Outlook for 2024/25 Winter

It’s the most often asked question at this time of year: what’s the winter going to be like?  Seasonal outlooks are what I call “educated guesses”. They’re not just the flip of a coin.  There is a lot of science behind them. But their accuracy is only a little better than a coin flip. 

For winter outlooks, the focus is on whether it is an El Niño, La Niña or neutral conditions in the equatorial waters of the Pacific. There are a lot of other things that come into play, but these are all in the atmosphere. And we currently can only predict the atmosphere out for about two weeks. But the oceans are much slower to react, and so we can make confident forecasts for them several months into the future. 

Last winter was a great example. It was an El Niño winter, and as expected, this brought mild conditions to the Inland Northwest.  Overall. But there was a week of brutal cold in the middle of January. But when you looked at the entire winter, it was warmer than normal. 

This year, it’s back to La Niña. We had three consecutive La Niña winters prior to last winter, and all three were different. And that’s typical. While a moderate to strong El Niño gives us a mild winter about 90% of the time, La Niña only delivers the anticipated results about 60-70% of the time. It’s not a slam dunk. 

La Niña typically brings colder and wetter weather to the Northwest as well as the Ohio valley. And this fits with the official outlook from the Climate Prediction Center. 

I ran across a blog from severe-weather.eu. They looked at the European and UK climate model forecasts for snowfall. They had some interesting findings. Here’s the anomaly snowfall outlook for December. Blue indicates snowier than normal, while warm colors indicate less snow than normal. 

If the ECMWF is right, the winter will get off to a slow start. But then look at January.  

The ECMWF expects snowier than normal conditions for much of the Northwest, except for the Columbia Basin. The biggest anomalies are in the Cascades and Rockies, which is to be expected. But this overall pattern could be suggestive of stronger westerly winds, shadowing the Basin while enhancing precipitation in the mountains. 

February is similar to January, but with above normal snowfall even in the Basin. 

The UK model is similar to the ECMWF. Both would expect a good mountain snowpack. The ski resorts should be happy. 

We’ve looked before at the NMME, which is an average of several climate models. They support a wet forecast for the northwest, with a good chance of above normal precipitation. 

But they’re not buying into the idea of a colder than normal winter. We’ve seen this before: active winters with lots of storms, but just as much rain as snow. 

I’ve seen several outlooks online recently.  Just about all of them are click bait, making it sound like this is going to be a harsh winter in some parts.  But this is forecast to be a weak La Niña. The Australian met agency isn’t even convinced that there will be a La Niña. 

So my best answer to folks asking me about the upcoming winter is this: we’ll get more snow than last year. Also, it looks like the full effect of La Niña will be in the second half of winter, which is also typical. It won’t be as mild as last year. But that doesn’t mean it will be a heavy winter for snowfall. Could it happen?  Sure. But the science isn’t to the point where we can be confident of it.