A punishing heat dome broiling Mexico and portions of the southern United States is expanding to the west and north, teeing up the season’s first major scorcher across the West. The extreme heat is poised to break records and pose a danger to vulnerable groups.
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On Tuesday, the heat dome broke numerous records in Texas as temperatures surpassed 110 degrees. As it swells to the northwest, warnings cover much of California’s Central Valley through Friday, including Redding, Sacramento and Bakersfield.
Heat warnings are also in effect for much of the Desert Southwest, including Tucson, Phoenix, Las Vegas and Palm Springs, Calif. Roughly 35 million people reside in these regions.
Highs of 100 to 110 — some 20 to 30 degrees above normal — are expected in the Central Valley. The Desert Southwest should reach 110 to 115 in many spots, with the hottest locations, such as Death Valley, Calif., topping 120. These temperatures are as high as they get this early in the season and even toasty by midsummer standards.
Numerous records are expected to be set through Friday, both for hot afternoons and abnormally warm nights.
“These extremely hot conditions will affect anyone without effective cooling and/or adequate hydration,” the National Weather Service warned.
Heat records have already fallen in Texas
Brutal heat spread over Texas on Tuesday, with suffocating heat indexes, which are a measure of how hot it feels factoring in humidity. The peak heat indexes ranged from 115 to 125 degrees.
Calendar-day record highs in Texas were set Tuesday in Del Rio (109), San Angelo (111) and Abilene (106). Record-warm nighttime lows were even more numerous, occurring in Houston (82), Corpus Christi (85), Austin (81) and Del Rio (81).
Corpus Christi matched its warmest minimum temperature of any month both Monday and Tuesday, with a low of only 85 degrees.
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As a sign of what’s to come, record warmth had already expanded westward Wednesday morning. Stockton in Northern California topped 100 on Tuesday and dipped to only 69 degrees overnight, its second-warmest low temperature so early in the season.
Potential for dangerous, record-setting heat
The Weather Service’s HeatRisk forecast, which rates the danger to human health on scale of 0 to 4, calls for widespread Level 3 or “major” heat effects covering much of interior California and parts of Arizona, Nevada and Utah through Friday, before easing some.
The potential for record highs reaches as far north as central California on Wednesday. Stockton should rise to near the calendar-day record of 105 from 1978. Desert areas just east of Los Angeles could endure similar heat; Palmdale and Lancaster could set records Wednesday afternoon.
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Las Vegas could see record highs each of the next three days, with temperatures soaring to near or above 110. The city’s heat risk is forecast to reach Level 4 from Thursday through Saturday.
Phoenix is forecast to reach 114 on Thursday, surpassing the calendar-day record by several degrees.
Temperatures in the southeastern deserts of California may rise as high as 115 to 125 degrees at peak. Needles, Calif., on the border with Arizona, has a forecast high of 115 on Thursday, which would be a record.
Death Valley is staring down four days in a row in the 120s. Anticipated highs Wednesday through Saturday are 121, 124, 123 and 120. If the temperature hits 124, that would be the highest so early in the year. By late weekend, highs slip into upper 110s before potentially tickling 120 again next week.
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Even places not known for intense heat will witness it. Record highs in the mid- and upper 90s are possible in Reno and at Mount Shasta, Calif., on Thursday and Friday.
Still hot into next week
The heat should ease somewhat this weekend, as the core of the heat dome shifts toward the Great Basin and Pacific Northwest, where it won’t be as intense. However, temperatures are still predicted to run 10 to 20 degrees above normal in much of the West for at least the next 10 days.
The unrelenting hot, dry weather pattern in Mexico could well become the breeding ground for excessive-heat events spilling into the United States throughout the summer.
Seems bad for Mexico. pic.twitter.com/4BzAbzQno3
— Brian Brettschneider (@Climatologist49) June 5, 2024
Even though California is drought-free, abnormally dry conditions cover much of the Southwest. The lack of moisture will allow heat events to become even more intense, much as they did last summer when Phoenix had a record 31 straight days above 110 degrees.
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Two wet winters in a row in California may not save it from heat and fire risks either; officials are warning of a potentially rough season ahead.
The western heat wave comes as scientists announced that May marked the 12th straight month of record global warmth, moving the planet ever closer to a dangerous climate threshold.
Scientists at the nonprofit organization Climate Central calculated that human-caused climate change is making this heat wave in the West three times as likely.
