ST. LOUIS — There is no debating that January 2023 has been incredibly mild.  In fact, through Wednesday (Jan 18) this ranks as the 2nd warmest start to any calendar year on record.  The average temperature is 11 degrees above normal.  This following the coldest Christmas holiday the region has seen in some 30 years. It has been a wild ride.

Now, there are signs that winter is going to make a comeback.  Those signs have been somewhat nebulous up until now and in the distant future.  But now, we are looking at the potential for winter weather next week. 

Two waves of winter weather

First snow system

There are two weather systems on the charts over the next seven days that have my attention.  The first cruises through the region over the weekend.  It will be disorganized, weak, has limited moisture and will be working with marginally cold temperatures.  All of this adds up to a light mix of light rain, some wet snow and probably some drizzle. 

The precipitation will begin Saturday evening and continue into Saturday night.  Some very light snow and/or drizzle will be possible as well, Sunday.  With such marginal temperatures, I just don’t see much, if any, accumulation from this weekend system.  It’s just going to be unpleasant, uncomfortable and modestly inconvenient.

Light snow expected Saturday

Snowy forecast next week

The next system in the cue is scheduled for the Tuesday-Wednesday time frame. It is a southern storm, and these typically have more moisture with which to work.  This system has the look of a much more organized, and hence much stronger weather system as well.  Temperatures will be a bit colder than the weekend system. A stronger system should be able to overcome the borderline temperatures in the heaviest precipitation. 

Second snow system

The biggest question right now is the track.  Several of our most reliable forecast models show the classic “Memphis Low” track, which is a benchmark track for snow producing winter storms in St. Louis.  Assuming the air is cold enough, a surface low passing near/over Memphis usually results in a solid shot of snow for the St. Louis area.  There is another cluster of model solutions that are somewhat weaker and more to the east and south.  So the track remains uncertain, and hence the forecast for this second system is still uncertain.  But it is definitely a storm to watch!

You can really see the differences between the weekend storm and the Tue-Wed storm by looking at the upper level winds and energy.  Here you have the weekend system. Notice how the isobars (technically geopotential heights) do not close off into a closed circulation.  Instead, you have a wavy open flow that looks disorganized.  That’s why I don’t expect a lot of excitement for the weekend storm, just light rain, some wet snow and drizzle.

Now look at those same parameters Tuesday night into Wednesday.  Notice the isobars (height lines) are completely closed off just to the south of St. Louis.  That indicates a much more organized and much stronger weather system. Which is why this system has my attention.

How much snow are we expecting?

With all this in mind, there is a potential for accumulating snow over a large part of St. Louis area from Tuesday night into Wednesday.  Whether it’s only an inch or two, or several inches more than an inch or two remains to be seen.  Just keep the Tuesday/Wednesday timeframe in the back of your mind over the weekend and remember to check back as you start the new week.

Snow expected in the St. Louis area

Now, looking long term (beyond the next seven days) we have to be concerned about what happens to the very cold air that has been building up in Siberia.  There is a reservoir of extremely cold air with temperatures of -50 to -70 degrees Fahrenheit. 

Frigid temperatures

Anytime you get extreme cold building up in Siberia, there is the potential for it to “slosh” over the North Pole and into North America.  It seems likely that at some point in the next 10 to 20 days, we will have to deal with the effects of this cold air.  How cold will it be when it gets here?  How long will it stick around?  Those are unknowns… but the message from this pattern is clear, winter is far from over.