What to know about clipper systems, which bring shots of cold air from Canada
The systems were named after shipping vessels of the mid-19th century.
— -- Since last weekend, the Midwest and the Northeast have been in a perfect atmospheric set up for quick-moving clipper systems bringing several inches of snow and reinforcing shots of cold air every other day, from Minnesota to New York.
What is a clipper system?
A clipper systems is an area of low pressure that usually forms in the southern provinces of Canada and quickly drops southeast into the eastern United States.
Because of the fast-moving nature of the system, it usually does not have time to tap into the moisture from the Gulf of Mexico or the Atlantic, and that’s why it usually does not bring much snow to the eastern U.S. -- generally 1 to 3 inches.
Sometimes, a system can bring a little more than a few inches of snow, especially when it slows down in the Northeast. Then, it has time to interact with the Atlantic Ocean and the Gulf Stream.
Because these low pressure systems form in Canada, they usually bring a shot of cold, arctic air with them.
Why are they called clipper systems?
A clipper was a very fast-sailing ship of the middle third of the 19th century. They were generally narrow for their length and small by later 19th century standards, but could carry limited bulk freight over a large total sail area.
There are several names for these clipper systems, depending from which Canadian province they originate.
The most common one is the Alberta Clipper, which forms in the province of Alberta. Then there are the Saskatchewan screamer, Manitoba mauler and the less common Ontario scari-o.