How will storms take shape the week of Thanksgiving?

AccuWeather

AccuWeather's Geoff Cornish breaks down the details of the Thanksgiving week forecast across the U.S.

Transcript

00:00On this Monday, about a week and a half before Thanksgiving, in our forecast feed,

00:05we want to specifically look at Thanksgiving week's travel impacts. What's the atmosphere

00:11we're going to send our way? And we'll look at some computer models. We'll find some points of

00:15agreement and disagreement among a couple of the primary models, and that bolsters or reduces our

00:21confidence sometimes in the specifics. But we can give you a few things to walk away with as we look

00:26ahead to planning that Thanksgiving travel week. And you can see the Thanksgiving week forecast overall,

00:32big picture view. We're looking at a storm track that's generally, in general, more active from the

00:38southwest right across the central U.S. into the northeast here. And in this case, the green on

00:43our map is for pleasant, dry weather. So again, down here in the southeast, we're looking good

00:49for the most part, at least in the far southeastern U.S. So again, that green, not for rain, but that's

00:54for pleasant, good, fair, dry travel weather. Let's look at the models, though. Get a little

00:59more specific, then we'll look at some day-to-day forecasts here in the forecast feed. So overall,

01:05as we look at the flow aloft, we're going to go about 20,000 feet up in the atmosphere to 500

01:11billibars. This is kind of maybe two-thirds of the way up through the chunk of the atmosphere,

01:15where the atmosphere produces weather that affects us. And this is often an area where we can look at the

01:21driving factors behind the rain or snow or just air masses that we're dealing with. And overall,

01:28at first glance, this is Sunday evening with the European model here, right, with the GFS model

01:33in this case. I'll look at the European as well. Generally, we've got low pressure systems off the

01:38northwest. Again, this one's actually just barely off the map over the eastern part of Canada and over

01:44the southwestern US. If we switch things over to the, let's switch over to the European. Similar

01:51story overall. Generally, similar story. We've got strong low pressure here over the southwest. It's

01:56a little farther south. We still have a zone of low pressure over eastern Canada. Weak zone of low

02:01pressure with the front tied to that over the plains. But again, there are some differences,

02:05but some similarities here in the model guidance for Sunday evening. As we move forward in time,

02:11a lot of what's going to happen will hinge upon the behavior of this central US area of low pressure,

02:18this situation here. You can see it's a little faster with the GFS. This is the GFS model.

02:23It's a little faster and a little more removed from the troughs in the northern branch of the jet

02:28stream. Consider this the disturbance in the southern branch of the jet stream down this way.

02:32So it's a little more removed and there's less interaction. Eventually, they kind of get in phase

02:37with one another, but it becomes a weak, flabby wave off the east coast and too late for

02:41any impacts. If we look at the European model, there's a little bit of a difference here.

02:45You can see the timing. It hangs back a little farther southwest, the southern branch

02:51system. In fact, this system here down over parts of the area, I'm trying to show you this area of

02:59low pressure, it hangs back over west Texas Tuesday morning. Look at the difference. Again,

03:05this is the European back over west Texas. Meanwhile, if we go back to the GFS, it's way over

03:12Omaha at that point. So because it's slower, it actually begins to kind of step in phase a little

03:17bit, not a powerful storm, but there's a little more interaction between this system and this northern

03:22branch feature in the jet stream. And as they move farther east, again, just a little bit of interaction.

03:28And then there's another disturbance that swings around the base of the trough here.

03:31And that can also interact with that system as well, this little disturbance. And this,

03:37interacting with that northern branch feature, it becomes somewhat of a negatively tilted trough here,

03:42that brings us kind of an interesting scenario for the weekend following Thanksgiving in the European.

03:46GFS, not so much. But in the European, there is that deeper trough over the east because of that

03:51interaction. So here we have a look at the surface. Here's the GFS. This is the slightly less eventful

03:57scenario where the system in the central U.S. doesn't really interact much with anything going

04:01on farther north. It's a system that moves east, and it's kind of quietly bringing some rain,

04:05maybe a little bit of wet snow up into Worcester, Mass or the Catskills and out to sea. And then the

04:10beginning of the weekend of Thanksgiving, the weekend following Thanksgiving, again, another

04:15disturbance, mainly restricted to the northern branch of the jet stream, a little bit of snow up there

04:19into New England. With the European, it's a slightly slower move here. There's that system that is a

04:26little more aggressive into Texas. It's slower. And again, a little east of the main trough,

04:32but then a second disturbance rotates around the base of that trough. And you can see this. Again,

04:38there's that interaction here between this extra disturbance that scoots through the base of this

04:44big trough and apparent low system, upper level low over the interior. And that produces kind of a

04:51sneaky rain or snow producer near the east coast following Thanksgiving. So again, there's still a

04:57lot of uncertainty out there. But just to give you the big picture, Tuesday, there's the likelihood

05:01somewhere between Texas and the Midwest, high impacts for travel weather. Wednesday, the day

05:06right before Thanksgiving, details are a little murky given the disagreement. But somewhere between

05:10Louisiana and the Great Lakes, we'll have some showers, maybe some thunderstorms south. And then

05:15Thanksgiving Day itself, we got rain for the Mid-Atlantic and down into parts of the southeast. But again,

05:19there are some big questions about perhaps, perhaps the chance for a coastal storm in the days

05:24following Thanksgiving, Sunday, and the Saturday before. So Saturday and Sunday after Thanksgiving.

05:29So that is your forecast feed for now. We'll get more specific later this week.

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