Soaring Temps in Pacific Northwest Shattered Records

http://www.climatecentral.org/news/record-temps-pacific-northwest-19179

By Andrea Thompson
July 1, 2015

Scorching temperatures above 110°F are more often associated with the stark landscapes of places like Death Valley than the cooler reaches of the Pacific Northwest. But a suped-up heat wave has left parts of Washington feeling much more like the desert Southwest and has shattered longstanding high temperature records in many spots.

The searing heat even broke the all-time state temperature record for the month of June, with two locations — Chief Joseph Dam and Walla Walla — both hitting 113°F on Sunday, when the event peaked, according to the National Weather Service office in Spokane.

While the skyrocketing temperatures are a marker of a particularly strong area of high pressure, such record-breaking temperatures are more likely to happen in a warming world. Summer temperatures have already increased across the U.S. in recent decades; in the Pacific Northwest they have risen by almost 0.5°F per decade since 1970.
[High pressure areas happen occasionally. They might cause higher than usual temperatures, but the fact that these are record highs is what is notable. We are not seeing nearly as many record low temperatures, which would be expected if this were just due to normal variation.]

•••••

Though these searing temperatures were the result of a weather event that can naturally happen, summer temperatures in the Pacific Northwest have followed the same upward trend as most of the rest of the U.S. and the world as a whole over recent decades. These rising temperatures are fueled by the buildup of heat-trapping greenhouse gases in the atmosphere that has intensified over this same period.

In the U.S., the biggest increases in summer temperatures have been in the Southwest, where they have risen by more than 3.5°F since 1970. The Pacific Northwest has also seen substantial increases in average summer temperatures, which have gone up as much as 2.6°F over that same time.

•••••

Warming temperatures in the region are a major concern for water resources, as eastern Washington depends on its winter snowpack to supply reservoirs and streams come the warmer summer months. Exceptionally warm temperatures this past winter led to dismally low snowfall which has led to a widespread drought and amped up concerns over the wildfire season.

•••••