Colder air and the chance for snow coming after Thanksgiving

AccuWeather

It may be a white Black Friday and Thanksgiving weekend for some people in the Upper Midwest and Northeast, especially near the Great Lakes.

Transcript

00:00In our forecast feed, we are looking deeper into the latter part of Thanksgiving week

00:04and in through the following week, the week after Thanksgiving, trying to sniff out significant

00:10snowfall.

00:11As we take a look at where we've been, our snow depth map shows that we've had a good

00:15start in California.

00:17Mammoth Mountain opened up for skiing last week.

00:19People have been out there, relatively deep snow cover.

00:22Now it's going to be a drier week this week until this coming weekend when we get a little

00:25bit more.

00:26Parts of the Tetons doing well.

00:27Wasatch, Uinta is into parts of areas around Utah.

00:32The Southern Rockies into Arizona.

00:34Some parts of New Mexico and in Colorado there, we're doing pretty well with snow.

00:38And other areas, a bit of heavier snow into the area around the Sierra, kind of hidden

00:43behind the banner.

00:44The Northeast, there was a time when we had a little more snow on the ground farther south,

00:47but that has since melted away.

00:49So it's the Adirondacks and the Green and White Mountains and up into parts of Maine

00:53where we're dealing with some pretty good snow.

00:54So pulling the map way north, you can see up into the Canadian Rockies.

00:58That's where we have some pretty good stuff on the ground as well.

01:01So let's take a look at what's going on with the models because we want to find, before

01:06we get more snow, we need to get more cold air in place.

01:09And the next significant snowmaker, which will be a big deal in the Dakotas, three to six

01:16inches of snow coming to Bismarck.

01:17We've been talking about that.

01:19And Duluth, a little bit of rain quickly changing over to snow on Tuesday.

01:23You're going to get a lot of snow there Tuesday into Wednesday.

01:26Parts of northern Michigan, one to two feet up near Marquette.

01:30And this big dip in the jet stream is going to be crossing the region.

01:33It's a fairly powerful storm.

01:35And on the west side of that, we're dealing with the first blast of cold to come back

01:40in just in time for Thanksgiving.

01:42So again, you can see the colder streamlines there coming in and the European model this

01:48close to the event.

01:49We're in good agreement.

01:51There is not much debate about this system here, crossing the northern plains into the

01:56Great Lakes.

01:56And then for Thanksgiving and the days that follow into Black Friday, we're looking at

02:01some cold flow over the lakes.

02:03And that means lake affects snow.

02:05And you can see the dip in the jet stream bringing cold back to the east, not as cold

02:10in the plains and parts of the west for a time.

02:13But the dip in the jet stream signifies cold air in the eastern U.S.

02:17So how does this play out?

02:18Initially, again, Tuesday afternoon in the GFS model, look at the tightly packed isobars.

02:24That strong wind combined with snow.

02:26So this could be a blizzard for some.

02:28The European model, similar story.

02:31And the Canadian model, similar story.

02:32Pretty good agreement there.

02:34And behind this, this sets the table Thursday and Friday for some lake effects.

02:38Now you can see the deeper blues in the areas around Erie, PA, up into Dunkirk, New York,

02:43and also off of Lake Ontario.

02:45The area is downwind of Lake Superior, northern Lake Michigan.

02:50Just one example there.

02:51Canadian model.

02:52Here's the European.

02:53And here is the GFS.

02:56This is a high-confidence leak effects snow forecast.

02:58We've been discussing this quite a bit here on AccuWeather.com and on the AccuWeather network

03:02as well.

03:03So as we take you a little farther down the line, here you can see Sunday, we get into

03:10a setup here with the GFS model where we're going to see a big stripe of snow from the

03:15Rockies up into the upper Midwest.

03:16How does that compare with the European?

03:19Pretty different.

03:20Pretty different.

03:20And the Canadian.

03:23We get into this time frame where the GFS is singing one song here, and the other two

03:30models that we're looking at here, the European and the GFS, are kind of in agreement with

03:34one another, but not with the GFS.

03:36So let's go back upstairs to see what's going on with the difference.

03:40The GFS model, again, is producing a bit of a different configuration to the jet stream

03:46here.

03:46If we go back to the time frame when the GFS is cranking out some pretty good snow up in,

03:50say, Wisconsin and northern Michigan, 7 a.m. Monday.

03:53If we go to 7 a.m. Monday here in the GFS model, if we go to the upper level flow, you can see

04:02we're dealing with a trough, and there's a short wave here pushing through the upper Midwest,

04:07but the long wave trough axis is way back into California.

04:10And if we compare that, the GFS to the European, it's a little different in some ways of how this

04:19handles this disturbance cruising through the upper Midwest.

04:23The GFS versus the European, again, the European far faster with a slightly more concise wave.

04:31So here's the European.

04:32It has, by Monday evening, a trough kicking through parts of Michigan.

04:37Meanwhile, the GFS, it's still hanging back.

04:39So the GFS is saying this is going to stay back.

04:44Meanwhile, the other models that are in agreement with one another a bit more are a little more

04:48progressive, bringing a weaker system into the Great Lakes.

04:52There's the European through Monday, and then the Canadian.

04:56This one brings some snow Sunday into Monday.

05:00So Sunday, we may have some travel trouble in parts of the interior northeast.

05:04We're hedging our bets toward this being maybe a little more rain than snow, unless you're

05:07west of I-81, and probably a good margin west of I-81.

05:11The Canadian, this keeps the opportunity for snow on the table into the Poconos.

05:15So we've got to keep an eye out for that.

05:17But it's very different from the GFS.

05:19The GFS is bringing this other, the slower arrival of this storm system.

05:23And I think we can toss this out.

05:25Talking to Bernie earlier today, again, there's just not much confidence in the GFS because

05:29it does not have the agreement of the European and the Canadian.

05:32And even the UK Met is more agreeing with the Canadian and the European model.

05:38So if we go farther out, you could see the GFS.

05:41It has a pretty exciting looking storm system at the middle of next week that would bring

05:45some widespread snow to Indianapolis and to Pennsylvania and other areas.

05:49But if you look at the same time frame, the European says, no, it's still in the southern

05:53Rockies.

05:54And the Canadian also says, no, it's still in the southern Rockies.

05:57So the confidence in this particular scenario of a Wednesday-Thursday snowmaker coming from

06:02western Oklahoma all the way up into southern New England is probably not that likely.

06:06But we need to keep an eye out regardless because the evolution of the cold air will be in

06:11place.

06:11And again, a lot of the time, Bernie often talks about this.

06:14If you get arctic air, there are often at least two opportunities for snow, one on the

06:18front end and one on the back end.

06:19So to close this out here, the GFS model, it produces widespread snow here into areas

06:27around midweek.

06:28I don't know if that's that likely, but the more likely scenario might be an earlier arrival

06:32of snow with the Sunday storm system that could impact, this is the European snowfall forecast,

06:39the Midwest and the far interior northeast.

06:42I think that's the most likely area to see some snow.

06:45So keep an eye out.

06:45Again, late this weekend, more likely impacts in the Midwest.

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