Multiple rounds of wintry weather to continue for the first half of December

AccuWeather

From snow in central Virginia on Dec. 5 to more chances for wintry weather in the Northeast in the coming days and an atmospheric river approaching the Northwest, busy weather patterns are ahead.

Transcript

00:00In the forecast feed, we have a lot to talk about here from a brief look at the mid-Atlantic storm

00:04cruising east through the early part of Friday. It's going to bring 1 to 3 inches of snow to

00:10Richmond, Virginia. That's a big deal. And then also more waves of cold, Arctic air. Will we get

00:16any relief? Is there going to be any kind of a warm-up in the next 10 days? We'll take a look

00:20at that in the Midwest and the Northeast. And also, the Pacific Northwest is getting into some

00:25incessant rainfall with the atmospheric river event. Actually, there's a bigger one setting

00:30up for early next week. So let's take a look at what's going on. Big picture into the weekend

00:34we go. And here you can see the overall jet stream configuration, the pattern. It is a

00:41big ridge in the west, big trough in the east. And overall, the waves of cold just continue

00:48to come on down following various Arctic fronts. So again, there's an Arctic front that has

00:53moved through and is moving through. But by the weekend, it will have moved through.

00:58And in the northwest, it is ridgy. So that's where the moisture is coming in. Rain and relatively

01:03high snow levels. In other words, lower passes will be dealing with rain, but snow in the

01:08higher elevations. And under the ridge, we have this big, nice zone of high pressure and

01:16really pleasant weather across the desert southwest and into Southern California as well. But looking

01:22ahead into mid-December, in general, the ridge to the west, the trough to the east will persist.

01:28This pattern is going to continue to send and hurl cold air, very cold air, into the mid-Atlantic

01:33and the northeast and the Midwest as well. Let's look at some models here. We can take a look at

01:38the overall pattern. In the short term, it's not an impressive storm system in terms of its

01:45jet stream energy. It's a relatively short wave. It's a flat wave. It is a short wave.

01:50But you can see this disturbance in the southern plains on, well, if we look back in time,

01:57back earlier today, earlier this Thursday afternoon and evening, that's the system is kind of racing

02:02east. And it's a very narrow, short, abbreviated dip in the jet stream on the short wave scale.

02:10Again, we talk about long waves and short waves. Long wave trough, but then little short wave

02:15troughs. And there's a very weak short wave trough that's producing a bit of snow into

02:20the mid-Atlantic. It's not a very strong storm system, but there's moisture nearby and it's

02:25cold out there. So it's going to be just enough to produce on the northern side of the storm track,

02:30this area of snow in Virginia. And it's going to bring some accumulations even into Delaware

02:36and Maryland. This time of the year, it's early, very early. But you can see the European producing

02:41a one to three inch event with even localized three plus out near Blacksburg and Roanoke.

02:46And we're forecasting Richmond to see one to three inches out of this one. Now, I really wanted to

02:52focus a bit more on the future. What's going to follow that system this weekend? Still chilly.

02:57There is another disturbance on Sunday night that comes in from the Great Lakes. There it is,

03:03Sunday, Sunday night into the lower Great Lakes. And again, there is some disagreement as to how

03:09this will play out. The GFS brings this through with some interaction from a system farther south.

03:16So as we take a look at the surface reflection, here's the GFS. It's not a huge storm, but it would

03:23bring us a few inches of snow on the west slopes of the mountains and maybe a coating to an inch down

03:28into areas like Allentown, PA. And again, it's just closer. Here's this disturbance to the south.

03:35There's a little more interaction between these two. You can see some of the greater precip amounts

03:41here with that southern disturbance kind of on the axis of Savannah, Georgia or so. Now, if we go to the

03:47European, it's not quite as deep of a dip in the jet stream there. You can see that disturbance

03:55moving through Cincinnati. There's bright colors. That's vorticity. It's spinning the atmosphere.

04:00And if that's approaching you, you're going to have lift and more rain and snow production.

04:04And again, there's the GFS. The European, it's a flatter wave that stays farther north. And then

04:10there's a southern branch contribution to this, but it's so far removed from it that again, they're

04:15sort of just out of step with one another and they're not really interacting much. So while we have

04:20this opportunity for some snow in the interior northeast on Sunday night in the GFS, Sunday

04:25evening, Sunday night, the European is pretty abbreviated and it brings snow showers. But again,

04:32it's not much and probably nothing falls east of the mountains with this one aside for maybe up into

04:37parts of Maine. So again, there's a little bit of a disparity there. The European is very timid with

04:42that, but the GFS would bring us some one to three, locally three to six inches in the heart of the

04:48snow belt areas. And again, a little bit of a disparity there. Behind that, here we get into

04:52the middle of the week. This hits just keep on coming long wave pattern, still ridge in the

04:57west trough in the east. And there's a pretty sharp shortwave that'll be riding the base of

05:02the trough. And here we get into Wednesday night, Thursday morning with the European also a

05:07disturbance there. And the GFS is actually tilts negatively and digs into the northeast and

05:14mid-Atlantic. So here we can see the GFS with this system. It brings us a burst of rain for South

05:19Jersey and some snow in the interior. And then behind that, again, the next warmup actually comes

05:25in. But in the European, similar story, Wednesday to Thursday, a disturbance that mainly brings some

05:32rain showers to I-95, or at least South Jersey, but some snow into the interior. Now I mentioned a

05:39little hint of a warmup. After a little clipper that may follow Friday, look at this. We begin to see

05:43these thickness lines in the atmosphere. The atmosphere is warmer. It expands. So the thickness

05:49lines kind of reflect that. You can see a little bit of a warming trend. In the GFS, it actually

05:54warms the atmosphere up in the Midwest ahead of the next cold front so that the 540 line, which is

06:00kind of the rain-snow line, just in general, real fuzzy math, comes all the way up north of Green Bay

06:06for a time. Now to get colder behind that, but the depth of the trough that follows may not be quite

06:11as dynamic. So overall, the big picture shows, again, disturbance in the mid-Atlantic in the short

06:16term. Sunday evening, another disturbance. Another one across the Midwest into the interior northeast

06:21Wednesday, Thursday. And then another one that may bring eventually some more cold that follows a

06:27brief warmup. So that's what's going on with, again, the next several days. I wanted to briefly

06:31take us early into Monday with an atmospheric river. This is the North Pacific. We're going about

06:3710,000 feet up. Look at this long, long ribbon of moisture coming into the Pacific Northwest.

06:43So another story to watch. Heavy, heavy rain coming to the Northwest early next week with some high

06:48elevation snow.

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