Where'd those 90s go?

Normally, I don't take such a long look out at the forecast here on the blog when we have a storm chance in a couple of days, but perhaps you've been scratching your head about the end-of-the-week heat we had in the forecast.

I've blogged before about how we like to look at computer forecast ensembles. When they suggest warmer than normal weather several days away, then our confidence in such a scenario increases. Such was the case with the ridge of heat that was expected to head our way later next week. However, looking at the data this afternoon, I was rather perplexed. Suddenly, what was originally one of the warmest day of the 7-Day Outlook looked like it could be one of the coolest. The ensembles swung back toward below normal temperatures! Digging deeper, I found the reason. A buckle in the jet stream became part of the weather picture. When one of those buckles develops near us, we get put under northwest flow - the same pattern we've been in recently. It brings in cooler Canadian air.

The kink will works its way out of here pretty quickly, though. The heat's not gone, it's just delayed. That warm air will eventually spill eastward as our flow becomes more out of the west. How long will it last? That's way too far away to figure out, although it should be noted that, as tropical systems get near the U.S., our weather systems tend to slow down a little. A lot of question marks remain regarding Bertha's future, but we'll have to see how it interacts with our weather down the road a piece.