Michigan winter outlook: What La Niña could mean for storms, temperatures

Latest outlook at what winter 2020-2021 could look like in Michigan

NOAA precipitation forecast for Dec. 2020-Feb. 2021.
NOAA precipitation forecast for Dec. 2020-Feb. 2021. (NOAA)

Back in August I gave a preliminary outlook about the winter ahead based upon the development of a La Nina pattern.

Before reading my updated outlook, you need to FIRST play this very short video, which also explains the different impacts on our winter weather pattern by El Ninos and La Ninas.

La Niña jet stream suggests stormier winter for Michigan
La Niña jet stream suggests stormier winter for Michigan

Since the time I did that report, the La Nina has continued to develop into a moderate event. So there’s no questioning that this will be the dominant influence on our winter weather pattern. But there are other things going on that also play a role.

For example, right now we have a strong polar vortex circling the high latitudes. When the polar vortex is strong, it’s more difficult for Arctic air to plunge south, that’s why we’ve been so mild this month, and this may continue into part of December.

However, according to Dr. Judah Cohen – a climatologist in M.I.T.’s Parsons lab – there are some signals down the road suggesting a clockwise rotation of large upper level atmospheric waves which could shift the main ridge (jet stream bulging north) from the eastern U.S. to the western U.S., which would then favor troughing (jet stream bulging south) in the eastern U.S. And that, should it come to fruition, would open the door for more typical early winter air masses to stream into the Great Lakes.

As I explained in the video above, La Nina winters are typically stormier winters for us. The big question is: will that storm track be a little north or south of us? That is a huge question because, if the storm track is north of us, then that means more rain than snow. However, if the storm track is farther south, then that would mean we get clobbered with lots of snow.

And there’s one more factor to consider: global warming. La Nina years are generally colder years for the planet, while El Nino years are warmer years. However, as a direct result of the warming climate, La Nina years are now warmer than El Nino years used to be. So these La Ninas we deal with today aren’t “our grandparents’ La Ninas.”

Global surface temperature 1980-2019. (NOAA)

So what are my thoughts about this winter?

Based upon everything I’ve explained above (plus a few other things I don’t have time to get into), I think our benign stretch of weather will continue for a few weeks, with little in the way of big storms.

However, don’t get complacent: this will probably end up being a back-loaded winter, with January and February bringing a stormier pattern…significant storm systems with a lot of moisture and wind. The only thing I don’t have a feel for yet is if those big storms will bring us rain or snow.

As I described above, this will be dictated by the jet stream (storm track). If it’s an oscillating pattern, we’ll alternate between mild stretches with rain, and cold stretches with snow…true weather whiplash. If a more persistent storm track sets up, then we could end up more consistently warm with rain, or cold with snow.

A quiet, dry winter would be a complete surprise to me at this point…even though we seem to be starting off that way.

Should I pay by the season, or pay by the push?

Every fall, I’m besieged with questions from people about if they should pay a snow plow guy by the push, or for the entire season. I give the same answer every time: consider your snow plow guy as insurance. If you pay by the season, you have a fixed cost (but check the fine print to be sure), whereas paying by the push means that you could end up paying a lot less…or a lot more.

Sure, in some winters (like last winter), the snow plow guy comes out on top if you pay by the season. However, in a winter like 2013-14, you would have come out ahead…way ahead. I prefer to know my costs up front, and not have to worry about it every time we get into a snowy pattern. Pay by the season!

About the Author:

Local 4 meteorologist Paul Gross was born in Detroit and has spent his entire life and career right here in southeast Michigan. Paul has researched, written and produced eight half-hour documentaries for WDIV, as well as many science, historical and environmental stories.