Snowpack news: Below average west and average east of the Great Divide, where is La Niña?



Click on the thumbnail graphics to the right for the U.S. Drought Monitor and current snowpack map. Here’s a report from Bob Berwyn writing for the Summit County Citizens Voice. From the article:

This year’s La Niña has been a bit of a disappointment so far, said Klaus Wolter a meteorologist with NOAA’s Climate Diagnostic Center who specializes in evaluating the impacts of the El Niño-La Niña cycle in the southwestern United States…

“The Front Range has done really well,” he said. At his backyard weather station, Wolter picked up 31 inches last week and has recorded more than 70 inches for the season, second only to 1997 in the past 20 years or so.

But Wolter, who recently updated the seasonal forecast for the SWcasts website, expects at least normal snowfall for the remainder of the winter.

The official three-month outlook (December to February) calls for a 33 to 40 percent chance of above-normal precipitation for most of northern Colorado, including the Summit County area.

The overall dryness from New Mexico into eastern Colorado since the beginning of October matches the forecast issued in September. The early November windstorms were also typical for a La Niña.

“My forecast for January through March 2012 is more optimistic than my earlier forecast from September for our north-central mountains, but not for the Four Corners region. The Arkansas Valley has better prospects (near-normal moisture) than is typical for La Niña, while northeastern Colorado has no clear preference for dry or wet this winter,” Wolter wrote in the SWcast outlook.

From the Vail Daily (Lauren Glendenning):

Weather forecasters say La Nina — a weather system where cold ocean temperatures in the eastern Pacific Ocean bring wetter than normal conditions across the Pacific Northwest and drier and warmer than normal conditions across much of the southern United States — is weaker than it was last winter. Recent weather patterns, however, just don’t follow any conventional wisdom about snow in northern Colorado, La Nina winter or otherwise. Joel Gratz, a meteorologist who runs the website, formerly, calls the weather pattern we’ve seen over the last six or so weeks “pretty difficult.” The computer forecasting models that Gratz and other weather forecasters use haven’t been helpful in predicting when the current pattern will shift…

The pattern is such that storms have been coming in from the Pacific Ocean over British Columbia, Washington or Oregon — as they typically do in La Nina winters — but then the systems have been splitting into two sections. The southern portion has been tracking farther south, while the northern portion stays north of Colorado, said Jim Daniels, a forecaster with the National Weather Service in Grand Junction. The systems have just been going too far south to bring any significant snowfall to the Interstate 70 corridor. The next 14 days just show more of the same, too, Daniels said…

The news has been great for resorts like Wolf Creek, which has received significant snowfall accumulations over the last week and a half or so. And Vail and Beaver Creek have seen some light snowstorms move through in the same time frame, but accumulations have been minimal. The U.S. Department of Agriculture’s Natural Resources Conservation Service snow measurement data shows Vail Mountain precipitation from Oct. 1 to Dec. 13 of this year at 72 percent of normal.

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