by Tim Vasquez
A utumn brings the arrival of fast-moving, benign systems that carry cold, dry Canadian air masses originating from the interior regions of Canada. These are known informally as Alberta clippers. Though cold fronts are common year-round in the northern tier states, the first true Alberta clippers appear in September and become more common in October and November. They differ from Pacific systems, which originate from the West Coast and tend to bring weaker temperature drops but stronger upper-level support with more organized precipitation areas. Alberta clippers are popularly associated with modest temperature drops, gusty wind, and brief precipitation, but more powerful, organized Alberta clippers with large precipitation areas are called “polar outbreaks” or simply called “cold fronts”.