Your long-range forecast for the week of Thanksgiving

AccuWeather

AccuWeather's Geoff Cornish breaks down how weather patterns are expected to develop across the U.S. as November progresses.

Transcript

00:00Well, we have a lot to talk about when it comes to Thanksgiving week.

00:06We want to look farther down the line, a true long-range forecast here, so you can best

00:12prepare for the transition into the holiday season, as many will be taking to the roads

00:17or the skies.

00:18And again, beginning with where we currently stand, just a quick look at the current setup,

00:25and we can kind of compare and contrast how the upper-level flow is going to be changing

00:28and morphing over the next several days.

00:31We have a really pronounced dip in the jet stream, and look at this cold air just spilling

00:35south across the Great Lakes, and we're dealing with some record lows that'll be shattered

00:40down into Florida early this Tuesday morning.

00:44And for now, we have a ridge across the west, but there's a storm system getting ready to

00:48move into the western U.S. as we step into the second half of the week.

00:52So we've got a low-pressure system offshore, we've got a big, deep low over the interior,

00:57and we've got a beefy ridge of high pressure that'll bring some new record highs to some

01:01areas, actually, on Tuesday.

01:02I think it's going to be changing in a big way, but overall, big picture, this is what

01:06the flow looks like right now.

01:08If you go about 20,000 feet up into the atmosphere, it's 500 millibars here in the steering flow,

01:13again, a pronounced deep dip in the jet stream with a really, really significant discharge

01:20of Arctic air.

01:21We've got some warmer air up in the Arctic, that's been displaced, so the polar vortex,

01:26this swirl of the coldest air of the hemisphere is generally spinning its wheels out over parts

01:32of the eastern sections of North America, well to our north here.

01:36But to the south, with this reflection of that, a chunk of the cold has really expanded

01:42southward.

01:43We're going to be watching, though, this is not the beginning of the continual winter season.

01:48This is going to actually be lifting, you can see later this week, it's still troughy across

01:53the east, there's still a dip in the jet stream, but it's not as amplified.

01:56The base of this, instead of being down near the Gulf Coast, it lifts north of Interstate

02:0140, and then we begin to see a trough in the west as well, so we're going to begin to get

02:06into a bit of a pattern change, where it's still going to be a little cooler, chilly late

02:10this week in the northeast.

02:11We're not going to bounce back quickly, but it will get a little more like late November

02:16as opposed to mid-January.

02:19And then look at the western U.S. here, Friday, Friday evening, Friday night, and big dip in

02:23the jet stream.

02:24Let's take a look at how this kind of evolves.

02:26There's the lake effect snow that fades, a weak disturbance that actually scoots through

02:30the region of the northeast on Wednesday.

02:33And as we look ahead to Friday, kind of marrying our 7 a.m. Saturday morning view aloft, big dip

02:41in the jet stream across the southwest with the rain and even mountain snow there in parts

02:46of Arizona with the GFS model and then the European model, where things are a little farther

02:52south with this upper-level low.

02:54That will bring some rain down to parts of Arizona.

02:56So again, the overall big picture messaging is about the same.

03:01Southwestern storm system, chilly in the northeast, not as cold though.

03:04And then look at this flow out of the south here.

03:07Everything is interconnected when it comes to the weather.

03:09And there's an area of low pressure spinning its wheels over the Dakotas and east of there.

03:13Strong flow from the south.

03:14See these wind lines, those isobars, the pressure lines, tightly packed.

03:18That's going to drive a strong pressure gradient that will impart a pretty good warm-up.

03:22And as we look at the temperature anomaly, how we are compared to average, deep blue in

03:28the east, deep red in the west, much colder in the east, pretty good warmth builds into

03:33the west.

03:34And then as we step into Friday and Saturday, you can see there's that warmth expanding into

03:38the plains.

03:39Still colder than average in the northeast, chillier than average in the southwest, but

03:43warmth winds out into the plains.

03:45That's the GFS model.

03:46European, it's not as dynamic, not quite as amplified with that signal.

03:51But the signal holds, chillier than average in the northeast, much warmer than average

03:56in the central U.S. here for the weekend.

03:59And again, it's just a sign, I wanted to play that out there because I wanted to emphasize

04:02that the cold that we're experiencing now in the east is not necessarily here to stay.

04:08I wanted to point out another thing.

04:10Early to midweek next week, we have a dip in the jet stream and a little low pressure

04:14system that moves across the plains.

04:16There is some agreement that we're going to see that feature.

04:19This time of the year, it doesn't take a whole lot to spin up severe weather.

04:22And there's potential for some strong storms early next week here in this region across

04:27the lower Mississippi Valley.

04:29You can see how this plays out in the European and the GFS.

04:32The differences, they're subtle, big picture.

04:35But on a city-by-city basis, they can mean a lot.

04:39Whether you're in Paducah or Shreveport, again, there are still some questions as to specifically

04:44who will see that severe weather threat on Monday of next week.

04:47We got to keep an eye out for that.

04:48There may be a second zone of severe weather as this trough, late next week, around the

04:5320th or 21st, it's negatively tilted.

04:55Do you see that?

04:56And that is the GFS model.

04:59The European, if we look at the precise same time, it looks different.

05:03But go forward one extra day and suddenly, actually, if you go forward an extra half day

05:12with the GFS, you go back a little bit in time in the European.

05:16The differences are a little bit off-kilter timing-wise.

05:20But here in the European, there's also a negatively tilted trough.

05:24Something to keep an eye on, as there could be a round of severe weather within a day

05:28or two of the 20th, 21st, late next week into the south.

05:32Details to be determined again.

05:34But then we go into Thanksgiving week, Monday, Tuesday, Wednesday.

05:38Here we are again with, it looks like an Omega block with this configuration, ridge, trough,

05:45and trough.

05:47And again, that would lead to a somewhat blocking pattern, but we'd be dealing with an active

05:52storm track across the northern part of the nation.

05:55So big picture, just to close this out, I'm going to end this with a quick look.

06:00Thanksgiving week, look out for, now whether it's a blocking pattern or not, the storms

06:05will be in the northern part of the nation.

06:07So red zone here for travel trouble to the north, with the greatest confidence and trouble

06:11in the New England states and the northwest.

06:14Perhaps a transient storm system in the north central.

06:16The green light to the south, good dry weather in the southern U.S. Thanksgiving week.

06:21.

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