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Brutal, Triple-digit Heat Grips The Southwest

The intense, sweltering heat will continue to grip the Southwest this week, which can place additional stress on the energy grid.

The intense, sweltering heat will continue to grip the Southwest this week, which can place additional stress on the energy grid, elevate the threat of wildfires and increase the risk for heat-related illnesses. AccuWeather meteorologists say that the scorching conditions can even spread to parts of the Plains by the following week.

Plants for sale at Texas state organizer Erandi Trevino home and also Verandi Secret Garden plant nursery in Houston, Texas on June 27, 2023. Extreme temperatures have combined with habitual smog in Houston for more than two weeks, and Erandi Trevino feels the hazardous combination in her body. “It burns my face. I feel it in my nostrils,” Trevino says. The heat wave sprawling across the southern United States has lasted since June 14, and the sultry air and humidity make for temperatures that feel like they are higher than 40 degrees C (104 degrees F). (MARK FELIX/AFP /AFP via Getty Images) 

“The source of this upcoming heat is a large, sprawling ridge of high pressure positioned over the Southwest. This will help to keep most showers or storms at bay and allow for sunny skies that will help boost temperatures,” said AccuWeather Meteorologist Andrew Johnson-Levine.

A northward bulge in the jet stream will remain in place across the Southwest for the majority of this week; however, forecasters note that the jet stream can shift farther north across the West by this upcoming weekend and gradually shift eastward over the Plains by the week beginning on July 17. This shift in the upper-level atmospheric pattern indicates that the heat dome in place may build across the Central states as well as the Southeast.

Several records will likely be challenged throughout mid-July across this corner of the country, including metro areas like Phoenix. Daily highs can be at risk throughout the upcoming week in Arizona’s Valley of the Sun, with the peak of the heat this week likely to occur by Thursday. In addition to daily high temperature records being at risk, a separate, long-standing record also stands a chance of being broken.

Observations show that Phoenix has reached the 110-degree mark or higher daily since June 30. AccuWeather forecasters say the area can challenge the existing 18-day record for that temperature mark as July trudges on. The previous record was set almost 50 years ago, in 1974.

In addition to potentially challenging the 110-degree stretch record, daytime high temperatures forecast for Phoenix may even contend with reaching the 120-degree mark.

“Phoenix has only reached the 120-degree Fahrenheit mark three times since records have been kept dating back to 1929. The last time temperatures topped that mark was on July 28, 1995, when a high of 121 was recorded. The all-time record high of 122 was set on June 26, 1990,” said AccuWeather Senior Meteorologist Alex Sosnowski in a highlight.

As long as the dome of high pressure across the Four Corners keeps thunderstorms at bay this week, locations including Phoenix may stand a chance of climbing near or to the 120-degree mark by late week. Currently, the city is forecast to meet or exceed the existing daily max temperature record on more than one occasion later this week, and experts warn that residents are unlikely to get relief from the heat once the sun goes down.

“Aside from daytime temperatures, heat may stick around at night. Summertime temperatures in the desert usually plunge into the 70s or 80s. Later this week, some spots, including Phoenix, may be stuck in the 90s overnight,” said Johnson-Levine.

Elevated overnight temperatures can become an unseen health danger, particularly to those in highly urbanized areas that face the urban heat island effect. Metropolitan areas constructed of a high density of buildings and roadways are often made up of materials that can contain the daytime heat more easily than rural or vegetative landscapes, allowing surfaces such as concrete or asphalt to continue to release heat after the sun goes down.

During a heat wave, residents can still face elevated temperatures during the overnight hours compared to what is typically observed, which can place additional strain on the heart as the body tries to regulate the internal temperature. With overnight low temperatures this week expected to linger in the upper 80s to mid-90s F, residents are urged to take steps to stay cool at night.

Very high cooling demands are expected to persist in the Southwest this week and even into next week as fans and air conditioners are cranked into high gear.

“While the Desert Southwest cities are usually quite hot in July, this week will bring heat that is highly anomalous. In Las Vegas, daytime highs usually hover around 105 degrees in July, with Phoenix a few degrees warmer. As temperatures may surge into the 120s, this will not be typical heat for the region.”

This week, Albuquerque, New Mexico, is forecast to climb to 100 on multiple days, which would be the first time this year reaching the mark. Although, observations indicate they came close on numerous occasions the previous week. Last year, the city reached the 100-degree mark roughly a month earlier, on June 10.

As the heat dome lingers in place across parts of the West this week, chances for any substantial moisture across the Four Corners will be limited. Afternoon thunderstorms will be possible at times this week, but coverage will be rather spotty across Arizona and New Mexico.

Experts warn that although the storms may be rather spotty across the region, they can be mainly dry and still contain lightning. Given the dry conditions and baking heat, the risk of lightning strikes igniting wildfires can become elevated.

Produced in association with AccuWeather

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