Abundance of cold, many opportunities for snow

AccuWeather

In tonight's Forecast Feed, AccuWeather's Geoff Cornish looks ahead to the end of the week and explains which regions of U.S. will receive more snow after the Midwest and Northeast have been blanketed.

Transcript

00:00Well, we have plenty of snow on the ground across most of the Midwest and the interior

00:08Northeast. With our forecast feed, we want to look ahead to more opportunities for snow.

00:14Who will get into some additional snowfall late this week? Who could see your first snowflakes

00:19of the season, parts of the Mid-Atlantic, this Friday? And who also could see some more

00:24accumulating snow next week? A lot of cold air in view. A quick look at the snow cover,

00:28about 41% of the nation has snow cover. That's the second most for December 3rd among the

00:34past 15, 16 years or so in the current database of apples-to-apples snowfall and snow depth,

00:42snow depth comparison for snow cover this time of the year. And look at the big picture pattern

00:46here. We got a big dip in the jet stream. There is going to be another zone of cold that dislodges

00:53from the Arctic. And it's going to be following this Arctic front that barrels through the region.

00:59We're going to see a new round of lake effect, lake enhanced snow, and even some snow squalls

01:03that break out into Thursday. So there will be some hazards on the roads. But overall, big picture,

01:09when you get a pattern like this, and you have storm systems like the one in Colorado that'll

01:14be rounding the base of the trough and ultimately heading out to sea. We'll also have occasional

01:18northern branch disturbances that scoot through from a different trajectory. The pattern is right

01:23for more snow and more cold. And let's take a look at what's going on out there upstairs. So

01:29the storm system that's moving through the desert southwest and Colorado, that's going to be scooting

01:34east. You'll notice it's a more dynamic, more pronounced dip in the jet stream now and even through

01:40tonight than it will be as it kind of becomes kind of a real low amplitude trough. These bright colors

01:48indicate vorticity, which is a measure of spin. If the bright colors are coming toward you from the

01:52west, you'll likely see cloud production, rain and snow production, depending on the thermal

01:58characteristics of what's going on. But it's a flat wave. It's a very flat wave as this kind of

02:02streaks east. And another disturbance will follow. But it's kind of a low amplitude short wave,

02:10big picture, long wave pattern. We got a ridge in the west, big trough in the east. But the short wave

02:16itself, that is initially a pretty dynamic system, producing meaningful significant snow in Colorado.

02:22Here's the NAM. It similarly streaks east, has a little bit of a slightly more potent dip. But

02:29overall, it's still a low amplitude trough as it races east. So the explosive potential of this storm

02:37is not going to be present. It's not going to be a big one for us in the mid-Atlantic. There will be

02:41some decent moisture that this interacts with across the south. Here is yet another opinion. The European

02:46model, flat wave. Here's another one that follows. Here's another disturbance up near Lake Superior.

02:51But the message is pretty consistent here. We're going to be dealing with a relatively flat,

02:56fast-moving wave of low pressure. But it doesn't take much to produce snow when you've got cold air in

03:03place and just a hint of moisture. So here we are with the GFS model. And look at this. This one

03:09produces a signal of some snow. Now, I don't think it's really going to be snow into areas quite as far

03:14south. But part of this area, you'll see snow and some ice on Thursday night and Friday as this

03:20relatively flat wave scoots through. Heaviest precipitation on the wet, warm side near I-10.

03:25But to the north, here is the European model. And this has a pretty realistic-looking depiction of

03:31things. A little bit of snow out there and some ice in that pink zone as that scoots through.

03:36And you can see into Friday during the day, perhaps we could see a coating to an inch

03:40in Washington, D.C. Maybe a little more than that southwest of the city. Maybe near

03:44places like Charlottesville, Harrisonburg, maybe Warrington, for example. And look at this. Friday

03:50during the day, again, South Jersey, Delaware, maybe a little bit of a snow-ice mix. There's pretty

03:56good agreement that we could see something like that. Here's a third indication, a third opinion.

04:00The Canadian model, again, I'm maybe a little skeptical that we see flakes of Virginia Beach,

04:06perhaps on the front end. We could see a few snowflakes before a changeover to a little

04:09bit of rain at Virginia Beach. But west and north of there, Richmond, Virginia, you can see a little

04:14bit of snow. And into Delaware as well. Fourth opinion, here's the NAMM. So we look at the GFS,

04:18the European. Again, Friday morning, GFS, European, the Canadian. And here is the NAMM,

04:26which doesn't produce a whole lot of precipitation on the north side. But anything up this way would

04:31be in the form of some frozen precip. I wanted to point out, you can see the dips in the isobars,

04:37the kinks that push south. And again, that's a sign that we're looking at cold air damming. Cold

04:43air is dense. It hugs the ground. And the orientation of the mountains here, when you have an area of

04:49high pressure to the north, it just clams up the cold that gets stuck east of the spine of the

04:55mountains. That's why we see a lot more of these occasional snow and ice events in east central

04:59North Carolina compared to in Crossville or Cookville, Tennessee. The same latitude east of

05:06the mountains versus west of the mountains. That cold gets stuck on the east side. And that's why

05:11we see a lot of those events. Now, taking you into a model depiction of how much snow might fall,

05:17again, we should keep our expectations in check. But this time of the year, before December 10th,

05:21this is early in the season. So if you're looking for snow in Virginia or northern North Carolina,

05:28this is a little bit early. And you can see a couple of pixels there. Just a hint. We don't

05:31want to take the models too literally, but somebody out there could see three to six inches in the

05:35highest elevations. A one to three inch event there in the GFS for the interior of Virginia.

05:39The NAMS kind of timid. Again, we didn't see a whole lot of precipitation on the north side. But even

05:43this produces nine tenths of an inch of snow in areas like Richmond. And the European,

05:47again, was able to crank out an inch plus in Richmond. And two to three inches from

05:53Charlottesville down into areas like Blacksburg and Roanoke. So what is our team actually thinking

05:59here forecast-wise? Here's our forecast map. A general coding to an inch or two in the blue

06:03areas. That includes Delaware, South Jersey. Probably no precip north of the PA Turnpike.

06:09Maybe not even in Philadelphia. But we do think that that'll be happening in places like Smyrna,

06:13Delaware, Dover, Baltimore, D.C., Warrington, Harrisonburg, Charlottesville. A lot of these

06:20areas down into Roanoke, Blacksburg. I think that's the highest confidence area down there

06:23to the south. And overall behind that, we stay cold this weekend, dip in the jet stream,

06:29and there's more Arctic air that'll be around into mid-December.

06:33So to wrap this up here, yes, we're dealing with cold in the Midwest. Not much organized snow there,

06:37but snow and ice coming to the Mid-Atlantic on Friday. And then early next week,

06:41and even late next week, more opportunities in parts of the Midwest and the Northeast.

06:47So as we take a look ahead, just a quick, quick little snapshot. You get an idea.

06:50The chance for some snow out there coming to more areas across the Great Lakes.

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