Relief from the (mostly) dry weather?

Precipitation forecast February 15 thru February 19, 2015 via the Climate Prediction Center
Precipitation forecast February 15 thru February 19, 2015 via the Climate Prediction Center

From the Vail Daily (Scott N. Miller):

While snowfall is being measured in feet in the northeastern U.S., particularly New England — Boston has broken a 30-day snowfall record — the western part of the country has been clear and dry. In fact, the last sustained snowfall in the valley dates back weeks now, probably into the last days of 2014.

HIGH PRESSURE SYSTEM

The culprit has been a lingering high pressure system in the western U.S. that has shuffled Pacific storm systems into a persistent low-pressure system in the eastern part of the country. The result has been great gobs of snow there, with just a few random snowstorms in this part of the country.

The question, then, is when those patterns will change, bringing relief to the Northeast and the relief of fresh powder to the Mountain West?

‘EVENTUALLY’

The answer, at this point, is a somewhat vague, “eventually.”

Ellen Heffernan, a forecaster at the National Weather Service’s Grand Junction office, said next week could bring a slight disturbance in those persistent patterns. The predicted snow, though, could track mostly into the southern part of the state.

But if you think this part of the state could use some snow, Southern Colorado is really hurting. The U.S. Drought Monitor website shows the southeastern part of the state is already in a “severe” drought, with other areas rated as being in a “moderate” drought.

West Drought Monitor February 3, 2015
West Drought Monitor February 3, 2015

Most of Western Colorado is rated as “abnormally dry.”

WATER SUPPLY FOR SUMMER

That’s bad for powder-loving skiers, of course. It could also be bad news for summer water supplies, since virtually all of Colorado relies on mountain snowfall for agricultural and domestic water.

But Jim Pringle, another forecaster at the National Weather Service’s Grand Junction office, said current snowpack numbers are OK, despite several dry weeks. Still, he said, the warm weather is abnormal for the region.

According to a Feb. 5 release from the U.S. Natural Resources Conservation Service, the Colorado River basin, of which Eagle County is a part, still had 95 percent of its average snowpack despite a very dry January.

But snow is needed, and fairly soon, to maintain a good snow supply for the summer.

Diane Johnson of the Eagle River Water & Sanitation District said it’s important to look ahead into the spring, toward the dates when snowpack generally is at its peak for the snow season.

“Every day you don’t get precipitation, you’re affecting that peak,” Johnson said.

That’s why good numbers now can quickly turn dismal if the weather doesn’t cooperate.

The peak dates are also important because snowpack numbers tend to fall quickly once the warm days of spring arrive. Even a big snowfall in late April won’t have much of an impact because that snow tends to melt quickly.

LONGTERM OUTLOOK

Forecasters can’t predict specific storm patterns past 10 days or so. On the other hand, the long-term outlook is pretty positive. The National Weather Service Climate Prediction Center calls for near-normal temperatures and above-average precipitation through the end of March and into April.

Pringle acknowledged the difficulty of long-range forecasts for specific storms, but added the Climate Prediction Center’s more general forecasts are generally pretty reliable.

Don’t put away the boots and shovels or drain the gas tanks on the snow blowers just yet.

From Steamboat Today (Tom Ross):

In spite of sparse January snowfall and the early spring skiing weather that prevailed during the first week of February, the moisture stored in the snow on the West Summit of Rabbit Ears Pass is a healthy 98 percent of median for Feb. 9.

To the south, in the foothills of the Flat Tops at Crosho Lake, that number is 119 percent of the median for the date. Snowpack numbers at Rabbit Ears and Crosho Lake don’t jive with the overall Feb. 1 snowpack numbers released Feb. 5 for the combined Yampa/White River basins by the Natural Resources Conservation Service. And in other locations in Northwest Colorado, snowpack is much lower.

Colorado Snow Survey Supervisor Brian Domonkos said in a news release that the North Platte River Basin along with the combined Yampa/White River Basins saw snowpack decrease in January by margins of 23 and 26 percent of normal respectively.

“With nearly one-third of the winter remaining, Colorado is running short of time to catch up,” Domonkos said. “Statewide snowfall would need to amount to 124 percent of normal from now until mid-April to achieve normal snowpack peak levels.”[…]

Domonkos said that although summer outlooks for streamflow volumes for April through July vary significantly around the state, most are forecasted to be between 60 percent and 85 percent of average.

streamflowforecast02012015nrcs

The forecast for the Yampa stood at 81 percent of average streamflow on Feb. 1. The Little Snake River drainage to the northwest of Routt County was forecasted to have only 71 percent of average flows. And the forecast for the White is 79 percent.

If there is a reason for optimism, it could be found in the current water storage in reservoirs around Colorado. Reservoirs in the Yampa/White River drainages are among the strongest in the state, averaging 112 percent after heavy rainfall in July, August and September, according to the Conservation Service.

The snowpack numbers around the Yampa and Elk River drainages are spotty.

On Buffalo Pass at the tower measuring site, snowpack was 79 percent of median on Monday. But even Buffalo Pass seems to be benefitting from the fact that the relative handful of snow storms that have passed over the northern Flat Tops and the Park Range have been high-moisture events.

At Rabbit Ears on Feb. 2, the snow depth was a modest 37 inches and contained 12.2 inches of moisture. Four days later on Feb. 6, 15 inches of additional snow depth had bumped the water content to 14.8 inches, or an additional 2.6 inches of snowpack.

It was a similar story on top of Buffalo Pass where the snowpack picked up an additional 4.3 inches of water thanks to 20 inches of new snow that boosted snow depth to 77 inches.

North of Steamboat, the Elk River and Lost Dog sites at 8,700 feet on the edge of the Mount Zirkel Wilderness area both stand at 83 percent of average.

Click on a thumbnail graphic below to view a gallery of snowpack data from the Natural Resources Conservation Service.

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