You’ve probably heard that La Niña weather conditions are expected to affect Michigan this winter. But how does that happen and what does that mean for your winter plans?
Johnna Infanti is a meteorologist with the National Oceanic and Atmospheric Administration's Climate Prediction Center and the author of the National Weather Service’s latest Fall and Winter Outlook report. She spoke with Michigan Public Morning Edition producer Caoilinn Goss.
Caoilinn Goss: To start us off, can you explain what is a La Niña event?
Johnna Infanti: Currently, we are under what we call a La Niña Watch, and that's issued when conditions are favorable for La Niña to form within the next six months. And a La Niña occurs when sea surface temperatures in the equatorial Pacific are below normal or cooler than normal. And it may not seem like it, but those cooler than average or cooler than normal SSTs can cause changes in the atmosphere over the equatorial Pacific, and that can lead to a kind of chain reaction of changes in atmospheric patterns globally.
CG: Can meteorologists like yourself predict when these cooler ocean temperatures are coming?
JI: We can predict the phases of La Niña or El Niño. This is all part of what we call the El Niño Southern Oscillation. And we have some key things that we can look at when we're looking at those predictions, such as how the sea surface temperatures are trending towards warmer or cooler. And what we're predicting right now is a brief period of La Niña conditions in the fall and early winter, 2025-2026, before reverting back to neutral conditions when those sea surface temperatures in the equatorial Pacific aren't really warmer than average and they're not really colder than average, they're just neutral.
CG: So with all that going on in the equatorial Pacific, what does that mean for the weather we experience in our day to day lives here in Michigan?
JI: In the case of La Niña, what happens is the jet stream can be shifted northward from its typical location, and that can cause some common impacts to precipitation and temperatures over the U.S. For Michigan, there can be some increased precipitation - and that does include the potential for more snow if it gets cool enough during La Niña events - but temperatures are usually near average. I will note that there's still some uncertainty surrounding this event, and in addition, no two La Niñas are alike in terms of impacts. We can forecast some of the typical impacts that we might see. But things like the strength of the La Niña event can lead to variations in some of these typical impacts.
CG: And how do you measure the strength of the La Niña event?
JI: We measure the strength of La Niña events based on how cold the SSTs are in the equatorial Pacific. So a weaker event would have those SSTs be closer to average, whereas a stronger event they would be further from average or more cold.
CG: And SSTs are sea surface temperatures?
JI: Yep.
CG: So how will the La Niña conditions impact Michigan's farmers?
JI: February, March and April, that's when we might see some of the stronger impacts over Michigan. And we have much of the state covered in a weak chance of above normal precipitation, meaning that we have a 33-40% chance of above normal precipitation across the state. I'm sure for agriculture, some of those chances of above normal precipitation might have impacts, but I will note that this particular forecast does not have anything to do with the chance for extremes of precipitation. We're just simply saying that there is a higher chance for this season to have above normal precipitation.
CG: You've talked a lot about how we're going to get a wetter winter due to changes in climate. In recent years, a lot of beloved Michigan winter sports have suffered skiing, dog sledding, the list goes on and on. Would you say this forecast is good news for winter sports enthusiasts here in Michigan?
JI: I'd say yes, but it is still a bit of an uncertain forecast. And what I would suggest for winter sports enthusiasts in Michigan is to keep an eye on some of our shorter term forecasts, like our 8 to 14 day hazards that we have on the web that would show chances of snowfall as we go throughout the winter.
CG: Thanks a lot for your time today.
JI: Thank you so much for having me. I really appreciate it.
Editor's note: Some quotes in this article have been lightly edited for length and clarity. You can hear the full conversation near the top of this page.
