Groundhog Day has been used as a predictor of the end winter for many years, does the folklore hold true in the Twin Cities?
February 2 is the day that tradition has the Groundhog leaving it's den and if seeing his shadow there will be six more weeks of winter. If he doesn't see his shadow, spring is right around the corner. With the way that the winter of 2011-12 is going in the Twin Cities, it feels as though Spring is already here.
Looking back on February 2 for the past 20 years in the Twin Cities to 1992, the groundhog would have seen his shadow during the day in 13 of those years. The last one inch snow cover over the past 20 years has ranged from February 24th, 2000 to April 29th in 1994 (where the Groundhog did not see his shadow in both cases) When the Groundhog has seen its shadow in the last 20 years, the last 1 inch snow depth in the Twin Cities has ranged from March 16 in 1999 to April 28th in 2002. That said, there does to be a slight tendency to earlier ending winters when the Groundhog does not see his shadow.
There may be a climatological explanation for the success of the groundhog. If the groundhog does not see its shadow there could be plenty of clouds with around lots of moisture. The moisture can be in the air due to melting snow and generally warm weather, like Feb 1-2 2012 with dense fog as well. When the groundhog sees his shadow, it can be due to clear and cold conditions associated with arctic high pressure. The groundhog would have seen its shadow in 2011.
One interesting footnote is that February 2 is also the state record coldest temperature too set in 1996. With numerous members of the media present, the low dipped to -60 three miles south of Tower. Governor Arne Carlson canceled school statewide due to the cold.
Some weather statistics for February 2 for the Twin Cities
Average High 25 Average Low 9 Record High 48 (1991) Record Low -32 (1996) Most snowfall 6.2 (1983) Greatest snow depth 22 inches (1969) The average date of the last 1 inch snow cover in the Twin Cities is March 25.