RaysWeather.Com Winter Fearless Forecast

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1 Author: Dr. Ray Russell Founder and President of RaysWeather.Com Date: October 15, 2016 RaysWeather.Com Winter Fearless Forecast Background We had an impressively warm summer and early fall. The first frost has not even occurred for most of the Southern Appalachians, with the exception of deeper valleys on the nights of October 11 th and 12 th. This year's "leaf season" is the latest in my 25 years living in Boone. As a result, it seems that anticipation for winter weather is suppressed across the region. But one good cold snap will rev up the anticipation. Through the years, the RWC Fearless forecast has performed better than most; however, after a nearperfect forecast, both and were less than stellar to say the least. Table 1: Accuracy of Last Year s RWC Fearless Winter Forecast Location Forecast Actual Actual - Forecast Snowfall Snowfall Asheville, NC 20" 11" -9" Banner Elk, NC 67" 38" -29" Beech Mtn, NC 110" 70" -40" Boone, NC 54" 25" -29" Hendersonville 15" 11" Hickory 9" 6" -3" Independence, VA 29" 17" Jefferson and West 35" 15" -20" Jefferson Lenoir 11" 5" -6" Morganton 12" 8" -4" Sparta 31" 14" -17" Spruce Pine 27" 19" -9" Sugar Mountain 105" 66" -39" Waynesville 19" 9" -10" (Actual reports even within each location varied from site to site. I chose a snowfall total that fairly represented the average for each location.) Overall, actual snow totals were one-half to two-thirds of the forecast amounts. Temperatures were forecast to be slightly below average but were actually slightly above average. However, several aspects of last year's forecast did work out; we predicted: 1) a late start to winter (wow, was that true!), 2) that

2 the bulk of snow would come in January and February (that worked out), and 3) that it would be a strong El Niño season but that El Niño would wane by the end of winter (an accurate prediction). So in essence, the players lined up on the field correctly but underperformed expectations. We expected a couple of big storms in the core of winter; the ingredients never came together. It happens to the best of long-range forecasts. Summary of the Fearless Forecast for Winter Snow lovers will hope we are wrong; however, most signals at this point indicate a drier than average winter with less than average snowfall and temperatures near average % less snow than the long-term average Temperatures averaging near to one degree above long-term averages. Below are forecast totals for many locations in the Southern Appalachians. (Note: The forecast snowfall total includes snow/ice falling between October 2016 and May 2017.) Table 2: Specific Snowfall Forecasts for Selected Locations Location Expected Total Snow/Ice for Winter Asheville, NC 10" Banner Elk, NC 34" Beech Mountain, NC 70" Boone, NC 30" Galax, VA 15" Hendersonville, NC 6" Hickory, NC 5" Independence, VA 16" Jefferson and West Jefferson 20" Lenoir, NC 5" Morganton, NC 6" Mt. Airy, NC 9" Old Fort, NC 6" Sparta, NC 16" Spruce Pine, NC 19" Sugar Mountain, NC 70" Waynesville, NC 9" Wilkesboro and N. Wilkesboro 8" Wytheville, VA 17" Happy Skiing and Snowboarding! We ll keep you informed with the most reliable day-to-day forecasts for the Southern Appalachians and Foothills all winter. This forecast does not come out of thin air. It comes from serious analysis; continue reading for the explanation.

3 Fearless Forecast Rationale ENSO Analysis As always, the first data points for a Winter forecast are the current state and forecast for the El Niño/Southern Oscillation (ENSO). ENSO is a measure of large-scale weather conditions in the Equatorial Pacific. It fluctuates between El Niño (associated with warmer than average sea surface temperatures in the Equatorial Pacific) and La Niña (associated with colder than average sea surface temperatures in the Equatorial Pacific). Currently, the ENSO is classified as Neutral, but it is bordering on a weak La Niña. Figure 1 shows the Sea Surface Temperature Anomaly from October 7, In spite of warmer than average Sea Surface Temperatures (SST) across much of the Atlantic and Pacific Oceans, you see a thin band of cooler than average temperatures in the Equatorial Pacific (the darker blues). Those cooler ocean temperatures may be the beginning of a weak La Niña. Figure 1: Sea Surface Temperature Anomaly 10/7/2016 (from In contrast, last year at this time, one of the strongest El Niños on record was in progress. The El Niño weakened in late winter and ended abruptly in Spring, A slow drift toward La Niña commenced during the summer. That trend may result in an official classification of La Niña in the next couple months (but barely). From there, it's about a 50/50 chance of ENSO remaining as a weak La Niña through the coming winter or drifting back to neutral conditions. Figure 2 below shows current ENSO model predictions. To be classified as a La Niña, the index in Figure 2 needs to be -.5 or below for 3 consecutive months. For simplicity sake, we'll call the ENSO forecast "Weak La Niña"; the difference between an index of -.4 and -.6 will make little practical difference in our winter forecast.

4 Figure 3 shows snow data from Boone, NC. You see seasonal snow data for 57-years classified by ENSO type (Strong El Niño through Strong La Niña). The graph also shows the long-term average and a 10- year moving average. Note that the average snowfall for Neutral Winters is only 1" greater than Weak La Niña Winters. Based on expected ENSO conditions, we chose 10 Best Fit Winters. All these winters were either Neutral ENSO Winters but shaded on the negative side of the index or Weak El Niño Winters with index values less than 1. The Best Fit Winters are: , , , , , , , , , Figure 2: Forecast for ENSO (from analysis_monitoring/enso_advisory/ensodisc.html) Average total snowfall in the Best Fit Winters in Boone, NC, is 32.2", 22% less than the long-term average of 41.1". Also, only 2 of these winters had snowfall greater than the 10-moving average at the time. Figure 4 shows the Best Fit Winters relative to their 10-year moving average. Figure 3: Total Winter Snowfall in Boone, NC, Classified by ENSO (ENSO classifications derived from

5 Figure 4: Best Fit Winters Total Snowfall Compared to Their 10-year Average. Figure 5 compares Best Fit Winter Snowfall with all Weak La Niña Winters and all other Winters. Note that all three classifications are similar in months other than January and February. This usually results from drier than average weather in the Southeast U. S. La Niña winters tend to lack consistent transport of energy from the Equatorial Pacific region into the Gulf and the Southeast U. S. Instead, the Pacific flow is directed toward the Northwest U. S. and Western Canada and then across thousands of miles of land before reaching the Southeast that's a much drier flow pattern. See Figure 6 for a depiction of the typical La Niña pattern in winter. Figure 5: Snow totals from our Best-Fit Winters ( , , , , , , , , , and ) compared with all Weak La Niña Winters and all other winters. Snow totals shown are from Boone, NC.

6 La Niña winters can be relatively cold for the Southern Appalachians because of the predominant northwest flow. They are also prone to "northwest flow snow events" that favor the west side of the Appalachians for snowfall. But the greatest factor in our winter may be dry conditions. Our exceptionally dry late summer and fall will "aid and abet" a continuation of less than average precipitation well into winter. Figure 7 compares average temperatures in our Best Fit Winters with all Weak La Niña Winters and all other winters. Note that there's very little temperature differences between the three lines (so close it was almost impossible to label all the lines clearly!). However, the Best Fit Winters and the Weak La Niña Winters tended slightly colder than other winters. Figure 6: El Nino Winter Climate Pattern (from The main takeaways from the analysis of ENSO forecast for the coming winter are: 1. Moderate confidence in less snow than average. 2. Temperatures in our Best Fit Winters tend to be slightly below average. Figure 7: Average temperatures from our Best-Fit Winters compared with all La Nina Winters and all other winters. Temperature data is from Boone, NC. Climate Change While we have hinted at effects of Climate Change in our previous Fearless Forecasts, we have never specifically addressed that issue. First of all, climate change is real. If you are interested in a good source of scientific data and analysis on the subject, see But two items demonstrating effects of climate change are shown in graphs below: Diminishing Arctic Ice (Figure 8) and Average Temperatures in North America (Figure 9). July 2016 was the warmest month ever recorded (at the time), only be exceeded by August has been amazingly warm compared to any year in recorded history. The areal extent of Arctic Sea Ice is persistently at or less than 2 standard deviations below the 30-year mean.

7 Figure 9: Average Temperature in North America (from Figure 8: Extent of Arctic Ice (from nsidc.org/arcticseaicenews/) However, the effects of climate change are not linear or uniform in either time or space. Warming, that has been experienced across most of the world, has not evidenced itself as strongly in the Southeast U. S. A report in analyzes data in the Southeast U. S. through It will be interesting to see the same result holds after the last couple years are added to the dataset. Figure 10 shows average annual temperature in Boone, NC through The Boone data is consistent with the globalchange.gov report. (The "Dust Bowl Years are clearly evident in the 1930s and 1940s.) Figure 10: Average Annual Temperature for Boone, NC

8 However, even though temperatures have not yet shown warming since the 1980s, the amount of snow overall has definitely decreased as shown in the Figure 11. Figure 11: Average Annual Temperature in Boone, NC Regarding the winter forecast as it relates to climate change data, our takeaway is to shade snow totals lower than the 57-year average but favor temperatures not far from long-term averages. The North Atlantic Oscillation Wildcard Every year, the North Atlantic Oscillation (NAO) is the wild card for long-range winter forecasts. Without belaboring the details, the NAO is the North Atlantic's distant cousin of ENSO. (See for details on both the Arctic Oscillation and NAO.) I know of no reliable way to forecast the NAO three to four months in advance. If the ENSO state tends toward neutral, the NAO tends to produce even more variable results in the Eastern U. S. Summary Long-range winter forecast is always a risky proposition. Don't put much stock in this or any other longrange forecast. But here's what we think: Moderate confidence in a drier than average winter. Moderate confidence in less than average snow. Less confidence in temperatures near or slightly above average. Yes, there will still be skiing in the Western North Carolina!!!