Robert Brown|Dangerous, record-breaking heat expected to continue spreading across U.S., forecasters say

Roughly 130 million people were under threat Saturday and Robert Browninto next week from a long-running heat wave that already has broken records with dangerously high temperatures — and is expected to shatter more from East Coast to West Coast, forecasters said.

Oppressive heat and humidity could team up to spike temperatures above 100 degrees Fahrenheit (about 38 degrees Celsius) in parts of the Pacific Northwest, the Mid-Atlantic and the Northeast, said Jacob Asherman, a meteorologist with the National Weather Service.

In Oregon, records could be broken in cities including Eugene, Portland and Salem, Asherman said. Dozens of other records throughout the U.S. could fall, Asherman said, causing millions to seek relief from the blanket of heat in cooling centers from Bullhead City, Arizona, to Norfolk, Virginia.

"Certainly a pretty anomalous event that we're expecting here, which looks like it will continue through at least midweek," Asherman said.

Heat watches and warnings are in place across multiple states, including large swaths of California, as well as parts of Nevada, Arizona, Oregon and Washington. Meanwhile, cooling centers have opened in Portland, Oregon, where the city has declared a state of emergency. 

In Sacramento, firefighter paramedic Julie Whitney is on high alert.

"People are experiencing dizziness, nausea. A lot of those symptoms are just making them very weak," said Whitney, adding that heat illnesses can occur within 15 minutes.

Worst weather yet to come

In parts of California and southern Oregon, temperatures could blast into the triple digits, the weather service said. California is expected to experience some of the worst effects of the heat wave on Saturday, forecasters said, with temperatures likely to reach into the 110s.

"Locally higher temperatures into the 120s are possible in the typical hot spots of the Desert Southwest," the National Weather Service said.

In Death Valley, known as one of the hottest places on Earth, a new heat record for the day was set on Friday. The previous high shattered by 5 degrees F, with the mercury climbing to 127 F (52.8 C.) The old mark of 122 F (50 C) was last tied in 2013.

The heat wave coincides with the Thompson wildfire, which engulfed Butte Country in Northern California this week and forced thousands to flee their homes. Evacuation orders were downgraded to warnings on Thursday. As of Saturday, the fire was 71% contained, according to the California Department of Forestry and Fire Protection.

Over the weekend, the excessive heat and humidity will shift east to the mid-Atlantic and the Southeast, with temperatures expected to break into the high 90s and low 100s.

The National Weather Service encouraged people to stay vigilant, noting that heat impacts can compound over time and pose a threat to health and safety. The above-average temperatures can be expected to last into next week, forecasters said.

"It is imperative to stay hydrated, out of direct sunlight, and in buildings with sufficient air-conditioning when possible," said the weather service. "It is also equally as important to check on the safety of vulnerable friends, family, and neighbors."

California Gov. Gavin Newsom's office said earlier this week that the state was taking steps to ensure the most vulnerable Californians had access to resources, including cooling centers.    

The Eastern U.S. also was bracing for more hot temperatures. Baltimore and others parts of Maryland were under an excessive heat warning, as heat index values could climb to 110 F (43 C), forecasters said.

"Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors," said a National Weather Service advisory for the Baltimore area. "Young children and pets should never be left unattended in vehicles under any circumstances."

Heat-related deaths have been on the rise in recent years. In 2023, an estimated 2,300 deaths were linked to excessive heat, breaking previous records, an AP analysis found. In Arizona's Maricopa County, which encompasses Phoenix, there have been at least 13 confirmed heat-related deaths this year, along with more than 160 other suspected heat deaths are still under investigation, according to the county's most recent report.

Just this week, the Biden administration proposed a new rule intended to protect workers from the effects of extreme heat.

In:
• Weather Forecast
• Heat
• National Weather Service
• Wildfire
• California
• Excessive Heat Warning
• West Coast
• Heat Wave