Another brutal heat dome will begin to toast parts of the United States starting this weekend as a result of a major change in weather patterns.
The East Coast has been in the spotlight this past week, and the West will see a heat dome, a large area of high pressure that settles over an area, trapping heat and raising temperatures.
In the hottest month of the year, high temperatures are expected to rise 10 to 15 degrees higher than normal, reaching triple digits in some places. The renewed heat wave could also raise concerns about wildfires.
The heaviest heat will be concentrated in the Rockies, where some daily records are likely to be set or broken, and several places could be within a few degrees of all-time high temperature records.
Dangerous extreme heat could also move into the central US early next week as the heat dome expands, but it will take several days for confidence in the forecast to increase.
Heat has long been the deadliest weather in the United States, but the threat is growing. Heat waves are now longer lasting, more intense, and more frequently caused by emissions from burning fossil fuels.
A quick study found that the combination of extreme heat and high humidity seen in the East Coast heat dome last week would not have been possible if not for greenhouse gas emissions.
Here’s what we know.
In anticipation of the model change, the rest Much of the West will experience a seasonally hot week this week. Temperatures will begin to rise to more uncomfortable levels on Friday as a large area of high pressure develops. As the heat dome strengthens, it will also move the jet stream—the river of air that determines where stormy weather will develop—from the United States into southern Canada.
Widespread high temperatures of 90 to 100 degrees Fahrenheit are likely on Saturday from the Rockies to eastern Oregon and parts of California. Areas along the West Coast will be able to escape the worst of the heat.
The heat will increase further on Sunday, with high temperatures near 105 degrees forecast for parts of Montana, Wyoming and the Dakotas.
In Billings, Montana, temperatures are expected to rise to around 104 degrees on Saturday. Then the city could jeopardize its record high temperature of 108 degrees on Sunday.
Salt Lake City and Grand Junction, Colorado, are in a similar situation. The record temperature in Salt Lake City is 107 degrees, and the city’s high is forecast to be around 104 degrees on Saturday and 105 degrees on Sunday. Highs in Grand Junction of about 104 degrees Saturday and about 106 degrees Sunday kept pace with the city’s record high of 107 degrees.
The heat will increase next week
By Monday, the hot weather will spread further east, reaching the foothills of the Rocky Mountains and much of the Plains.
Monday and Tuesday could be the hottest days of the coming period in the Denver area, where high temperatures could reach triple digits. The city’s record high temperature is 105 degrees.
The heat will likely spread across parts of the Midwest on Tuesday and Wednesday, with the Northern Plains and Rockies remaining hot.
Temperatures are forecast to climb into the 90s next week in Minneapolis, which will be about 10 degrees hotter than normal.
The heat across the western and central US will likely continue into next week, with the heat dome slowly eroding over time.
What the heat dome means for wildfire activity in the West is less clear.
U.S. wildfires have burned more than 3.3 million acres this year, well above average. Much of this fire activity has occurred in the West, with devastating fires occurring in parts of Colorado and Utah in recent weeks.
Normally, such heat would dry out vegetation and make it more susceptible to fire, but the drought-stricken region is already very dry.
Hot, dry conditions are dangerous for fires, but because the heat dome is a large area of high pressure, this upcoming stretch is less likely to experience gusty winds that could fan the flames.
The expanding heat dome could also push moisture into parts of the Rockies next week as winds shift out of the south. This surge of moisture can help lower temperatures, but it can also contribute to the development of thunderstorms and lightning strikes.
We will continue to monitor what this changing pattern may mean for wildfire activity.
CNN’s Andrew Friedman contributed to this story.