After one of the worst windstorms in recent memory and an Arctic blast over the weekend, how does several days of summer sound?
That’s the outlook for the next week of Wyoming’s weather. Hurricane-force winds and heavy snow dumps will yield to temperatures pushing 80 degrees beginning Wednesday, according to forecasters.
It’s all part of the almost unprecedented seasonal weather that Cowboy State Daily meteorologist Don Day called a “once-in-a-generation” winter. After five months of this, he’s running out of adjectives to describe it.
“On Monday morning, I was watching it snow heavily in northern Alabama,” he said. “We'll be studying this season for a while, but I’m very jaded at the moment.”
Summer Sampler
It’s going to be a warm week across Wyoming. Meteorologist Adam Dziewaltowski with the National Weather Service office in Riverton described it as abnormal, atypical or in his terms, “anomalously warm.”
“All-time temperature records for a lot of those places are only in the mid-70s,” he said. “I think there's a good chance a lot of places, like Riverton, Casper, and the Bighorn Basin, might get near or above 80 by Friday. Multiple records in jeopardy of being broken across Wyoming.”
The warmup begins on Tuesday, but everyone will feel the wave of warm temperatures between Wednesday and Saturday. Daytime highs on Friday, the peak of the wave, are expected to be at least in the high 70s.
As Wyoming warms, it’ll continue to dry out. Dziewaltowski said there isn’t any precipitation in the forecast this week and doesn’t see any chances “anytime soon.”
“Those warm temperatures are going to last through much of the weekend,” he said. “We might see a little cool down by Sunday, but it’d still be 10 to 20 degrees above normal.”
Day said 70-degree days in March aren’t unprecedented, but this is still quite the warm streak to expect this early into spring.
“It’ll noticeably warm up by Tuesday, and this wave will extend from Wednesday through Saturday, with Friday and Saturday being the warmest days,” he said.
Blame The Block
What’s the reason for this wave of potentially record-breaking warmth? Yet another “logjam” of high pressure, blocking off Wyoming and the Rockies from cold air and moisture and siphoning it elsewhere.
High-pressure ridges have been the bane of Wyoming’s winter weather since November. Day’s been diving into the state’s climatological records, trying to understand the severity of this disparity.
“If you were to add it up, the number of blocking situations that happen during the course of the winter in North America is between zero and two,” he said. “This season, we’ve had five, and each one has been exactly the same.”
With the benefit of hindsight, Day can see a recurring pattern in Wyoming’s weather since November. The incredible windstorm that blew over dozens of trees and semi-trucks is part of that pattern.
“The end result on all five of these blocks has been exactly the same. We get a high wind event, then we get clipped by Arctic air, then we go warm and dry, and then we wait for the pattern to work its way out again,” he said.
Day pointed to similar cycles in December, January, and February, and believes he found a similar-enough event in November each time a high-pressure ridge formed. Considering each of these ridges stayed in place for several days, the numbers are harrowing.
“The average lifespan of these blocks was between eight and 12 days,” he said. “Just doing the math, that’s 40 to 50-plus days of the winter season that we didn’t get. If you remove a month and a half of winter, you're giving yourself a significant handicap.”
Thanks For Next To Nothing, March
March is the beginning of Wyoming’s wet season. The month started out strong with an influx of precipitation where it was needed most, but that trend didn’t last.
According to Day, it might be time to write off March. With another high-pressure ridge setting up that could last over a week, there won’t be much time for March to make up for the overall lack of moisture over the winter months.
“You don't want to give up a week of moisture in March, even if you have plenty of moisture,” he said. “March is the first month when it starts to get wetter, and it has, but you want to keep that momentum going into April and May. Now, we’re looking at several days without anything.”
Last week’s winter weather was an overall improvement for Wyoming’s snowpack. While many basins are still struggling with record-low levels, some received a slight boost from the wet, heavy snow that blanketed most of the state before and after the destructive windstorm.
Dziewaltowski believes the snowpacks will stay resilient, even with the potentially record-breaking temperatures later this week. It’s not an ideal situation, but another persistent trend over the last several months was that the high elevations did okay, for the most part.
“The snow is up relatively high and overnight temperatures should get low enough to where those higher elevations should see freezing temperatures,” he said. “You will see some melting during the day and refreezing overnight, so it isn’t super-concerning.”
Day’s assessment is that even when conditions change, it might be too late for March.
“Many parts of Wyoming have picked up some decent moisture in the last two weeks, but we’re already halfway through March with another blocking pattern settling in,” he said. “We're just going to have to put all of our eggs in the basket for April and May.”
A Worried Eye On What’s Ahead
There’s a lot of uncertainty ahead, even amongst meteorologists who thrive on discerning that uncertainty. The block might break early next week, which could, hopefully, make March go out like a cold winter lion rather than a warm spring lamb.
“There’s going to be a five-day streak of warmth, then we're probably looking at the block weakening enough to allow a stronger cold front end around Tuesday and Wednesday of next week,” Day said. “If we get into that first week of April and don't see another block returning, then we can expect a trend into more seasonal conditions.”
That’s a big “if” after the winter we’ve had. As far as Day is concerned, it’s a sign of how far long-range weather models have to go as reliable indicators of seasonal trends.
“Nobody saw this mid-March blocking pattern at the beginning of March,” he said. “Do the models show an April block? No. Is it harder for blocks to form in April and May? Yes, but based on what has happened this winter, I am not going to say that it couldn't happen again, by any means.”
Day still holds there’s a historical precedent for this extremely abnormal weather. He cites the 1976-1977 winter season as the best analogy for what’s happened over the last five months, which he categorized as a “once-in-a-generation” aberration that occurs every 40 years or so.
“That winter, it was really warm in the West during one of the coldest winters in the eastern U.S.,” he said. “Both of those winters had high numbers of blocking patterns, so the comparison is really uncanny, but I've never seen anything like what we've had of the course of this winter.”
Dziewaltowski isn’t hedging his bets. Meteorologists tend to avoid looking too far ahead, but the outgoing winter season has been an alarming experience for experts everywhere.
“Hopefully, this is just like a once in a blue moon kind of thing,” he said. “I definitely hope this is not a sign of what's to come this summer, because a continuous pattern like this would be very unfortunate.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
