The January-February 2015 Winter Blitzkrieg over the Northeastern United States: Significant Predictability Issues and Communicating Uncertainty Problems

Winter 2014–2015 began with a vengeance in mid-November 2014 over much of the CONUS east of the Rockies. The coldest November weather in 35 years was ushered in by a sequence of arctic air masses that progressively advanced eastward and southward across the CONUS. An epic lake-effect snowstorm that buried parts of western New York on 18–19 November was followed by a series of snow and ice storms that disrupted Thanksgiving holiday travel. Arctic air retreated poleward during the first part of December 2014, but returned in force over much of the eastern CONUS late in the month. Between mid-January and mid-February 2015, multiple extreme weather events that featured record-breaking monthly and seasonal snowfalls and record-breaking daily minimum temperatures were observed over parts of the northeastern United States and adjacent Atlantic Canada.

Beginning in January 2015, a high-amplitude flow pattern developed that featured persistent high-amplitude ridges over northeastern Russia, Alaska, western North America, and the North Atlantic and deep troughs over the eastern North Pacific and eastern North America. This persistent amplified flow pattern supported the occurrence of frequent heavy snowstorms, including blizzards, over parts of the northeastern CONUS during the latter part of January and much of February 2015. The discussion will focus on the coastal storm of 26–27 January 2015 which was noteworthy for creating blizzard conditions in the Boston area and a significant snowstorm in the New York City area. Special attention will be devoted to predictability issues and communicating uncertainty problems associated with this storm. We will compare and contrast the real-time challenges of using operational ensemble snowfall amount forecasts to make public snowfall amount forecasts in the Boston and New York City metropolitan areas.