Typically, I'm not a big fan of seasonal winter outlooks. They're more of a gimmick than beneficial for long-range planning. However, this season is looking a bit different.
Sometimes there are one or two signs that may signal a winter will trend one way or another. This year, the confidence in the winter forecast is much higher based on several important factors.
We already got the season started with the November 15 ice storm and several rounds of winter-like air. The only other time Roanoke had ice this early, was the exact same day in 1986. Interestingly, we ended the winter with the second highest snowfall on record, topping 56".
Looking back at the Top 10 snowiest winters on record, nearly all had some form of early season wintry weather in either November, December, or at least by the first week of January.
While forecasting months into the future isn't nearly as easy as reviewing the past, there are some indicators this is going to be a busy winter season.
The most obvious sign is warmer than average water in the tropical Pacific ocean known as El Niño . We have seen this pattern in place for the past several months, bringing our stretch of above average rainfall. This active storm track is expected to continue into the winter months.
Many of our snowiest winters have occurred during either a weak or moderate El Niño . These include the winters of 1986-87 (56"), 2002-03 (25"), 2009-10 (43") and 2014-15 (22").
We also need cold air to make the big storms happen. Bring in the Polar Vortex. When it's strong, cold air hugs tighter to the North Pole. Likewise, when it's disturbed or in a weakened state, it can wobble and stretch, sending frigid air south.
Increased sunspot activity has been known to produce a stronger polar vortex, while low sunspot activity can produce a weaker one. Being at a minimum now, odds favor more disruption and a colder outlook.
More snowfall this season in Canada and Siberia could also mean there's plenty of cold air ready to be unleashed when an outbreak does occur.
Let's dive into the forecast. Trying to pinpoint ranges for various locations is like the Farmer's Almanac trying to pick the exact week it will snow. I've been forecasting here for decades and have seen winters where Danville gets more snow than Blacksburg and Hot Springs. It just depends on where the storms track. This forecast which is meant to be more of an average snowfall for the region.
Expect a more active winter than the past few with numerous unseasonably cold air outbreaks. This, along with an active storm track, will likely lead to several major winter storms of 6"+ snowfalls.
Based on the factors listed above, specifically a weak to moderate El Niño , I expect an above average amount of snowfall, with the potential for 22" to 35". Depending on the path of storms, the higher elevations have the potential to see even greater totals that could top 40". For comparison, an average winter brings around 18.5" for the Roanoke Valley.
In summary, the winter forecast is nothing more than taking a stab at long-range forecasting, which by nature is extremely difficult. Southwest Virginia's winter storms come together during the final hours when the perfect combination of cold air and southern moisture meet. Knowing when, or if that will happen is nearly impossible.