No clear guide to winter weather patterns | VailDaily.com

No clear guide to winter weather patterns

EAGLE COUNTY — Weather forecasting has come a long way from the height of skunk cabbage or Uncle John's achy knee. In fact, short-term forecasting is generally pretty accurate. But long-range forecasting remains imprecise, at best.

Still, "when is it going to snow?" becomes a more common question this time of year. And this year, beyond the next week or so, the answer is, "We really don't know."

SOME SNOW POSSIBLE THIS WEEK AT ALTITUDE

Starting with the short term, it looks like parts of Colorado's western Rocky Mountains may see some small accumulations of snow this week.

The National Weather Service office in Grand Junction and OpenSnow.com meteorologist Joel Gratz are both predicting some snow in the region this week, with the best chance coming Thursday. Even the Old Farmer's Almanac forecast — which is largely for entertainment purposes only — is calling for scattered showers and cooler weather this week.

Gratz's forecast calls for "random showers" this week, with the snow level falling to 10,500 feet or so. The system coming this way Monday dropped snow at the base of Showdown Mountain, Montana, at an elevation of 7,500 feet.

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National Weather Service Meteorologist Joe Ramey said the snow level could fall to 9,500 feet.

Ramey added that he doesn't expect to see much snow in this area, but the mountains between Aspen and Crested Butte could perhaps see as much as six inches of snow.

Gratz wrote in an email that some snow this time of year is pretty normal.

The question, of course, is: do any of these storms mean anything for the cooler season to come?

The short answer is "probably not."

HARD TO SAY

Weather forecasting more than about 10 days ahead gets harder the farther in the future those predictions come. In fact, Gratz just won't do it, calling long-range forecasts all but useless.

The National Weather Service's Climate Prediction Center does provide those forecasts, but also notes that those forecasts are far from authoritative.

With that in mind, the forecast for September, October and November calls for above-average temperatures and an equal chance of either above- or below-normal precipitation. Think of it as a scientific shoulder-shrug.

The longer-range forecast isn't much help, either, calling for a chance of below-normal precipitation into the winter.

Again, those forecasts are iffy at best. On the other hand, Ramey's research pretty much called the last snow season in the Vail Valley, with good snow early, a dry winter and then a wet late winter and early spring.

That forecast was based on the history of the El Nino weather pattern, generated by warmer-than-average water temperatures in the zone of the Pacific Ocean along the equator between Ecuador and the International Date Line.

Ramey said El Nino patterns usually send storms tracking into the desert southwest. That's good news for skiing at Wolf Creek Pass and bad news for us.

La Nina patterns generally send storms into the U.S. through the Pacific Northwest. That's usually better news for Colorado's northern mountains, including Vail and Beaver Creek.

Nino-neutral years

This year, the waters in that part of the Pacific have cooled, but not enough to create a La Nina pattern.

That leaves forecasters in an even more precarious position.

The Nino/Nina phenomenon — called the El Nino Southern Oscillation — is the most powerful tool long-range forecasters have, Ramey said. Without it, these seasons become very much wild cards as far as forecasting is concerned, leaving meteorologists looking for more subtle ways to track storm systems.

Historically, neutral years haven't been particularly kind to the central Rockies. Ramey said that since 1950, the Nino-neutral years have seen both wet and dry seasons in this part of Colorado, but the dry years outnumber the wet.

No matter what weather does, Ramey said it's good to remember something Gratz told him a few years ago: "It's going to snow, and we're going to have fun."

Vail Daily Business Editor Scott Miller can be reached at 970-748-2930, smiller@vaildaily.com and @scottnmiller.

Who are these kids?

La Nina: Cooler-than-average water temperatures in a portion of the Pacific Ocean along the equator between, roughly, the coast of Ecuador and the International Dateline.

El Nino: Warmer-than-average water temperatures in that zone.