Published by CNBC.COM
Summary generated on August 15, 2020
More than 80 million people were under heat alerts Friday from the Central and Southern Plains as well as for nearly the entire West Coast.
The myriad heat alerts covering the map included heat advisories, excessive heat watches and excessive heat warnings all issued by the National Weather Service.
Dallas, Houston, Phoenix, Las Vegas, Los Angeles, Portland and Seattle are among the cities under heat alerts.
For the Plains, high temperatures were forecast to be 100 to 107 degrees, and heat index values 105-115 degrees.
This heat is forecast to last through Sunday with cooler temperatures expected next week.
For the West, an excessive heat warning is in effect until Wednesday for parts of Arizona, California and Nevada, with high temperatures expected to reach 110-125 degrees.
Two factors making this heat event especially dangerous are the long duration into next week and high humidity.
"The longevity of the heat is more concerning than the record-breaking temperatures," said National Weather Service meteorologist Trevor Boucher.
When talking about the West, the heat is often described as a "Dry heat." This time tropical moisture streaming into the region from what was Hurricane Elida will make conditions more muggy than usual and more dangerous.
By the time the heat event is over, more than 100 daily record highs could fall.
This heat will be exceptionally dangerous for the more vulnerable populations, especially in cities, where the urban heat island effect - where a city's temperature is much warmer than rural areas nearby - combined with less access to air conditioning will amplify the risk for heat illness.
Boucher stressed the importance of public cooling stations to help people get out of the heat, as well as people being smart about their home's energy use, given that people will likely be running their air conditioning throughout the day and night.
Alexander Gershunov, a research meteorologist at Scripps Institution of Oceanography, University of California, San Diego, said heat waves of this nature are becoming more common due to climate change.
"These large and long-lasting heat waves are typically caused by a dome of high pressure building overhead, and this one has a particularly strong high pressure and it's very extensive in that it pretty much dominates the entire Southwest of the United States," Gershunov said.
"So these patterns happen, and when they occur at the time of the warmest summertime temperatures in late July and early August, they can cause severe heat waves."
The heat wave stands to exasperate the Covid-19 pandemic - and the pandemic will make matters worse for those facing the heat, too.
Heat waves, like the coronavirus, both impact the respiratory system.
Climate change is increasing the frequency, duration, and intensity of heat waves like this, especially out West.
The heat is no doubt exacerbating the fire risk across the West.
The intense heat ramping up across the West comes on the heels of the National Oceanic and Atmospheric Association releasing its July monthly climate report on Thursday stating that July 2020 was the second hottest July on record for the planet, and the #1 hottest on record for the Northern Hemisphere.