Millions of people across the US have had a hot week.

The Southwest, Central Plains, and Midwest have had record breaking temperatures this week. More than 100 million people in the United States have been advised to stay indoors due to the heat.

An 89-year-old man collapsed in his yard while a 39-year-old woman was found dead in her home. The medical examiner's office said they were probable heat deaths. A man died in California's Death Valley National Park after running out of gas and walking through the heat.

Thousands of people were without power. In order to avoid the hottest hours of the day, school districts in Michigan and Pittsburgh switched to half days. In Texas, a broken water line left residents without running water for more than a day.

man watches children play on waterslide
Issac Montelongo watches neighborhood kids play in the water during a heat wave in Dallas, Texas, on June 12, 2022.
Shelby Tauber/Reuters

Approximately 2,000 cattle died from heat stress in Kansas as of Tuesday.

"It's really a combination of the heat and the humidity which causes some of these impacts," Chenard said. Depending on how used to that type of weather these areas are. It might be a little early for some parts of the country.

The cooling process of sweat on people's skin is hampered by humidity. The heat index can be pushed higher by humidity.

people sit in hammocks between tree limbs on river
People relax in hammocks strung between the limbs of a tree on Belle Isle, Virginia, on June 15, 2022.
Steve Helber/PA Photo

On Tuesday, the heat index in Milwaukee hit a new high of109 degrees. The temperature in Las Vegas was recorded at109 degrees. The city of North Platte had a June temperature of108 degrees. The temperature in Phoenix went to 114 degrees. Death Valley was the hottest place with a temperature of 123 degrees.

According to forecasts from the Climate Prediction Center, the heat will likely continue into next week for a lot of the US.

united states heat map one-week outlook shows deep red above average temperatures across central and eastern regions NOAA/National Weather Service Climate Prediction Center

The heat and high temperatures have been impressive for early to mid June.

The Climate Prediction Center has a temperature outlook for the next three months. The entire US is expected to experience above-average heat this summer with the exception of two small pockets in the north.

united states heat map three-month outlook shows orange above average temperatures across the country NOAA/National Weather Service Climate Prediction Center

I don't think we'll see record temperatures every day through the summer. Chenard thinks that the conditions will be favorable to see rounds of well-above-normal temperatures.

As global temperatures rise, heat waves are getting worse. The average heat wave season has increased by 45 days since the 1960s, according to the National Climate Assessment.

A 'heat dome' with tornadoes and thunderstorms around the edges

person throws water bottles in a plastic bin
A volunteer with Dominion Tabernacle Ministries prepares cold water bottles to hand out in Dallas, Texas, on June 12, 2022.
Shelby Tauber/Reuters

The heat dome is a ridge of high pressure in the upper and middle layers of the atmosphere that traps heat. The dome began in the Southwest and then moved to the central and eastern US.

"This bubble of heat that's been over the central part of the country has been going on for a long time," Chenard said.

There was a rare instance of a circulation system threatening to become a tornado over the city. The La Crosse Tribune reported that there were two large tornadoes in central Wisconsin.

Chenard said that storms typically brew around the fringes of heat domes, where they interact with other weather systems.

There are rounds of storms on the edges of the domes. He said that they don't usually have tornadoes.