CONTEST STATUS - Updated: MON ... 19-OCT-20 @ 6:20 PM EDT

Winter '20 / '21 - Snowfall Forecast Contests
22nd Annual 'Snow Storm' Snowfall Forecast Contest
Season starts when flakes start a'flyin'.
Watch this space ...

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20th Annual 'Season-total' Snowfall Forecast Contest
Deadline for entries: 11:59 PM EST ... MON ... 30-NOV-20
Details here

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Winter '19 / '20 - Snowfall Forecast Contests
21st Annual 'Snow Storm' Snowfall Forecast Contest
Season ended as quickly as it started.
No winner this go'round ... too few storms (minimum of three required)

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19th Annual 'Season-total' Snowfall Forecast Contest
FINAL Results here

Tuesday, November 10, 2020

Winter '20 / '21 - North Atlantic Oscillation (NAO): Analog Composites of 500 mb Height and 2-meter Temperature Anomalies ... as of OCT-20

Analogs and weights for composites:
'61 / '62 (2)
'91 / '92 (0)
'95 / '96 (0)
'99 / '00 (1)
'03 / '04 (0).

Two analogs averaged < 0 over D-J-F
Three analogs averaged > 0 over D-J-F
Little in the way of consensus which isn/t especially unusual for analogs.

We assess NAO/s analog winters with the upcoming winter/s expected states of ENSO (moderate-to-strong La Nina) ... QBO-W ... and (cool) PDO.

Recall ... '95 / '96 of 'Storm of the Century' fame was one of the better winter/s evah; however ... despite its weak La Nina profile ... its QBO-E and warm PDO eliminates the strongest calculated match for Winter '20 / '21 from the running.  Analog weight:  0

'91 / '92 drops out as well b/c its winter had a strong a El Niño ... QBO-E ... and a warm PDO.  The '03/'04 La Nada winter doesn't make the cut either.  Analog weights:  0

The two remaining winters '61 / '62 and '99 / '00 are strong analogs for Winter '20 / '21.  Both were moderate La Nina (per MEI) ... QBO-W < 10 ... and a cool PDO.  '61 / '62 set snowfall records in more than a few stations. Analog weight: 2

Season-total snowfall for '99 / '00 was above average for southern mid-Atlantic stations and generally below average elsewhere.  Analog weight:  1

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The 500 mb and 2m T weighted analyses below are based on the winters of '61 / '62 and '99 / '00.

North Atlantic Oscillation (NAO) analog composites of 500 mb (5H) geopotential height anomalies (GPHa) and 2-meter air temperature anomalies (2m Ta) for Winter '20 / '21.

5H GPHa weighted-composite

Main features:
La Nina ridge over SE CONUS
-PNA
Positive geopotential height anomaly south of Greenland ==> -NAO (??? lo-lat action center)
Storm track across northern CONUS

2m Ta weighted-composite

Main features:
Above normal temperature across the Deep South and SE CONUS
Cold AK ==> warm East


NAO analog data table (unranked)
Analog statistic (not shown):  sum of squared errors


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