A punishing heat dome will only worsen. Here’s when temperatures could peak | CNN (2024)


A brutal heat dome is ramping up and sending temperatures to dangerous levels in California and the West in what is the region’s first significant heat wave of the year.

And heat hasn’t peaked yet. July-like high temperatures will top out at 20 to 25 degrees above normal in multiple Western states this week and could break several daily record high temperatures. Thursday will be the hottest day of the week for millions of people.

The temperatures will be dangerous for those exposed to the elements and unable to cool off. Relief from the heat won’t be found at night, either – another symptom of a world warming due to fossil fuel pollution.

The extreme heat already turned deadly over the weekend with worse to come.

Excessive heat warnings are in effect for nearly 19 million people in California, Nevada, Arizona and Utah and South Texas. The warnings are the most extreme form of heat alert issued by the National Weather Service and are used when widespread, dangerous heat is expected.

The soaring temperatures are being caused by aheat dome, a large area of high pressure that parks over an area, traps air and heats it with abundant sunshine for days or weeks. The resulting heat becomes more intense the longer a heat dome lasts.

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The intense heat began Tuesday in parts of California and the West. Sacramento, California, hit triple digits for the first time this year while Las Vegas ended up just a degree shy of its hottest temperature of the year so far. Numerous daily records were also broken in Texas.

Temperatures will soar higher on Wednesday across a larger portion of the Southwest. The most extreme heat will avoid major population centers along the coast, but Los Angeles will still be 5 to 10 degrees warmer than normal this week.

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Triple-digit temperatures will become widespread in California’s Central Valley Wednesday and stick around into the weekend. Conditions will also sizzle in Southern California’s desert regions.

Death Valley, the hottest place in the world, will likely reach a high temperature of at least 120 degrees by Thursday. Even the brutal desert landscape doesn’t typically get this hot until mid-to-late June.

Phoenix will likely hit 110 degrees for the first time this year by Thursday, even though the city doesn’t typically encounter these temperatures until mid-June. High temperatures are forecast to climb into the low 110s in Las Vegas, likely tying this year with 2010 for the earliest such reading on record in the city.

Summerlike heat will also send daily high temperature records tumbling. Phoenix; Las Vegas; Flagstaff, Arizona; Reno, Nevada; and Fresno, California, are just a handful of cities where the day’s high temperature record could fall on one or more days this week.

By Friday, records could be broken in parts of Oregon, Washington, Idaho and Colorado as heat expands north and east.

Deadly heat on the US-Mexico border

Dangerous heat isn’t new for the far southern US. Brutal heat in Mexico crept north into southern Texas earlier this spring and has been unrelenting for weeks. Several cities along the Texas-Mexico border experienced their hottest May on record.

Read more about extreme heat

  • A heat dome, explained
  • How to stay healthy during a heat wave
  • What happens to your body during extreme heat
  • How to sleep during a heat wave
  • How to pick the coolest clothing for a heat wave
  • Why nighttime heat can be so dangerous

    The triple digit temperatures at the border proved deadly last weekend after US Border Patrol agents said four migrants died “from heat stroke and dehydration.”

    The deaths were part of “several emergencies” involving heat-related illnesses last weekend, according to the US Border Patrol, El Paso Sector. The sector includes portions of southeastern New Mexico and western Texas.

    Heat is the deadliest weather threat in the US. It kills more than twice as many people each year as hurricanes and tornadoes combined, according to the National Weather Service.

    High temperatures in the area were about 5 degrees above normal from last Friday through Sunday, but are likely to climb to 10 degrees above normal Thursday and Friday.

    Note: The CNN Original Series “Violent Earth with Liev Schreiberexplores harrowingweatherevents such as wildfires that are increasingly frequent in our changingclimate. It airs on Sundays at 9pm ET/PT.

    A punishing heat dome will only worsen. Here’s when temperatures could peak | CNN (2024)


    How long do heat domes last? ›

    How long does a heat dome last? It can last for several days to a few weeks. In some cases, a heat dome can carry on for two weeks or more.

    What causes a heat dome? ›

    When a high-pressure system develops in the upper atmosphere, it causes the air below it to sink and compress. That raises temperatures in the lower atmosphere. Because hot air expands, it creates a bulging dome.

    How does climate change affect heat domes? ›

    The study, published this week in Communications Earth and Environment, found the heat dome was 34 per cent larger and lasted 59 per cent longer, or 27 more days, than a heat wave would have without the effects of global heating caused by humans.

    Where is the heat dome? ›

    The heat dome will affect a broad swath of the eastern half of the country, from roughly the Great Plains states up through Maine. Some locations could see their hottest temperatures on record for any month, Masters said.

    What are the symptoms of a heat dome? ›

    Once heat exhaustion sets in, symptoms can include:
    • A body temperature over 100 F (though it's possible to have heat exhaustion with a normal temperature)
    • Dizziness or faintness.
    • Cool, moist skin with goosebumps.
    • Blurred vision.
    • Fatigue.
    • Headache.
    • Nausea and vomiting.
    • Heavy sweating.
    Jun 11, 2024

    Are heat domes rare? ›

    How rare is a heat dome? Heat domes have occurred more frequently as global temperatures have increased over the years. However, this specific heat dome is one of the rarest. Jeff Berardelli, a CBS News meteorologist, tweeted on Sunday the chances of experiencing this heat wave is a 1 in 10,000 chance.

    What is causing the heat dome over Texas? ›

    Heat domes typically form when the jet stream keeps strong air masses with high pressure in a stationary position during the summer months.

    How hot is 2024? ›

    The year is already off to a warm start, with April 2024 coming in as the 11th month in a row to be the hottest on record. 2024 may be the first year to hit 1.5°C of warming (relative to the global above-average temperature from 1991-2020).

    How to survive a heat wave? ›

    Keep cool: use air conditioning or a fan, wear light and loose-fitting clothing, and keep skin wet, using a spray bottle or damp sponge and by taking cool showers. Stay hydrated: during days of extreme heat, keep drinking water before you feel thirsty, especially if outdoors or performing physical activity.

    Is heat dome a new term? ›

    A heat dome isn't technically a scientific term and is a fairly new term that has gained popularity in recent years. It is a condition that occurs when a persistent region of high pressure traps heat over a certain area for a period of time, according to the American Meteorological Society.

    What is extreme heat temperature? ›

    There is hot, and then there is hot! Extreme heat is a period of high heat and humidity with temperatures above 90 degrees for at least two to three days. In extreme heat your body works extra hard to maintain a normal temperature, which can lead to death.

    How long is a heat wave? ›

    A heat wave is a period of abnormally hot weather generally lasting more than two days. Heat waves can occur with or without high humidity.

    How long do heat waves usually last? ›

    Heat Safety Resources

    A heat wave is a period of abnormally hot weather generally lasting more than two days. Heat waves can occur with or without high humidity.

    What is the difference between heat dome and heat wave? ›

    A heat dome is different from a heat wave,” explains Weather.com. A heatwave describes a period of high heat that can be dry or humid and caused by a myriad of factors, including a heat dome. This means that the period of high temperatures caused by the heat dome counts as a heat wave.

    Why is there a heat dome over Texas? ›

    Heat domes typically form when the jet stream keeps strong air masses with high pressure in a stationary position during the summer months.

    What people are most at risk during a heat wave? ›

    Older adults, the very young, and people with mental illness and chronic diseases are at highest risk. However, even young and healthy people can be affected if they participate in strenuous physical activities during hot weather.


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