A ‘rex’ block has nothing to do with dinosaurs (as exciting as that may sound). It’s actually an upper-level blocking pattern that features high pressure north of low pressure.

A trough of low pressure will pass through the Midwest and Great Lakes Sunday night and Monday. This will cause clouds to thicken up through Sunday evening, lasting into Monday. As the trough passes through the Great Lakes a cut-off low will develop, closing off from the main flow of the jet stream.

This low will settles across the southern U.S., remaining fairly stationary throughout the week. In turn, it causes a northward shift in the jet stream allowing temperatures to warm well above average. Blocking patterns tend to remain fairly stationary for several days until something comes along and breaks the block. This break in our pattern looks to come by the end of the week and next weekend.

Highs throughout this week will warm into the 70s, perhaps even close to 80 degrees Wednesday and Thursday. By the end of the week, we’ll settle back to a little more seasonable pattern with temperatures in the 50s/60s, but it may be short-lived. Highs the following week look to warm back into the 70s.