Any Hope for Snow in the East?

The North Atlantic Oscillation holds the key, and we should all be thinking negative thoughts.
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The North Atlantic Oscillation holds the key, and we should all be thinking negative thoughts.
snow in the east

Finally, Western US ski areas might be in for a break, with successive storms lined up off the Pacific coast, ready to roll in with loads of snow. But is there any end in sight to the Eastern snow drought?

Fortunately for New England resorts, last week’s Thursday/Friday storm (Jan. 12-13) brought the snowpack up to some semblance of normalcy. At Sugarbush (pictured), skiers enjoyed 18 total inches in the days before the important Martin Luther King holiday, and the resort became one of the very few in the nation to be 100 percent open. Yes, even Castlerock was open, though it was hike-to only.

Snow is still relatively thin in Northern New England. The stake at Mt. Mansfield stands in about 32 inches as of today (Jan. 18), only about 75 percent of normal for this time of year (44 inches). (We love the Stake: the only objective snow reporter in ski country: http://www.uvm.edu/skivt-l/?Page=depths.php)

Winters like this turn frustrated Eastern skiers into weather geeks. And sooner or later, they all stumble onto the North Atlantic Oscillation as what appears to be the biggest weather maker (and breaker) for the Eastern U.S. The NAO index tracks differences in atmospheric pressure between two points: the low-pressure area over Iceland, and the high-pressure area over the Azores in the Eastern Atlantic. When the index is negative, good things happen. That means the Icelandic low is weak, which allows cold air to spread further south over the Northeastern U.S., where it collides with moist air and produces snow. When it’s positive, all that cold air gets sucked straight across Northern Canada, and Northeastern skiers suffer above-average temperatures.

So, last year’s epic winter? You got it: the NAO was deeply negative, and Easterners reveled in deep snow. But take a look at this year’s NAO Index.
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index.html

Sure enough, it’s depressingly positive for all but a few days in the past four months. You can see the brief dip into negative territory that coincided with last week’s storms, but you can also see how the index immediately returned to positive numbers and is right now trending upward.

To learn more about the NAO, here are a couple of useful sites:

http://www.ldeo.columbia.edu/res/pi/NAO/
http://newengland-nao.blogspot.com/

The latter offers NAO forecasts for the coming weeks. But Eastern skiers might not want to look.