The other shoe? Hints of colder air and snow late next week

Some forecast models suggest snow and colder weather in about 10 days.

File this medium-range forecast post under plausible, but not a sure thing.

Yet.

Minnesota’s weather pattern still looks benign for December through most of next week. But a couple of recent forecast model runs have hinted at a possible pattern change late next week into the weekend of December 12-13.

It starts with a dip in the jet stream aloft around December 12. This type of pattern aloft is conducive to producing storms in the Upper Midwest.

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Upper air forecast map for 6 pm December 12
Upper air forecast map for 6 pm December 12
NOAA

So far it’s just one forecast model, but a couple runs of NOAA’s GFS model have hinted at solutions that bring a possible winter storm into the Upper Midwest around Saturday, December 12.

NOAA GFS model for 6 am Saturday, December 12
NOAA GFS model output for 6 am Saturday, December 12
NOAA via Weather Bell

Again, it’s too far out to place significant confidence on these few possible forecast solutions 10 days out. But this type of pattern is close to what we would expect as we move into mid-December. So in my view, it’s worth a mention now and keeping an eye on later.

Colder too?

Again, we’re talking about relatively low confidence here two weeks out. But NOAA’s GFS seems to be sputtering onto a pattern change that I’ve been looking for for a few weeks now.

It suggests the notion of much colder air pouring south from Canada in mid-December. Don’t take the map below literally, but if the pattern shifts this way the chances of our first sub-zero shot may be growing around mid-month. Focus on the trend and not the specifics.

NOAA GFS temperature output for 6 am Tuesday, December 15
NOAA GFS temperature output for 6 am Tuesday, December 15
NOAA via tropical tidbits

In the next few days, I’ll be closely watching the medium-range upper air forecast maps to see if the notion of a stormy and colder La Niña type pattern emerges.

Stay tuned.