After an abnormally warm, dry winter season, Wyoming’s miserable March transitioned into an April that was almost as abysmal.
There are still a few days of active weather before the end of April, but meteorologists are already analyzing the trends in temperature and precipitation. The prognosis isn't great.
“For most of the state, April has been drier than average,” said Cowboy State Daily meteorologist Don Day. “There are a couple of exceptions, but the majority of Wyoming has had below-average moisture for the last 30 days.”
If it weren’t for the last week of rain and snow, particularly in northern Wyoming, April would have been almost as dry as March. That’s bad news for what’s, historically, one of the wettest months of the year.
After the winter that wasn’t, Day is more “gun-shy” than at any other point in his career. He’d love to present Wyomingites with a confident extended forecast, but he doesn’t think that’s fair or possible.
“People are asking for 10 to 30-day forecasts, and I’m only confident going four or five days out right now,” he said. “That's how bad it is. It's uncharted waters, and this past winter and spring so far have really exemplified that point.”
Less Than Half
April wasn’t as dry as March, but it was pretty close. Meteorologist Adam Dziewaltowski with the National Weather Service (NWS) office cited statistics out of Lander to show how stark it’s been.
“So far, Lander’s seen 0.87 inches of precipitation in April,” he said. “The normal amount for April is 1.9 inches.”
Dziewaltowski said Lander usually receives around 4.4 inches of precipitation by the end of April. This year, it’s received only 2.31 inches.
“Snow is a completely different story,” he said. “There’s currently only 24.4 inches of snow out of an average, by now, of 82.1 inches. Since it’s been warmer, most of that precipitation has fallen as rain, if at all.”
That's on track to be the worst winter in Lander since 1925, which still holds the record for the least amount of snow in the city's history.
And that's one of the better spots.
According to the U.S. Drought Monitor, the entire state of Wyoming is abnormally dry, at best. By their metrics, over 97% is in moderate drought, over 80% is in severe drought, and nearly 35%, mostly in eastern Wyoming, is in extreme drought.
That’s why Day’s so unconfident about extended forecasts, including his own. The outlook at the beginning of April was drastically different than the reality at the end of April.
“The weather models that everybody uses to make forecasts with have been consistently predicting two to four inches of water across portions of Eastern Wyoming, the heart of the drought area,” he said. “No one has gotten even a quarter of that prediction.”
“Ground zero” for Wyoming’s ongoing drought is Platte, Albany, and Carbon Counties. They are experiencing exceptional drought, the most severe level according to the U.S. Drought Monitor.
“When you see a model that says there will be four inches of rain in Platte County over the next month, and it ends up with a fraction of that, you get really skeptical,” Day said.
Same Old Story
Why is Wyoming, and most of the western U.S., so dry in April? The same reason it’s been dry since November.
The only explanation is the ongoing pattern of high-pressure ridges that blocked winter weather across the West and channeled it eastward. That trend only started to change in a meaningful way in April, but not enough to reverse.
“It's not uncommon to see that for some periods of time during the winter,” Dziewaltowski said. “The thing that was really surprising this year is just how stubborn and persistent that was. It struggled to ever break down or get out of the area, so it just stayed there, and it stayed warm and dry through the winter.”
A contributing factor that Day feels has gone underreported is the 2022 eruption of Hunga Tonga–Hunga Haʻapai, the submarine volcano in the South Pacific. He’s called it “the most unreported climate story of the decade.”
“That transported the volume of two Lake Eries of water vapor into the stratosphere,” he said. “We're seeing the natural response to that process, and the response has been different with each season.”
Weather models struggle to account for the effects of volcanic eruptions, such as the global impact of the 1991 eruption of Mount Pinatubo. Modern meteorological technology has exponentially improved in the last 35 years, but there’s no precedent for anything like Hunga Tonga–Hunga.
“That water in the stratosphere has really messed things up,” Day said. “It’s normally very dry in the stratosphere. Now, as the stratosphere is working through all this extra water, the impacts have matured, and our seasonal modeling tools can’t account for that variable.”
Getting Better?
There’s one drop of good news in these arid assessments. Dziewaltowski said conditions have “definitely changed” for the better.
“Looking at the first three weeks of April, most places saw trace amounts of precipitation,” he said. “Without these past couple of days, we could have ended April with almost nothing. That’s definitely a big improvement for what could have been.”
North-central Wyoming reported between one and six inches of snowfall over the weekend. Scattered snow was still falling across eastern Wyoming, where it’s most desperately needed, on Tuesday morning.
There are also encouraging signs over the Pacific Ocean. Dziewaltowski and Day are monitoring the developing El Niño, which could be extremely favorable for wetter weather in May and June.
“We are kind of transitioning to an El Niño,” Dziewaltowski said. “The patterns are looking active, as in there’s a chance for showers and possibly the big, blockbuster system we’ve missed out on over the past couple weeks.”
Because Wyoming is such a large state with varied terrain, the impacts of the warm, dry winter are highly variable. Any precipitation is good news, but it’s far from enough to change the dire drought conditions.
“These drought situations are vicious,” Day said. “They’re self-perpetuating, in a way. The drier the ground gets, the harder it is to overcome the drought. It’s like eating an elephant – you have to nibble and chop away at it.”
Day said a significant amount of precipitation would be required to “turn the ship around.” Some forecasts project that exact scenario, but even the professionals don’t find that reassuring.
“The seasonal models continue to say, yes, May and June should see an uptick in precipitation,” he said. “We've seen improvement, but how much of that do you take to the bank? I would have to say my confidence is really low.”
Ask Again Later
For Wyoming’s weather, April was better than March. But it wasn’t much better.
After months of frustration and false positives, Day isn’t putting much stock into long-range weather modeling. Whether it’s good or bad, it’s increasingly hard to trust the accuracy.
“We can say that the western U.S. has seen improvements in April, but it has not gotten all of Wyoming yet,” he said. “While there are encouraging signs for May and June, I'm going to remain skeptical until we get back into something that looks more like we normally would at this time of year.”
So, what’s Day’s forecast for the remaining days of April and the first week of May? Ask when it’s over.
“Where I’m at right now, you ask me what today’s weather was like in 10 days,” he said. “It sounds like a cop out, but we can’t control what’s happening. We need to be patient and wait and see what happens. It’s not usually the case, but that’s where we’re at.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
