Because they are anticipating an El Nino pattern to develop in the tropical Pacific, the National Weather Service’s winter outlook for December, January and February is calling for “equal chances” for either above normal or below normal temperatures for our part of the country.
Their outlook for precipitation is the same.
Unfortunately, that doesn’t tell us much as far as what kind of winter we will have, or how much snow we may see.
So let’s look at what our average snowfall is, and what we’ve seen the last two years.
The average amount of snowfall in Nashville is 6.5 inches. Last winter, we had a little less than half of that with three inches. The winter of 2016-2017 had even less with 2.2 inches
Another important aspect of El Nino years is the prevalence of the “sub-tropical jet stream,” which can run across the Gulf states.
This can be trouble as far as severe weather is concerned when winter cold fronts meet up with the warm, moist Gulf of Mexico air. That jet stream can enhance the chance for severe weather, including tornadoes.
That is more likely to our south, but we have seen examples in the past of that jet slipping farther north into Tennessee.