June 4, 2024

Extreme heat builds across the western U.S. this week

The atmosphere looked at the calendar this week and decided to turn up the heat.

We're at the beginning of a multi-day stretch of dangerously hot temperatures across the interior West, with temperatures in the triple digits expected for the deserts and California's Central Valley.

Excessive heat warnings are in effect for much of the region.


Image: Tropical Tidbits

A powerful ridge of high pressure building over the western U.S. is responsible for the impressive heat we'll see over the next few days. Air warms up and dries out as it sinks beneath an upper-level ridge, keeping temperatures much hotter than normal beneath the blazing sunshine.

That ridge will put in work this week as temperatures soar from Oregon to Texas.

The National Weather Service has issued excessive heat warnings and heat advisories for much of the region to warn folks of the hazards they'll face through the end of the week.

Daytime highs will climb over 100°F in Sacramento, Las Vegas, and Phoenix on Tuesday, with the worst heat arriving on Wednesday and Thursday.

This is the first widespread test of the NWS's new HeatRisk product, which offers guidance on the impacts of extreme heat across the country.

We'll see major to extreme impacts for many communities affected by the hot temperatures over the next couple of days, with the most widespread impacts likely during the day Wednesday.

Even though nighttime lows will provide some relief from the extreme daytime heat, this is going to be a dangerous spell of hot temperatures for vulnerable people. Fans alone won't be adequate to cool indoor spaces. People will need air conditioning to avoid heat-related illnesses, which can set in quickly when temperatures rise into the 100s.

Extreme heat affects people who are otherwise healthy. It's very easy to get dehydrated in extreme heat, especially out west where humidity is often quite low during major heat events. Sweat evaporates more efficiently when it's dry outside—too dry and too hot and you'll quite literally sweat yourself into dehydration, which can quickly lead to heat exhaustion or heat stroke.

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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.