Who Could See an Early Snowfall?

Light Blue: 25-50%
Dark Blue: 50% <

I believe the Upper Midwest, Central and Eastern Great Lakes will encounter an early snowfall for the upcoming fall and winter seasons.

As the chart above shows, I have highlighted much of the Northern Plains, Midwest, Ohio Valley and Northeast for the risk of an early snowfall event. I have put these areas in a 25-50% chance for an early snowfall. The states of Minnesota, Wisconsin, Michigan, northern Ohio, northwest Pennsylvania, New York and portions of the far Northeast will have above a 50% chance for an earlier than normal snowfall event. This comes as a result of what could be a favorable pattern for colder weather to hit the nation as we head into fall. Should a storm system come along in the midst of this cold air, it is very possible that a snow event could come about.

Long range forecasts for the Arctic Oscillation show a definite negative trend for the index as we head through fall and even into early December. The graphic above shows this long range forecast by today's four CFS ensemble member's forecasts for the AO, as well as the forecasts from yesterday's four CFS ensemble members. These eight forecasts average out to a decisively negative phase throughout the fall and into winter. I have little doubt that this forecast will not verify as is shown above, but it is possible we see enhanced chances for a prolonged negative AO pattern. If such a situation were to arise, the risk of an earlier than normal snowfall would rise.

Andrew