CINCINNATI — One of the questions that I have been asked the most over the last few weeks is “Are we going to have a lot of snow this winter?" While that is a loaded question, we finally have some data that can help us find an answer.
NOAA’s Climate Prediction Center (CPC) officially released its 2024-2025 Winter Outlook Thursday, October 17. The outlook covers December 2024 through February 2025, which is considered Meteorological Winter.
The official forecast from CPC highlights the Tri-State to have a winter that experiences warmer-than-average temperature, as well as wetter-than-average conditions, which are highlighted in figure 1 and figure 2 below.
This is all because we are anticipated to observe a La Niña this winter according to National Weather Service forecasters. This comes one year after having a strong El Niño.
The phase of the El Niño-Southern Oscillation (ENSO) is one of the most important climate phenomena when it comes to forecasting as well as the weather’s outcome in a given location. This is because it can change the global circulation, which then impacts temperatures and precipitation.
A La Niña is when the sea surface temperatures in the central and eastern Pacific Ocean, along the Equator, is at least 0.5°C colder than the long-term average. Last winter we experienced an El Niño after experiencing La Niña the three winters prior.
The Climate Prediction Center’s (CPC) forecast is 60% that we will have an La Niña through February and into March. It is also expected to be a weaker La Niña. The last time we had a winter with these conditions was not too long ago: The winter of 2022-2023.
What Does It Mean For The Tri-State
When ENSO is in a La Niña phase, it usually leads to the Polar Jet Stream shifting further to the south, which in turn also brings colder temperatures into the northern United States. Here in the Tri-State, that southward shift in the Polar Jet Stream generally leads to a wetter winter pattern.
This generally leads to a cooler and wetter winter for areas in the northern U.S. and Canada, while drier than normal and warmer than normal periods are expected for the southern U.S. and the U.S. Gulf Coast.
As I have mentioned in the past two years, it would be a cop-out to use these general national trends to determine what our winter in Cincinnati and the Tri-State will bring. We should see if we can use past data to find if there are any trends to pick up on.
Before we give a forecast for the winter, we have to define what a “normal winter” is for those of us in the Tri-State. While the winter months are defined as December, January, & February, we can see snow from October through April. So when it comes to snowfall, the seasonal average for Cincinnati is 22.6 inches over the last 30 years. We will use the winter months (Dec-Feb) to define the average temperature, which equates to 34.2°. These numbers will be our comparison points.
In the last 30 years, we have seen 10 El Niño winters, six neutral winters, and 14 La Niña winters. Below is the list of the 14 years with La Niña phases and where we finished among snowfall and temperatures in those respective years. Those that are in bold were La Niñas that are considered “strong.”
Of those nine El Niño winters, seven finished with ABOVE average snowfall, while seven finished with BELOW normal snowfall. As for temperatures, it was the exact same outcome. Seven winters finished ABOVE normal while seven finished BELOW normal.
Looking at it on a macro level, there isn’t really a trend. But as mentioned earlier, this La Niña is expected to be relatively weak. Is there a correlation between the La Niña winters and a pattern? Let’s look at all winters in that same timespan with a sea surface temperature anomaly of -0.5° to -0.9°.
That paints a much more definitive picture. Of the six winters that seemingly fit in the same type of conditions that we are expected to see in 2024/2025, five of the six finished with BELOW normal snowfall. The only winter that finished above normal was only above by 0.4”. Four of the six winters finished with an ABOVE normal temperature as well. If that trend continues, it will not be a great winter for snow lovers.
The Forecast
Using all of that previous data, and seeing the trend we have had in previous winters, I am going with a forecast that our 2024-2025 winter will finish warmer than normal with below-normal snowfall.
In my forecast for 2022/2023's winter (August 16, 2022) I said:
It is still too early to know if we will definitively see a La Niña this winter, but if we do, I would suspect that we see a warmer-than-normal winter with below-normal snowfall.
That winter finished with an average temperature of 38.6° (above normal) and only 14.4” of snow (well below normal).
In my forecast for 2023/2024's winter (October 9, 2023) I forecast:
With all of that being said, I would still suspect that we see a warmer-than-normal winter with below-normal snowfall.
Last winter finished with an average temperature of 38.4° (above normal) and the ninth lowest winter snow total on record in Cincinnati, of just 7.8” of snow (well below normal).
Let’s see if we can make it three years in a row.
