Published: Monday, December 11, 2017 @ 3:18 PM
By: Eric Elwell
— What is typically born in Alberta, Canada, and tends to love La Nina winters? An Alberta Clipper, of course.
It’s one of the most significant synoptic-scale winter weather phenomena affecting central North America and the Great Lakes.
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We had one bring us snow last weekend, and we have another one crossing the Great Lakes Tuesday. They occur most frequently during December and January and substantially less during October and March.
Alberta Clippers are defined as very fast moving low-pressure systems, usually with low in moisture content, originating in Alberta in the lee of the Canadian Rockies, and then travel southeastward.
Because clipper systems develop and track usually far away from large moisture sources, they typically do not produce a lot of precipitation. They also tend to move very quickly, sometimes as fast as 40 miles per hour.
Clippers are most known for producing strong, frigid winds, and the strongest ones can blast a region with 30 to 50 mph gusts or stronger.
With freshly fallen snow, clippers can create blizzard-like conditions. With the low moisture content, these systems usually only produce a few inches of snow at most. This can vary, though, depending on how much moisture the clipper can bring with it and how cold the air is. The colder the temperature, the higher the liquid to snow ratio will be. Basically, if it is quite cold, snowflakes can “fluff up” more, leading to higher accumulations.
Because we are likely entering a La Nina winter, it is likely that much of the snowfall we see this coming season will be from Alberta Clippers. Alberta Clippers love La Nina years.
La Nina means the Jet Stream or storm track usually dives south across the Great Lakes. That can often mean areas surrounding the lakes often see a white Christmas.
The Great Lakes southern and eastern shores often receive enhanced snowfall from Clippers during the winter months from lake enhancement. Lake-effect snow substantially increases snowfall totals.
Also, if conditions are favorable, an Alberta Clipper can rapidly intensify off the East Coast. Once the storm taps the relatively warm moist air over the Atlantic Ocean, the storm sometimes spreads heavy snow over New England and Southeastern Canada. Such a system appears to be brewing for this region this week.
While not quite as common, there are two variations of Alberta Clippers. Manitoba Maulers and Saskatchewan Screamers are the names given to the other two. These systems are still often referred to as Clippers. The main difference between the three is from which Canadian province they begin their southward track.
While the pattern may try to moderate some as we head through this week, we have clearly entered a weather pattern prone to frequent clippers. If we can maintain or get a reinforcement of fresh cold air, it is looking like our chances for a white Christmas this year may be higher than normal.
There are signs in the long-range models that more cold air should arrive toward the end of the month. In fact, it is possible that the Ohio Valley could see a “battle-zone” of sorts set up around Christmas week between colder air trying to get reinforced from the northwest and moist, warmer air trying to get pushed northward.
This could mean a bigger storm system could be brewing around that time-frame somewhere in our region. Of course, timing is everything, but it still looks like the weather will be busy the rest of the month.