Winter '15 / '16 - Sudden Stratospheric Warming: Watch #1

Following a recent cross-hemisphere shift of the polar vortex's (PV) center of circulation from NW Greenland to the Barents Sea ... the first signs of upward propagating wave energy have appeared on the ECMWF/s 13-DEC-15 100 / 70 / 50 mb progs.

The potential for a PV split faces a stiff headwind.  The quasi-biennial oscillation (QBO) began it westerly phase in JUN and has yet to reach its peak suggesting the PV stays intact.

Of course ... if a SSW comes to fruition ... it takes time for the initial wave to reach 10 mb and then propagate to the surface on average about three weeks later making the 'if and when' of it all wait until late JAN.