The StormTrack 9 Winter Outlook (2017-2018)
CHATTANOOGA, Tenn. —
StromTrack 9 2017-18 Winter Outlook
For more than 35 years, the StormTrack 9 tradition continues with the annual Winter Outlook! It was my favorite forecast of the year when I was a kid growing up in Chickamauga, GA and still is today as I am now the one delivering the seasonal outlook! In fact, I get asked about the upcoming Winter as early as the Summer. So, I understand how important it is to do my best!
RECENT LOCAL WINTERS
Let’s look at the past 5 Winters locally. 2 were colder than average, while 3 were above average including last Winter that was the 4th warmest on record. The total snowfall over the past 5 Winters is 19” which is an average of 3.8” per year. That almost equals our normal snowfall average each year of 3.9”. But, those averages do not mean that every Winter will have snow. For example, last Winter hardly had any snowfall at all. But, the 5 year stats do indicate that while some Winters locally are snow-less, there are Winters in our recent past that have been quite snowy!
WELL, THE ALMANAC SAYS…..
Hey, the Farmer’s Almanac and the Old Farmer’s Almanac have been predicting the Winter Outlooks longer than I have. So, I always give them a tip of the cap! Both publications are projecting a chilly & wet Winter with possibly near normal snowfall.
WHAT ABOUT THE WOOLY WORMS?
I never, ever leave out folklore when researching the upcoming Winter. The wooly worms are a local favorite as being the go to natural indicator for Winter. I saw a few wooly worms and all had alternating bands of brown and black. Folklore suggests that such a pattern projects periods of warm and cold throughout the season (I think they are on to something…..).
I also looked at other natural indicators. For example, the yellow jackets were especially aggressive during the Fall. I bring this up because the past two Autumns, they were not and the following Winters were warm. Could those pesky stingers know something?
Also, spider webs seemed to be everywhere this Fall. Folklore suggests that to be a sign of a cold Winter. Trust the spider senses?
WEATHER PATTERNS PRESENT & PAST
The upcoming Winter months could be affected by a weak La Nina pattern. This cooler than normal condition of the equatorial waters off South America can lead to a Polar Jet that stays farther north of us. But, this La Nina pattern is weak and expected to fade through the Spring. Researching similar patterns locally in the past yielded some mixed results. Past similar seasons had below average snowfall, but a few like the Winter of 2001 had near normal snowfall. Temperature & rainfall trends during these past similar Winters were all over the place with some warmer and others colder. But, most of the past Winters had back and forth swings in temperature during the season. Likewise, rainfall varied as well. For example, the Winter of 1989-1990 was extremely wet, while others were closer to normal.
FORECAST MODEL OUTLOOKS
I’ve factored in the success rate of forecast models over the past few years along with the projections over the past few months. La Nina has been a big factor in these outlooks. The Climate Forecast System models have consistently projected a warmer than normal winter locally. But, I have noticed that over the past few model runs that the models have trended closer to normal with temperatures and being just “slightly above normal” This could be a reaction to the weakening La Nina pattern. The JAMSTEC model or Japanese Model has had a very good track record the past few years. During the Fall the JAMSTEC has shown a warmer than normal Winter locally trend to one that is closer to normal. In other words, these models have been trending a tad cooler the last few runs over the past month. Finally, a peek at the European Model 45 day outlook has an eyebrow raising look. It gives an indication that some colder shots of air are possible locally into December and early January. Mild in between those blasts, some chills nevertheless.
SO, WHAT’S THE VERDICT?
Going over all of these factors, it’s just hard to see a repeat of last year. I think we are heading for a Winter that might still be slightly milder than average, but colder than last Winter. I think the average temperature through March might trend just above normal. This could be the result of back and forth swings in temperature through the season. Milder periods offset by much colder ones. And, those colder periods could be longer in duration and colder compared to last Winter.
Winter rainfall has the potential to be closer to normal. This is based on current model projections and also an average of past similar Winter seasons.
Now, for snow and ice potential. I always call this the “Wild Card” category. Why? Well, we average very little snow/ice each year anyway at just under 4”. So, just one snowy day can give us a season’s worth. As I mentioned above, even though past similar Winters had a below average snowfall trend, there were some Winter’s that at least yielded some totals close to normal. And, some ice threats as well. Remember, it only takes an inch of snow/ice to create problems locally. And, the storm tracks even with a weak La Nina could provide a couple of snow opportunities during the season. I like snow, so I am always hopeful. I’ll keep this year’s outlook at just below normal, but better chances than last year.
Each year I always emphasize the risk of Ice. We haven’t had a crippling ice storm locally since the Winter of 1972-1973. That’s a long time, but also a reminder that we have that threat each year.
CHRISTMAS DAY SNOW?
It is way too soon to know whether or not there will be snow on Christmas Day. The snowy Christmas Day of 2010 was so much fun and I know a lot of you are wanting a repeat of that. For now, all we can do is look at the statistical averages from past Winter's. Our year to year chance of a White Christmas is just under 20%. Hey, it's better than 0% chance!
DEPEND ON US!
No matter what happens this Winter, you can always depend on the StormTrack 9 Team. Our forecasting team is 4 members strong who are all dedicated to bringing you the best weather coverage. Keeping you and your family safe every season, you can depend on the StormTrack 9 Team!