Snowstorms

Temperature has dropped below freezing at YYZ. Should help allow the ground to cool for better accumulations when the storm arrives. Latest HRDPS sets up a pretty stout deformation band across the Niagara/Buffalo region. Could definitely see totals approaching 8-12" in this region.

Looking good for 3-5" across the GTA with amounts approaching 6-8" around Hamilton. Depending where the deformation zone sets up will determine what areas of the GTA see closer to 5". As of now it appears to be around the lake and further south towards Niagara. Let it snow!

Got down to ~21.5F last night at YYZ. Coldest low since March 23rd, lol.

Got about 1.3" here this morning. YYZ recorded ~1.0". First snowfall of the season.

I agree. 0z ECMWF had an interesting set-up.

The beginning of an epic LES outbreak, haha.

Coldest night/day of the year in Toronto today. Overnight low predicted to be around -11.0F feeling like -36F.

Got a surprise 1.5" this morning that later melted. Still no prospective storms on the horizon through December 20th.

One of the most quietest starts to December I can remember. And no immediate snow threats either. December snows have been hard to come by in recent years, minus the last two years, in my neck of the woods.

There seems to be a split flow pattern across the Pacific, enhancing the Pacific jet allowing for continuous storms along the west coast. With the NAO block, we can retain the cold and the split flow will work in our favour allowing for more storminess into our region. We'll see how this transpires. The overall look is a combo of both Nina and Nino with the +PNA and neutral EPO. This will later evolve into a more -EPO blocking pattern and a -PNA. How long it lasts, we'll see.

Wow, that's an insane cut-off. It's common up our way as well, thanks to the lake. Still got the whole season to get through so don't sweat it. It's only November.

Wow, that's the worst. I know exactly how you feel. What part of Chicago do you reside? I'm assuming (without looking at the maps), lack of dynamic cooling and warmer lake temps. definitely playing a role.

What an impressive early season storm. It's going to make history for Chicago and surrounding areas. Radar returns look amazing. Would love to experience the blizzard. Stay safe everyone!

It takes just one decent storm to change everything.

YYZ got down to ~7.0F last night, breaking the old record of 9.6F. As per a tweet on twitter, its tied for 3rd coldest ever on record for the month of November. And Happy Thanksgiving to all you people! :)

Can't remember the last time we had a sunny day, certainly not this month.

Official snow total from this storm was 5.2" at YYZ. Season total now at 6.7" at YYZ.

~5" at YYZ with this storm, making it the largest snowstorm at YYZ since Nov. 2002. Winter wonderland out there.

Moderate to heavy wet snow across Toronto right now. About 2.5" so far.

Some of the trees may still have leaves on them, I'm assuming? Regardless, just a terrible ice event so early in the season.

Looking great for a nice 2-4" across the GTA away from the lake. First widespread snow event in November since 2014. Going to have to monitor sfc temps. as they're expected to hover around the freezing mark. The heaviest precip should come in the evening so this should allow for some cooling to take place.

The UKMET is also on board for a quick developing storm.

That piece of energy becomes almost like a cut-off low with a strong upper level jet streak. Not much room for it amplify though. Its still worth watching especially for eastern sub-forum areas.

That winter, albeit I was born one-two years later, per historic records was also great up here. Toronto recorded 64.1". How much did BOS get in the historic March storm?

The GEFS, an ensemble model, basically takes the data from the GFS (it's numerical weather model counterpart) and looks at the different uncertainties that can exist in actual weather observations. The GEFS corrects this uncertainty through its multiple ensemble forecasts during each model run (0z, 6z, 12z and 18z) and looks at the different scenarios that could play out from a single forecast. Despite trying to reduce the uncertainty, especially in the medium-long range, there still exists some spread between each run, hence any forecast beyond a certain point should be taken with caution (spread-skill relationship). As well, this spread is actually quite noticeable when you look at spaghetti plots. This is all I know.