CONTEST STATUS - Updated: FRI ... 16-MAR-18 @ 7:40 PM EDT

Winter '17 / '18 - Snowfall Forecast Contests

19th Annual 'Regular Season'
- Interim Standings ... as of Snow Storm #6 here
- Forecaster Storm Stats ... as of Snow Storm #6 here

- Snow Storm #8
Synoptiscope in VCP32

- Snow Storm #7: 11-MAR-18
The Forecasts here
Preliminary STP verifications here

- Snow Storm #6: 07-MAR-18
FINAL Results here
Winning forecast issued by: Donald Rosenfeld

17th Annual 'Season-total'
Deadline for entries has passed
Forecasters' summary here

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

16th Annual 'Season-total'
FINAL results here

Wednesday, January 2, 2013

Winter '12/ '13 - Arctic Oscillation: Is December A Leading Indicator?

December AO:  -1.749
Rank:  11th (17th percentile)

Original post date:  26-DEC-12 @6:31 PM EST

Little doubt DEC/s index will come in negative given the 30-day moving average stands at -1.965.

Does the sign of DEC/s AO have any predictive value?  The sign of NOV/s AO was shown to have predictive value for the sign meteorological winter/s (D-J-F) average AO.

The 2x2 contingency table of DEC/s AO index and JAN/s index shown below suggests there/s a strong association between the two...especially when DEC/s AO is < 0.

Each cell in the table shows the number of years where the sign of the DEC/s AO was associated with the sign of JAN/s AO.

When DEC/s AO is < 0...there/s an 82% chance the JAN/s average AO will also be negative. 

The table/s precision is 74%...where precision is the proportion of negative cases predicted correctly [a / (a + c)].  The probability of a 'false positive' (-AO forecast; + AO observed) is 36%.

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