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

Friday, December 26, 2014

Winter '14 / '15 - Weakening Polar Vortex ==> Sudden Stratospheric Warming: UPDATE 2

The 12z / 25-DEC-14 run of the ECMWF continued its current campaign for a sudden stratospheric warming (SSW) event come JAN.

Progs suggest the birthing of daughter vortices around 04-JAN-15 induced by the upward propagation of a large tropospheric Rossby wave in a QBO-east environment.  A 'major' SSW event is indicated.
"A major SSW occurs when the 10 mb 60°N zonal mean zonal wind reverses from westerly to easterly and the 10 mb zonal mean temperature gradient increases poleward of 60°N." (.pdf)
Another view of the impeding split at the 475K level from a potential vorticity (NASA) perspective ... 
The downward propagation of the stratospheric easterly circulation (or a significant weakening of west wind) and the establishment of the Arctic Oscillation (AO) in its negative phase usually follows major SSW events.

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