39-day heat wave could last into August after smashing 2,300-plus records

By Jennifer Gray, CNN meteorologist

(CNN) — As the unrelenting heat wave in the US enters its 39th consecutive day, millions of people from California to Florida are asking: When will it end?

The long-term forecast looks bleak. The extreme heat could continue into August in some of the hardest-hit areas and even a brief glimmer of cooler hope for some parts of the country headed into the weekend will only mean new areas swelter as a heat dome slides west.

The first heat alerts went out on June 10 and more than 2,300 heat records have fallen from Florida to California. That number will only grow as millions of people suffer through dangerous temperatures.

Phoenix hit 110 degrees for a record-breaking 19th consecutive day on Tuesday. The temperature kept climbing to a new daily record of 118 degrees, one of 20 record highs set yesterday. Then it hardly cooled overnight, and on Wednesday morning, the city set a new all-time record for highest low temperature of 97 degrees.

The longevity of this heat wave, combined with the dangerously low overnight temperatures, are taking a toll on human health and infrastructure in Arizona. There have been 12 confirmed heat-related deaths in Phoenix’s Maricopa County in the first week of July, and 55 deaths in the county are suspected to be heat related and are under investigation, according to data from the Maricopa County Department of Public Health.

“The heat is taking a major toll,” Frank LoVecchio, an emergency room doctor at Valleywise Health Medical Center in Phoenix, told CNN. “The hospital has not been this busy with overflow since a few peaks in the COVID pandemic.”

The heat also turned deadly in California on Saturday when Kai Torres Bronson, 24, died in San Diego County’s Anza-Borrego Desert State Park, Brent Pascua, CalFire Captain told CNN.

Bronson and a group of other mountain bikers came to the aid of four hikers who were suffering from heat exhaustion on one of the park’s trails. The hikers were eventually airlifted from the trail and treated for heat illness after two of the bikers rode to the trailhead and called emergency responders for help. Torres Bronson stayed back with the hikers, but he was later found unresponsive on the trail and died.

Heat is the number one killer of all extreme weather, National Weather Service data shows, and as temperatures continue to rise, scientists expect it to make even more people ill.

Historic heat dome to shift later this week

An enormous, relentless stubborn ridge of high pressure has trapped air inside in a “heat dome” resulting in extreme temperatures as the dome parks itself over areas.

The heat will remain until a shift in the weather pattern occurs and either breaks apart the heat dome or moves it out of the country completely. That’s not expected anytime soon.

Instead, the dangerous heat will continue through this week, with more records broken each day.

The Desert Southwest and Texas will continue to see daytime highs in the triple digits this week. High temperatures along the Gulf Coast and mid-South will be in the upper 90s for the rest of the week, with heat indices as high as 120 degrees. Record-breaking warm low temperatures will provide little relief in what’s typically the coolest time of the day.

Only the Southern Plains and Gulf Coast could see some relief in the coming days as the heat dome shifts back to the west and a cold front advances across the area. By the end of the week, numerous cities will at least temporarily get out of the most intense heat.

Little Rock, Arkansas, will go from a high of 99 degrees on Wednesday to a high of 86 degrees on Saturday. Oklahoma City will also go from triple digits Wednesday to the mid-80s on Friday.

But that just means that new areas as far north as Montana could see serious heat starting this weekend. Temperatures in Billings, Montana, will go from a high of 84 degrees on Wednesday to a high of 99 degrees on Saturday.

Extreme heat could last into August

The heat streak will continue next week and potentially into August in the Desert Southwest, Texas and South Florida.

The only hope for the Southwest is that sporadic monsoonal rain will bring some temporary relief, however, the overall temperature pattern will remain hot. Areas that do see any rain could see higher heat indices because of additional moisture and higher humidity coming in from Mexico.

According to the Climate Prediction Center, the greatest chance for above normal temperatures the next two weeks is in the Plains, parts of the South, including South Florida, and the Southwest, meaning temperatures should stay hot, it’s just a matter of how hot it will get.

If that holds true, then the heat wave will be approaching two consecutive months, or more than 50 days, over these same areas.

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CNN’s Eric Zerkel and Laura Studley contributed to this report