The first weeks of August tend to be the hottest of the summer season in Wyoming. It's also the beginning of the long-range winter forecast season with some agencies already coming in with bold predictions for what the upcoming winter will bring.
The National Oceanic and Atmospheric Administration updated its long-range forecast for the 2024-2025 winter season in mid-July.
Snowmobilers immediately and eagerly embraced the NOAA report, celebrating the agency’s prediction of "a 79% chance of a La Niña winter."
But Wyomingites who love to play in the snow shouldn't get their hopes up too early, said Cowboy State Daily meteorologist Don Day, who doesn't trust any long-range forecasts released this soon in the summer.
"I hate those things because it makes me look bad," he said. "People's impressions of weather tend to be with the first thing they hear. So, if something comes out and says the winter is going to be 'X,' they will remember what they first heard. It's just the way human brains work.”
Day is working on his long-range forecast for the state of Wyoming, but said he needs a few more weeks of modeling and real-time weather before it's ready. He trusts the data, so he hopes people in Wyoming will trust his patience.
"People might ask what good is a long-range forecast you have to get closer in," he said. "My answer to that is, would you rather have a more accurate forecast closer in or an outrageously bad forecast further out? I don't have anything against NOAA's product, but it's still too early for me."
Modeling Madness
What goes into a long-range forecast? NOAA and many other agencies can be pretty secretive about what they use to develop their forecasts, but Day said it's mostly modeling.
"The National Weather Service goes into what they're using to make their projections, and it's very technical and heavily model-based," he said. “They're using their projections for winter with a heavy emphasis on the models that they've developed to try to predict future weather and climate events."
NOAA's Seasonal Precipitation and Temperature Outlooks, last updated July 18, anticipate a warmer-than-average winter for most of Wyoming with an average amount of precipitation. That's based on NOAA’s long-range climate and weather models, which are based on current observable weather.
But what was accurate today could be rendered useless and wrong tomorrow. That's why Day is skeptical of a model-based forecast this early in the season.
"A lot of those things may change or fluctuate between now and the start of winter, which we call initialization," he said. "If you initialize your data six months from now, you risk the forecast possibly going a different direction."
NOAA's mid-July update has probably been altered by Hurricane Debby, which made landfall over Florida on Monday. Several weather events could happen between now and December, impacting any already-released long-range forecasts.
Even so, there's nothing wrong with using long-range weather modeling. Day uses the same models as NOAA and the National Weather Service, but augments his forecasts with local and regional information that other agencies don't prioritize.
"NOAA doesn't use many analog techniques," he said. “That's examining what has happened in the past to find what's like what we're seeing now or what we're expecting to see as we get closer to the start of the fall season. Those are analog techniques, while NOAA is more heavily based on modeling."
Patience Pays Off
Day anticipates his long-range forecast for the 2024-2025 winter season will be finished by mid-September. He referenced the famous quote from the American Revolution's Battle of Bunker Hill: Don't fire until you see the whites of their eyes.
At Bunker Hill, the saying was intended to conserve ammunition and ensure every shot fired from horribly inaccurate muskets had a good chance of hitting one of the advancing British regulars. Day has a less militaristic reason for citing the saying.
"Don't pull the trigger until you absolutely wait until the last minute, because that's going to give you the most accurate projections," he said. “People want a long-range forecast now for winter. I get it. But it's way too early to start talking about December, January, and February."
As for the excited snowmobilers who can hardly wait to get back out on frozen trails, Day understands why they'd be optimistic about any forecast calling for above-average snow. But their enthusiasm has been undercut more often than naught.
"At this time last year, NOAA's long-range forecast showed snow all the way to Florida," he said. "The reality was snowmobile season was a real downer for most of the U.S. If you go back and look at last year's snowmobile forecast, it was way off. That's the risk of sticking your neck out too far."
Here's A Hint
Since he's still compiling all the modeling and analog techniques for his long-range winter forecast, Day didn't reveal much about what he sees in Wyoming's forecast future. But he concurred with some "hints" in NOAA's forecast.
"The NOAA map for temperature shows the Pacific Northwest and the Northern Rockies being colder," he said. "I think there are hints that this winter will be colder than last winter. Wyoming's a big place, and the weather is not evenly distributed across the state, but historically, that's what's favored (during a La Niña winter)."
Day intends to "fine-tune" these trends and predictions as Wyoming moves through August and into September. His advice to Wyomingites is to keep their cool for the rest of the summer and not get heated over long-range forecasts until the fall.
"Be careful what you decide to believe," he said. "There's risk and reward in these long-range forecasts, but we don't have the capabilities to be really precise this far out. I hope to fine-tune those things as we get into September, but we have to get there first."
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
