U.S. faces exceptional day of ‘climate change-driven heat’ Friday
2024-08-01T19:49:17.421ZClimate Shift Index for Aug. 2. (Climate Central) A coast-to-coast heat wave is bringing abnormally high temperatures to nearly half of the United States population. And human-caused climate change is a big reason.According to the Climate Shift Index from the science communications group Climate Central, Friday’s heat is being made at least three times as probable because of climate change.“A forecast RECORD 148 million Americans (~half of the country’s population) are expected to experience excessive temperatures made at least 3x more likely due to climate change,” Climate Central wrote on X.Shel Winkley, a meteorologist for Climate Central, wrote that it would be “an unprecedented day of climate change-driven heat for the United States” on Friday.Climate Central launched the Climate Shift Index in 2022 to help quantify and communicate how much climate change is contributing to the magnitude of heat waves.The previous record population exposed to heat intensified by climate change was 140.6 million on June 13, 2022, Climate Central wrote.Heat alerts currently cover portions of 33 states and affect 150 million people. On Friday, the worst of the heat is expected from the South to the Mid-Atlantic where heat indexes, a measure of how hot it feels factoring in humidity, of 105 to 110 are predicted. Parts of the West will also be exceptionally hot, but not as humid. And the heat is forecast to last longer there.Heat alerts as of Friday. (National Weather Service)Almost the entire United States is forecast to experience above normal temperatures, with many locations forecast to be 10 to 20 degrees higher than typical.It comes on the heels of the hottest weather of the summer so far in parts of the Upper Midwest and central Plains and a scorching July for both the United States and the entire planet.July was the planet’s second hottest month on record; only July of 2023 was hotter. The western United States was particularly hot as Sacramento and Las Vegas experienced their hottest July on record. Death Valley, Calif., registered the hottest month ever observed anywhere on the planet.The role of climate changeThe heat so far this summer has been intensified by human-caused climate change, according to the analyses from Climate Central as well as other groups such as the World Weather Attribution project.Climate Central’s Climate Shift Index calculates how much more (or less) likely temperatures are on a given day because of the influence of human-caused climate change. Its index ranges from minus-5 to plus-5 — and is a measure how many more times more probable climate change made the day’s temperatures.(Climate Central) Within the Lower 48, locations not expecting climate-change influenced heat to close the week are few and confined mainly to the Midwest and parts of the Great Lakes region. Large zones of temperatures made five times more likely because of climate change are found in a large U-shaped crescent from the coast of British Columbia through much of the interior west and into Mexico, before spreading across the Gulf Coast and northward up the East Coast into Atlantic Canada.How hotForecast temperatures compared to normal late Friday. (weatherbell.com)While the combination of heat and humidity will be most intense from the South to the Mid-Atlantic on Friday, the magnitude and duration of the heat will be most notable in the western United States, especially the Pacific Northwest, over the next several days.Highs of 105 to 110 are forecast east of the Cascades through Idaho and into Montana and Wyoming. Not coincidentally, the region is also dealing with a growing drought and numerous large wildfires.Boise is forecast to reach a record high of 107 on Friday, which will be its 18th day at or above 100, tying the most on record to date. On Saturday, Salt Lake City could come close to its calendar day record of 101.Phoenix is poised to start a run of record-threatening highs 112 to 115 through at least early next week.In the eastern United States, the D.C. area — which is under an excessive-heat warning — will see highs near 100 Friday, threatening some records. Should Baltimore reach 100 or higher as it did Thursday, and as forecast, it will be the eighth day this year at least that hot. The seven 100-degree days so far this year is tied with 2010, 1988 and 1930 for the most on record.(Ian Livingston)Unusually warm overnight lows will have an even larger footprint than record highs. In many places, the increase in very warm nights has far outpaced the rise in daytime temperatures.Heat relief on the horizon?As cold fronts dip into the northern United States, the heat should gradually begin to ease in parts of the north central and northeastern United States.(Ian Livingston)Elsewhere, any relief from the heat will only be brief or spotty. A heat dome is likely to remain anchored over the Desert Southwest and South through at least the first third of August.A zone running from southwes
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A coast-to-coast heat wave is bringing abnormally high temperatures to nearly half of the United States population. And human-caused climate change is a big reason.
According to the Climate Shift Index from the science communications group Climate Central, Friday’s heat is being made at least three times as probable because of climate change.
“A forecast RECORD 148 million Americans (~half of the country’s population) are expected to experience excessive temperatures made at least 3x more likely due to climate change,” Climate Central wrote on X.
Shel Winkley, a meteorologist for Climate Central, wrote that it would be “an unprecedented day of climate change-driven heat for the United States” on Friday.
Climate Central launched the Climate Shift Index in 2022 to help quantify and communicate how much climate change is contributing to the magnitude of heat waves.
The previous record population exposed to heat intensified by climate change was 140.6 million on June 13, 2022, Climate Central wrote.
Heat alerts currently cover portions of 33 states and affect 150 million people. On Friday, the worst of the heat is expected from the South to the Mid-Atlantic where heat indexes, a measure of how hot it feels factoring in humidity, of 105 to 110 are predicted. Parts of the West will also be exceptionally hot, but not as humid. And the heat is forecast to last longer there.
Almost the entire United States is forecast to experience above normal temperatures, with many locations forecast to be 10 to 20 degrees higher than typical.
It comes on the heels of the hottest weather of the summer so far in parts of the Upper Midwest and central Plains and a scorching July for both the United States and the entire planet.
July was the planet’s second hottest month on record; only July of 2023 was hotter. The western United States was particularly hot as Sacramento and Las Vegas experienced their hottest July on record. Death Valley, Calif., registered the hottest month ever observed anywhere on the planet.
The role of climate change
The heat so far this summer has been intensified by human-caused climate change, according to the analyses from Climate Central as well as other groups such as the World Weather Attribution project.
Climate Central’s Climate Shift Index calculates how much more (or less) likely temperatures are on a given day because of the influence of human-caused climate change. Its index ranges from minus-5 to plus-5 — and is a measure how many more times more probable climate change made the day’s temperatures.
Within the Lower 48, locations not expecting climate-change influenced heat to close the week are few and confined mainly to the Midwest and parts of the Great Lakes region. Large zones of temperatures made five times more likely because of climate change are found in a large U-shaped crescent from the coast of British Columbia through much of the interior west and into Mexico, before spreading across the Gulf Coast and northward up the East Coast into Atlantic Canada.
How hot
While the combination of heat and humidity will be most intense from the South to the Mid-Atlantic on Friday, the magnitude and duration of the heat will be most notable in the western United States, especially the Pacific Northwest, over the next several days.
Highs of 105 to 110 are forecast east of the Cascades through Idaho and into Montana and Wyoming. Not coincidentally, the region is also dealing with a growing drought and numerous large wildfires.
Boise is forecast to reach a record high of 107 on Friday, which will be its 18th day at or above 100, tying the most on record to date. On Saturday, Salt Lake City could come close to its calendar day record of 101.
Phoenix is poised to start a run of record-threatening highs 112 to 115 through at least early next week.
In the eastern United States, the D.C. area — which is under an excessive-heat warning — will see highs near 100 Friday, threatening some records. Should Baltimore reach 100 or higher as it did Thursday, and as forecast, it will be the eighth day this year at least that hot. The seven 100-degree days so far this year is tied with 2010, 1988 and 1930 for the most on record.
Unusually warm overnight lows will have an even larger footprint than record highs. In many places, the increase in very warm nights has far outpaced the rise in daytime temperatures.
Heat relief on the horizon?
As cold fronts dip into the northern United States, the heat should gradually begin to ease in parts of the north central and northeastern United States.
Elsewhere, any relief from the heat will only be brief or spotty. A heat dome is likely to remain anchored over the Desert Southwest and South through at least the first third of August.
A zone running from southwest Canada through the Intermountain West and into the south-central states could stay much warmer than average through at least mid-month and perhaps beyond. The most recent outlooks for August continue to favor above normal temperatures for most of the country.
Jason Samenow contributed to this report.
