SALT LAKE CITY (AP) — Things are about to heat up in much of the U.S. with dangerously hot temperatures in the Midwest and Northeast next week, prompting health officials to urge people to make plans now to stay safe.

The heat wave follows an earlier-than-usual one in the Southwest last week, which saw triple-digit temperatures in cities like Phoenix, where there were 645 heat-related deaths last year.

Last year the U.S. had the most heat waves — abnormally hot weather lasting more than two days — since 1936. In the South and Southwest, last year was the worst on record, according to the National Oceanic and Atmospheric Administration.

The next heat wave will ramp up Sunday in the center of the country before spreading eastward, the National Weather Service said, with some areas likely to see extreme heat in reaching daily records. The heat wave could last all week and into the weekend in many places.

Here are some things to know:

What areas will see extreme heat?

There will be areas of extreme heat — when there’s little or no overnight relief — from eastern Kansas to Maine, according to a National Weather Service heat risk map. Heat will build over the Plains states on Sunday, where there will be extreme heat by Monday that spreads eastward into the Great Lakes states and Northeast.

Temperatures will be in the mid- to high-90s in many areas and likely will be at daily records in the Ohio Valley and Northeast, with the dew point making some areas feel as hot as 105 degrees Fahrenheit (41 degrees Celsius), the weather service said.

It’ll be the Detroit metro area’s worst heat wave in 20 years or more, with temperatures forecasted in the mid-90s and heat indices around 100 F (38 C) starting Monday and potentially lasting into the weekend, National Weather Service meteorologist Steven Freitag said. There’s a chance the area could see its first 100-degree day since July 2012.

Although nighttime temperatures will dip into the 70s, providing some relief, the duration of the heat can have a cumulative and potentially dangerous effect on the body, Freitag said.

What are the dangers of extreme heat?

Heat-related illness can be deadly if not recognized and treated early, and often starts with muscle cramps or spasms, experts say. Heat exhaustion and heat stroke could follow.

Young children and infants, pregnant women, the elderly and people with chronic medical conditions are especially vulnerable, as are those who can’t get around well or who live alone.

Symptoms of heat exhaustion may include heavy sweating and fatigue; a weak pulse; skin that’s cool, pale or clammy; and headache, dizziness, nausea and fainting. The person should be moved to an air-conditioned space and offered sips of water. Loosen their clothing and apply cool, wet cloths or put them in a cool bath. Seek medical help if they vomit.

A person suffering heat stroke may experience headache, confusion, nausea, dizziness and a body temperature above 103 F (39.4 C). They also may have hot, red dry or damp skin; rapid pulse and faint or lose consciousness. The CDC advises people to call 911 immediately and, while waiting for help, use cool cloths or a cool bath and move them to an air-conditioned space, but do not give them anything to drink.

How can you stay safe?

Stay indoors in an air-conditioned space and limit outdoor activities, experts said. If you don’t have air conditioning, find out if your community will open cooling centers. But even those with air conditioning should plan ahead in the event of a power outage, said Freitag, from the National Weather Service. Limit outdoor activities to the morning or, better yet, don’t go outside, he said.

Other tips from the Centers for Disease Control and Prevention:

1. Drink plenty of water and take a cool shower or bath.

2. Wear lightweight, loose-fitting clothing, and use your stove and oven less.

3. Check on friends and relatives, especially those without air conditioning.

Communities also can prepare by opening cooling centers in places like schools and libraries. Some also send text messages to residents or have hotlines that people can call for help.

In Franklin County, Ohio, the office on aging is distributing fans to residents 60 and older, spokeswoman Kristin Howard said.

And some businesses whose employees work outside say they will start earlier to avoid the worst heat.

“When you get this sort of heat, any outdoor activities has to be a short duration (preferably) … in the early morning hours,” said Freitag. “But otherwise, there really shouldn’t be any outdoor activity with physical exertion during the peak of the day.”

WASHINGTON (AP) — The Supreme Court on Thursday made it harder for the federal government to win court orders when it suspects a company of interfering in unionization campaigns in a case that stemmed from a labor dispute with Starbucks.

The justices tightened the standards for when a federal court should issue an order to protect the jobs of workers during a union organizing campaign.

The court unanimously rejected a rule that some courts had applied to orders sought by the National Labor Relations Board in favor of a higher threshold, sought by Starbucks, that must be met in most other fights over court orders, or injunctions.

The NLRB had argued that the National Labor Relations Act, the law that governs the agency, has for more than 75 years allowed courts to grant temporary injunctions if they find requests “just and proper.” The agency said the law doesn’t require it to prove other factors and was intended to limit the role of the courts.

Following the decision, Starbucks said, “Consistent federal standards are important in ensuring that employees know their rights and consistent labor practices are upheld no matter where in the country they work and live.”

But Lynne Fox, president of the union representing the workers, said Starbucks should have dropped the case as part of its more conciliatory attitude toward union organizing efforts. “Working people have so few tools to protect and defend themselves when their employers break the law. That makes today’s ruling by the Supreme Court particularly egregious,” said Fox, president of Workers United.

The case began in February 2022, when Starbucks fired seven workers who were trying to unionize their Tennessee store. The NLRB obtained a court order forcing the company to rehire the workers while the case wound its way through the agency’s administrative proceedings. Such proceedings can take up to two years.

A district court judge agreed with the NLRB and issued a temporary injunction ordering Starbucks to rehire the workers in August 2022. After the 6th U.S. Circuit Court of Appeals upheld that ruling, Starbucks appealed to the Supreme Court.

Five of the seven workers are still employed at the Memphis store, while the other two remain involved with the organizing effort, according to Workers United, the union organizing Starbucks workers. The Memphis store voted to unionize in June 2022.

As as the case proceeded, animosity between Workers United and Starbucks began to fade. The two sides announced in February that they would restart talks with the aim of reaching contract agreements this year, and they held their first bargaining session in nearly a year in late April.

Workers at 437 company-owned U.S. Starbucks stores have voted to unionize since late 2021, according to the NLRB, but none of those stores has secured a labor agreement with Starbucks.

Starbucks said it’s pursuing its goal reaching ratified contracts for those stores this year.