Extreme Heat Wave Grills Parts of US, Forecasters Warn the Worst Is Yet to Come

Construction worker Fernando Padilla wipes his face as he works in the heat, in Nashville, Tenn., on June 30, 2023. George Walker IV/AP Photo

An extreme heat wave is grilling the southern United States, bringing scorching temperatures and putting over 100 million Americans under various grades of heat alerts, with forecasters warning that the worst is yet to come.

“The heat is going to be expanding across California, Nevada, Arizona and all the way into west Texas into this weekend, and the core of the strongest heat seems to be setting up for Friday through Monday. So we'll be looking at records,” said Tom Frieders, Warning Coordination Meteorologist with the National Weather Service (NWS) in Phoenix.

Over the past week or so, forecasters have been warning of a long and intense heat wave coming for the U.S. Southwest that could well rank among the most severe in recent history.

So far, NWS has issued excessive heat advisories, watches, and warnings for areas in which around 100 million Americans live.

A sign warns people of extreme heat in Death Valley National Park, Calif., on July 11, 2023. Ty ONeil/AP Photo

The sweltering heat comes at the tail end of a week that hit an average global record high temperature, according to the University of Maine’s Climate Reanalyzer project.

The focal point of the blistering heat in the United States is expected to fall mostly in Arizona, California, and New Mexico, as well as parts of Texas, with peak intensity expected on Saturday, according to NWS regional offices.

The Southwest is bracing for what could be deadly heat, with much of the region under an excessive heat warning.

‘Extreme Heat’ in Arizona

In Phoenix, there have been nearly 14 consecutive 110-plus-degree days, with forecasts predicting that the city will break its record of 18 straight days over 110, which was set all the way back in 1974.

Forecasters at NWS Phoenix said in an advisory that the long-duration heatwave is expected to persist through early next week, with the heat risk level rising to “major” and “extreme” levels on Friday and into the weekend.

“Forecast highs for today through Sunday are generally in a 111-118 degree range across the lower deserts with temperatures likely peaking on Saturday when dew points are at their lowest,” NWS Phoenix said in a forecast discussion.

Even though models updated on July 14 are predicting temperatures in Arizona to slowly decrease early next week, NWS Phoenix forecasters say that residents won’t likely feel much relief because of increasing moisture and “so in reality how hot it actually feels like may not be any different than over the weekend.”

A lone motorcycle rider travels on historic Route 66 across the western Arizona desert on the approach to Oatman, Ariz., on July 12, 2003. Robyn Beck/AFP/Getty Images

Near record heat continued across Arizona on Friday, with an excessive heat warning in effect across the lower deserts.

“Please limit outdoor activities due to the extreme heat,” NWS Phoenix said in a statement on Twitter, urging residents to drink plenty of water, apply sunscreen, take regular breaks in the shade, and wear lightweight, loose-fitting clothing to mitigate the effect of the scorching heat.

Parts of California ‘Dangerously Hot’

In California, inland temperature forecasts predict readings of 110 degrees or more in some locations on Saturday, with some areas showing a 90-plus percent chance of breaking daily records.

Over 50 percent of California’s population is currently under a heat advisory or excessive heat warning.

The long-duration heat wave will impact interior areas through Monday, spreading into the valleys closer to the coast on Friday, NWS Los Angeles said in an advisory.

“Highs will peak between 100 to 110 degrees, and possibly higher,” the agency said, adding that the most intense heat is expected over the LA County interior.

Saturday “still looks to be the warmest day in most areas,” NWS Los Angeles said in a forecast discussion.

Heat warnings and advisories blanket all non-coastal areas in California.

There is a possibility of a “little cooling” in coastal areas on Saturday and so NWS Los Angeles is keeping a heat advisory there rather than a full warning.

“Though cooler, the temperatures will still be dangerously hot,” the forecast said.

The San Antonio Fire spreads uphill west of Petaluma, Calif., on June 30, 2023. Kent Porter/The Press Democrat via AP

Excessive heat warnings are in effect in inland parts of the Bay Area and the Central Coast, where hot conditions could cause life-threatening impacts, according to NWS San Francisco.

“There is a high to very high risk for much of the population due to long-duration heat with little to no overnight relief,” the agency said.

“Prepare for dangerous heat, limit outdoor activities,” it added.

The warmest inland locations are expected to be East Bay hills and valleys, southern Santa Clara Valley, northern Napa and Sonoma Counties, and inland Monterey and southern San Benito Counties, NWS San Francisco said in a forecast discussion.

“The peak of the heat event arrives this weekend. This is when the combination of hot days and warm nights allows the HeatRisk to reach the moderate to high range for inland areas,” the agency said.

‘Numerous Daily Record Highs’ in New Mexico

New Mexico is bracing for scorching temperatures across much of the state, while another round of strong to severe storms is expected across northeast New Mexico, NWS forecasters said.

“Record to near-record heat will continue with most lower terrain areas at or above 100 today,” NWS Albuquerque said in a discussion note on Friday.

A backdoor cold front will move across the eastern part of the state later on Friday, however, which is likely to bring with it cooler temperatures that are closer to the norm for mid-July.

“More Heat Advisories are expected today along the middle to lower Rio Grande Valley, as well as in Chaves and San Juan Counties,” NWS Albuquerque said in an alert on social media. “Be sure to limit your time spent outside and stay hydrated!”

Val Martin and Ashford Joseph rehydrate after climbing stairs in Eleanor Tinsley Park as temperatures hit 100 degrees Fahrenheit in Houston, Texas, on July 12, 2023. Adrees Latif/Reuters

‘Dangerous Heat Continues’ in Texas

All of south-central Texas will be under a heat advisory or excessive heat warning through 9 p.m. on Friday, according to NWS Austin.

“There is an increased risk for heat-related illness for those spending extended time outdoors and not taking precautions,” the agency warned.

Hot and dry conditions are expected across all of north and central Texas through next week, according to NWS Dallas.

Increased cloud cover should provide some relief on Sunday, however, the agency said in a forecast discussion.

“High temperatures on Sunday should be closer to seasonal normals across North Texas due to the increased cloud cover with highs in the upper 90s, but Central Texas will still be hot with highs in the 100-104 degree range,” the agency said.

It comes as the Earth’s average temperature set a new unofficial record high last week, according to data compiled by the University of Maine’s Climate Reanalyzer project.

Last Thursday’s planetary average exceeded the 62.9-degree mark set Tuesday and matched on Wednesday.

“It is certainly plausible that the past couple days and past week were the warmest days globally in 120,000 years,” University of Pennsylvania scientist Michael Mann told The Associated Press.

High land temperatures have generally been matched by those on the sea, with warming intensified by an El Nino event, a natural cycle that adds more heat to the Earth’s system.

Warmer seas could also mean less wind and rain, leading to even more heat on land, some scientists say.

In order to cope with higher temperatures, NWS recommends drinking plenty of water, wearing light clothing, finding air conditioned places, avoiding strenuous activities, never leaving people or pets in cars, and watching for heat cramps, exhaustion, and stroke.