RaysWeather.Com
Winter 2012-13 Fearless Forecast

Introduction

This is the 12^th Fearless Forecast. In the end, we will conclude that Winter 2012-13 will have:

• near or slightly above normal snow and

• slightly below normal temperatures

2009-10 and 2010-11 were cold/snowy winters, but last winter was a bust for snow-lovers. The table below shows snow totals in a few Western North Carolina locations for the past three winters.

Winter	Beech Mountain	Boone	Asheville	Hickory
2009-10	134”	83”	39”	13”
2010-11	136”	59”	21”	9”
2011-12	49”	14”	Trace	Trace

The most remarkable tidbit about last winter--it is the only winter without measurable snowfall at the Asheville Airport since the airport opened in the early 1960s.

After several excellent RaysWeather.Com Fearless Forecasts in a row, the last two years have not worked out. Such is the nature of seasonal forecasting. While there are trends that can be analyzed, the variability from year to year is very large even for years that look similar in October. Don’t put much stock in any forecast for the weather from 2-5 months out, including this one.

Rationale for the Coming Winter Season

The El Niño/Southern Oscillation

The most important input for a winter forecast in North America is the El Niño/Southern Oscillation (ENSO) in the Pacific. The image below shows current Sea Surface Temperature Anomalies across the globe.

Warm water (yellows and oranges in the above graphic) in the Equatorial Pacific is indicative of an El Niño while cooler water (blues in the graphic above) there indicates the presence of La Nina conditions. This year the Equatorial Pacific is slightly warmer than normal for October; however, not warm enough to be classified as El Niño. The forecast is for similar ENSO conditions to persist through winter (neutral to weak El Niño).

Going back to 1959-60, the following winters have had similar ENSO states: 1969-70, 1976-77, 1977-78, 1979-80, 1990-91, 2003-04, 2004-05. The tables below show how much snow and average November-March temperatures for each of those years (Boone data) and differences from long-term averages.

Winter	Snow Data (41.8” is the long-term average for Boone)		Temperatures (Boone, degrees F)
	Total Annual Snow (Boone)	Difference from Average	Average High	Average Low	Difference from Long-term Average
1969-70	41.3”	-0.5	44.3	25.5	-2.3
1976-77	47.5”	5.7	44.2	23.7	-3.3
1977-78	55.4”	13.6	43.8	24.6	-3.0
1979-80	36.0”	-5.8	45.5	25/6	-1.6
1990-91	12.5”	-29.3	48.3	31.3	+2.6
2003-04	56.2”	14.4	44.5	23.5	-3.2
2004-05	35.5”	-6.3	47.4	27.8	+0.5
Avgs for Comparison Years	40.06	-1.1	45.4	26.0	-1.5

While 1990-91 is a big exception, the obvious conclusion is that these winters have slightly more snow and somewhat colder temperatures compared to average. Our forecast for the coming winter will follow this guidance.

Historical Data

For a historical perspective, below are charts showing snow amounts for Boone NC for the last 53 years.

The 10-year running average of total snow in Boone (for each year, the average of the last 10 years) is also interesting.

Two things stand out in this graphic: 1) the decades of the 60s and 80s tended to have more snow and 2) 2009-10 and 2010-11 went a long way toward reversing a huge trend toward less snow.

The North Atlantic Oscillation

The winter wildcard is usually the Atlantic's NAO (North Atlantic Oscillation). NAO cycles are generally much shorter than ENSO cycles. No one has a good track record for predicting the NAO. 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. In the winters of 2009-10 and 2010-11, the NAO was overwhelmingly negative (thus the cold and snow), last winter’s was generally positive (mild with less snow).

Also related to the NAO… All that warm water just off the Northeast U. S. and Eastern Canada coasts could be an indicator of generally negative NAO in the coming months. You may have seen discussion of the effects of dramatically less Arctic Ice on the NAO in the last couple months. (See www.noaanews.noaa.gov/stories2012/20121010_arcticwinds.html.) Climatologists are also studying the link between more tropical storms reaching higher latitudes (as was the case this year) and the corresponding effect on harsher winters in North America and Europe. There’s much more study yet to be done before anyone can say definitively about either of these hypotheses. While they may give some credence to a forecast for more snow/cold in the Eastern U. S., we have NOT used these as significant factors in this forecast.

The 2012-2013 Winter Forecast

In a decision/forecast with many unknowns and much variability (such as a forecast for weather 2-5 months away), it’s generally best to stay close to long-term averages in similar situations.

So, here's the RaysWeather.Com Winter 2012-2013 Fearless Forecast:

• Total snowfall: Slightly above the long-term average.

• Temperatures: Slightly colder than normal (about 1 degree colder than long-term averages).

• Confidence level: The same as always for a long-term forecast—low. :-)

Below are forecast snow totals for selected Western NC Locations:

Cities/Towns	Expected Total Snow/Ice for 2012-13
Asheville	16"
Banner Elk	50"
Beech Mountain	115"
Boone	43"
Hickory	8"
Jefferson and West Jefferson	30"
Lenoir	9"
Morganton	10”
Mount Airy	13”
Sparta	27"
Spruce Pine	27"
Sugar Mountain	100"
Waynesville	17"
Wilkesboro	12"

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