the state Thursday afternoon through Thursday evening. Given the aforementioned low end environment in place, a severe t'storm threat will exist with this activity, with widely scattered severe t'storms being possible. Hail, damaging winds and an isolated tornadoes will be possible with any severe t'storm.
In addition to the severe t'storm potential, windy conditions are expected Thursday afternoon through Friday morning, across Northeast, Eastern and Southern Illinois. High winds aloft, characterized by a low level jet of 40-65KT, will develop as the associated storm system rapidly strengthens as it moves through the region. Mixing depth will support wind gusts of 25-45MPH across Northeast, Eastern and Southern Illinois, Thursday afternoon through Friday morning.
Below is the severe t'storm and wind forecasts for this event.