CONTEST STATUS - Updated: WED ... 21-MAR-18 @ 11:40 AM EDT

Winter '17 / '18 - Snowfall Forecast Contests

19th Annual 'Regular Season'
- Interim Standings ... as of Snow Storm #7 here
- Forecaster Storm Stats ... as of Snow Storm #7 here

- Snow Storm #8: 21-MAR-18
Deadline for entries has passed
The Forecasts! here

- Snow Storm #7: 12-MAR-18
FINAL Results here
Winning forecast issued by: iralibov

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, January 11, 2008

Going Negative - How Much for Dulles?

For lesser daily snowfalls and snowfalls of 12" or more...there/s a higher chance of occurrence with +PNA...+NAO...and -AO. -NAO is preferred for 7 - < 12" amounts.

With +PNA...+NAO is more likely for daily snowfall below 7".

With +NAO...-AO is more likely for lesser daily snowfalls and daily snowfalls of 12" or more.

Dulles is a short distance WNW of DCA…yet IAD/s snowfall climatology is 35% greater than DCA. Each station/s micro-climate and elevation may be why more snow is observed at IAD (307” MSL) than DCA (59’ MSL).

Neither location will ever be considered a snow capital but there are interesting differences between them for the preferred sign of NAO.

For the Big 3…
For daily snowfalls up to 5” and +12” amounts…
IAD prefers +PNA…+NAO…-AO
DCA prefers +PNA…-NAO…-AO

For 5 < 7”…

For 7 - < 12”…

+PNA and -AO are common contributing factors @ both stations except for 5 - < 7” amounts. The sign of NAO flip flops taking the opposite sign between daily snowfall categories and stations.

The more stations examined...the -NAO CW b/comes more and more questionable.

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