Forecasters consider long-term predictions
October 18, 2013
EAGLE COUNTY — Winter could smack us early and late, and in between it could be dry-ish, say long-range weather forecasters.
Then again …
"It can always change," said Joe Ramey, meteorologist and climatologist with the National Weather Service in Grand Junction. "There's always hope for a wet winter, and I bought a ski pass. I'm putting my money on a strong winter."
Warm weather that kicked off autumn could be followed quickly by cold and snow, said Paul Pastelok, long-rang forecaster for accuweather.com.
"The northern Plains and the Rockies, however, will be bitterly cold at times and buried in snow," Pastelok said.
Water temperatures are warmer in the northeastern Pacific, Pastelok said. That could allow the jet stream to bring moisture in multiple-week periods.
"February can be a wild month, temperature-wise. There is a chance for a strong, arctic surge of cold air, especially for the northern Rockies," Pastelok said.
Reservoirs could catch up, some drought relief could be on the horizon and some early snow could help ski resorts, especially after slow starts to the past two ski seasons, Pastelok said.
Joel Gratz crunches data for Open Snow, a website that tracks ski industry trends, including weather patterns. He says he sees the same patterns.
He has been constantly asked if there's a correlation between September precipitation in Boulder and the Front Range, and winter snow in the mountains.
It turns out there is.
In the five wettest Septembers in Boulder history, the snowfall during the ensuing winter was above average for central and northern Colorado, Gratz said.
"In the winters following a wet September in the Front Range, snowfall in the Colorado mountains is well above average before Dec. 1, then stays about average through the remaining months of winter. There is no guarantee that this winter will follow the trend, but the data points in this direction," Gratz said.
Ramey said seasonal outlooks are fraught with danger.
"When you're talking about a forecast further out than a few hours, what you're calculating is a shift in probabilities," Ramey said.
They look into the atmosphere above the Pacific Ocean where El Nino or La Nina put grooves in the atmosphere that the jet stream tends to follow, bringing us a dry winter, a wet winter or a neutral winter.
That's called El Nino Seasonal Oscillation, or ENSO, and so far this year we're in an ENSO-neutral pattern, Ramey said. There's no groove in the weather highway and that makes it even tougher to predict, Ramey said.
So Ramey crunched the data and found that since 1950, we've had 19 ENSO-neutral years. Most came in below normal snowfalls. Two were extremely wet, 1992-93 and 1996-97, Ramey said.
Staff Writer Randy Wyrick can be reached at 970-748-2935 and firstname.lastname@example.org.