By Mike Ekberg, manager of water resources monitoring and analysis
It’s the beginning of November and winter is right around the corner. What will winter 2021–2022 be like? Will the Miami Valley experience a mild winter or can we expect frigid temperatures and lots of snow? Here are some predictions based on MCD’s research and expertise.
According to the National Oceanic and Atmospheric Administration (NOAA), winter 2021–2022 is likely to be warmer and wetter than average. Two factors that favor this outcome are the increasing winter temperature and precipitation trends, and the forecasted presence this winter of a La Niña pattern in the tropical Pacific Ocean.
Ohio Winter Temperatures and Precipitation Trending Upward
We have been watching the winter temperatures and precipitation in Ohio trending up. A comparison of average temperatures for Cincinnati, Cleveland, Columbus, and Dayton illustrates that the average winter temperatures have warmed anywhere between 0.3 to 2.3 degrees Fahrenheit between 1981–2010 and 1991–2020 (NOAA, 2021). The average winter precipitation increased between 0.31 and 1.02 inches for the same time periods. These trends are expected to continue, and they influence how winters in southwest Ohio play out.
La Niña will influence wet conditions
La Niña is an atmospheric pattern characterized by stronger-than-normal trade winds and cooler-than-normal ocean temperatures in the equatorial Pacific Ocean. According to NOAA, these conditions are expected to develop and persist as we move into the winter months.
How does an atmospheric phenomenon such as La Niña thousands of miles away in the tropical Pacific Ocean influence winter weather in southwest Ohio?
The answer lies in La Niña’s influence on the position of the polar jet stream across North America. According to NOAA, jet streams are narrow bands of strong wind in the upper atmosphere that blow from west to east. The polar jet stream often marks the boundary between cold and warm air masses across North America and it often acts as a transport mechanism for storm systems across the United States.
La Niñas tend to cause the polar jet stream to dip south over the Midwest and the Ohio Valley. This creates favorable conditions for winter storm systems to track across this region. The result is lots of moisture delivery in the form of rain, sleet, and snow leading to above-average precipitation.
Putting the two weather patterns together
When we combine warming winter temperature and precipitation trends with the expected presence of La Niña conditions in the Pacific Ocean, the outcome is a warm and wet winter forecast for the Miami Valley and the surrounding region.
Other factors influence local weather, too
Remember last year? NOAA issued a very similar forecast for winter 2020–2021. La Niña conditions were present, yet winter 2020-2021 ended up being drier than normal. How could the forecast have been so wrong? The answer is the earth’s weather systems are complicated, and predicting how they will behave is difficult.
La Niña events tend to be persistent over time periods of six to 18 months making them more predictable. There are, however, other global atmospheric circulation patterns or teleconnections such as the Pacific/North American (PNA), Arctic Oscillation (AO), and the North Atlantic Oscillation (NAO) which fluctuate on shorter time scales. These teleconnections also influence the path of the jet stream across the United States and may interact with La Niña, amplifying or canceling out its impact. Predicting these teleconnection patterns can be difficult.
Local factors such as soil moisture conditions and snow cover can also influence winter precipitation in the Miami Valley. Long-term climate trends may also play a role as we’ve alluded to earlier.
Obviously, there is a lot of uncertainty when it comes to predicting what winter 2021–2022 will look like. Still, it’s interesting to look at all of the factors each year and try to make an accurate prediction.
MCD ready to respond no matter what winter 2021-2022 brings
No matter what this winter brings, there is one thing our region can count on. MCD is ready to respond to whatever weather comes our way. The MCD flood protection system has been in place for 100 years, significantly reducing flood risk in cities along the Great Miami River from Piqua to Hamilton. If this winter turns out to be wetter than normal as predicted, MCD will be ready.
For information about our region’s precipitation, water quality, groundwater levels and and more, visit MCD’s water data portal.
National Oceanic and Atmospheric Administration, 2021, National Centers for Environmental Information, U.S. Climate Normals: From URL https://www.ncei.noaa.gov/access/us-climate-normals/#dataset=normals-annualseasonal&timeframe=81, accessed October 5, 2021, HTML format.