- Cities such as Dallas, Las Vegas and Oklahoma City should all see their hottest temperatures so far this year.
- A heat dome occurs when a persistent region of high pressure traps heat over an area.
- Excessive heat is especially dangerous for vulnerable populations, the weather service said.
Although it’s already been sizzling in many locations recently, the hottest temperatures of the summer are likely still to come across portions of the southern tier of the U.S. over the next several days, forecasters said.
In fact, as a so-called heat dome expands, cities such as Dallas, Las Vegas and Oklahoma City should all see their hottest temperatures so far this year, AccuWeather said.
For example, Dallas could surpass the 103-degree mark for the first time this year over the next seven days. And Las Vegas, which has not hit the 110-degree mark so far this year, could do so either during the weekend or early next week, AccuWeather predicted.
After Oklahoma City reached 100 degrees on Tuesday for the first time this year, multiple days with triple-digit highs are possible: A high of 103 degrees is forecast for Thursday, the National Weather Service said.
Overall, more than 77 million people in the U.S. were under extreme heat advisories, watches and warnings Wednesday.
What is a heat dome?
A heat dome occurs when a persistent region of high pressure traps heat over an area, according to William Gallus, professor of atmospheric science at Iowa State University. “The heat dome can stretch over several states and linger for days to weeks, leaving the people, crops and animals below to suffer through stagnant, hot air that can feel like an oven,” Gallus said, in an article in the Conversation.
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In southern Texas, the heat has already been intense this summer: San Antonio has accumulated more than two dozen days of 100-degree temperatures so far this year, compared to an average of nine such days, according to AccuWeather meteorologist Nicole LoBiondo.
The “dangerous” summer heat wave will also continue for much of the Plains, mid- to lower Mississippi Valley and the Southeast on. both Wednesday and Thursday, the weather service said.
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Temperatures continue to remain “dangerously high” over much of the Mid-South where excessive heat warnings and heat advisories are currently in effect, according to the weather service. High temperatures for much of Kansas, Oklahoma, Missouri, eastern Tennessee and Arkansas are expected to be in the upper 90s to low 100s both Wednesday and Thursday.
Lows in the upper 70s to low 80s will offer little respite overnight and are likely to tie or break existing records over the next few days, the weather service said. Excessive heat is especially dangerous for vulnerable populations, such as the elderly and those without air conditioning.