For the past few weeks, snow cover has been increasing across the northern hemisphere, as it is usual for autumn. Snow cover extent over North America has been rapidly increasing, thanks to a specific weather pattern. On the other side, over Eurasia, we currently have below normal snow extent. Ensemble forecast does indicate a possible change in the near future.
In the first two weeks of October there was a very specific weather pattern across the north hemisphere. We had ridging over the Bering Sea and the Arctic, which caused a cross-polar flow from the Arctic down into North America. That has helped increase the snow cover over the continent. On the other side of the world in Siberia, the same pattern had the opposite effect, and has contributed to slower snow cover advance.
http://www.severe-weather.eu//complete-analysis-record-sn/
