It's a weather pattern for the summer related to the jet stream.
Normal:

Current:

If you look at the normal pattern the jet normally dips own thru TX and flows up toward IL then dips again and flows up to the North East
The jet stream steers the weather (wx). If you look the current the summer jet is way North allowing the low (L) too push into the Mid South, bringing Gulf moisture. An old rule of thumb. Winter Jet is normally to the north and the Summer Jet normally dips way south. The current jet you might see in January....
Global cooling?

Ren