Thursday brings brief break (kind of), then heat and humidity roar back

Good Wednesday morning! Almost everyone in southern Illinois picking up at least some rain on Tuesday afternoon as storms finally moved south of I-64 a bit. Upper-level high pressure over South Texas continues to be the driving force for weather across the middle of the country. This is a pretty typical Summer-time pattern.

On this Wednesday, we're watching a cold front moving through the Midwest with some slight temperature and humidity relief behind it. Surface high pressure is set to move in behind the front and shift eastward into the Great Lakes over the next 24 hours.

Wednesday morning dew point map highlighting the drier air moving in from the north.

It doesn't appear we're going to get a huge break from the humidity, but the north winds should be enough to take dew points from the low to mid 70s back into the low to mid 60s by Thursday afternoon with the front becoming nearly stationary running parallel to the Mississippi River.

High dew points are evident Thursday afternoon west of the front, while drier air takes over southern Illinois

Once high pressure moves eastward Friday morning, heat and humidity quickly roar back, with an oppressive combination we haven't quite seen yet this year. The upper-level high pressure is set to move from South Texas right into the Mid-South towards the end of the week. While daily chances for storms have become the norm, the big dome of high pressure moving overhead will essentially cut off storms.

Upper-level high pressure location Wednesday

Upper-level high pressure location Friday

Under the dome, it's going to be hot, dry, humid. The weekend will likely bring temperatures in the low 90s with heat indices cracking the century mark.

This big upper-level ridge looks to be a staple in weather for the middle U.S. through at least the remainder of the month. A shift westward would allow some relief and possibly the return of storms, but many of the longer range forecast models continue to hold onto this idea of hot and dry through the next 10 days.

Rainfall projection over the next 10 days. Notice the rain seems to circulate around the position of the dome of high pressure