Behind the Forecast: What is a Clipper

LOUISVILLE, Ky. (WAVE) - Clippers are a typical part of Winter weather in the Ohio Valley. But, what exactly are they.

The National Weather Service defines an Alberta Clipper as a “fast-moving, low pressure system that moves southeast out of Canadian Province of Alberta through the Plains, Midwest, and Great Lakes region usually during the winter.” As an Alberta Clipper moves by, it usually brings strong winds, light snow, and much colder temperatures to a region.

An Alberta Clipper begins to form when an area of low-pressure moves towards British Columbia’s Pacific coast, causing the wind flowing across the Rocky Mountains to increase and a trough (an elongated area of relatively low atmospheric pressure) to develop. The trough lingers on the leeward side (in this case the eastern side) of the mountains and continues to strengthen. Once a cold front overtakes the trough, the Clipper begins to push east. The Clipper then usually pushes southeast moving through the northern Midwest and Plains, over the Great Lakes, and towards the northeastern United States.

Clippers get their name from the fast sailing yachts that were popular in the 19th century. They are fast-moving storm systems, marching southeast at 30 to 35 MPH.

Typically, clippers don’t produce heavy snowfall since they are far away from a moisture source. However, when they can tap into additional moisture (such as from the Great Lakes) they can produce substantial amounts of snow.

These areas of low pressure can leave behind very cold air in their wake. Temperatures could drop as 30°F in 12 hours with some Clippers. In addition to the cold temperatures, Clippers can produce very strong wind gusts; sustained 40 MPH winds with 60 MPH gusts are possible with stronger Clippers.

Alberta Clippers are more common during December and January; they are few and far between during October and March.

They go by a few other names including the Manitoba Mauler or Saskatchewan Screamer and Ontario Scary-os.

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