Freezing Rain, Sleet, Snow, Rain...Kitchen Sink (12/15-16)

[SD]

Imagine if we trend colder here View attachment 57216

Ping city.

 

[BirdManDoomW]

This is not a favorable event for south western North Carolina. Hardest area to forecast will be near Asheville. Cold rain near.

 

[SD]

In an ideal world the trailing kicker over the PNW would trend slower, the wave would dig, and the low in the north atlantic would slow and help suppress heights over the eastern us. Don't think it happens but there is room here to continue slowly inching south and colder

 

[Myfrotho704_]

As I mentioned yesterday, I find it suspect that this is entirely a snow -> ZR changeover, with little room for sleet. These things most always never verify that way. I would expect, especially if there are colder trends, this to be mostly sleet.
View attachment 57218

Yeah soundings do have that look near Lake norman NC for example

 

[BHS1975]

Gonna be ugly for the roads as you will end with a glacier with the sleet mixed with ZR.


Sent from my iPhone using Tapatalk

 

[SD]

Euro is slowly moving toward lower height across the NE but it's also raising heights across the SE blah

 

[Myfrotho704_]

Euro is slowly moving toward lower height across the NE but it's also raising heights across the SE blahView attachment 57223

We need one pretty big shift south with the confluence to press down on the ridge, otherwise yeah that’s ugly

 

[ForsythSnow]

I do see a bit of a trend in North Ga as well for onset ZR becoming possible. It's getting closer each run but I'm not too sure about the ridge strength only being a 1037.

 

[Myfrotho704_]

 

[iGRXY]

I do see a bit of a trend in North Ga as well for onset ZR becoming possible. It's getting closer each run but I'm not too sure about the ridge strength only being a 1037.

It’s increasing every run and inching south. These CAD situations always trend colder, stronger, and generally press into NE Georgia at least.

 

[Webberweather53]

I do see a bit of a trend in North Ga as well for onset ZR becoming possible. It's getting closer each run but I'm not too sure about the ridge strength only being a 1037.

1037 is very intense for a CAD high, getting close to rivaling Dec 2002 in terms of parent high intensity

 

[RVD]

I hinted at this in a post yesterday, but one of the big things that's going to make it difficult to see a significant period of snow (and also makes trending away from a true Miller B more or less impossible) is that this system will already be starting with a well-defined closed 850 mb circulation (and also 925 as @SD pointed out), which will trek NW of the Appalachians. As long as the flow associated with that low is dominant, we will end up with mainly southerly winds that will create a big ol' warm nose.

Avoiding this requires one of a few things to happen:

- The 850 mb low needs to weaken; not sure there's been much of a trend for this, but there's still time.
- The 850 mb low needs to shift more south; again, haven't seen much of a trend of this in the last few runs; it was happening yesterday some though.
- The 850 mb low needs to slow down/shift west. This has been happening, and it allows a) the SE Canada trough to provide a dominant flow to advect more cold air ahead of the storm, and b) more time for the secondary low to develop/induce its own flow. That second point is unlikely to actually come into play (transfer is currently modeled as happening around DC-Philly), but it is a possibility. If you look closely, you can already see how the coastal low is changing 850 mb wind vectors in the image above.

What the latest models show for the strength/position of this circulation a day or so before impact:


I think absolute best case (not expecting it) would be a trend towards a Jan. 2016 type ptype evolution; I got about 3" snow/sleet with a crust of ZR, and would be happy with half of that. Not sure if we're comparable in the precip department though (I seem to remember that storm had very high QPF?).

 

[Webberweather53]

Looking probable if not likely that somewhere in the Piedmont of NC and probably upstate of SC is going to see a major ice storm on Wednesday, whether or not that’s Greensboro, Charlotte, Raleigh-Durham, or Greenville-Spartanburg, &/or all of the above remains to be seen but I think someone is going to get clocked and it might be lights out

 

[Spurs up]

1037 is very intense for a CAD high, getting close to rivaling Dec 2002 in terms of parent high intensity

so how can I get this down to Columbia? ?

 

[Webberweather53]

so how can I get this down to Columbia? ?

You honestly probably don’t want any part of this lol. Having your power knocked out for several days to a week or more is no fun

 

[Spurs up]

You honestly probably don’t want any part of this lol. Having your power knocked out for several days to a week or more is no fun

i agree ive been there before and it sucks

 

[Dewpoint Dan]

1037 is very intense for a CAD high, getting close to rivaling Dec 2002 in terms of parent high intensity

What was the intensity of CAD in January 2005 ?

 

[SNOWMANN]

After the ice storm of 2002 December I think, yall can have ur damn ice. Ten trees fell on our driveway. And I hate sleet it's a slap in the face....all snow or cold rain bahumbug

 

[iGRXY]

so how can I get this down to Columbia? ?

High needs to press further south but you are seeing ensemble members that have the northern midlands and northern suburbs in on the ice potential and there’s still plenty of time for changes to happen.

 

[RVD]

And since we're talking about CAD and warm noses and their model biases, it's worth noting that phenomena are, to some degree, two sides of the same coin. Perhaps somewhat counterintuitively, strong warm air advection above the boundary layer is really good for CAD. It creates a strong temperature inversion, which is really where the cold air at the surface derives its stability from. Because of that inversion, the cold air faces even more resistance if it tries to rise upward (over the mountain range).

In some ways, I wonder if the model bias of making CAD too weak has the same underlying reason as the bias to make warm noses too weak.