August 9, 2021

Extreme Heat Will Roast The U.S. From Coast To Coast This Week

Summer has no plans on letting up anytime soon. A double-barreled heat wave will set up over the United States this week, bringing another round of searing heat from the Pacific coast to the Atlantic seaboard. Widespread highs in the 100s are likely across the west, while folks back east deal with a dangerous spell of heat and humidity.

The Setup

This is our...what, sixth?...major heat wave so far this summer. The setup is pretty much the same as the others, with the added flair of two ridges instead of just one.
Source: Tropical Tidbits

A strong upper-level ridge will develop over the eastern Pacific at the same time a center of high pressure strengthens over or just off the coast of the southeastern United States.

Ridges aloft foster sinking air. Air dries out and warms up as it descends. The sinking air and bright sunshine can send temperatures soaring, and local wind patterns—related to terrain in the west, and humid southerly winds once you're east of the Rockies—can exacerbate the heat. 

The Context

It's been a rough summer. Dozens of communities in Washington and Oregon broke their all-time heat records with an unprecedented heat wave that roasted the region in late June.

Portland, Oregon's predicted high temperature of 104°F on Thursday would've approached the all-time record high before it fell in late June. The city's previous all-time record high was 107°F until that heat wave broke that record on three consecutive days, topping out at a searing 116°F on June 28th.

We're not going to see temperatures nearly that hot this time around, but it's going to be a dangerous stretch of heat that'll be rough on anyone who lives with health issues or doesn't have reliable access to air conditioning.

There's also the issue of wildfires.

This summer's string of heat waves out west allowed wildfires to flourish long before traditional wildfire season begins. We've witnessed the effects of these fires in just about every corner of the U.S. and Canada over the past couple of months as wildfire smoke choked cities like Denver and New York.

California's ongoing Dixie Fire is now the second-largest wildfire on record in the state. The impending heat wave will lead to another stretch of favorable conditions for wildfires to spark and grow.

The Temperatures

It's tough to rattle off all the cities that are at risk of dangerously high heat and humidity this week. Take a look at these high temperature forecasts from the National Weather Service.

Tuesday, August 10:

Wednesday, August 11:

Thursday, August 12:

Friday, August 13:

Saturday, August 14:

It's a widespread, coast-to-coast affair for everyone except for the highest elevations in the Rockies and some spots in the Upper Midwest that'll feel the effects of an upper-level low traversing the Canadian Prairies.

The Risks

This kind of hot weather is dangerous for vulnerable people and those who don't have access to air conditioning.

Source: CDC

Much of the Pacific Northwest is under an extreme heat warning for the duration of the heat wave. Hundreds (if not thousands) of people died in Washington, Oregon, and British Columbia during the major heat event in late June.

Heat advisories are beginning to paint the U.S. east of the Rockies, as well, as the heat will be accompanied by stifling humidity.

Humidity makes high heat even worse because it precludes our ability to cool off effectively. Our bodies sweat to take advantage of evaporative cooling. Sweat is slow to evaporate when the air is humid, which can cause our bodies to overheat. This can easily lead to life-threatening heat-related illnesses.

If you know any elderly folks who live alone or those who live with health issues that make them vulnerable to the heat, check in on them throughout the heat wave and make sure they're doing okay. If you don't have access to air conditioning, try to go somewhere cool if you can. Limit the amount of time you spend outdoors. Even a healthy, physically fit person can develop heat exhaustion or heat stroke in this kind of weather.

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I graduated from the University of South Alabama in 2014 with a degree in political science and a minor in meteorology. I contribute to The Weather Network as a digital writer, and I've written for Forbes, the Washington Post's Capital Weather Gang, Popular Science, Mental Floss, and Gawker's The Vane. My latest book, The Skies Above, is now available. My first book, The Extreme Weather Survival Manual, arrived in October 2015.