‘Pineapple Express’ bringing week of rain for St. George, snow for Iron County

ST. GEORGE — It might be time to perfect your ark-building techniques. Or at least consider adding pineapple to your diet. 

Rainwater pools in Washington City, Utah, Sept. 1, 2023 | Photo by Vin Cappiello, St. George News

Other than a break or two, the weather service says residents in St. George can expect rain, while folks in Iron County and the higher elevations can expect snow — from Thursday through to Super Bowl Sunday.

That includes a winter weather warning issued by the weather service starting at 8 a.m. Thursday and extending to 5 a.m. Saturday for the local mountains with one to two feet of snow expected at places like Brian Head and the Pine Valley Mountains.

Nicole DeSmet with the National Weather Service’s Salt Lake City office said what was an unusually warm early part of the week, where car air conditioners saw a rare January use, will give way to an unusual atmospheric river of moisture into Southern Utah for the next week and a half.

Atmospheric rivers are sections of the Earth’s atmosphere that carry moisture from the tropics near the equator to the poles. It isn’t wrong to think of them as rivers in the sky, as they usually carry the amount of water in vapor form as the flow of water in the Mississippi River, according to the National Oceanic and Atmospheric Administration.

But they don’t often meander their way over Southern Utah, and they are especially rare in January. 

“Essentially they carry, um, a really substantial amount of water vapor in a very narrow area,” DeSmet said. “So this is streaming in from the Pacific Ocean. Sometimes they’re referred to as the ‘Pineapple Express’ because they’re streaming in from Hawaii.”

An atmospheric river condition was blamed for the large amount of rain that caused the flooding that surged the Santa Clara River last March.

Undated graphic describes the components of an atmospheric river | Graphic by National Oceanic and Atmospheric Administration, St. George News

As of Wednesday morning, the forecast was for a 90% chance of precipitation in Southern Utah for Thursday and Friday tapering off late Saturday, followed by another substantial chance of rain and snow starting late Sunday and continuing off and on through Feb. 11. 

“It’s definitely an atypical system for this time of year,” DeSmet said. “We normally don’t see this amount of substantial of, well, both liquid and snow amount this time of year … especially down for you guys.”

At this point, forecasters see at least three major bands of storms in the coming days, two big ones with a smaller one sandwiched in between.

“For the first wave, we’ve got about three-quarters of an inch of precip for St. George proper. And we’re forecasting a lot of snow for the mountains anywhere from one to two feet for the higher elevations,” DeSmet said. “Then for the second batch, this late weekend Saturday into Sunday, we’re not looking at a whole lot of precip with that right now. It’s maybe trace amounts of snow to half an inch, and then there’ll be another round of both rain and snow again headed into Monday, which is right now it’s looking like a fairly similar amount of both rain and snow to the first wave.”

While the mountains and Brian Head will be getting a lot of snow, DeSmet said it won’t be as bad down in the flats of Cedar City. 

“Right in the city, we’re not particularly forecasting a lot of snow,” she said.

While it won’t be a good week for sunscreen sales,  DeSmet says don’t fret. The moments will be fleeting, but there will be a few chances where the sun will make an appearance in the next week and a half.

“I think there’ll be a break,” she added. “You’ll see some patches of sun.”

Copyright St. George News, SaintGeorgeUtah.com LLC, 2024, all rights reserved.

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