We of course saw a 2-4, locally 6-10 inch swath of snow from Colorado up through Nebraska, South Dakota into Iowa and Minnesota in the last 24 hours and that storm is heading up into Canada.

Here was the scene along I-94 NW of Minneapolis late last night.

Another push of chillier air pushes into the Northeast on the backside of this system following a couple of days in the 70s and 60s from Richmond to Boston. Through the weekend we have a flatter west-east flow across the country.

While there’s a strong jet and mild air crossing the Lower 48, Canada is filling with arctic air thanks to a cross polar connection which can be seen by the isobars connecting Siberia with Canada. The trouble is the modelling, particularly GFS and ECMWF are swinging wildly with NEXT WEEK’S snowstorm potential.

Both models show a sizable storm developing as a big cold Canadian high pushes south. The ECMWF initially went crazy with the trough into the Eastern US producing a big snow event, now it’s backed off with a much flatter upper pattern, now it’s the GFS with it’s wild scenario.

Check this 168 hour GFS snow chart. Way overdone in my opinion.

Here’s the now much less enthusiastic ECMWF.

Below is the ECMWF 500mb chart with 850 temps and it’s clear to see the west-east flow across the Lower 48 while Canada gets fed Siberian air. The mild that both crosses the country from the Pacific as well as some warmth which lifts north from the Gulf sets up quite the fight into next week.

[s2If current_user_can(access_s2member_level1)]

The ECM has the upper low holding back west off the BC coast which keeps the zonal upper pattern across the Lower 48 but notice the cold pool dropping south over Canada.

By Monday, a system may try to develop over the Southern Plains and lift north towards the Lakes while arctic air is knocks on the US doorstep, meeting the warmth to the south. Snow should break out over the Dakotas, Minnesota into Michigan.

The question is how much of a trough do we see with the a positive NAO/AO/-PNA? I believe the newer run of the ECMWF which shows far less southward extent of any trough is more likely. Ultimately a flatter upper pattern with the real cold mainly staying in Canada or over the Lakes.

Will the current GFS or ECMWF by correct or perhaps their both overdone. We could still get a big Dakotas to DC snow event with some tremendous backside cold but the indexes don’t support a big deep trough but more of a system and arctic blast which skirts the Northern Tier.

Here’s a look at the latest indexes.

Towards the end of November you can see the possible trend towards a colder pattern. By late November, much of Canada will be abnormally cold and the snowpack will be widespread. I’m wondering if what the models are suggesting for next week is perhaps too early but is a sign of what is more likely LATER this month.

The potential cold pool Canada should have by late month may be too much for the pattern to hold north and so a shift would unleash a significant early December arctic outbreak into the US.

Here’s the CPC 8-14 day temperatures which I agree with based on the lack of blocking and above indexes.

The latest CFSv2 shows arctic-Siberian air continue to fill Canada in coming weeks. I think the week 3 and 4 should trend colder towards December for the Lower 48 once the indexes change.

Week 1-2

Week 3-4

 

[/s2If][s2If is_user_logged_in() AND current_user_cannot(access_s2member_level1)]

That’s it, [s2Get constant=”S2MEMBER_CURRENT_USER_DISPLAY_NAME” /]!

To continue reading, you need to have a valid subscription to access premium content exclusive to members. Please join a subscription plan if you would like to continue.[/s2If][s2If !is_user_logged_in()]

Sign in to read the full forecast…

Not yet a member? Join today for unlimited access

Sign up to markvoganweather.com today to get unlimited access to Mark Vogan’s premium articles, video forecasts and expert analysis.
[/s2If]