By Mike Ekberg, manager of water resources monitoring and analysis
It’s late November, and winter 2019–2020 is right around the corner. That means it’s time to discuss the National Oceanic and Atmospheric Administration’s (NOAA’s) Winter Outlook. Before I do, I thought it might be interesting to take a look at last year’s Winter Outlook and see how it fared.
Last winter
The NOAA Winter Outlook for last winter predicted a 50-50 chance of a warmer-than-normal or colder-than-normal winter in the Miami Valley. It also predicted a drier-than-normal winter in the Miami Valley. How did the outlook perform?
Not well at least on the precipitation side. Last winter in the Miami Valley turned out to be warmer than normal and much wetter than normal. In fact, MCD recorded above-average precipitation in December, January, and February, with February setting a new record high of 5.68 inches.
So, what happened? The answer lies with the position of the jet stream over the United States. In February, a persistent high pressure pattern developed over the Gulf of Alaska and the southeastern United States. This caused the jet stream to shift northward over the Ohio Valley, bringing precipitation and lots of it to the Ohio Valley, including the Miami Valley. The jet stream has a strong influence on winter storm tracks. Where the jet stream lies is where precipitation falls.
This winter
NOAA’s Winter Outlook for this winter predicts a warmer- and wetter-than-normal winter for the Miami Valley. This forecast is based upon long-term trends as well as anticipated global climate patterns.
Three of these global climate patterns are the El Nino Southern Oscillation (ENSO), the Madden-Julian Oscillation (MJO), and the Arctic Oscillation (AO). The problem is two of these global climate patterns (AO and MJO) are short lived and hard to predict for more than a couple of weeks at a time.
The more persistent climate pattern, ENSO, is not sending a particularly strong signal favoring warmer-than-normal or cooler-than-normal conditions this winter. In other words, there is a lot of uncertainty in the Winter Outlook this year.
Outlook for December through February
Could this winter be a repeat of last winter?
Last winter was noted for above-normal precipitation in the Miami Valley. Will this coming winter be just as wet?
We know ENSO conditions between the two winters are likely to be different. But it doesn’t look like it will offer much of a signal for the upcoming winter.
A better indicator may be long-term trends, which favor warmer and wetter conditions in the Miami Valley. Winter temperatures and precipitation are trending up, according to long-term climate records.
Predicting seasonal weather conditions is difficult under the best of circumstances. Without any clear longer term global atmospheric signal, the upcoming winter has a lot of uncertainty.
Although the Winter Outlook may not be definitive, we’ll definitely do our part at MCD to manage whatever weather ENSO and the jet stream bring to our region.
