Can you say “Arctic Air?”

January 15th, 2013 at 9:06 pm by under Weather

Are you ready for a real, winter reality check?  A wave of arctic air is on the way, likely to be here in less than a week.  Sadly, I feel I may over use this term a bit over the next week, since there is not much else to talk about in the overall weather picture.  (I am not saying dry and quiet is a bad thing, I am just saying this is the next big weather impact to affect your life.)

So, how do we know this surge of arctic air is coming?   Check out this forecast map here:

European Forecast Model Temperature Plot, courtesy weather.cod.edu

This is a plot of the air temperatures across North America next Tuesday morning.   The temperatures are plotted in the Celsius scale and this is the air temperatures at the 850mb pressure level.   Why do we look at the 850mb level (a few thousand feet above the ground) and not the surface?  Well, we look at both, but surface temperatures and a daily basis can be affected or masked by cloud cover and pockets of precipitation.  So, what are we looking at then?  Here is the same image with an explain-er:

European Forecast Model Temperature Plot, courtesy weather.cod.edu

I have highlighted the core of the arctic air with the white circle.   The passing of this airmass is a direct hit for us as the flow in the lower parts of the atmosphere are set up just for that:  A polar low just south of the Arctic Circle and high pressure over the Southern Plains.  Again, when looking at the pressure maps, the winds mainly flow parallel to the black lines, or the lines of constant pressure.

So, is this a for sure thing?  If I was a betting man, I would say, hands down… yes.   Check out the 6-10 day temperature outlook from the Climate Prediction Center:

6-10 Temperature Outlook courtesy the Climate Prediction Center

The area highlighted in blue is for below average temperatures and as you can see, we are running a 75%  chance of below average temperatures.   So, how cold are we talking?  That’s the million dollar question, but the big unknown right now is how will that cold air change as it moves over parts of Michigan, which doesn’t have any snow cover.

As of this second, this is what we know:

  • Front arrives on Sunday, with highs in the 20s.
  • As the colder air rushes over Lake Michigan, look for flurries Sunday and Monday.
  • Teens on tap for Monday and Tuesday, mainly the lower to mid teens.
  • Depending on the final details, we could most certainly see highs in the upper single digits and sub zero lows.

At least we won’t have it as bad for the folks in California: Jimmy Kimmel Weather Segment

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