1 hour 49 min ago
By Chris Dolce


Iced Cars and Feet of Snow

The return of arctic air to the Lower 48 states set the stage for feet of snow this week in the snow belts of the Great Lakes. In addition, a windy clipper low pressure system will bring a general light snow to the Great Lakes, Ohio Valley and parts of the Northeast, resulting in hazardous travel conditions.

(MORE: Arctic Air Returns to the U.S.)

The first round of lake-effect snow has developed behind the now departed Winter Storm Hera. This allowed cold winds to flow over the relatively milder waters of the Great Lakes, leading to the development of lake-effect snow. (Note: For more on what lake-effect snow is, see the final section of this article.)

An intense band of lake-effect snow off of Lake Erie has already produced accumulations of up to 25 inches in southwest New York as of Monday night. Up to 34 inches of snow has been measured east of Lake Ontario in Lorraine, New York, so far.

Great Lakes Radar

Great Lakes Radar

This first round of lake-effect snow will get interrupted by a low pressure system that will bring a more general snowfall to parts of the Great Lakes region, followed by another round of lake snow.

Below we have a look at the forecast for the clipper and the next round of heavy lake-effect snow.

Clipper Brings Snow, Wind Through Tuesday

A fast-moving low pressure is moving through the Upper Midwest and will pass through the Great Lakes and Northeast Tuesday, spreading a general swath of light snow accumulations across those regions. As mentioned before, this will also briefly disrupt the lake-effect snows as winds change direction with its passage.

Winter Alerts

Winter Alerts

Winter storm warnings have been issued for portions of western Michigan and Maine where snow total of more than 6 inches are possible. Winter weather advisories have been posted from Michigan southward into Kentucky and West Virginia, as well as in parts of Upstate New York and northern New England. In these areas light to moderate snow in combination with gusty winds may limit visibility and impact travel.

This low pressure system is what meteorologists call a “clipper”.  Clipper systems are fairly common in the winter when the weather pattern features a dip, or a developing dip, in the jet stream east of the Rockies. Disturbances in the upper atmosphere and/or low pressure systems near the surface of the earth dive down across the Midwest from Canada and charge eastward rapidly. These fast-moving systems can produce light-to-moderate snowfall across a wide area, gusty winds and falling temperatures.

(VIDEO: What is a Clipper?)

Snow in most areas should only be a few inches at most. However, gusty winds will likely contribute to blowing snow and low visibility as it passes through the Upper Midwest, Great Lakes, Ohio Valley, western/northern Pennsylvania, New York, the central Appalachians and New England. Please use caution while driving in those areas as this is the type of situation where even a brief burst of intense snow and wind could cause travel problems, including pileups.

(MORE: Is Light Snow More Dangerous For Drivers Than Major Storms?)

A burst of snow or rain mixed with snow may also reach as far south as New York City Tuesday evening.

Tuesday's Forecast

Tuesday’s Forecast

Accumulations will be light in most areas, but dangerous travel conditions are possible.

Tuesday night, some heavier snow amounts are possible in Maine as low pressure develops off the New England coast in response to clipper’s upper-level energy. The National Weather Service has issued a winter storm warning for northern and central Maine Tuesday night into Wednesday morning, where more than 6 inches of snow is likely.

That clipper system will also set the stage for even more lake-effect snow in the Great Lakes midweek onward.

Lake-Effect Snow Round Two: Late Tuesday-Thursday

After the clipper passes through, more lake-effect snow will likely develop from west to east throughout the Great Lakes later Tuesday and Tuesday night, and then lasting through Thursday.

As is typical, the heaviest snow totals will likely be found in the eastern Great Lakes region to the east of Lakes Erie and Ontario. Snowfall rates of several inches per hour along with thunder and lightning may accompany the heaviest snow bands. Totals in excess of a foot are likely in areas where snow bands are most persistent.

(FORECAST: Erie, Pennsylvania | Buffalo, New York | Watertown, New York)

Lake-Effect Snow Alerts

Lake-Effect Snow Alerts

The National Weather Service has issued lake-effect snow warnings for parts of western New York, including Buffalo, far northwest Pennsylvania and areas east of Lake Ontario into the Tug Hill of northern New York. Snow totals of 1 to 2 feet (locally 3 feet east of Lake Ontario) are possible in locations where snow bands are most persistent, along with strong winds.

Elsewhere, lake-effect snow advisories are in place for parts of northeastern Ohio and the Upper Peninsula of Michigan.

(MAP: Winter Weather Alerts)

The snow and wind may lead to travel problems on I-81 east of Lake Ontario in northern New York, and along stretches of I-90 in western New York, northwest Pennsylvania and northeast Ohio.

Periods of snow will also impact other parts of the Great Lakes region from midweek into late week.

Our forecast snowfall map gives a general idea of where the heaviest totals are expected from both rounds of lake effect and the clipper system through Thursday. Areas shaded in dark purple or pink could see snow amounts in excess of a foot, including parts of Upper Michigan, northwest Lower Michigan, northwest Pennsylvania, and western parts of New York.

Snowfall Forecast Through Thursday

Snowfall Forecast Through Thursday

What is Lake-Effect Snow?

Lake-effect snow is a common sight in the snowbelts downwind of the Great Lakes in late fall and winter.

After a cold front passes through, chilly winds mainly from the west or northwest flow over the relatively warmer waters of the lakes and gather moisture, allowing clouds and bands of lake-effect snow to develop. This snow, sometimes heavy, then piles up in locations generally to the east and southeast of the Great Lakes.

The direction and duration of the winds in combination with the difference in temperature between the air mass and the water of the lake typically dictates how much snow will fall in any one location. See the video at the link below for more information.

(VIDEO: Science Behind Lake-Effect Snow)

For two of America’s snowiest cities, Boonville, N.Y. (193.5 inches each season) and Hancock, Mich. (211.9 inches each season), lake-effect snow is a big contributor to the monstrous snow totals seen each season.

But it’s not just the Great Lakes where this phenomenon occurs. Click this link to see some of the other bodies of water in the United States and around the world, including lakes, bays and oceans, that have produced snow from the same basic ingredients described above.

PHOTOS: Epic Lake-Effect Snow in Western New York November 2014

Lake Effect Snow: Lancaster, N.Y
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