Winter '12 / '13 - Arctic Oscillation: Meteorological Winter - Day 15

Not sure what if anything it means but here's the state of the AO on Day 15 of meteorological winter during its 63 year period-of-record.

Blue line is the observed AO on 15-DEC.

Red line is a 9-point binomial filter.  The filter removes noise from the signal to highlight trends.

The 15-DEC-12 AO ranks 19th (25th percentile).

Same idea for AO/s sister...the North Atlantic Oscillation (NAO).

The 15-DEC-12 NAO ranks 36th (57th percentile).