CONTEST STATUS - Last update: THU ... 20-APR-17 @ 9:40 PM EDT

Winter '17 / '18 - Snowfall Forecast Contests

19th Annual 'Regular Season'

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17th Annual 'Season-total'

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Winter '16 / '17 - Snowfall Forecast Contests
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18th Annual 'Regular Season'
FINAL results here
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16th Annual 'Season-total'
FINAL results here

Monday, January 21, 2013

Winter '12 / '13 - Arctic Oscillation: Meteorological Winter/s Mid-point

Not sure what if anything it means but here's the state of the AO at the mid-point of meteorological winter during its 64 year period-of-record.



Blue line is the observed AO on 15-JAN.

Red line is a 9-point binomial filter.  The filter removes noise from the signal to highlight trends.
Yellow line is an 11-year moving average.

The 15-JAN-13 AO (-0.646) ranks 26th (41th percentile).



Same idea for AO/s sister...the North Atlantic Oscillation (NAO).
The 15-JAN-13 NAO (0.011) ranks 26th (41th percentile).

Three things to note...
1)  The highly variable AO index on D+45 compared to its sister index...then NAO.
2)  The 11-year moving average between 1960 and1980 is negative...followed by a 30-year period were the average is above zero.
3)  This season/s mid-winter AO and NAO values are slightly below normal for all mid-winter values during the period-of-record (Z = -0.207 and Z = -0.045, respectively).

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