ST. LOUIS – This summer’s heat has come in short bursts, interrupted only by shots of relatively cool air by summer standards.

And remember, an official heat wave is made up of three or more consecutive days with temperatures greater than 90°. So far in 2023, we have seen 41 days over 90°.

But because we’ve had so many cold fronts this summer, that only breaks down into six relatively short heat waves – the longest of which was seven days, back in late July. That mark may be challenged in the next week to 10 days, as the long-range weather charts are all solidly pointing to what could the longest stretch of the hottest temperatures we’ve seen all season long.

The reason? The jet stream! We have been cooled by a northwest flow the past several days, but the heat that has backed Texas all summer is going to expand rapidly north and east this weekend as the jet stream retreats north into Canada.

Unlike previous patterns, this one looks to have some staying power!

Look for temperatures to approach 100° as early as Sunday, with near 100° degree days through at least the middle of next week. In addition, the humidity will be increasing leading to daily heat index values in the 105° to 110° range. This will be some pretty dangerous stuff and folks who are susceptible to heat related illnesses will need to take this heat seriously.