70-degree days in July really unusual

Chris Oaks spoke with WTOL StormTrack meteorologist Chris Vickers.
Q: I’ve heard this week’s unseasonably cool spell described as a “polar vortex in July,” but is that an accurate description?
A: It’s funny how people latch on to a term sometimes. We call this a highly-amplified jet stream pattern. A big ridge extends over the West Coast and a large trough of high pressure drops down into the Great Lakes region, and that trough means cooler weather.
Q: So it’s somewhat similar to the conditions that brought us the extreme cold last winter.
A: It is similar in terms of the atmospheric setup. And it is fairly rare to see in the summer. But, we did have a couple of days last July that were right around 70 degrees. You may remember that 2009 was said to be “the summer without a summer.” Overall, though, we’ve only had five July days that cool since 1997. So you can see how unusual it really is.
Q: So is this some type of carryover from what we had this past winter? Are the two related at all?
A: They are not related whatsoever. That said, the atmosphere is cyclical, offering similar or repeating patterns fairly regularly. So it’s not out of the question to see a pattern we had in any given winter season repeat itself in the summer. But if you’re wondering if it signals some sort of larger trend, then, no, there’s no direct connection in that respect.
Q: Ironically, at the same time we were enjoying the cool weather, the Pacific Northwest has been enduring record heat.
A: You expect mild conditions in that part of the country this time of year, but this is the other side of the same coin. It’s like a teeter-totter on the playground, and when we have one extreme at our side, it’s the West Coast that sees the other extreme. The big ridge over the Pacific that I mentioned is drawing up extreme heat from the south and bringing temperatures even into the triple-digits as far north as Washington state.
Q: And this break in the heat and humidity will be short-lived?
A: This pattern has been slowly breaking down, allowing more warm weather to move in, as compared to earlier in the week. As the jet stream moderates, it will bring those temperatures back into the upper 80s. It will also provide a little extra moisture in the atmosphere, meaning an increase in humidity and an increasing potential for storms. Rain at this point will be welcomed, but it doesn’t look like we’re going to completely escape the dog days.
“Good Mornings!” with Chris Oaks airs from 6 a.m. to 9 a.m. weekdays on WFIN, 1330 kHz. He can be reached by email at chrisoaks@wfin.com, or at 419-422-4545.


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