Ray's "Fearless Forecast" for Winter 2007-2008

Introduction

RaysWeather.Com, Inc., has been publishing winter forecasts since 2000. We have had one disaster year (2001-2002), one bad year (last year), two only fair years (2004-2005, 2005-2006), two good forecast years (2000-2001 and 2002-2003) and one excellent year (2003-2004). That's not stellar, but it's better than most.

Here's a quick comment on last year's forecast, not to make an excuse but to illustrate one way (of 1000s) long range forecasts can go wrong. In October of last year, it appeared that we were headed toward a weak El Niño Winter-the snowiest of them all on average in Western North Carolina. Almost before the "pixels dried" on the forecast, it became apparent that "this baby boy" fading away quickly. The SOI (Southern Oscillation Index) went strongly positive and the weather behaved more like a La Niña winter than its stormier brother. So, our winter forecast based on forecast for El Niño went bust basically before winter started. It reminds me an episode I witnessed many years ago when a professor at Georgia Tech destroyed a student's PhD dissertation defense (thankfully not my defense) by saying, "Your logic was fine but your premise was false!"

Rationale

And it's on to a new year… The factors expected to be important in the coming winter are:

• Developing La Niña
• Shrinking polar ice cap
• Prolonged "Snow Drought"

Developing La Niña

As usual, the single biggest factor in forecasting the coming winter is the state of the El Niño/Southern Oscillation (see the NOAA ENSO page for more details.) This year, the waters in the Equatorial Pacific are headed toward La Niña-a cooling of the surface waters from Chili to northern Australia. The image below shows the current state of Sea Surface Temperatures; notice the abnormally cool waters in the Equatorial Pacific.

 

The magnitude of this La Niña cycle is expected rather strong. If a strong La Niña does develop, it will be the 10th such winter since 1950. This is not good news for snow lovers in Western NC. The chart below shows that on average "Strong La Niña" events bring the least snow of the ENSO stages: an average of 31.5" of snow compared to the 48-year average of 41.9" (75% of normal). The last two strong La Niña winters were 1998-99 (21.3" of snow) and 1999-2000 (15.8" of snow). All we can say as snow lovers is "yuck". (All this data comes from Boone, we'll show what this means for other locations at the end of this forecast rationale.)

 

The tendency in La Niña winters is temperatures only slightly above normal as shown in the chart below. So, the fundamental reason for the lack of snow has to do with dry weather more than warm weather. That fact should give some hope for snow making; however, a continuation of overall dry weather is not good news for anyone.

 

Shrinking Polar Ice Cap

The second important factor in determining the winter forecast is a shrinking polar cap. Numerous news reports tell the story. A BBC report summaries the issue-"Measurements made by the US National Snow and Ice Data Center (NSIDC) showed the extent of sea ice on 8 August (2007) was almost 30% below the long-term average." "How does that affect our weather?" Ice reflects a relatively large percentage of solar radiation; however, (liquid) water reflects very little direct solar radiation. With less area in covered by ice, the earth will absorb more solar radiation and thus produce more heat. The net effect should be a diminished capacity to cool the air over the poles. (Of course during the winter, the North Pole receives no sunlight; however, warmer conditions leading into winter should result in a less cooling during winter.) That does not mean that it can't get cold in the High Country; however, we do expect that cold snaps will be much like we saw last winter-relatively short-lived events. One interesting result of our analysis is that Boone has NOT been significantly warmer over the past 10 years even though we have had significantly less snow during the last 10 years. The table below illustrates the temperature consistency…

The bottom line regarding polar ice it that somewhat above normal temperatures is more likely.

Prolonged "Snow Drought"

The third factor in the winter forecast is our ongoing "Snow Drought". In the past ten years, Boone has averaged 28.9" of snow per year. In contrast, the 10 winters prior to and including 1996-97 averaged 36.1" total snow per winter; the 10 years prior to and including 1986-87 had 50.4"; the 10 years prior to and including 1976-77 had 42.3". Our 10-year average of 28.9" is 69% of the 48-year average of 41.9". Kids if your parents tell you that it used to snow more than it does now, it's not just mental fatigue. The chart below shows the trend… there is no doubt that we are in a "bear snow market".

 

Conclusion

So the Fearless Forecast from Ray's Weather Center is … trumpets please…

• 60% of average snow
• Temperatures 1-2 degrees above normal
• Drier than normal

How does that translate to snow totals at different locations? Here is the forecast for selected locations in the RaysWeather.Com coverage area.

 
So we can "compete" with the Woolly Worm, here's a week-by-week breakdown...