A Prolonged Moist Winter Storm over the Central Rockies: Storm Overview and Forecast Challenges

A complex winter storm impacted the central Rockies during 30 January – 3 February 2016. The first phase of the storm was characterized by a moist “Atmospheric River” which fed the storm with anomalous moisture. The focus of the precipitation was modulated by a cold front which slid slowly south across Colorado during the early portion of the storm. Timing and onset of this precipitation, as well as forecasted rain-snow line, was problematic from the forecaster's perspective. The second phase of the storm was forced by a closed low which moved slowly east across the region onto the High Plains. A combination of strong dynamical and jet support along with good orographic forcing and instability resulted in 3-5 feet of snowfall in some mountainous location, with lesser amounts over lower elevations. This study will examine the storm evolution, with focus on the track of the cold front, and the factors that contributed to the extreme snowfall amounts over the higher terrain.