Second Extreme Heat Wave of June Coming This Weekend to the Pacific NW


Another high-amplitude upper-level ridge will develop this weekend over the US West Coast–for the second time this month. This time around, extreme heat will develop farther North in places like Washington, Oregon, & Idaho. Record-breaking high temperatures in the 100s to 110s are expected most of this weekend & early next week…

An Excessive Heat Watch is currently in effect until next Tuesday evening for a large chunk of Washington & Oregon, and also includes portions of Northern Idaho & Northern California. This includes some of the regions largest cities like Seattle, Spokane, Yakima, Portland, and Eugene.

Below are the forecast temperatures during the hottest part of the day this weekend. Many places will crest the 100° mark starting Saturday afternoon, then potentially heat up as high as the 110s Sunday afternoon. Temperatures this hot could potentially break all-time records for the region…

This extreme heatwave will be prolonged into next week, as the upper-level ridge remains nearly stationary through next Tuesday & Wednesday. By that time, the axis of greatest excessive heat will like shift East ever-so-slightly East towards the Eastern part of Washington & into Idaho, but the heat will barely ease off for places affected this weekend as temps stay in the 100s & possibly 110s early next week.

Such an event like this often raises a very valid question: Is this happening because of climate change?

SHORT ANSWER: In large part, yes.

LONG ANSWER: All different types of extreme weather events, i.e. hurricanes, tornadoes, extreme heat, winter storms, etc. are affected by the long-term anthropogenic warming of our oceans & our atmosphere. Each of them, however, are affected by this warming by different orders of magnitude. A majority of scientific studies have found that severe thunderstorms & tornadoes, for example, to be the least correlated to that warming trend. In other words, severe thunderstorm frequency & intensity, generally speaking, is not affected to a significant degree by anthropogenic climate change.

Infographic from the National Academy of Sciences March 2016 report on Attribution of Extreme Weather Events in the
Context of Climate Change.
Graph showing Annual Strong to Violent Tornadoes from 1954 to 2014, with no statistically significant trend upward or downward during that time.
Source: National Climatic Data Center (NCDC)

Those same studies have found that extreme heat, however, is the most correlated to long-term global warming. In other words, the #1 way climate change manifests itself through extreme weather is via extreme heat waves generated by prolonged upper-level ridging. Below is a graph from the National Climatic Data Center, showing a clear increasing trend in “Much Above Normal” high temperatures across the Contiguous US, with a simultaneous decreasing trend in “Much Below Normal” high temperatures, especially within the past 10 years.

Source: National Climatic Data Center (NCDC)

For more information on climate change-related weather extremes, be sure to check out the National Climatic Data Center’s webpage on the “Climate Extremes Index”, or CEI for short. Link below.

That’s all for now…stay in touch with me on social media! You can always find the latest on our forecast in Central AL on Twitter by following me, @GriffinHardyWX. You can always reach out to me with forecast questions anytime by sending an e-mail to

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