NEW YORK — Upstate New York is seeing perfect lake effect snow conditions this week leading to some areas getting over three feet of snow by Saturday, Feb. 28. This portion of New York along with the Upper Peninsula of Michigan average some of the most snow in the entire country but a few factors have to come together to make that possible.
The first ingredient needed is wind but it’s important where it’s coming from. A prevailing northwest wind generally means dry and cold arctic air is moving into the United States. As that cold/dry air moves over the Great Lakes, the warmer moist air at the lake’s surface is able to condense and be more buoyant than the surrounding cold air. This warm moist parcel of air is able to rise freely into the colder upper atmosphere and produce snowflakes and lots of them!
The most important factor though is the lakes themselves. You can’t just get lake effect on any old lake, large expanses of unfrozen water are required. Our current ice coverage resembles that of most early winters.
Large exposed areas of water that’s warmer than the surrounding air allow plenty of moisture to build up in the cloud and start dumping snow downwind. As mentioned earlier warm and moist air is more buoyant and as that warm air rises and cools it condenses out as precipitation! This same process is possible over oceans and other large lakes across the world. All you need is cold and dry air moving over a warmer very large body of water.