(11:45AM - 7/13/21) Multiple disturbances are expected to move through the region Wednesday and Thursday, bringing periods of severe t'storm potential to portions of the state Wednesday afternoon through Thursday night.
Multiple disturbances will eject out of the Plains, and push eastward across the Midwest and Mid-Mississippi Valley on Wednesday and Thursday. These disturbances will bring periods of severe t'storm potential to portions of the state, Wednesday afternoon through Thursday night. Little to no change was needed with this update, as going forecasts are on track.
Wednesday Afternoon - Wednesday Night, July 14th...
The favored scenario for Wednesday is the following... A lead wave and associated weakening complex of rain and t'storms that originates in the Plains tonight will move into Minnesota and Wisconsin Wednesday morning. Regeneration and new development associated with this wave is then expected to occur during Wednesday afternoon across portions of Minnesota, Iowa and Wisconsin. This activity is then expected to push eastward and across portions of Northern Illinois, Wednesday afternoon into Wednesday night. This environment will feature moderate instability of 1,500-3,500J/KG, dew points in the mid 60's to mid 70's, good shear, good forcing, and modest lapse rates of 5.5-7.5C. This environment will be supportive of upwards of a an isolated to widely scattered severe t'storm risk (levels 1-2) across Northern Illinois. Damaging winds and hail will be the severe weather threats, though an isolated tornado can't be ruled out.
Thursday Morning - Thursday Night, July 15th...
Severe t'storm potential will once again exist across portions of the state for Thursday. More information regarding this potential will be provided in future updates.
Below are the severe t'storm forecasts for this event.