Global warming and winter temperatures
The Great Lakes contribute to a huge thermal inertia, which will even out short-term temperature fluctuations, and delay the smoothed seasonal temperature peak. On the other hand, more sinuous looping of the jet stream  is likely to have a comparable, if not larger, effect upon the temperatures in Buffalo. The process is this: As global warming progresses there is a disproportionate warming towards the polar regions. This results in a reduced temperature gradient with respect to latitude. It is this gradient which is largely responsible for the jet stream intensity. As the jet stream weakens it becomes more sluggish and sinuous, resulting in regional hot and cold anomalies. If Buffalo happens to get caught in one of these jet stream loops, it is quite possible to have periods of anomalously low temperature, even though there is an overall North American warming. It is also possible for Buffalo to get caught in a negative loop, and hence experience anomalously hot temperatures.