Snowfall Alert Triggered Because Great Lakes Still Warm.

http://www.bloomberg.com/news/2014-11-14/snowfall-alert-triggered-because-great-lakes-still-warm.html

It doesn’t take a storm to pile up the snow. Sometimes a cold, steady breeze over warm water will do the trick.

The chilly air spilling down from Canada that has sent temperatures plunging as far south as Texashas provided one part of the recipe. Water temperatures mainly in the 40s Fahrenheit (single digits Celsius) across the Great Lakes serve up the other.

The result -- lake-effect snow.

“Basically, what causes it is cold air over a warmer lake,” said Dan Kelly, a U.S. National Weather Service meteorologist in Cheektowaga, New York, just east of Buffalo.n “The lake provides the moisture and you get this prolonged snow event downwind.”

The results can be dramatic. An early such snowfall, in October 2006, dropped two feet (60 centimeters) of snow in 16 hours along the northeast corner of Lake Erie, according to the National Oceanic and Atmospheric Administration. A few months later, Redfield, New York, on southeastern Lake Ontario, got almost 12 feet over 10 days, the agency said.

Warnings and advisories are in force along the Great Lakes’ shorelines from Wisconsin to New York, according to the National Weather Service. Environment Canada has posted its own for Ontario.

Buffalo Outlook

As of yesterday, only a trace of snow had fallen in Buffalo. By this morning, at least 2 inches were expected to fall with more in Watertown, New York.

This isn’t coming because of a storm. A cold front passed through earlier this week and the westerly winds it helped set up are just triggering snow.

Further to the west, the projected amounts go up.

Erie, Pennsylvania, has been warned to be on guard for lake-effect snow through the weekend, with as much as 10 inches falling, the weather service said. Michigan’s Upper Peninsula may get as much as 10 inches on top of more than 3 feet of snow the region has received since Nov. 1.

As much as 6 inches may fall along coastal Ontario.

Kelly said prolonged cold can actually help over time, at least in Buffalo.

“Lake Erie will usually freeze over, and once that happens it greatly reduces the lake effect,” Kelly said.