Winter '10 / '11 - Stratospheric Warming - Take 3

Appears associated with the ECMWF's forecast for hi-latitude blocking over Siberia beginning 1/11/11.  Note the dramatic weakening of the stratosphere's polar vortex between the initial panel (west @60 m/s = ~120 kts) and its reversal on D+10 (east @15 m/s = ~30 kts).

Also depicted on D+10 zonal mean wind chart are deep layer easterlies throughout the troposphere suggesting a strongly negative AO.