When you think of heat waves, Portland, Oregon, does not leap to mind. The temperatures there are usually so moderate that a lot of people do not have air conditioning. But this week, Portland temperatures spiked to a high of 108 degrees, the sort of temperature that meteorologists say is a one-in-a-thousand-year event. At least, they hope so.
Climatologist Brian Brettschneider pulled together this data map, which shows you how rare these temperatures are for the Northwest:
(Brian Brettschneider)
And, Brettschneider points out, the usual warmest months are still ahead:
(Brian Brettschneider)
The heat dome over the Northwest, which is a sprawling, intense area of high pressure aloft, causes air to sink, or compress. As it does so, the air temperatures increase. Winds blowing from land to sea around this high are pushing temperatures higher.
Studies have shown that severe heat events such as this one are now on average about 3°F to 5°F hotter than they would be without the many decades of greenhouse gas emissions.
However, climate scientists tell Axios this actually understates climate change’s influence, since warming is also altering weather patterns in ways that makes strong heat domes more common and prolonged.
Daniel Swain, a climate researcher at UCLA, told Axios that the mean warming in the region is “more likely a floor than a ceiling,” given climate change’s potential effects on atmospheric circulation, soil moisture, and other conditions that can amplify extreme heat.
I have been interested to see how many newscasts have opened with stories of severe weather but failed to cover the underlying climate change. It still gets far less coverage, flowing upward around midterms and presidential elections.
Look at this Axios chart:
(Axios)
At the same time, the tropics are doing what they usually do: A couple of tropical waves are cooking.
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