Skiers and snowboarders scan for signs each year as fall spins into winter to glean some inkling of what lies ahead. Will winter bring cold and snow, warm rain, some combination? Will cold and wet air masses match up in such a way that snow results?
So what can Denver expect this coming winter, according to the Lords of Climate at the National Weather Service? Short and sweet: The NWS long-range forecast for the Southern Rockies for December, January, and February predicts above normal temperatures, and an equal chance for above, normal, and below-normal precipitation.
Everything is relative, however, and a bad snow year in the Rockies could be a record-breaker in other parts of the country.
Denver, lying a mile high just east of Colorado's Front Range, has an average annual snowfall of 60 inches. Once over those mountains, however, you're in snow country where snowfall is measured in feet. Vail, for instance, averages more than 350 inches a year.
The National Weather Service puts out long-range forecasts for the entire country. These prognostications are based on historic weather patterns, temperature and precipitation records, and other climate indicators from around the globe. They sometimes hit the nail on the head, but often do not.
Some seek counsel elsewhere. Do woolly bear caterpillars have thicker coats than normal? Are there more nuts falling, and are squirrels scampering even more madly than usual to store up winter food? It's a mystery why people ascribe powers of foreknowledge to insects, rodents, and nuts, but some do. After comparing long-range predictions with what actually happens, some conclude the critters and acorns are just as reliable as the scientists.
Jeremy Davis, senior meteorologist with Weather Routing Inc., a weather service in upstate New York, questions the wisdom of over-reliance on long-range forecasts. Davis suggests that the devil in forecasting lies in the little details of timing that determine the shape of the weather.
"Whether you have snow or rain depends on exactly when the precipitation falls," Davis said. "It can be warm and dry, or cold and precipitating. The long-range forecasts missed the cold snap in January, and the rainy June."