Overheat warnings, or high temperature warnings, cover several areas, including California’s Central Valley; Las Vegas to Phoenix in the southwest; San Antonio to Birmingham, Alabama in the south; and Myrtle Beach, South Carolina, along the east coast to Boston.
In Texas and Oklahoma, many places are experiencing one of the hottest summers on record, with temperatures well above 100 degrees expected for the foreseeable future. Both states hit 115 degrees on Tuesday, and while Thursday’s relatively cool temperatures were still dangerous for vulnerable groups.
Major cities in the Northeast will experience near-95-degree heat on Thursday and will feel 5 to 10 degrees and suffocating humidity levels. High temperatures are expected to be more intense this weekend: Washington could hit 100 for the first time since 2016.
DC Mayor Muriel E. Bowser has declared a heat emergency for the city through Monday.
The U.S. heatwave hit at least 60 records, peaking this week as historic, unusually high temperatures killed more than 1,000 people in Europe. Britain hit record highs on Tuesday as several stations exceeded 40 degrees Celsius (104 degrees Fahrenheit) for the first time ever.
Unusually high temperatures in the UK have shattered records. This is what happened.
While summers are sure to be hot, the trend of increasingly severe and longer-lasting heat events carries the fingerprint of human-induced climate change.
So far this week, 60 daily heat records have been broken/broken as dangerous heat blankets much of the country. Some notable records include a tie for all-time highs in Salt Lake City, Utah, and Abilene, Texas. More records could be set next week. pic.twitter.com/uI1JeHIwcW
— NWS Weather Forecast Centre (@NWSWPC) July 21, 2022
The nation’s hottest weather on Thursday was concentrated in the Southwest. The National Weather Service warned that Las Vegas had a “high risk of heat-related illness”, with highs expected to exceed 110 degrees by Friday.
⚠️ Las Vegas will be hot for the next few days, but most of southern Nevada and northwest Arizona will be hot.
Take extra precautions to avoid heat stroke! 🥵️ pic.twitter.com/rvMgHaSxqY
— NWS Las Vegas (@NWSVegas) July 21, 2022
The Bureau of Meteorology also warned of “dangerous heat conditions” in Phoenix, with highs expected to reach 110 to 115 degrees. The city is also under pollution warnings due to high ground-level ozone levels.
High temperatures could reach 120 degrees in Death Valley, California, by Saturday.
Heat waves are getting hotter and more frequent. Here’s how to prepare.
Heat in Texas and Oklahoma
The sweltering heat in Texas and the Southern Plains has been unbearable this summer, with temperatures in San Antonio, Austin and Houston reaching their highest on record. There are few signs of relief.
Each of the 120 weather stations in Mesonet, Oklahoma, recorded highs of 103 degrees or above for the first time on Tuesday. Mesonet has been in operation since the mid-1990s, which means that recording time is limited. Regardless, the heat is boiling.
At least 24 Mesonet sites hit record highs yesterday, according to preliminary data. There are a few newer sites out there, but there are plenty today that can show heat that matches any of the Mesonet temperature eras, going back to 1997! #okwx #okmesonet pic.twitter.com/uVSPIyqYVx
— Mesonet, Oklahoma (@okmesonet) July 20, 2022
Oklahoma City surged to 100 degrees Wednesday, reaching the century mark for five straight days. When it hit 110 degrees on Tuesday, it was the second time since 2012. High temperatures are expected to stay in the low 90s or 100s next week, at least.
On Tuesday, temperatures jumped to 115 degrees in Mangham, Oklahoma, and Wichita Falls, Texas. Although unbearably hot, these temperatures were still below the 120-degree reading on August 12, 1936, in Altus, southwest Oklahoma. This is the highest temperature ever recorded.
There are about a dozen small wildfires in Oklahoma’s Red River Valley and north-central Texas, with the largest in Somerville County southwest of the Dallas-Fort Worth metropolis. The Chalk Hill Fire has burned 6,339 acres since it ignited around 2:30 p.m. Monday. It only contains 10%.
Attempts to calculate show a deviation from the average hours so far this year with a heat index of at least 100°F. Consider all heat index reports (ie below air temperature). X represents the site with the largest value this year compared to 1973-2021. pic.twitter.com/SlFabOUm31
— Daryl Hertzman (@akrherz) July 21, 2022
Dallas, Austin, San Antonio and Tulsa will remain at 100 degrees or above for at least next week, while areas further south and east — Houston, Little Rock or Shreveport, Louisiana — will remain at 90 degree or more. Those slightly cooler temperatures will be offset by greater humidity blowing from the Gulf of Mexico, resulting in heat index values in the range of 105 to 110 degrees.
Much of the state, from Louisiana and Arkansas to Georgia, is experiencing one of its 10 hottest summers, and temperatures will remain sweltering through early next week. Highs are expected to be in the 90s to 100s, but oppressive humidity levels create a feeling of 100s to 110s.
With high temperature index values approaching 110 degrees, overheat warnings will be issued for our western counties by 7 p.m. tonight. A high temperature warning will be issued for all counties except Far East County, where high temperature index values will be in the 105-108 degree range until 7 p.m. tonight. pic.twitter.com/AXiP6KCOZq
— NWS Birmingham (@NWSBirmingham) July 21, 2022
Birmingham, Alabama, was under a heat warning Thursday, with temperatures expected to peak around 95 degrees. Western Alabama may reach its highs in the 1990s. While the daytime high wasn’t particularly impressive from a record perspective, the overnight low was.
“Yesterday our low temperature was 79 degrees [Wednesday] “In the morning,” said Jason Holmes, a meteorologist at the Met Office in Birmingham. “A nighttime low temperature like this — it’s hard on your body because you’re not cooling down. “
How does high temperature affect the human body?
Heat in the Mid-Atlantic and Northeast
It is expected to be hot and humid today. There will be scattered showers and thunderstorms this afternoon, mostly in southern Washington, D.C. Severe storms with damaging winds are possible. pic.twitter.com/XSmE4p1YZA
— NWS Baltimore-Washington (@NWS_BaltWash) July 21, 2022
The mid-Atlantic and Northeast have largely avoided heat and humidity this summer, but that’s changing rapidly.
Temperatures are expected to hit the 90s from Richmond to Boston on Thursday, with heat index values in the triple digits.
While humidity will ease on Friday after a weak cold front, the muggy weather will return over the weekend.
New York’s highs will hit the 90s on Saturday before soaring into the mid-to-high 90s on Sunday. Temperatures will remain in the 90s in Washington, Baltimore and Philadelphia through Saturday, and near 100 on Sunday. Heat index values can range from 105 to 110.
what causes heat
The source of the heat is a high-pressure ridge known as the “thermal dome,” which is centered to the southwest but sometimes curves eastward into the mid-Atlantic.
Beneath these thermal domes, the air sinks, clearing the clouds while letting the sun shine down relentlessly. On the thermal dome are jet streams that mark the southern periphery for cooler weather.
The science of thermal domes and how drought and climate change are making them worse
Over the weekend, the jet stream will slope toward the north central U.S. and the Great Lakes, bringing cool air to those regions. However, strong to severe thunderstorms could break out on Saturday as cooler air arrives.