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Winter Weather Center

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As any Central New Yorker can attest to, winters here are rough. From lake effect snow, to nor'easters, to storms that bring a mixed bag of wintry precipitation, none one else quite gets the wide variety of winter weather that we get.

Lake Effect Snow

Lake 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.

Finger Lakes Lake Effect Snow on Radar This zoomed in view of the National Weather Service radar shows a band of Finger Lake Effect snow impacting Ithaca from Cayuga Lake.
Lake effect snow tends to form in bands along the direction of the wind. The more time the clouds have to spend over the warm lake waters, the more intense the band may become. That is why areas east of Lake Ontario get significantly more snow than even Syracuse. A wind blowing from the west has the entire length of Lake Ontario to create a strong lake effect storm, while a wind from the northwest has a much shorter time over water. When lake effect does not spend enough time over water, multiple smaller bands can form. This is often the case for the eastern Finger Lakes Region.

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.


Weather Satellite Shows Nor'Easter Striking the Northeast A powerful nor'easter is seen on this satellite image from 2006. Note the hurricane-like eye in the center of the storm, just southeast of New Jersey.
Lake effect is not the only storm that can bring heavy snow to the area. Nor'easters are powerful storms that form just off the east coast of the United States, usually near the Carolinas, before moving north to New England. Like lake effect, they also feed off of the temperature differences between the warm waters of the Gulf Stream and the cooler land. These storms are capable of bringing extremely heavy precipitation over a large area. The track of a nor'easter is an extremely important determining factor on what type, and how much precipitation an area sees. A storm track further off the coast can leave central New York with little more than clouds while major cities like New York and Boston get buried. A track right along the coast will give these places rain, while the heavy snow comes further inland, sometimes to our area.

Alberta Clippers

Alberta 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 Events

Confusing Winter Precipitation

Sleet- Precipitation that falls to the ground as ice
Freezing Rain- Precipitation that falls as liquid rain, but freezes on contact with a surface.
Graupel- Precipitation formed when water freezes to a snowflake. Often occurs in the fall and is confused for hail.

Winds 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 Chill

Did You Know? Wind Chill

The criteria for a wind chill advisory or warning varies by location. Those who are exposed to more cold have a higher tolerance, while those rarely exposed to cold need to take precautions in temperatures others may consider mild. For example, in Alaska, a wind chill warning is not issued until the wind chill is colder than -60F! Meanwhile, in Florida, a wind chill advisory can be issued for wind chills of 35-40F due to the risk of hypothermia.

The 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 -15F and -25F. Wind chill readings colder than -25 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!

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