Storm and cold

I must confess the change over to ice pellets/rain this morning has caught me (and everybody) by surprise. I still expect a significant snow event tonight into tomorrow but today might be a wash.   I will keep an eye on it.

An update with regards to the forecast cold on Sunday morning
Env. Can. current forecast -22C
TWN forcast - 25C
Accuweather:  -17C

Interesting tidbit of info about the weekend cold

Even Env. Can. is not believing their own model.   Just for kicks, I checked out the Canadian model raw temps for Sunday morning and they have Ottawa well into the -20s C.  See map below.   So why is their official forecast for Sunday morning still -17C?   Well, without asking them personally, I've read that it is because they take into account the climatology, ie the "normal" temperatures for a particular place and date.   If a model output is too many standard deviations from the "normal", they adjust temperatures back closer to normal.  And what do you know, the "normal" low temperature for Ottawa is -17C.

TWN forecast low for Sunday morning is currently -19C
Accuweather forecast low for Sunday morning:  -19C
Raw GFS and Euro temps for Sunday morning:  between -25 and -30C

Western Canada and snow

Much of BC and Alberta is going to be much colder than normal for much of next week.   Colder than current Env. Can. forecasts for sure.  The map below is the 7 day mean of temperature deviations in Farhenheit ending next Thursday.

No change for snow totals for Thursday/Friday.  It's still looking like a 10-20cm storm.
Updated snowmap below (note it does not include the loads of Lake Effect Snow coming Friday/Saturday)

The weekend's cold

EC forecast low for Sunday morning:  -17C
TWN forecast low for Sunday morning:  -18C
Accuweather forecast for Sunday morning:  -21C

Raw GFS output: well into the -25C to -30C area.   Let's see who changes. 

10 degree bust

Note that Env. Can. forecast for Thursday's high temp is now -5C.  You'll remember that yesterday morning their forecast high for Thursday was +5C.   A ten degree difference in 24hrs.    Yes that is how bad the Canadian Model is.

Petewawa has dropped 4 degrees in the last 3hrs.   So Ottawa will start dropping soon too.

Snow totals for Thursday and Friday still look okay but they may trend toward the low end of my estimate as the NAM model is not showing as much precip as before.

Addendum:   Look for low temps in the -20s over the weekend

The week and beyond

First, I believe that Environment is likely out to lunch with the storm Thursday/Friday.   Their current predicted high of 5C on Thursday is too high.   And therefore their predicted rain/snow mix will likely be more snow that rain.   This should be a healthy storm giving us 10 - 20cm (my current estimate).
Update: EC afternoon forecast has now a high of zero for Thursday.

However, this storm is not the main story.   As intimated by my post last week Tuesday, there is major cold coming down that pipe that has staying power.   There will be a little bit of back and forth temps, but unlike the winter so far, there will be more cold than warm.   Let me show you one pic of the temperatures predicted a couple weeks from now.   While the exact temps may not be correct, it definitely shows the tone for the next few weeks.

Took a peek

The storm next week is still there late next week on both the Euro and GFS.   I'm trying hard not to jinx it.

In the short term, we not going to get much of anything, just up and down temps.

Don't look now

But both the GFS and Euro have a major storm for around the 12th.

Jabs of cold until the knock out punch?

Looking at the weather pattern and trends in the modeling, the middle of the month is getting set up to be a major flip in the pattern we are in.   About that time a ridge is predicted to set up over Alaska and the polar vortex is predicted over Baffin Island (see below).  If this comes true, this will send major cold cross polar air down the plains which will spread east.   The NAO and AO are also trending towards negative territory around that time.   Again, if true, this will set up a very cold and wintery pattern for much of North America.   Until then, it looks like we'll be in a back and forth pattern with no major snows on the horizon.

Lake Effect Snow

First major outbreak of the season: