Flash freeze update 2

As of 11 AM, it's -3C, a drop of 9C since 8AM.

Flash freeze update

Cool down will come sooner than I expected. It looks like it's already started in Ottawa.   It has dropped two degrees in the last hour.  Kingston has dropped 7 degrees in the last 3 hours.

Flash freeze...

Most everything is covered in ice this morning even though it's several degrees above zero... But the cold is coming.  The cold front has reached Peterborough which has dropped at least 5 degrees in the last two hours.  I'm guessing our temps will start dropping by noon.

Ice rain in Ottawa

As of 10:00 PM Sunday, it is ice raining.  Has been for a while given the good coat so far on my car.   It is -4C.  Question is whether it gets above 0C by morning.

Regional win...flash freeze warning.

All models, regional and global, are converging on the regional track from yesterday.  That is, over eastern Lake Erie, Golden Horseshoe to eastern Algonquin Park.  The main band of snow is currently in Michegan heading NE.

What that means for us is that the snow today will change to freezing rain to rain overnight into the morning.   The chance of school cancellation tomorrow depends on the freezing rain to rain ratio and when exactly that change happens.

Also of note is the temperature crash on Monday.   If you don't clear your snow piles from where you don't want them, you're going to have piles of ice instead.  There is also the driving danger of a flash freeze as well.  We will go from a morning temperature of a couple degrees above 0 with rain to the negative teens in the evening. 

Regional vs Global battle

The global models have pretty much remained stable with the storm track and timing that I described in my previous post, except that the start of the snowfall is likely to happen during the day on Sunday.

The fly in the ointment are the regional models, which are higher resolution versions of their global counterparts.  Due to the higher resolution, an error will get more amplifed (compared to global models) the farther out from the base period.  As such, the regional models are just starting to get into the zone of reasonable accuracy with Monday's storm.  However, they are showing the storm going NE over Lake Erie into central Ontario, putting us well east of main snow and definitely in the warm sector.

Here is the latest snow map.  It's based on the Global models.

Messy, messy, messy

The storm is going to be a VERY messy storm for all of southern and eastern Ontario.  Currently the models are converging on a track that take the storm center just south of Lake Erie and over Lake Ontario to eastern Ontario by Monday morning.  To the north and west of the storm track will be heavy snows with high ratio liquid equivalent values due to the very cold air behind this.   If the current track and timing holds, the we will be getting 10-15 cm of snow overnight Sunday with mixed precip Monday morning, changing back to snow Monday afternoon, after the storm center passes.
Here is the latest snow map from A/W.  Not to many arguments with it at this point.   Hoping for a 50 mile shift south though.  Note that it goes only to Sunday and doesn't include the precip Monday.

First snow map

For Monday's storm:

Models converging for Monday's storm

Looking like a very messy storm for us on Monday as the models have converged on a Eastern Great Lakes track which will give us mostly snow with perhaps a mix of ice rain thrown in.

Stay tuned.

Another Storm update

Today/tomorrow's storm going well south of our area:

Still a divergance in tracks for Monday's storm.  The Euro has gone for a SW to NE track that is west of us, the GFS has it east of us and the Canadian and JMA has it right between the two.  As such the Canadian GEM has the biggest storm for us.