The role of the Siberian high in Northern Hemisphere climate variability

The dominant mode of sea level pressure (SLP) variability during the winter months in the Northern Hemisphere (NH) is characterized by a dipole with o ne anomaly center covering the Arctic with the opposite sign anomaly stretc hed across the mid-latitudes. Associated with the SLP anomaly, is a surface temperature anomaly induced by the anomalous circulation. We will show tha t this anomaly pattern originates in the early fall, on a much more regiona l scale, in Siberia. As the season progresses this anomaly pattern propagat es and amplifies to dominate much of the extratropical NH, making the Siber ian high a dominant force in NH climate variability in winter. Also since t he SLP and surface temperature anomalies originate in a region of maximum f all snow cover variability, we argue that snow cover partially forces the p hase of winter variability and can potentially be used for the skillful pre diction of winter climate.