Buffalo and much of the lakeshore towns of New York and Pennsylvania are well known for the heavy lake effect snow they receives each winter.
Up until now, things have been quite calm, but over the next couple of days some 2 to 3 feet of snow will fall. The snow that falls on the leeward side of the Great Lakes could be monumental and bring travel to a full halt, even in the snow hardy areas of Western New York and Pennsylvania.
The reason for the extreme snow is quite simple actually. Meteorologically cold dry air blows over the comparatively warm Great Lakes and picks up moisture. As the wind goes from the windward to the leeward side of the Great Lakes, it continues to evaporate moisture eventually depositing it in the form of heavy snow.
These bands of heavy snow are relatively narrow and 5 or 10 miles away the sun can be out while areas under the heavy snow bands have zero visibility thunder and snowfall rates of 2 to 4 inches per hour. It’s quite a fascinating phenomena.
The bigger the difference between the air temperature and the water temperature the greater the potential for heavy snow. If you look at the current temperature of Lake Erie, it’s running quite high for the time of year.
This is one of the reasons this particular event is so powerful. If the water temperature were even just a few degrees cooler, the difference between the air and the water would be smaller, and the amount of heavy snow would decrease.
In order to get significant lake effect snow, you have to have cold air and a wind blowing from the north the west or even a little bit southwest. The different wind directions bring lake effect snow to different towns on the leeward side of the lakes.
You might wonder if the same phenomena can occur here with our big ocean just to the east. The answer is a resounding yes, however it is somewhat less likely. If however we get cold Arctic air coming down from the north or the northeast, the outer tip of the Cape and and parts of the South Shore, as well as, Cape Cod can experience ocean effect snow.
The meteorological process is identical to the lake effect. One of the reasons why it’s not quite as extreme is because our prevailing wind is from the west or northwest. When we do get cold Arctic air coming from the north, you can see these lake effect bands across parts of Cape Cod.
Indeed, the weather service puts out advisories mentioning this in most winters.
Although it’s going to be chilly the next several days because we’ll have a westerly wind, we won’t have to worry about any ocean effect snow. However, sometime over the Thanksgiving weekend we may have to be concerned about a nor’easter. More on that next week.