KNOXVILLE, Tenn. (WATE) -- A lot goes into making a long-range forecast and they can be quite difficult, especially here in East Tennessee.

It starts by looking on the global scale and I usually start with looking at the current state of the El Niño Southern Oscillation (ENSO). This is a global pattern that forms from wind variations and sea surface temperature changes across the Topical Pacific Ocean. It appears as though a "weak" La Niña pattern has set up and there is around about a 60% chance it will last through the winter months.

La Niña occurs when you get cooler than average sea surfaces temperatures in the Pacific Ocean off of the coast of South America. When this forms it can influence weather patterns across the United States and the World.

We can often see a large ridge or dome of high pressure set-up across the Gulf of Alaska that acts as a "block" and pushes the northern branch of the Jet Stream farther north into Alaska and Western Canada. This can often increase temperatures across portions of the Pacific Northwest and keep the main storm tracks across these areas. It can often mean drier conditions for places like California and the inland desert states.

This "blocking high" causes the Polar Jet to dip down into the lower 48, especially across the Northern Plains and intermountain Rockies, keeping them colder than average during winter months. This in turn keeps the Southern half of the U.S. warmer than average and often drier than average. The steering currents that help develop storm systems remain well to the north. This doesn't mean that the southern half of the U.S. won't see any rain or any cold air, it just means the overall winter patterns could end up this way.

Arctic Oscillation

Another global feature we want to study and try to forecast is the Arctic Oscillation (AO). This is a climate pattern that helps to determine the shifts in pressure between the Arctic and the mid-latitudes across the Northern Hemisphere.

When the AO is in a "positive phase", the Polar Vortex is "tight" due to the pressure being strong between the Arctic and mid-latitudes. This keeps the jet stream in a flatter position and keeps the colder air trapped to the north.

When the AO is in the "negative phase", the Polar Vortex is "loose" as the pressure is weaker between the Arctic and the mid-latitudes. This causes the jet stream to become weaker and wavier, which allows chunks of colder air to spill southward. When this occurs, East Tennessee can see big cool downs. These wavier patterns can be predicted from a few weeks to about a month in advance, but where the cold air goes can be more difficult to pinpoint.

These two global patterns are just a few of the things we look at before we start to look locally. Since we are most likely going to remain in a weak La Niña phase throughout the winter, we can compare it to past winters when La Niña was present. We were in a stronger El Niño pattern last winter and only really saw one snow event. However, it was a doozy that brought Knoxville 8.5'' of snow in under 36 hours.

Before that, Knoxville saw a "triple dip" La Niña from the winters of 2020-2022. These winters didn't produce that much snow, common for La Niña winters, but there was a caveat in 2021 as we saw a total of 10.7'' that year. But, 6.5'' of that fell, outside of meteorological winter (December, January, February), in mid-March. With this event, we actually had thundersnow as well.

So, here are some of my thoughts broken down into each month this winter:

December

It does look like we will see a negative Arctic Oscillation (AO) phase begin the month and I am thinking that we could see at least a small chunk of this colder air early in the month. The question will be, will it match up with some moisture?

Overall, the snow chances for the month look low. There is a more likely chance early in the month as some warmer air seems poised to come back later in December which will cause the overall temperature profile to be above average for the entire month with precipitation being near-average as well.

January

This is usually one of the coldest winter months on average each winter and this should be the case this year as well. There are hints that the beginning of this month will be colder as well, which may aid in our chances of seeing some wintry weather, but the month does appear to end on a milder note leveling out to a near-average overall. This month should be our best chance for wintry weather of the three.

February

Once again, we could see a chunk of the Polar Vortex break off and head our way, but there wasn't anything showing that we would feel the full brunt of it. Therefore, we will predict above-average temperatures for the month overall. With the milder air and possibly weakening La Niña, we will go with above-average precipitation as well. That said, due to the expected warmer surge through the month, we will keep the overall wintry weather chances low.

Here is the forecast for snow totals for each of our four zones:

With the anticipated warmer than average end to February and a weakening La Niña, we will be keeping a close on March. Severe weather season in East Tennessee is typically March to May (although we know severe weather can happen at anytime of the year). If temperatures in March remain much above average as we're thinking, our "wild card" forecast is for possibly a busier and earlier severe weather season.

Don't worry though, Storm Team 6 has you covered and will keep you ahead of the storms.