An extreme heat wave is headed for Wyoming, and it’s going to be one for the record books.
The National Weather Service (NWS) issued an Extreme Heat Watch for much of northern and central Wyoming from Saturday through Monday in anticipation of “dangerously hot conditions.”
How hot will it get?
According to the NWS, 110 degrees in Worland.
Around 105 degrees in Cody.
Up to 103 in Casper.
And it won't be a single day of intense heat. It's expected to be an extended period — multiple days of triple-digit temperatures.
“It’s definitely a big deal,” Cowboy State Daily meteorologist Don Day said. “It’s a significant heat wave, and I expect some record temperatures. I’d certainly be concerned about people and animals.”
Day After Day After Day
July and August are Wyoming's hottest months, so days with triple-digit temperatures are expected. This heat wave is different and dangerous.
“This is going to be an extended period of hot, hot temperatures,” said lead meteorologist Grant Smith with the NWS office in Rapid City, South Dakota. “A ridge of high pressure will set over (the western U.S.), keeping the hot air in place, and we won’t see any change in temperatures until we see a drastic change in the weather pattern.”
According to Smith, that period will be at least from Saturday through Monday and could easily extend beyond that. He wouldn't be surprised if the entire region was just as hot Tuesday and Wednesday.
Day expected this heat wave to catch many Wyomingites off guard. While this has been a year of record-breaking warmth, this is the first “prolonged heat snap” of the summer.
“The combination of heat and low humidity is going to be impactful, especially for north-central and northeastern Wyoming,” Day said. “That's where it's going to be the worst.”
How Hot?
The NWS is already anticipating record-breaking temperatures across most of Wyoming.
Smith said residents of northeast Wyoming should expect highs of 105 degrees on Sunday and Monday.
“That’s just the first draft,” he said. “They’ll be flirting with highs between 101 and 105 degrees on Tuesday and Wednesday, and even beyond that.”
Nobody will be hotter than the Bighorn Basin. It’s always a hot spot during heat waves, and this will be exceptional.
“The eastern edge of the Bighorn Basin will be our warmest spot,” said meteorologist Richard Lowe with the NWS office in Riverton. “Greybull, Worland, Thermopolis, and even Cody and Meeteetse will be in the area of greatest concern for the highest temperatures.”
Worland’s daytime high is 110 degrees on Sunday and 105 degrees on Monday. It could be even hotter in Greybull, with a daytime high of 111 degrees on Sunday.
That would break all-time highs for July 12 in Greybull and Worland.
It won’t be as hot in southern Wyoming, but it’ll still be historically hot.
Lander’s all-time high for July 12 is 102 degrees. Sunday’s high is anticipated to be 103, according to the NWS.
“We’re in a state where everything with the weather is being amplified,” Day said. “Southern Wyoming will have temperatures well into the 90s, while northern and central Wyoming may hit triple-digit highs for three or four days in a row.”
High Altitude, Low Humidity
Throughout the heat wave, it won’t feel quite as hot as the thermometer says. Because the atmosphere will be mostly dry, the heat shouldn’t be amplified by humidity.
“We’ll have relative humidity values below 10% over the weekend,” Lowe said. “Even though it could be 105 degrees, it might feel a couple of degrees less than that. I'm not going to say that’s cooler, but it won’t be as hot as the actual temperature.”
There shouldn’t be enough moisture for afternoon thunderstorms to form, though, and the wind will be relatively mild. That will reduce wildfire danger across Wyoming, provided nobody accidentally starts one.
“Once the heat dome really kicks in, it lowers our risk for thunderstorms until the pattern changes,” Smith said. “You can't rule out the little thunderstorms that pop up, but they’d last only 15 or 20 minutes before they fade out.”
For anyone seeking a naturalistic solution to beat the heat, Day recommended a trip to Yellowstone, the Bighorns or the Snowy Range.
“Every 1,000 feet you go up, you'll be six to seven degrees cooler,” he said. “This would be a great time to head into the mountains.”
Too Darn Hot
Air conditioners will be working overtime this weekend, and that might be one of the safest ways to beat the heat. These temperatures should be a legitimate cause of concern, Day said.
“Dehydration, sunstroke, and over-exertion will be real problems,” he said. “Pets and the elderly are really susceptible to this, so make sure to take care and check on them until things get cooler.”
Day, Lowe and Smith emphasized how severe this heat wave will be, especially because it’ll last multiple days without a break. That’ll be taxing on everybody.
“People should definitely take precautions,” Lowe said. “If you have to be outside, try to get out in the morning or evening, drink plenty of fluids, and stay out of the sun. Check in on your neighbors and relatives and keep an eye on everybody from Saturday to Tuesday and onward.”
The second half of July is actually looking wetter and slightly cooler than the first half, but we have to get there first.
“We’re going to have at least three or four days under this big dome of heat,” Lowe said. “It’s going to get worse before it gets better.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
