Thur-Mon, June 24-28th Severe T'Storm Event Update #8

(11:45AM - 6/27/21) Multiple disturbances will continue to move through the region through Monday, bringing periods of severe t'storm potential to portions of the state through Monday night.

Summary...
Multiple disturbances will eject out of the Plains, and push eastward across the Midwest and Great Lakes through Monday. These disturbances will bring periods of severe t'storm potential to portions of the state, this through Monday night. Little to no change to going forecasts was needed with this update.

Forecast...
This Afternoon - Tonight, June 27th...
In the wake of a few isolated showers and t'storms across Central and Southern Illinois this morning, another disturbance will move through the region today, and a frontal boundary will be in place across Central and Southern Illinois. A new round of isolated to scattered showers and t'storms will develop this afternoon across Central and Southern Illinois, spreading across a large portion of the state this afternoon through this night. The overall environment supportive of a severe t'storm threat will be in place across Central and Southern Illinois. This environment will feature moderate instability of 1,000-3,000J/KG, dew points in the mid 60's to mid 70's, decent shear, decent forcing, and  modest lapse rates of 5.0-6.0C. This environment will be supportive of upwards of a an isolated severe t'storm risk (level 1) across a large portion of Central and Southern Illinois. Damaging winds and hail will be the severe weather threats.

Monday Morning - Monday Night, June 28th...
Areas of isolated showers and t'storms may be ongoing across portions of Northern Illinois Monday morning. In the wake of this early activity, another disturbance will move through the region, and a frontal boundary will be in place across Northern and Central Illinois. A new round of isolated to scattered showers and t'storms will develop Monday afternoon across portions of Northern and Central Illinois, spreading across a large portion of the state Monday afternoon through Monday night. The overall environment supportive of a severe t'storm threat will be in place across Central and Southern Illinois. This environment will feature moderate instability of 1,500-3,500J/KG, dew points in the mid 60's to mid 70's, decent shear, decent forcing, and  modest lapse rates of 5.0-6.0C. This environment will be supportive of upwards of a an isolated severe t'storm risk (level 1) across a large portion of Northern and Central Illinois. Damaging winds and hail will be the severe weather threats.

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

​Recap...
Thursday Morning - Thursday Night, June 24th...
An initial complex of showers and t'storms spread across a large portion of the state Thursday morning into Thursday afternoon. Another large complex of showers and t'storms developed later Thursday afternoon and evening across Northeast Kansas, Southeast Nebraska, Southern Iowa, Northern Missouri and Central Illinois. This large complex then spread across much of the state, Thursday evening through Friday morning. Along the way, some severe t'storms occurred across portions of Western and Southwestern Illinois. Damaging winds, small hail and isolated tornadoes occurred with this activity.

Friday Morning - Friday Night, June 25th...
An initial large complex of rain and t'storms spread across the state Friday morning. In the wake of this early activity, a new round of scattered showers and t'storms developed Friday afternoon and evening across Central Illinois, Missouri and Kansas. This activity then spread across much of Northern and Central Illinois, later Friday afternoon through Friday night. Some of this activity was severe across Central Illinois, producing damaging winds, large hail and a few tornadoes.

Saturday Morning - Saturday Night, June 26th...
An initial large complex of rain and t'storms spread across portions of Northern and Central Illinois Saturday morning. In the wake of this early activity, a new round of scattered showers and t'storms developed late Saturday morning into Saturday afternoon across portions of Northern, Central and Southwestern Illinois. This activity then spread across much of Northeastern, Central and Southern Illinois, Saturday afternoon through Saturday night. Some of this activity was severe across Northeastern, Central and Southern Illinois, producing damaging winds and possibly a tornado or two.

JP