February 2007 North America Blizzard - Prior To The Storm

Prior To The Storm

In sharp contrast to the mostly mild weather in the first few weeks of winter, the eastern half of the continent was under the influence of cold temperatures. Numerous areas had substantial snowfall deficits before this storm. After several weak Alberta Clippers crossed the eastern half of the continent and brought occasional light snowfalls, a large dip in the Northern branch of the jet stream favored a more active pattern, which, as it connected with the southern branch, led to the development of the storm.

An area of low pressure tracked across southeastern Canada during the 12th, which brought an arctic front across the Mid Atlantic region late on the 12th. As this occurred, a strong area of high pressure located across central Canada built down into the Northeast, allowing very cold air to spill southward ultimately leading to what is known as cold air damming. This occurs east of the mountains down through the Mid Atlantic states. Meanwhile, a Pacific storm slammed onto the California coast during the 11th and as it moved eastward, a new area of low pressure developed across southeastern Colorado and the Texas Panhandle.

Previously, portions of the Great Lakes were hit by a significant lake effect snow event which dumped incredible amounts of snow over portions of central New York. Several areas received over 115 inches (over 2.5 m) of snow in a ten-day period just before the large winter storm as northwesterly winds and unfrozen lake surfaces due to the early winter warm weather favored the heavy snowfall. Several areas across Michigan and Ontario also received significant amounts of snow with locally 1 meter (3.3 ft) of snow east of Georgian Bay in Ontario.