Predicting short-term seasonal characteristics
A correlation study found that:
The extent of snow cover over Eurasia during autumn has been shown to be influential in shaping atmospheric circulation over the Northern Hemisphere the following winter via the Arctic Oscillation (AO), North Atlantic Oscillation (NAO), and the Pacific/North American (PNA) teleconnections.
Regions of Eurasian snow cover were derived from Principal Component Analysis and compared to winter temperatures across North America for 1967/1968–2007/2008, excluding 1969/1970 and 1971/1972.
The score time series of each principal component was then compared to winter averages of the AO, NAO, and PNA indices in order to identify possible links in the snow-temperature relationship.
Results showed that autumn snow cover from northern Scandinavia to the West Siberian Plain is most significantly associated with winter temperatures over the interior of North America. More (less) frequent snow cover over this region is related to lower (higher) winter temperatures over the interior of North America in January, extending to the eastern and southern United States in February.
The greatest temperature response to anomalous snow cover occurred near the geographic centre of North America where winter temperature differences exceeded 5 °C. More (less) frequent autumn snow cover across the eastern Tibetan Plateau was associated with higher (lower) temperatures in the Great Basin and eastern Canada.
Thomas L. Mote and Emily R. Kutney, Regions of autumn Eurasian snow cover and associations with North American winter temperatures, International Journal of Climatology, doi: 10.1002/joc.2341 (early online publication, 17 May 2011)
An interview with the lead author, climatologist Thomas Mote (University of Georgia), revealed that:
“The goal of this research was to determine whether there is a significant relationship between autumn snow extent in specific regions of Eurasia and temperatures across North America during the subsequent winter.”
[T]he new study is the first to narrow down the location of the area that causes the most direct effect on U.S. winters—an area in northwest Eurasia that includes part of Siberia—though the entire effective area extends as far west as northern Scandinavia.
Years with extensive autumn snow in northwest Eurasia were associated with subsequent winter temperatures as much as seven degrees (Fahrenheit) lower near the center of North America. This difference is roughly the same as a one-month shift in climate.
© 2011 Philip Lee Williams, Northern Eurasian snowpack could be an important predictor of winter weather in U. S., team from UGA reports, University of Georgia Office of Public Affairs (22 June 2011)
Sea ice as another contributor to North American winter characteristics
Writer Williams noted that Dr. Mote hypothesized that sea ice coverage in the Arctic and Atlantic oceans may reveal that it affects Eurasian autumn snow cover.
Consequently, Mote thinks that the sea ice and Eurasian snow cover totality may have just as much of an effect on immediately following North American winters as the more studied Pacific Ocean El Niño and La Niña events.
If true, the finding about Eurasian autumn snow coverage should make predicting North American winters more accurate.