As I noted yesterday a couple of snow potentials are popping up on the models from the November 19th – 30th time frame.  Since this correlates to the switch over normal temperatures this is no surprise given the time of year.

So the tricky part will be getting these first couple storms predicted right.  Couple of factors to consider, 1) The models poor performance – they have been lacking in the department over the past couple of weeks and 2) the models can’t agree!

In classic style that plagues all weather forecasters, the main models can’t quite agree.  For example, here is the look from the usual best model (Euro) for early Monday AM:euro-monday-am

Compared to the fairly reliant but the sometimes underperforming GFS model which is getting closer to the Euro:gfs-monday-am

Compared to the other big 3 model the GEM/CMC, which is warmer and more rain than snow:gem-monday-am

Both have a little different look, but what they do agree with:

  • A Great Lake Cutter (GLC*) type storm develops Saturday.
  • A secondary low develops from the storm on Saturday and slides through Southern Ontario strengthening towards the East Coast.
  • The storm slows going through Quebec and moves North/East giving Eastern On/Southern Quebec more of a snow chance.

This scenario could produce some decent snow totals around Eastern Ontario and maybe Lakes Effect Snow (LES) downwind of Georgian Bay and Lake Huron.

A couple factors playing against much snow accumulating will be the fact that surface temperatures, meaning near the ground,could still be hovering near or slightly above 0c so you could see less accumulations on the ground for these areas.  Since we don’t have really cold Arctic air to work with yet its possible it could be wet snow/rain event.

I will have my storm snow totals predictions out by Wednesday or Thursday once we have more consensuses from the models.  For now, brace yourself for the change 😉

(*GLC means a storm that develops usually across the America mid west or Texas and moves in cutting across somewhere between Lake Superior and Lake Huron and riding North/East towards James Bay or Northern Quebec.  This storm on Saturday doesn’t quite meet the criteria because it tracks more across Northwestern Ont through Lake Superior.  Still these type of storms usually bring warm air and less precipitation on the east side with cold and stormy on the west side.  So often Southern/Eastern Ontario gets rain and rising warm, temperatures while points further Northwest get snow and a cold strong wind.  I refer to these storms as snoweaters during the winter, because they can really put a dent in a snowpack on the ground.  You might often hear me refer to them, they are pretty hated in my books, they rarely produce snow in Southern Ontario unless its in January and they cross closer to Lake Huron/Lake Erie)  Here is a look at what this more west based GLC looks like:

sat-storm

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