More than 39 million under excessive heat warnings as scorching heat wave expands
An extreme heat wave that has been ongoing for days across much of the West will show no signs of fading over the Labor Day weekend. In fact, while some in the Northwest may encounter a reprieve from the heat, others will see the mercury rise even more over the coming days as the intense heat spreads eastward.
Death Valley National Park, considered to be among the hottest places on the planet, has endured the most staggering display of scorching heat in recent days. According to the National Weather Service, Death Valley broke daily high-temperature records on both Thursday and Friday when the mercury hit an astounding 124 F.
Video from Thursday showed the national park's famous Furnace Creek thermometer displaying a reading of 127 F, which, if confirmed, would be the highest temperature ever recorded in September globally. However, this data is preliminary and officials have yet to confirm this reading. It may take months or even years to determine if the record was broken.
Death Valley wasn't the only place to have daily record highs broken recently. Many of the major population centers in inland California, as well much of the Intermountain West, saw daily records fall on over the weekend.
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The continued heat will be driven by a massive ridge of high pressure, sometimes referred to as a heat dome, that is stubbornly remaining in place over the Intermountain West. Furthermore, recent dry conditions, and a lack of moisture in the ground in some areas, have added several degrees to already high temperatures across the region.
"The risks associated with this heat wave are even more concerning than other heat waves because this will be happening through the Labor Day weekend, a holiday weekend when many people are spending additional time outdoors and may be less aware of the heat risks," explained AccuWeather Chief Meteorologist Jonathan Porter.
Porter also noted that many tourists and vacationers are expected to visit the impacted areas through the holiday weekend, and these visitors may be less accustomed to extreme heat precautions.
A majority of California and portions of Nevada, Utah and Arizona, are under excessive heat warnings this weekend as temperatures are forecast to reach dangerous levels. Nearly 40 million people live in counties where these excessive heat warnings are in place.
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For some, mainly in the Pacific Northwest, the high heat will be fleeting. In Spokane, Washington, where the high temperature peaked at 96 F on Friday, heat will drop to much more manageable levels early this week with highs in the low to mid-80s. In Portland, Oregon, after highs near 90 on Thursday and Friday, the mercury failed to reach 80 on Saturday, and low 80s are expected from Monday onward. With average high temperatures for early September near 80 F, it will be a welcome change.
"The Northwest is particularly susceptible to this extreme heat. Air conditioning is much less common in this region than in places farther south, increasing the risk of heat-related illnesses and fatalities. While the heat wave will continue for many, cooler weather in the Northwest is certainly a silver lining," AccuWeather Meteorologist Alex DaSilva explained.
Farther south, such luck will be harder to come by. Even worse, the heat will only grow stronger into the new week.
Fresno, California, located in the Central Valley, should easily surpass 100 degrees each day for the foreseeable future. This week, high temperatures should surge back above 110 degrees, and are expected to break the daily record high each day through Wednesday. Relief will be tough to find at night as well, with lows struggling to get below 80 degrees.
Just to the north in Sacramento, a similar setup is expected. Heat is likely to peak from Monday to Thursday, with a daily record-breaking high of 111 F forecast for California's capital city on 3 of those 4 days.
As broiling heat continues for millions in the Southwest, it will also expand to new real estate farther east. In Billings, Montana, highs in the upper 90s will become common, even peaking at 100 on Wednesday according to the current forecast. High heat will even reach as far east as Sioux Falls, South Dakota, with expected highs in the low 90s on Tuesday and Wednesday, up to 15 degrees above normal.
"An active storm track will force the heat dome out of the Northwest states over the weekend, but push it eastward and increase temperatures across the Rockies and much of the Plains," DaSilva said.
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With such a consistent weather pattern, getting relief from the heat may be tough for many this week. However, the increasingly active tropics may change things. It is increasingly likely that a tropical storm or hurricane tracks northward toward the Baja Peninsula of Mexico this week, possibly even making landfall along the coastline. Such a storm could also bring a large amount of moisture into the Southwest, increasing the chances for rainfall and leading to lower temperatures.
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