Historic Buffalo Lake Effect Snowstorm November 18-19, 2014: A Preliminary Look at the Sharp Northern Gradient in Snowfall

November 18 and 19th, 2014 brought the first half of a week-long, historic lake effect snow (LES) storm off of Lake Erie. More than 5 feet of snow fell across the Buffalo Southtowns, with mere inches of snowfall a few miles to the north. The dramatic difference in snowfall over such a short distance was accentuated by three main factors: 1) the sharp gradient in snowfall as observed in the reflectivity from the Buffalo WSR-88D radar on the northern edge of the lake effect snowband, 2) the near stationary position of the band for almost 24 hours, and 3) very intense snowfall rates of 3 to 5 inches per hour.

The goal of this study is to investigate the lesser understood aspects of the event, namely the sharp gradient along the northern edge of the band and the near stationary position for an extended period of time. Anecdotal evidence from forecaster experience within the National Weather Service (NWS) Weather Forecast Office (WFO) Buffalo, NY suggests that a sharp gradient along the northern edge of long lake axis parallel (LLAP) LES bands are more commonly observed on Lake Erie than on Lake Ontario. From a forecast stand point, the sharp northern edge of the Lake Erie snowband was anticipated from prior experience; however, the physical process by which it forms is not well understood.

While a steady-state, intense band of LES was anticipated for Tuesday the 18th, the forecast called for the band to linger over the Buffalo Southtowns during the day before settling south into the Boston Hills by Tuesday night (roughly 25 km south). However, the band did not settle south; instead, the band developed a kinked structure, which followed a 260 degree direction over central Lake Erie, but bent to a 240 degree direction over eastern Lake Erie into the Buffalo Southtowns. This structure allowed the more intense northern edge of the band to linger over the Buffalo Southtowns, significantly increasing snowfall totals.

This study shows preliminary observational analysis of the kinked structure of the band and the tight northern gradient, and how they might be related. The focus is to examine hypotheses that could be used to better understand the physical processes driving the observed structure of the snowband, from terrain influences to diabatic heating. The observed structure and placement is compared to operational numerical model representations, and the shortcomings of the models discussed. The study concludes with ideas for future research, including high resolution numerical model simulations, which could help improve the forecasting of these extreme LES events.