ST. LOUIS — What happened to the fall weather? It is nearly October and a lot of Midwesterners want to know when it will start showing up in the forecast. The National Weather Service says that an Omega Block is shifting the jet stream over the Midwest, near Canada. This is keeping the cooler temperatures along the coasts while the center of the country remains warm and dry.

Omega Block jet stream pattern
Omega Block jet stream pattern

The chance for rain is over after the storms rolled out of the area Wednesday morning. The rest of the week will be sunny and dry with above-average temperatures. Average highs this time of year are in the upper 70s. Forecast highs are well into the 80s.

The Omega Block is expected to stick around from Thursday until early next week. The pattern in the jet stream gets its name from its resemblance to the Greek letter Ω.

Meteorologist Glenn Zimmerman explained during his long-range fall weather forecast that the first freeze near St. Louis typically comes in late October or early November. It will start out dry and then shift to a more active weather pattern later in the month.

October 2022 had some warm days in the first half, then a big temperature drop middle of the month with the frost and freeze. Current projections show a mild month with some 30s, but a freeze might hold off until November.

Last year, October was pretty dry, with one big rainfall late in the month. This year could be pretty similar: Dry to start, but more rain and storm chances late.