SWOP Weekly Weather Discussion

HEADLINE

Summertime heat and humidity will return to central Illinois next week as heat index values once again climb above 100 degrees.

DISCUSSION

A prominent upper-level high that has been consistently centered over the Desert Southwest for the past few weeks will temporarily shift eastward early next week. As the high re-positions over the lower Mississippi River Valley and Deep South, upper heights will rise and temperatures will climb across central Illinois. High temperatures will reach the lower 90s by Sunday, August 30th...then will rise into the middle 90s next Monday through Wednesday. With dewpoints well into the 60s and perhaps the lower 70s, afternoon heat index readings will routinely climb to 100 degrees or higher for the first half of next week. After that, there are signs the high may gradually shift back westward...reintroducing at least weak northwesterly flow across the Midwest. As a result, rain chances will increase and temperatures will decrease a bit toward next weekend.

The latest 6-10 day outlooks (Sep 2-6) from the Climate Prediction Center (CPC) suggest ABOVE normal temperatures and NEAR normal precipitation across central Illinois.

Issued: 8/27/26