Mon-Tue, May 3-4th Severe T'Storm Risk Update #2

(10:00PM - 5/2/21) Multiple disturbances will move through the region Monday and Tuesday, bringing a severe t'storm risk to much of the state Monday afternoon through Tuesday evening.

Summary...
Multiple disturbances will eject out through the Central US, moving through the region Monday and Tuesday. These disturbances will bring a severe t'storm risk to much of the state, Monday afternoon through Tuesday evening. Model guidance continues to be in overall agreement regarding this event. With this update we have upgraded portions of Northwest and West-Central Illinois to a level 2 severe t'storm risk, for widely scattered severe t'storm potential...Elsewhere, no changes were needed.

Forecast...
Monday Afternoon-Tuesday Morning...
Scattered showers and t'storms are expected to develop across Iowa, Missouri and Northwest Illinois Monday afternoon, associated a disturbance moving through. This activity will then spread eastward across Northern and Central Illinois, Monday afternoon through Monday night. An environment featuring instability of 1,000-2,500J/KG, dew points of 59-66, good forcing and good shear is expected to be in place. Given the aforementioned environment expected, this will set the stage for an isolated to widely scattered (level 1-2) severe t'storm risk across Northern and Central Illinois, Monday afternoon through Monday night. Hail, damaging winds and an isolated tornado will be the main threats.

As another disturbance moves through the region, another round of scattered showers and t'storms will develop across Missouri, Arkansas and Southern Illinois Monday evening. This activity will then spread northeastward across Southern Illinois, Monday evening through Tuesday morning. An environment featuring instability of 1,500-3,000J/KG, dew points of 65-71, good forcing and good shear is expected to be in place. Given the aforementioned good environment expected, this will set the stage for an isolated to widely scattered (level 1-2) severe t'storm risk across Southern Illinois, Monday evening through Tuesday morning. Hail, damaging winds and an isolated tornado will be the main threats.

Tuesday Morning-Tuesday Evening...
In the wake of early day activity and as another disturbance moves through the region,  a new round of scattered showers and t'storms are expected to develop across portions of Missouri, Arkansas and Southern Illinois Tuesday afternoon. This activity will then spread eastward across Southern Illinois, Tuesday afternoon through Tuesday evening. An environment featuring instability of 2,000-4,000J/KG, dew points of 65-72, good forcing and good shear is expected to be in place. Given the aforementioned environment expected, this will set the stage for an isolated to widely scattered (level 1-2) severe t'storm risk across Southern Illinois, Tuesday afternoon through Tuesday evening. Hail, damaging winds and an isolated tornado will be the main threats.

​Below is the severe t'storm forecasts for this event.

JP