Snow Cover Update 10/26/12

Snow cover buildup in October and November is often a key as to what our winter may look like. Even though the weather has been warm in our neck of the woods lately, major changes are taking place in the Arctic that should eventually translate into the colder and snowier weather that we didn’t get last winter.

I have placed the Northern Hemisphere snow cover charts for October 25 from 2011 and 2012 side-to-side for comparison’s sake:

Snow cover comparison between 2011 and 2012

Snow cover comparison between 2011 and 2012

Siberia has a greater expanse of snow cover this year. But the important thing to note is that snow cover is much more robust over North America than it was last year. On the 2012 chart, you can see snow cover aggressively expanding into the north-central United States. This confirms the Arctic Oscillation is presently in its negative phase, relaxing the jet stream and allowing deeper southward penetration of cold air. This is great to see! A significant buildup of snow cover over western Canada should allow for more frequent cold air outbreaks over the eastern United States as we transition to winter.

National Ice Center’s website offers a great snow cover analysis that is updated daily, including archives that date back to 1997.

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