Dueling Models and Our First Snow

GFS and the Euro just can't play nicely together.  Our two main weather models are fighting again, and if you're a fan of winter, you're rooting for the Euro to win.  If you don't, you're pulling for GFS.

If you've been keeping up with Rippeology, you know that my forecasts have favored the potential for early season snow and cold as we wait patiently for El Nino to set up.  In my Winter Outlook on October 14th, I discussed early season snow pack in Canada, and how that might impact our November.  In last week's post (pertaining to the current November 3-10 period), I showed you how cold and slow-moving systems could set us up for snow in the near future.

Those predictions look like they may verify.  It's snowing in northern Wisconsin this morning; some spots will see 3-5" by late afternoon.  And looking ahead 7-10 days, it's quite possible (likely even) that southern Wisconsin could see its first accumulating snow.

Before we discuss that, let's take a quick look at the short term:

• Today's rain will amount to over an inch in spots and be accompanied by some fog.
• Another system will quickly replace today's low. Look for rain to redevelop again Monday night as low pressure deepens to our southeast. 
• For election day on Tuesday, that low will also create a fair amount of wind. Here's noon Tuesday wind as that low quickly scoots north of the Hudson Valley.  Be prepared for blustery conditions as you head out to vote.

(Remember you can click on any image to enlarge).

 

Once we get through Tuesday, things start to get interesting.  Reinforcing shots of Canadian air will bring us our coldest temperatures of the season.  But this is where the GFS and Euro models start to throw down different solutions.

Take a look at 6:00 Friday evening.  Note where GFS puts low pressure, off the east coast:

 

 Now look where the Euro puts the low:

 

As a result of the closer proximity of the low (remember, winds rotate counter-clockwise around a low), here's how the Euro sees surface temps at 6am Saturday morning...

And how GFS sees it...

So, the models disagree by 8 degrees in Madison.  But that 8 degrees makes a difference.  If the Euro is right, the cold pocket settles long enough to sustain snow.  If GFS is right, temps easily rebound to more seasonal levels and snow becomes less likely.

Watch how the Euro spills cold air into our area over the next 10 days...

With that cold air in place, Euro sees two chances for snow: 1) a slight chance Thursday night into early Friday, and 2) a better chance next Sunday night into Monday.  Again, GFS disagrees.

Here's 10-day total snowfall from GFS...

And from the Euro...

So, which model should we believe when they can't both be right (but could both be wrong)?  The Euro tends to do better in mid-range, and seems to handle winter storm tracks better.  But we're in a transitional window right now, fall to winter.  And seasonal transitions are really hard to call because temperature is SO important.  That's why that 8 degree difference caught my eye.

I still favor snow for south-central Wisconsin over the next 10 days.  How much remains to be seen.  But rest assured I'll be watching it closely and keeping you posted!

~Scott