The Winter Outlook for the Western U.S.

The big question right now for outdoor enthusiasts in the western U.S. is how much snow will fall this winter.

Last year was a mixed bag, with snow drought conditions in California and southern Utah, while Washington, Idaho and Montana made up for a dry fall to end up with above-normal snowpack by early spring.

The latest snowpack information from the USDA Snotel network indicates well-below-normal snowpack over the Sierra and Cascades, but near-normal conditions over Colorado, Wyoming, Montana and Idaho.

cliff mass 1

But what will happen next? Meteorologists’ most useful tool for predicting the nature of western U.S. winters is the correlation between El Nino/La Nina and regional weather. El Nino years are associated with warmer-than-normal tropical Pacific waters and often bring warmer-than-normal conditions to the western U.S., less snow in the northwest and more precipitation in the southwest.

It appears this winter we will be in a weak El Nino pattern, and forecasters at the National Weather Service’s Climate Prediction Center are predicting a winter with El Nino characteristics. There will be more precipitation over the southern tier of of the U.S. and drier-than-normal conditions over the Northwest.

cliff mass 2

The Climate Prediction Center forecasts warmer than normal conditions from the Rockies to the West Coast. Keep in mind that such long-range forecasts have imperfect skill, analogous to weighting a coin so that heads occurs perhaps 70 percent of the time.

cliff mass 3

The bottom line prediction for snow lovers?

There will be below-normal snowpack over the Northwest and more precipitation in California than last year, which means more snow in the high Sierras. Colorado will have a normal year. This forecast has imperfect skill, but it is the best we can do at this point.