After two very snowy previous winters, including last year's historic lake effect event when the southern suburbs of Buffalo, NY already had 5 - 7 feet of snow by November 21st, 2014, it may seem unusual for Buffalo, NY and some of the other lake effect areas to be without measurable snow at this point in the season. The combination of a lack of significant cold air nor any potent disturbances has contributed to the current deficit. Let's address two important questions: what has led to such a mild and quiet weather pattern and is this slow start to the snow season truly unprecedented?
So why is Mother Nature keeing most of the cold and snow at bay? We can partly blame the strong El Nino as well as other teleconnections such as the Pacific Decadal Oscillation and Eastern Pacific Oscillation which are also in phases that favor a wetter and milder Northeast winter. While the fall and early winter are the best times for lake effect snow along the Great Lakes, the lack of the cold air Canadian air masses traveling over the lakes and numerous broad areas of high pressure have kept snow away so far this season.
Even when a favorable lake effect scenario developed this year such as on November 22 - 23, 2015, one essential element was off: the fetch. Fetch is the distance and direction wind is able to travel across the open lake waters and considering how narrow lake effect bands or snow showers can form, it is vital to lake effect formation. Combine a good fetch with a large temperature difference between the cold land and warm lakes, and the lake effect snow machine is in business. On November 22-23, 2015, the southern tier of southwestern NY south of Buffalo received some unorganized lake effect snow showers as a northwest wind progressed over Lake Erie. However, Buffalo typically needs a west-southwest wind off Lake Erie to experience its famous lake effect snow. Without the appropriate fetch, the city recieves paltry lake effect snow, if any at all.
While such a warm and relatively snowless November and December may seem quite unusual, our reference for normal snowfall is skewed due to recent memories of abnormally early and high snowfall. Back in 2012, Buffalo witnessed a similar deficit as seasonable snowfall through December 9th, 2012 only amounted to 2.4", all of which occurred during the last half of November. That put Buffalo's snow deficit at just over a foot compared to the current deficit of about 13.3". And let us not forget the Winter of 2011-2012, in which the entire Northeast experienced significant seasonal snowfall deficits with Buffalo only recording 36.7" from October 1st, 2011 to April 30th, 2012. Its average winter snowfall is more than double that at 94.4".
