Predicting First Snowfall: Coming To The Midwest & Great Lakes
Many years of experiencing first snows, and 5 years of forecasting them for local markets prior to my joining the WeatherNation team, I am well aware of the significance of first snows…
You need to be careful, you need to underestimate the snow potential, and you need to reduce the hype… those are all things I kept in mind as I was a local forecaster. That being said, I am seeing MANY signs for next week that would indicate snow chances for the middle of next week across the Midwest and the Great Lakes region.
Will it look like this…(see below)?
Hopefully people will still use little furry animals (or trams, in this case – referencing the aerial tram that holds 100 people at Jackson Hole…), but they may need some thick blankets as well!
The big thing that is happening is a MAJOR shift in the weather pattern – that is allowing extremely cold Canadian air to sag southward, and stick around as well.
Those snowfall totals keep tallying up – and that isn’t a good sign either, if you’re keeping track of where the cold is. While this isn’t an accurate analogy at all – I tend to associate thickening snow packs with an almost refrigerator-effect of air on snow.
Speaking of that snow pack, though, check out the growth of Wyoming & Colorado’s snow pack. Now up over 20 inches in several spots around the Rockies – with more still to come.
It’s always amazing how quickly the seasons change – and this year is trending even quicker than most.
I pulled up the maps showing the average first snowfall dates for the nation, and take an especially close look at the northern tier of states… generally seeing their first average snow in November.
We’ve already bucked the usual trend for western South Dakota, with some lower elevation areas getting snow nearly a full month early – and now that trend could move east.
Check out these temperatures about a mile up in the atmosphere – for next Tuesday:
The first thing that should stand out as you look at the picture above is the blatantly large blob of blue. All of that indicates air at or below freezing at that level in the atmosphere. With cold surface temperatures you could get snow out of precipitation with that structure (not a given, but it’s possible). With warmer surface temperatures you start to have trouble getting snow – but as the column of air cools, you start to get snow (if you have precipitation & it is in this colder column of air).
The end result? Possible snow for areas that would be 2-3 weeks earlier than average.
I’m not completely sold on the timing of this image above (this would be Tuesday morning)… but the general trend is that temperatures will be cold enough, if you get enough precip falling from the sky, to get snow.
WeatherNation Meteorologist Aaron Shaffer @ashafferWNTV