Winter Weather Center
Lake Effect SnowLake Effect Snow is responsible for a good portion of our yearly snowfall. This is evident when looking at annual snowfall averages from around the region. North Central Pennsylvania, for example, does not get much lake effect snow and thus averages roughly 30" per year. Syracuse, on the other hand, averages over 100". Even over the eastern Finger Lakes region, seasonal snowfall varies greatly.
Lake effect snow is plentiful in our area because of our proximity to Lake Ontario and, to a much lesser extent, Lake Erie. The water temperature of these and the other Great Lakes stays relatively warm deep into the winter. As cold air flows over these warm bodies of water, a significant temperature difference between them forms. The warm water warms the air immediately above the surface, which then can quickly rise because warm air is less dense than cold air. As the air rises, it condenses into clouds and eventually precipitates. Precipitation can be enhanced by the upward slope of the terrain away from the lake shore. In fact, upward motions in some lake effect storms can be vigorous enough to lead to lightning.
Occasionally, if the winds are just right, lake effect snow from the Georgian Bay in Canada can actually enhance the lake effect snow off of Lake Ontario, creating blizzard conditions and rapidly accumulating snowfall. Lake effect snow can also occur of the Finger Lakes if the winds are just right. Areas to the south-southeast of the lakes can sometimes pick up a few additional inches of snow from Finger Lake Effect.
Alberta ClippersAlberta Clippers are usually much weaker storms than nor'easters or even lake effect. They tend to originate just east of the Canadian Rockies in the Canadian province of Alberta. They are often quick moving storms that dive down into the Mid West and across the Great Lakes. Stronger clippers may be able to bring a quick 6-10" of snow. Sometimes, a clipper will become a nor'easter once it reaches the East Coast. A shot of cold air typically follows these storms down from Canada, often leading to lake effect snow in our area after the clipper moves out.
Mixed Precipitation EventsWinds spin counterclockwise around areas of low pressure. As a result, winds are often out of the southeast or south as a storm approaches. These southerly winds can bring in warm air and lead to mixed precipitation events. The extent of the warm air, and how warm it is, can be very difficult to forecast, yet even a single degree can have significant impacts on what eventually happens. Often times, mixed precipitation events will start off with a shot of snow. While brief, the snow may be heavy. This is usually along a warm front, and is followed by the warm air. Warm air first moves in aloft before moving in at ground level. As a result, temperatures aloft can be above freezing, while temperatures at the surface below. This sets up the potential for a period of sleet or freezing rain. As more warm air comes in at the surface, the ice changes to plain rain. A cold front then will often come through, and the rain quickly turns back to snow.
Wind ChillThe wind chill is a measure of how cold the air feels due to the wind. As wind blows over a person's skin, it removes moisture. This acts to cool the skin, making it feel colder than it is. This cooling effect can lead to numbness and even frostbite. A wind chill advisory is issued for our area when the wind chill is expected to be between -15ºF and -25ºF. Wind chill readings colder than -25º can be expected with a wind chill warning. In these conditions, frost bite can occur on exposed skin, especially the finger, toes, ears and nose, in minutes. To prevent frostbite, make sure all skin is covered and stay indoors if possible. Should you suspect frostbite, seek immediate medical attention and only slowly warm the frostbit area.
If you have any questions regarding winter weather, feel free to contact me!