Extreme heat wave grips Pacific NW; Seattle and Portland break all-time records

Christmas Day
December 25 2021 12:00 am

An extremely anomalous upper-level ridge is breaking temperature records across a large part of the Pacific Northwest, breaking all time temperature records in places like Seattle, Portland, Kennewick, and Pasco.

Seattle recorded the hottest temperature the city has ever seen since modern records began in 1945, reaching a high temperature of 104 degrees on Sunday. Other places farther South & outside the city were even hotter, with Portland reaching an all time high of 112 degrees, and Pasco, Washington reaching an astounding 115 degrees yesterday.

Unfortunately, this incredible heat wave is expected to continue for at least the next two days. Thankfully for the more populated cities along Interstate 5, the ridge will push ever-so-slightly East, so record highs are not likely tomorrow. The same cannot be said for Eastern Washington & Northeastern Oregon, where highs are expected to crest all the way in the mid 110s — again likely breaking all time records for the area.

On the bright side, by Wednesday, the ridge will begin to broaden out over the region. This means that while temperatures will remain very unusually hot, it won’t be as outlandishly hot as what we’ll see today & tomorrow.

By Friday, while the summer heat sticks around for many, most of the record highs will become less likely as the ridge continues to flatten out and track East.

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.

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.

Infographic from the National Academy of Sciences March 2016 report on Attribution of Extreme Weather Events in the
Context of Climate Change.
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 ghardy@cbs42.com.

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