RaysWeather.Com
Winter 2011-12 Fearless Forecast

Introduction

This is the 11^th Fearless Forecast. In the end, we will conclude that the Winter 2011-12 will have:

• near normal snow and

• slightly colder than normal temperatures

The last two winters were snow-lovers' dreams. 2009-2010 brought 83" in Boone and 134" atop Beech Mountain. In 2010-2011, Boone had 59" of snow, and Beech had 136".

Last season, December 2010 and January 2011 were bitterly cold and very snowy. December 2010 was the coldest December ever recorded in Boone (24.9 degrees was the average temperature). It beat the second coldest (1963) by more than 1 degree; that's huge in climatological terms. It was the sixth coldest month ever recorded in Boone. With 27.85" of snow (again measuring in Boone), December 2010 was the snowiest December ever. January was very cold but not as dramatic compared to other years—temperatures 4 degrees below normal and the fifth most snow on record. The rest of last winter was warmer than normal and rather uneventful.

After three excellent long-range winter forecasts in a row, last year's forecast was a disaster. Even though February and March were warmer than normal and uneventful, our forecast for less than normal snow and slightly warmer than normal temperatures was laid to rest in a peaceful ceremony in our backyard in mid-January (with "Taps" gently playing in the background).

Rationale for the Coming Winter Season

Usually the dominant input for a seasonal forecast is the current and forecast state of the El Niño/Southern Oscillation in the Pacific; however, in both of the last two years, the Atlantic's NAO (North Atlantic Oscillation) has been the key factor in producing far more snow than normal in the Eastern United States. NAO cycles are generally much shorter than ENSO cycles and are much harder to forecast months in advance. Thus, the NAO is almost always the wild card in a long-range winter forecast. Generally speaking in winter, a negative NAO is associated with blocking high pressure in the North Atlantic into Greenland. Upstream, the jet stream "buckles" sending cold polar air southeastward into the Eastern U. S. producing a cold, stormy pattern. The 2009-2010 winter is what can happen when a moderate El Niño is combined with a negative NAO. The snow/cold of December and January of last winter is what can be produced by a negative NAO even with a normally less-stormy La Niña year. The whole story is far more complex, but this is the gist of what happened in the last two years.

Sea Surface Temperatures (SST) are a part of the ENSO and NAO story. The graphic below shows SST Anomalies (difference from normal) as of October 20, 2011:

The blue colors dominating the equatorial Pacific are indicative of a La Niña developing in the Pacific. The yellows and reds in the Atlantic show generally warmer than normal SSTs in the Atlantic. Compare this with the same graphic from October 21 last year:

The two graphics look very similar, don't they? The La Niña is not as strong and the Atlantic is not as warm overall; however, the theme is the same.

Looking only at the ENSO cycle, the graphic below shows that weak La Niña winters have slightly more snow than other years, strong La Niña winters usually have much less snow than average:

Finally, recent history counts for something. The graphic below shows the average snow for the previous 10 years for each year:

Two important trends are evident: 1) a trend toward less snow from the 90s until 2008 and 2) a sharp reversal of that trend in the last two years.

The 2011-2012 Winter Forecast

"History does not repeat itself, but it does rhyme." is a quote attributed to Mark Twain (although there's no solid evidence that he ever actually said this). That quote is the thrust of this year's winter forecast. The set-up going into winter looks very similar to last year. So, our forecast is for a winter that "rhymes" with last winter, but with less dramatic effects. A general theme of "relatively colder early (November, December, January) but relatively mild late (February, March, April)" will probably be a second rhyme with last winter. A third "rhyme" will be relatively more snow along the western escarpment (near the TN/NC line) because, like last year, much of the snow will come from NW flow events.

So, here's the RaysWeather.Com Winter 2011-2012 Fearless Forecast:

• Total snowfall: Close to the long-term average. Areas along the western upslope of the Appalachians (near the TN/VA state line) may have relatively more snow than the rest of the Southern Appalachians.

• Temperatures: Slightly colder than normal. Expect high temperatures about 1 degree colder than normal.

• Confidence level: Are you kidding? It's crazy to publish any seasonal forecast at all. :-)

Below is forecast snow totals for selected Western NC Cities:

City	Expected Total Snow/Ice for '11-'12
Asheville	15"
Banner Elk	48"
Beech Mountain	110"
Boone	42"
Hickory	7"
Jefferson and West Jefferson	29"
Lenoir	8"
Morganton	9"
Sparta	25"
Spruce Pine	25"
Sugar Mountain	90"
Waynesville	15"
Wilkesboro	11"