Highest-impact winter storm so far this season

AccuWeather

AccuWeather's Geoff Cornish forecasts a major winter storm that is expected to hit much of the country, affecting over 150 million people with freezing rain, heavy snow and record cold this weekend.

Transcript

00:00In the forecast feed we want to jump in on the details here. Lots to talk about regarding the

00:11Friday through Monday winter storm a mess and let's get into the details here. This is going

00:15to be the highest impact winter storm we've seen so far this winter east of the Rocky Mountains.

00:19150 million people will be impacted by this storm and as I get myself out of the way and the

00:27graphics you can see 150 million plus affected by this storm in a significant way. The storm

00:33is going to produce heavy freezing rain. Hundreds of thousands will be without power for a time,

00:38mainly across the south. I would not be surprised at all if we even see a million people without

00:44power for part of the middle of the weekend. Heavy snow will be falling from the southern

00:47plains and the Ozarks just north of the ice zone right into the northeast. Confidence is

00:53growing in significant snow in the northeast and record cold will be following this storm

00:58for some from Texas on Sunday into the Carolinas. We're talking about daily record lows for the

01:05calendar day into the Carolinas by Tuesday. Not everybody in that stripe but there will

01:10be some record lows out there and the big concern is we're looking at again tremendous cold and some

01:18will still be without power for a period of time. So I want to get over to the computer models here

01:24and there's so much to talk about I just want to budget my time right. First off let's talk about

01:30what's going on as this storm begins to set in. We've got and I'm going to exaggerate to say ear popping

01:36high pressure drifting south from the Canadian prairies drifting south into the northern plains. That is

01:42driving an arctic front very far to the south. It's going to push south. So overall Friday mid to late

01:50afternoon you begin with rain in Dallas. That's the easiest part of the storm for sure and then you

01:54can see this just bores south and you change over to ice. So another big factor in this is an upper

02:00level low entering the northwest part of Mexico and Arizona from the Pacific. That is also serving to pump

02:08extra moisture from the Pacific right into Texas and across much of the south and the low levels we

02:14still have the the gulf supplying plenty of moisture. So it's all there and it's going to be a big problem

02:19here as we again show the arctic front and that huge zone of high pressure all working together to

02:26drive a bit of a weather mess a huge mess and for some it might be a disaster regarding power outages

02:34followed by extreme cold. Now I want to take you upstairs here for a time because there are some

02:38questions about how this plays out and take a look at the disparity here between the GFS model Sunday

02:45at 1pm and the European model. Big picture they look similar right but if you look at the snow from

02:52Kentucky into say southern Pennsylvania in the GFS in the European model that ice is aggressively pushing

03:01up into Virginia as opposed to snow there in DC. It's a big difference in that DC forecast. Is it heavy

03:07heavy snow Sunday afternoon or are you seeing a sleet fest with some freezing rain even beginning to

03:11build in? So what's going to dictate the difference between the European and the GFS? Remember the GFS

03:17colder, snowier for central Virginia. The European brings that ice in farther north so the European

03:25is going to inflect this this northward push here with the storm more aggressively there and that is

03:31because the there's a northern branch to the jet stream and a southern branch of the jet stream.

03:37And if we go back in time to maybe Saturday it's kind of a scene setter here. We've got the northern

03:42branch of the jet stream a disturbance here in the northern branch and then the southern branch obviously

03:47separated from each other considerably. The European phases these together more rapidly and they have

03:54basically, you know, there's a spoke of energy here that carries moisture east, but the main

04:00thrust of this system, the the primary northern branch feature and the primary southern branch feature

04:06begin to phase together and work together on Sunday. By Sunday evening it's becoming one and that's going to

04:12torque this storm system in such a way that it lifts north more quickly. If we look at the

04:17GFS is 7 p.m. Sunday. It's becoming one in the European in the GFS. They're pretty well separated still the northern branch feature

04:24and the southern branch feature are separated and because they're a little more separated the GFS

04:30keeps this a slightly flatter wave. That means it's a little colder, a little slower to lift north.

04:36That keeps the cold in place in Charlottesville, Virginia and in DC so it's all snow in those areas

04:41for the most part. But in the European this storm will have phased. You got a sharper short wave and a

04:47long wave trough amplified by all this and it lifts north a little bit more rapidly. So we take it back

04:52downstairs and here you can see, to summarize that, the slightly flatter, slower to phase GFS keeps it

04:59a little colder, a little longer and that's a snowstorm. It's a 100% snowstorm in DC. Even Salisbury,

05:06Maryland barely sees some sleep, mainly a snowstorm there. South Jersey, it snowed in Cape May.

05:10With the European phasing faster, it lifts north a little earlier and look at this, you get an aggressive

05:17march forward of ice. This also has implications for Atlanta. Is Atlanta stuck in the ice for virtually

05:23the entire storm? Or does Atlanta go from significant ice over to rain? Maybe in Carrollton, Georgia,

05:29southwest of town with a faster change. So those are some of the issues that we're facing. The GFS,

05:35the Suppressed South version, look at all that ice down into Coleman and Huntsville, Alabama,

05:40and deep into Georgia. Look at the freezing rain in the European. It inflects north. That's a

05:45disastrous ice storm, no matter how you dice it there in parts of the south. A lot of ice there

05:51into Arkansas. My goodness, if you get half of that, you're going to have long lasting power outages.

05:55When it comes to snow, the GFS, big time snow amounts here across Virginia, North Carolina,

06:02Raleigh, tremendous snow, 16 inches of snow in Raleigh versus virtually an inch or two of snow in Raleigh,

06:09with ice changing over the European. Those are the big questions that remain on the table. How fast

06:13does this phase into areas around the plains? Does it phase quickly like the European? Think farther

06:20north faster, milder air in the mid-Atlantic, more ice? Or does it stay suppressed, slower to phase,

06:27more snow in the mid-Atlantic, and a slightly flatter storm? We're very confident in this heavy snow

06:32forecast here into parts of the southern plains, north of the ice zone. In the ice zone, we got big

06:38issues out there. And just a quick look, summarizing, a quick early look, this is the chance of six or

06:46more inches of snow. It is likely that you get six or more inches of snow in Washington, DC. So that

06:52is the forecast feed. We got more coming your way later this week.

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