Breakdown: Heat Dome - Why Northwest experienced a historic heat wave

Published: Jul. 7, 2021 at 12:05 PM CDT
Email This Link
Share on Pinterest
Share on LinkedIn

MEMPHIS, Tenn. (WMC) - The most extreme heat wave ever recorded in the Pacific Northwest continues to bring sweltering heat to the region. Millions of people are currently under excessive heat warnings — many areas baking under triple-digit temperatures without air conditioning in a region that usually enjoys mild summers.

Behind the misery is a weather phenomenon known as a heat dome.

What is a heat dome? A heat dome occurs when the atmosphere traps hot ocean air like a lid or cap, according to the National Oceanic and Atmospheric Administration (NOAA):

High-pressure circulation in the atmosphere acts like a dome or cap, trapping heat at the...
High-pressure circulation in the atmosphere acts like a dome or cap, trapping heat at the surface and favoring the formation of a heat wave.(NOAA)

All-time high temperature records were broken across Washington and Oregon.

If the triple digits weren’t enough, this type of heat is so rare in that part of the world that many homes and businesses don’t have air conditioning. So imagine suffering through multiple days of triple digit heat without AC! While it is usually a drier heat in that part of the country, 116 degrees is still 116 degrees... it’s hot for even the most seasoned folks in places like Las Vegas and Phoenix. But again, other areas that get this warm have widespread air conditioning.

NWS forecasters in Seattle said Friday they “have never seen Pacific Northwest data like this.”

The unprecedented heat wave has proven to be deadly, is impacting salmon migration, and agriculture. Additionally, it’s fueling wildfires.

Meteorologists from the National Weather Service in Medford, OR say, “Although temperatures aren’t as hot as they were, high temperatures will remain well above normal through the [July 4th] weekend. Heat Advisories remain in effect for most of the area through Saturday (July 3rd) when high temperatures are expected to peak again. Afterwards, temperatures will gradually lower into next week, but will remain 10 degrees above normal through much of next week. Make sure to stay hydrated and avoid strenuous activities during the hottest part of the day. Never leave children or pets in closed vehicles.”

Copyright 2021 WMC. All rights reserved.