Late-Season Heat Wave Hits the Northwest

The News

Even as it continues to swelter, the South may get a break from steamy weather this week while the Northwest bakes in some of the highest temperatures people there will endure all summer.

It isn’t unusual to get a day or two of 100-degree heat in places like Portland, Ore., but three days in a row this late in the season is uncommon, said Clinton Rockey, a forecaster with the National Weather Service in Portland.

According to Mr. Rockey, only about 40 percent of the people in northwestern Oregon have air-conditioning, which can be troublesome, especially when the low temperatures at night are expected to also break daily records for heat.

The duration of this heat wave, which began on Sunday, and the high overnight temperatures are also a big concern for Matthew Cullen, a Seattle-based forecaster with the Weather Service who said there have been only a few hot days in his region this summer and no significant stretches of heat like this one, which could last at least until Thursday.

While the heat is dangerous, Mr. Cullen doesn’t expect this to be anything like the heat wave of June 2021.

In the South: Only mild relief.

Looking southward, the heat index in New Orleans is expected to reach dangerous levels again on Monday and Tuesday. But on Wednesday, there might be brief relief from the oppressive heat as the heat index may not reach 100 degrees. (Look up the heat index forecast in your city or town.)

Background: The dog days have only just begun.

This relief will not be confined to Louisiana, as temperatures across much of the South, which felt like a steamy boiler room this past weekend, will dip to more seasonable high temperatures of the 80s and 90s by midweek.

However, temperatures will begin to ramp up again, first in the Central Plains and then in the South, late this week, reminding people in those regions that summer isn’t over yet and the dog days have just begun.

In the Northwest, it looks as if things might settle down on Friday, but there are a few factors, like a tropical development near Mexico, that could have an impact on the weather pattern and extend the heat wave.

What’s Next: Wildfire risk in the Northwest.

“The low humidity and heat will continue to maintain tinderbox conditions in the Cascades, where we already have a few big fires,” Mr. Rockey said. Many areas in Oregon haven’t had much rain since May, leading to dry brush and timber that is easy to burn once a fire starts.

Rain may finally return to the area next week, Mr. Rockey said.