00:00In the forecast feed, we have a lot to look at here regarding the storm, the powerful
00:04storm, the most significant winter storm east of the Rockies, probably in about five years
00:08if we look at the population affected.
00:11Widespread heavy snow for many from the southern plains, from Oklahoma City to Maine, heavy
00:16snow.
00:17And just south of there, from Dallas to Atlanta to Charlotte into southeast Virginia, significant
00:22freezing rain and sleet that'll lead to a lot of trouble as well.
00:26So big picture, look at this footprint of the storm here for the weekend, and keep
00:30in mind, most of this, I'm going to just arbitrarily draw a line, and again, this is fuzzy math,
00:37but in general, if you're southwest of that line, it's mainly a Saturday event.
00:41If you're northeast of that line, it's going to be mainly a Saturday night and Sunday event.
00:48So some of you in New York or Philly, you won't see anything on Saturday.
00:52It begins late Saturday night and Sunday.
00:54It will still continue through Sunday farther south, and this is a long, drawn-out storm
00:58in the south, and we've got a lot of different things to track.
01:01So overall, as we go upstairs here with the computer models, just, I don't want to spend
01:06much time on this particular map.
01:08This is the 500 millibar, 20,000 feet up view of the atmosphere, the flow, the bright colors
01:14are areas of spin or vorticity in the atmosphere.
01:17If you're east of there, east of one of those big blobs of color, you'll likely have significant
01:21lift in the atmosphere, and I wanted to show how we have a southwestern storm.
01:25It's been bringing a little bit of rain to southern California.
01:27We've got a big trough.
01:29Overall, a large trough in the northeast at the mid-Atlantic is leading to a lot of really
01:32cold air now setting in, and then we have these bits of energy, spokes of energy rotating
01:38around the trough, and there are spokes of energy associated with our area of low pressure
01:42in the southwest as well.
01:44And watch how we are going to see some phasing.
01:45These are going to work together.
01:47We have action from Canada, action from Mexico coming together, and they are well-timed so
01:52that it all consolidates into one storm.
01:56Northern branch of the jet stream, southern branch of the jet stream, they are going to
01:59be in phase with one another, and that will lead to enhanced rising motion in the atmosphere.
02:04I'm just scrolling through different computer models, so the details of exactly how they
02:07interact with one another are a little bit different from one to the next, but the big picture
02:11is we are going to see a lot of lift in the atmosphere, and there are multiple pieces
02:15of energy.
02:17One that will run into the mid-Atlantic while there is still more energy and lift in the
02:20atmosphere from the upper level low, hanging way back in Texas at the same time.
02:23So a huge area affected by precipitation and messy, wintry precipitation at the same time.
02:29Now there are a lot of questions still about places like Atlanta.
02:33In Atlanta, let's go Saturday night.
02:36We are going to see freezing rain and maybe a little sleet on the front end, but probably freezing
02:40rain in Atlanta.
02:41And here we are around 1am Saturday night to Sunday morning in Atlanta, Georgia.
02:45And we are in that pink zone with significant freezing rain, power outages happening.
02:49That's the GFS model, European model, pretty similar, pretty similar.
02:53Color coding may be a little different, but the message here is the same, significant freezing
02:56rain.
02:57Let's go to Sunday at 1pm.
03:00In the GFS model, there is still some significant ice, that whitish color here, with rain beginning
03:05to warm in a little bit west of there.
03:07But Atlanta is still dealing with some ice nearby, but the European also facing some
03:12ice there near Atlanta.
03:14If you go a little farther out though, we need to be concerned about exactly how this plays
03:18out.
03:19How quickly do we warm up in Atlanta?
03:22So I am going to take us to something called the SKU-T chart.
03:25Little chaotic looking, I realize.
03:27This is the thermal profile, temperature profile, and also the dew point profile going from the
03:33ground at the bottom of the chart here.
03:35This is where we live.
03:37All the way up to the top of the troposphere.
03:38A large airplane might fly around 30,000 feet, which might be up generally around this area.
03:43This is 300 millibars.
03:44This is 500 millibars, about 20,000 feet up.
03:47This is about a mile up down this way.
03:49And what I want you to notice is into the early part of the storm.
03:53Let's go Sunday at 7 AM.
03:56This is a sounding, so here's the zero degree isotherm.
04:01A little bit tricky because it's slanted.
04:03I know it takes some time to kind of interpret these things when they are new.
04:06But here's the thing to look at.
04:08We got snowflakes falling, snowflakes, snowflakes, snowflakes, and then a very large area where
04:12if you go about 850 millibars up, about a mile into the sky, it will be 50 degrees Fahrenheit,
04:2010 Celsius, 50 Fahrenheit, while you're at freezing at the ground.
04:24So any of those snowflakes certainly melting.
04:27You got rain falling, but at the ground, very shallow layer of cold air.
04:31That's going to lead to significant icing.
04:33Freezing rain is going to pile up and build up on power lines, tree limbs, water's heavy,
04:38weighs 8 pounds per gallon.
04:39That's an ice storm right there in Atlanta.
04:41Eventually, eventually, late Sunday, at some point Sunday afternoon or Sunday evening, you
04:45warm up above freezing.
04:47It may happen in the mid morning to late morning.
04:49But in the Sunday morning, an ice storm in Atlanta, and that's a big deal.
04:53Let's go a little farther down the road.
04:55Let's go, what did I pick here?
04:56I'm just going to scroll up.
04:57Philadelphia.
04:58Philly.
04:59This is a snowstorm for Philly, for the most part, for the most part.
05:02Snow moves in.
05:03Here we have snow building in by Sunday, 7 a.m., snow accumulating, very cold, very
05:08cold at the ground, snow falling through Sunday, heavy snow.
05:12And then we begin to see that orange, it's like a peach color built into Delaware, maybe
05:17extreme Southeast PA, South Jersey.
05:19What's that all about?
05:20Here we go back to the SKU-T for Philadelphia.
05:23I have two different models here.
05:25Sunday morning, let's go to 1 p.m. Sunday, mid-morning Sunday, or mid-day Sunday.
05:31Here's our freezing line.
05:32Everything, clearly to the left, nothing but snow, 100% snow in Philly, 1 p.m.
05:37You can take that to the bank.
05:39And here we are, the GFS, the European, they agree with one another.
05:44In fact, when you get nearly isothermal, the temperature's not changing much.
05:49If you go up through a large chunk of the snow growth zone, that could be some pretty heavy
05:53snow.
05:54But eventually, look at this.
05:55We're getting a little concerned as we get to that pink zone here.
05:59Sunday afternoon and evening, we get close, very close to this little zone here where we
06:05might see a little bit of warming, a tiny bit of warming.
06:08Some snowflakes may partially melt a little bit.
06:10We could see some sleet, perhaps mix in, but not much, not much.
06:14It's mainly a snow event.
06:15There could be a little sleet on the backside in Philly.
06:17So I wanted to just summarize this here as we wrap this up.
06:19I'm gonna get myself out of the way.
06:21Here's the ice zone that we're very concerned about.
06:24Freezing rain will be a huge problem.
06:27Sleet will be bouncing off the power lines, but the freezing rain weighs them down.
06:30That's a big deal.
06:31Snow, this is a big snowstorm, a major snowstorm.
06:34These areas, 6 to 12 inches of snow in many spots of just, I'm kind of rushing just to
06:41capture all this here.
06:43But also, I'm gonna zoom into the northeast as we close this out in the final seconds.
06:46There are areas that are gonna see over a foot of snow and again, a huge snowstorm coming
06:51to the northeast.
06:52That's your forecast feed.
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