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Millions of people across the Southwest are bracing for an unprecedented heatwave, with temperatures soaring past 100 degrees Fahrenheit, a full three months before the official start of summer.
What’s causing this unseasonal swelter is a formidable ‘heat dome’ that has settled over 14 states, including California, Nevada, Arizona, Utah, New Mexico, Colorado, and Wyoming. Even parts of Oregon, Idaho, Montana, Nebraska, Kansas, Oklahoma, and Texas are not spared from its reach.
According to meteorologists at AccuWeather, the region is set to endure temperatures that range from 15 to 30 degrees above the average for mid-March, a shocking deviation from the norm.
The mechanism behind this intense warmth is a heat dome, a high-pressure system that acts like a cap, trapping hot air close to the ground. This phenomenon suppresses cloud formation and amplifies sunlight, exacerbating the heat.
This historic heatwave is expected to persist through Thursday, with numerous cities across the affected region likely to shatter daily temperature records between March 17 and March 19.
By Wednesday, temperatures in Los Angeles, Phoenix and Las Vegas are expected to hover near 100 degrees Fahrenheit, which typically does not happen until mid-June.
Temperatures in California’s Death Valley, the hottest and driest national park, may reach 108 degrees by Wednesday, which would mark the earliest heat above 105 degrees ever recorded.
The AccuWeather team added that ‘little movement’ was expected heading into the weekend, meaning the extreme heat could last well beyond Thursday, and potentially lead to unexpected wildfires throughout Texas, Oklahoma and New Mexico.
A brutal heat dome is scorching over a dozen states across the Southwest, threatening to set multiple records for the earliest 100-degree days ever seen (Stock Image)
A heat dome is a high pressure system trapping heat and humidity near surface level
A heat dome forms when the jet stream, the fast-flowing river of air high over the US, develops a bulge or ridge.
This ridge creates a barrier that blocks normal weather patterns, allowing warm air to sink and get trapped under the ‘dome,’ while keeping storms and cooler fronts away.
AccuWeather Senior Meteorologist Alan Reppert said: ‘Heat domes are a lot like a balloon. They expand and contract as the day goes by, and when you are inside of it, it can be a very warm.’
In this case, the extreme conditions while much of the US is still battling fierce winter weather has set the stage for countless climate records to fall in just four days this week.
Meteorologists projected that Los Angeles will reach 98 degrees on Wednesday. However, if the heat dome pushes it to 100, forecasters revealed that would break a record set in 1874 for the earliest 100-degree day.
Phoenix, Arizona is expected to see back-to-back 100-degree days on Wednesday and Thursday, reaching 101 and 104, respectively.
The city typically sits in the mid to upper 70s in March. Until this week, the only day Phoenix has ever seen 100 degrees in March was on March 26, 1988.
In Las Vegas, Nevada, temperatures in mid-March usually stay in the low 70s. Breaking 100 degrees this week would shatter the record books, erasing the previous mark for the earliest 100-degree day set on May 1, 1947.Â
Dozens of cities are expected to set new records for warmth this week, from the Canadian border in Montana to the Southern border in California and Arizona
Even if some areas d not reach 100 degrees, most of the Southwest is expected to climb into the 90s this week.
In Denver, Colorado, residents are expecting the earliest 90-degree day to hit the city since 1992. The previous record for such heat was April 30, meaning this heatwave should smash that by five weeks.
Forecasters also warned that the intense heat will cause flowers to wilt during a period called ‘superbloom,’ – a rare natural event where huge numbers of wildflowers suddenly bloom all at once in desert areas.
‘The surging heat will dry out vegetation quickly, increasing the risk of wildfire ignition,’ the AccuWeather team added.
Temporary lakes that formed in the winter, such as in Death Valley, could also dry up due to the early blast of summer.
AccuWeather Meteorologist Elizabeth Danco said in a statement: ‘This heat is arriving far earlier than normal, with temperatures in parts of the Southwest running one to two months ahead of historical averages.’