Glenn Zimmerman’s long-range winter 2019-2020 forecast

Data pix.

ST. LOUIS, MO – The FOX 2 and News 11 Weather Team is ready for winter forecasting but are you ready for the types of weather the season may bring? Two organizations that must prepare and prepare early are the Missouri and Illinois Departments of Transportation. Sometimes, even with lots of planning, winter snow and ice can get the best of their efforts. John Fuller spoke with MoDOT and Missouri State Troopers about the absolute mess that a big snow on January 11, 2019 made of the roads. Then, Brigit Mahoney takes the Woods Basement System Storm Runner to check in on IDOT’s pre-storm planning process.

But what conditions create all the types of precipitation that can make our commutes a mess? Chris Higgins breaks down the difference between rain, freezing rain, sleet, and snow. Freezing rain occurs when the layer of freezing air is so thin that the raindrops do not have enough time to freeze before reaching the ground.  Sleet is frozen raindrops and occurs when the layer of freezing air along the surface is thicker.

When looking at long range forecasting, you really have to look back into the past to see what the future may hold. The Saint Louis University CIPS Analog Guidance is a great tool during the winter season. The analogs compare a current weather pattern or forecast to a past weather event. Jaime Travers explains how by incorporating historical impact data, forecasters can identify similar patterns and the risk of high-impact threats.

Have you put up your holiday lights yet? The region’s big holiday light displays have to start in October to get all the work done. St. Louis County Parks talks with Angela Hutti about how crews take a lot of precautions when they’re putting up the lights at Winter Wonderland in Tilles Park to protect it from winter weather.

Glenn Zimmerman’s Long-range Winter 2019-2020 Forecast:

When we look into the future to make forecasts, it’s important to do a few things. First, dig into the data that`s presented to us through computer modeling. This is always fundamentally challenging because these models, using high power math, try to simulate the atmosphere and how it moves. If you look at the atmosphere as a 'river of air,' it’s hard to predict where the ebbs and flows present themselves. And so goes computer modeling, it doesn’t have all the answers.

The second thing you have to do is look backwards. As Jaime pointed out, using the climate data from past years can also give us clues about what may be in store for us. In our forecasting for this upcoming season, we look for years with wet summers, hot and dry Septembers, and cooler than normal Octobers, plus a global look at sea surface temperatures. We have found a few of those: 1961, 1983, 2013 and 2014. I am going to add in last winter too because last winter was a return to more of a normal winter here in St. Louis, both in temperature and precipitation.

The last thing you have to look at is where we are right now. We’ve had an early start to winter for sure. An early November theme revolves around early season arctic cold fronts dropping into the Midwest. That’s a pattern that doesn’t really evolve until late in the winter. So, I think the stage is set for some deep cold ahead.

And as always, you have to remember that long range forecasting of specific storms events is impossible. That is a scientific fact that was reinforced last year with our trip to NOAAs Climate Prediction Center. With that in mind, let’s look at the winter months of December, January and February.

December’s countdown to the holidays is always enhanced by snowfall. Everybody wants a White Christmas. But after a cold November, some of our data is pointing to a moderation in temperatures for much of the month. That’s not to say it won’t be cold at times, it just won`t be of the magnitude of November’s 20 to 30 below normal cold outbreak. And with a moderation in temps, any major storms will be few and far between across the nation. So, I am leaning to a slightly warmer that average December as the cold retreats for a while and the warm air balances out November`s chill. December will also carry the 'drier that average' banner too. Snow may be hard to find, so I will once again make the bold prediction of NO WHITE CHRISTMAS this year. Climate averages always point to that, and I am betting on a quiet December.

After the new year begins, winter will reboot! We could call it second winter this year after a chilly November, but that same cold November pattern will reemerge in January and that alone should bring us some of the coldest air we’ve seen in a few years. Arctic air will build into the Midwest and will shut down any chance of warm air building. With this type of cold pattern, snow will be a bit limited too. But let’s be prepared for a sneaky southern storm to hitch to the jet stream and give the Bi-State some big snow.

February is the shortest month, but it’s the longest month. Clouds are a big part of the month, limiting the views of sunshine, and limiting the warmup. This year, I expect a battle in the atmosphere to set up in February as the cold January pattern starts to breakdown. That breakdown all depends on when exactly in January the pattern starts. But middle February is the time to watch for more snow as the atmosphere is in flux. I think snowfall this year will be just a bit above average, which means that most of that could fall in the months of February and maybe March too. So, February starts cold, but transitions toward normal. And that transition will bring snow.

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