Monday 5/27/19 6:30am
The threat for severe weather and heavy rain returns to the region this afternoon and evening.
A complex of showers and thunderstorms in central Iowa early this morning will continue to race northeast and impact te Sauk Valley around the noon hour. Gusty winds, frequent lightning, and heavy rain will be possible with this activity.
Should skies begin to clear out after this activity moves through during the early afternoon hours, we'll be at risk for even stronger activity after 2pm this afternoon.
The combination of an area of low pressure moving through central Iowa, a strong warm front lifting north through southeast Iowa and north central Illinois, building instability, sufficient shear (or turning of winds with height) has the potential to come together producing supercell thunderstorms just to the west of the Mississippi River after 2pm.
These storms will contain all hazards, including large hail, damaging wind gusts in excess of 60 MPH and a few tornadoes. The greatest threat for tornadoes will exist along the advancing warm front, which is expected to land fairly close to I80, if not slightly north. Any storm that can interact with that boundary will be more than capable of producing tornadoes.
Should showers, storms, and clouds stick around for the majority of the early afternoon, our severe threat will be somewhat decreased. There is still some uncertainty regarding how quickly skies can clear out behind the activity earlier in the day.
What will be a solid guarantee is the threat for more heavy rain. The amount of moisture will continue to increase throughout the day and storms will be efficient rain producers with some localized rainfall amounts of more than two inches likely.
Bottom line: If you have outdoor plans, make sure you have a way to receive warnings should they be issued for your area.