Building western US heat dome may set records, cause wildfires to surge

As cooler air sprawls in the eastern United States, heat will throttle up in the zone from west of the Rockies to east of the Interstate 5 corridor in the week ahead. The heat and winds will spur new wildfires.

The heat dome that roasted and sweltered more than 100 million people on a daily basis during July in the eastern United States has broken down. However, a new heat dome is already building in the western half of the nation and may not only bring the highest temperatures of the summer, but could also boost wildfire potential and dangerous erratic wildfire behavior in part of the region, AccuWeather meteorologists warn.

In the week ahead, high pressure will build at most levels of the atmosphere over the interior Southwest. When this happens, the sinking air not only tends to make it difficult to rain, but the atmosphere tends to heat up a bit more day after day as the ground dries out even more.

Temperatures will well exceed 100 degrees Fahrenheit over much of the desert region for the first full week of August with a number of locations, such as Phoenix, Las Vegas and Palm Springs, California, topping 110 degrees for multiple days. Temperatures will be far less extreme along the Interstate 5 corridor compared to farther inland in the week ahead.

While it may seem fitting for the time of the year, temperatures will challenge daily record highs in multiple locations as the heat wave peaks from mid-to-late week. Temperatures will come within a few degrees of summer highs with the latest heat dome. A similar, but more brief setup in mid-June set the high-temperature mark for the year so far in many areas.

People are urged to avoid strenuous activity during the midday and afternoon hours when the sun and heat are most intense. Proper hydration is essential, and experts advise people to avoid excessive alcohol and caffeine consumption, which can expedite dehydration.

Drought, fire danger to worsen

While storms will frequent the zone from Montana and the Dakotas to northern Texas into much of the week ahead, thunderstorms will be hard to come by west of the Rockies and south of Idaho.

“Recent heat and dry conditions have led to worsening drought across the southwestern U.S.," AccuWeather Meteorologist Alex Duffus said. "This alone has helped set the stage for some large fires in the region already this summer."

On Thursday, Utah Gov. Spencer Cox issued a state of emergency in response to escalating wildfires across the state. The situation is about to get much worse, given the anticipated heat buildup and another factor this week.

"A slow-moving storm at the level in the atmosphere where jets cruise at will crawl across the Northwest states through midweek," Duffus said. "This storm will lead to periods of gusty winds, paired with low relative humidity, which will boost the risk of multiple and fast-moving wildfires from the Great Basin to parts of the Northwest through at least the first half of the week."

As of early August 2025, there have been 40,945 wildfires in the U.S., burning a total of 3,253,963 acres according to the National Interagency Fire Center. This is a significant increase compared to the same period in 2024, when 21,970 fires occurred.

A fire that erupted on Arizona's Grand Canyon north rim around July 4 continues to burn. The fire has burned well over 110,000 acres, and crews continue to struggle with containment this weekend.

Given the upcoming weather pattern in the days ahead, the number of fires and acres burned will likely increase substantially over the interior western U.S.

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