Jump to content
  • Member Statistics

    17,163
    Total Members
    7,904
    Most Online
    Michael Butler
    Newest Member
    Michael Butler
    Joined

January 20-22 “bring the mojo” winter storm threat


lilj4425
 Share

Recommended Posts

Definitely could see some accretion on Friday night here in Charleston, but it'll be so difficult with today's warm weather I think for things to get too dicey around here. If anything I think the "re-freeze" opportunities on Saturday night could create more challenges than the actual freezing rain event itself, inland temps around the Charleston metro will probably dip below 20! 

  • Like 1
Link to comment
Share on other sites

3 minutes ago, nwohweather said:

Definitely could see some accretion on Friday night here in Charleston, but it'll be so difficult with today's warm weather I think for things to get too dicey around here. If anything I think the "re-freeze" opportunities on Saturday night could create more challenges than the actual freezing rain event itself, inland temps around the Charleston metro will probably dip below 20! 

Wondered about that. Imby, it was 64 yesterday and 68 today. Wondering how that affects things during the day tomorrow myself. 

Link to comment
Share on other sites

3 minutes ago, senc30 said:

Wondered about that. Imby, it was 64 yesterday and 68 today. Wondering how that affects things during the day tomorrow myself. 

From my personal experience with freezing rain, it matters A LOT at ground level but not at all in the trees. To get ice to accumulate on the ground it generally needs to be in the 20’s and the freezing rain needs to be light. Overpasses are a different story

Link to comment
Share on other sites

9 minutes ago, Sandstorm94 said:

Looking at the maps, EURO had slight improvements over 6z, it passed the trend test

Sent from my SM-S115DL using Tapatalk


 

As eyewall pointed out, it was much closer to phasing like some of the other models did. This was a good run in the correct direction 

  • Like 3
Link to comment
Share on other sites

27 minutes ago, CaryWx said:

Can someone drop in Fishel's magic 2:30 tweet if it's out?

Here is Fishel’s post on FB. 
 

SORRY I'M LATE. HERE WE GO!

I want to discuss two concepts with you, so I hope you'll take the time to read this in its entirety. I'm going to discuss 2 things in a fair amount of detail.

First, the atmosphere is an incredibly complex system. It can be simulated extremely well by a myriad of mathematical equations that mimic the laws of physics and thermodynamics. However, these equations do not provide exact solutions, and add to that the fact that models are very dependent on initial conditions. And no analysis of current conditions is perfect, because we don't have enough observations to make it perfect. So there is inherent error in model forecasts right from the start, and those errors only grow with time. 

A trained monkey can read a map! What I as a meteorologist try to do is look at the processes involved in a given weather event, and try to decide if the model output is consistent with those processes. I mentioned yesterday that the disturbance in the southern branch of the jet stream was weakening, and that the disturbance in the northern branch could very well be too far north to do us any good with regard to snow. My views on that haven't changed, even though the models are oscillating wildly as to how much, if any snow we will get. 

Now, concept #2 is instability. You usually only hear me talk about that when it comes to thunderstorms and tornadoes. But it's a much broader concept. Imagine a ball at the base of a valley. No matter how hard you push that ball up the hill, it's eventually gonna return to its original place. Now imagine a ball at the top of a mountain. You give it a shove and it accelerates down the hill and never returns to it's original location. There is something in meteorology called baroclinic instability. The word baroclinic refers to a zone of temperature contrast, which we clearly have with this front moving through today. The instability refers to a certain threshold that must be met for a low pressure area to form and intensify. What I feel is happening here is that one model run falls just short of that threshold, while the next barely exceeds it, and hence the differences in how far west the precipitation gets tomorrow afternoon and night. And frankly, I'm not smart enough to know which side of that threshold we will end up on. 

So all I know to do is give you the range of possibilities. I will not take credit for any outcome, as I have already admitted to you that my confidence level is very low. The best(worst) case scenario for snow lovers is 3-5 inches. The worst(best) case scenario for the Triangle is a Trace of snow tomorrow afternoon and night. The most likely solution in my mind is 1-3", but I am in no hurry to call my bookie in Vegas and put any money on it!

I know this was a long read, and I hope at least some of it makes sense. I'm not gonna pretend to be confident when I'm not. That would be lying, and my parents brought me up better than to do that! As always, I will keep an eye on things and update as needed. Happy Thursday!

  • Like 1
Link to comment
Share on other sites

5 minutes ago, Brick Tamland said:

Looks like the NAM might have more precip farther west this time. 

Precip didn't really expand west on the 18z nam.  There is more precip to the south.  I would expect amounts in the RDU area to be close to 12z.

Link to comment
Share on other sites

8 minutes ago, Brick Tamland said:

Looks like the NAM might have more precip farther west this time. 

It does (barely) but the northern wave is slightly faster and weaker this run compared to the last run. I wouldn't put much faith in that expansion west of moisture as it is not driven by the ull energy and will be hitting very dry air and is often overdone in modeling.

  • Like 1
Link to comment
Share on other sites

15 minutes ago, 27596WXNUT said:

Here is Fishel’s post on FB. 
 

SORRY I'M LATE. HERE WE GO!

I want to discuss two concepts with you, so I hope you'll take the time to read this in its entirety. I'm going to discuss 2 things in a fair amount of detail.

First, the atmosphere is an incredibly complex system. It can be simulated extremely well by a myriad of mathematical equations that mimic the laws of physics and thermodynamics. However, these equations do not provide exact solutions, and add to that the fact that models are very dependent on initial conditions. And no analysis of current conditions is perfect, because we don't have enough observations to make it perfect. So there is inherent error in model forecasts right from the start, and those errors only grow with time. 

A trained monkey can read a map! What I as a meteorologist try to do is look at the processes involved in a given weather event, and try to decide if the model output is consistent with those processes. I mentioned yesterday that the disturbance in the southern branch of the jet stream was weakening, and that the disturbance in the northern branch could very well be too far north to do us any good with regard to snow. My views on that haven't changed, even though the models are oscillating wildly as to how much, if any snow we will get. 

Now, concept #2 is instability. You usually only hear me talk about that when it comes to thunderstorms and tornadoes. But it's a much broader concept. Imagine a ball at the base of a valley. No matter how hard you push that ball up the hill, it's eventually gonna return to its original place. Now imagine a ball at the top of a mountain. You give it a shove and it accelerates down the hill and never returns to it's original location. There is something in meteorology called baroclinic instability. The word baroclinic refers to a zone of temperature contrast, which we clearly have with this front moving through today. The instability refers to a certain threshold that must be met for a low pressure area to form and intensify. What I feel is happening here is that one model run falls just short of that threshold, while the next barely exceeds it, and hence the differences in how far west the precipitation gets tomorrow afternoon and night. And frankly, I'm not smart enough to know which side of that threshold we will end up on. 

So all I know to do is give you the range of possibilities. I will not take credit for any outcome, as I have already admitted to you that my confidence level is very low. The best(worst) case scenario for snow lovers is 3-5 inches. The worst(best) case scenario for the Triangle is a Trace of snow tomorrow afternoon and night. The most likely solution in my mind is 1-3", but I am in no hurry to call my bookie in Vegas and put any money on it!

I know this was a long read, and I hope at least some of it makes sense. I'm not gonna pretend to be confident when I'm not. That would be lying, and my parents brought me up better than to do that! As always, I will keep an eye on things and update as needed. Happy Thursday!

Ole Gregg has been burned so many times on past storms he's become the snow grinch

  • Like 1
  • Haha 2
Link to comment
Share on other sites

1 hour ago, senc30 said:

Wondered about that. Imby, it was 64 yesterday and 68 today. Wondering how that affects things during the day tomorrow myself. 

It will take longer for it to freeze on the roads and ground, but as soon as it drops below freezing it will start attaching to trees, fences, cars, and power lines.

Link to comment
Share on other sites

2 minutes ago, eyewall said:

Paywalled. Can you give the general idea?

How did forecasts end up being so wrong? The flawed predictions can be traced to computer model errors and the inability of human forecasters to adequately account for them.

When fronts come in from the north and west, models sometimes have a bias of drawing in cold air too quickly. Some of our biggest winter storm busts over the years have occurred when we’ve accepted model forecasts indicating temperatures would rapidly cool to near freezing with rain changing to snow.

In short, we probably should have been more skeptical of the models. But we gave them considerable credence since they had done a good job with the other events this month. Notably, they nailed the Jan. 3 snow forecast the day after it was 63 degrees.

  • Like 2
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...