Wednesday, August 29, 2012

Winter Weather Outlook 2012-13



With temps near 90 degrees the last two days in Jackson Hole it is hard to even think about snow and the coming Winter Season. But it happens every year in late August, the questions begin as to, “What kind of winter are we going to have?”

With the start of the Fall Season still three weeks away and Winter officially another three months beyond that, it seems silly to even start worrying about it while still in my shorts and flip-flops.

The reason the question gets raised this early in ski towns is because people are trying to make that decision of whether or not to buy a season ski pass, at the discounted rate, before the prices go up in September.
(Reminder: Prices increase Sept 1st for the Jackson Hole Mountain Resort. After Sept. 16th for Grand Targhee).

My standard answer to this annual question is, “It will be a great winter!”

After spending most of the last 30 of them here in Jackson Hole, I can tell you that a lean winter here still beats a good winter almost everywhere else! Sure, we’ve had our BIG winters that everyone would like to see repeated every winter (2010-11, for instance), but even when we have had lower snowfall winters, we’ve still had some tremendously great skiing.

So, let’s look at what the long range forecasts are saying for the upcoming Winter Season 2012-13.

Long Range Outlooks

A sneak peek at the Old Farmer’s Almanac, which comes out this week, tells a tale of warmer than normal temperatures for the Northwestern U.S. with below normal snowfall. They could be wrong, as they were way off on last winter’s prediction, after all.

The Climate Prediction Center (a division of NOAA and the National Weather Service) does show the start of the season, October-November- December with warmer than normal temps and “equal chances” for above or below normal snowfall.

(See maps below and keep up with all the latest short & long range outlooks on the
NWS Discussions Page
of mountainweather.com)

3-Month Outlook Maps for October-November-December 2012


Temperatures
Precipitation


El Nino Year

The fluctuation in the Equatorial Pacific that we commonly refer to as “El Nino & La Nina” is technically known as the “El Nino Southern Oscillation (ENSO)”. This is what the Climate Prediction Center focuses a lot of their time on when making these long range forecasts.

Last Winter (2011-12) we were also in a La Nina year, weaker than 2010-11’s, and the storm track went way north to Alaska most of the Winter & Spring of 2011-12. That is one of the things that can happen in some La Nina years. Or, it can get locked in over the Northwestern U.S. and Northern Rockies, like it did two winters ago, 2010-11, when winter didn’t end until June!

Most of the Summer of 2012 we have seen a “Neutral” condition with the ENSO, and now we are trending towards a weak to moderate El Nino condition that is expected to persist for the Fall & Winter of 2012-13.

Usually, during El Nino winters, the storm track coming out of the Pacific favors a more southern route, and the Southwestern U.S. gets more precipitation. The opposite of a “normal” La Nina, where the Northwestern U.S. is favored and the Southwest is dry.

Don’t let that scare you, because statistically El Nino for us is a 50/50 proposition. Half of El Nino Winters in Jackson Hole produce below normal snowfall and half produce above normal snowfall.

The last time we had “weak” El Nino conditions was during the Winter of 2006-07, with below average snowfall. The last time we had moderate El Nino conditions was the Winter of 2009-10, and we saw above normal snowfall.

A 50/50 bet seems like decent odds to go ahead and buy that Season Pass!

 Chart below of ENSO Index 
(El Nino years in blue and La Nina Years in red.)












Text submitted by meteorologist Jim Woodmencey
Graphics from NOAA

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