December 8-10, 2018 Winter Storm

[lilj4425]

Just now, DopplerWx said:

this is a telling statement from nws gsp.

We are approaching increases in the
official fcst QPF cautiously since even modest snow ratios from
these values would result in snow/sleet accumulations that might
be a once-in-a-generation event for parts of the Piedmont.

Wow. Totally opposite of what RAH is saying. 

[strongwxnc]

2 minutes ago, Tony Sisk said:

The latest discussion from the GSP NWS...they are still being extremely cautious.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
As of 240 PM Wed: CAD will take shape across the region Saturday
with strong continental high pressure pushing to the Mid-Atlantic
Coast under strong upper confluence, just as a well-defined trough
(with embedded shortwave) initiates cyclogenesis along the central
Gulf Coast. The low subsequently will move across the Southeast
Coastal Plain in a Miller A-type configuration. Confidence has
increased that with the cold high in place, deep moisture, and
strong dynamic/isentropic forcing, a winter storm will affect a
large portion of the CWFA at the end of the week.

The strength of the high appears likely to keep temps below
freezing from early Saturday until early Monday across the
mountains/foothills and most of the NC Piedmont. Further south
temps are a bit more in question but certainly won`t be warm enough
to rule out wintry precip. There has been some disagreement among
the various guidance members as to how soon precip gets underway
Saturday as the initially stationary front develops between the
damming high and the coastal low. Low PoPs have been advertised
for this period with temps supportive of a rain/snow mix. That
front will develop into the typical wedge warm front Saturday
night as the forcing increases rapidly, peaking Sunday. Held close
to raw model temp trends Sat night and Sunday. The GFS is faster
with onset and also warmer aloft than the EC and Canadian. Even
with it being warmer, however, the warm nose is still small/cool
enough that it implies limited melting of falling hydrometeors. A
fairly large portion of the east-facing Blue Ridge and adjacent
Piedmont areas should remain below freezing aloft and therefore
will experience mostly if not all snow. The transition to sleet
should occur over a narrow region, with sfc temps expected to
be warm enough outside the "core" of the CAD airmass for a sharp
gradient to rain surrounding the sleet. Sfc temps could very well
trend colder given the strength of the CAD, so an expansion of
the snow/sleet area is still possible on subsequent fcsts. And of
course if warm advection aloft is more effective than currently
anticipated, a wider mention of FZRA could return. In terms of
amounts, the spectrum of QPF guidance has trended appreciably
upward this cycle, as have WPC`s numbers. Our fcst is slightly
below the EC ensemble mean at the sampled locations, and even
further below the GEFS mean. We are approaching increases in the
official fcst QPF cautiously since even modest snow ratios from
these values would result in snow/sleet accumulations that might
be a once-in-a-generation event for parts of the Piedmont.

Sunday night at least a brief lull is expected as the coastal low
moves off the Outer Banks. However, the consensus of the global
models is now for the aforementioned shortwave to meander thru the
area from then through Monday, by which time temps should be colder
aloft and the threat of sleet/FZRA should have ended. The shortwave
has the potential to generate more snow from lingering moisture,
and/or to drive convective snow showers through Monday. By Tuesday
morning dry high pressure will spread over the region along with
shortwave ridging. Temps will remain below normal, especially so
in areas with snow cover.

[burgertime]

2 minutes ago, DopplerWx said:

this is a telling statement from nws gsp.

We are approaching increases in the
official fcst QPF cautiously since even modest snow ratios from
these values would result in snow/sleet accumulations that might
be a once-in-a-generation event for parts of the Piedmont.

What the models are putting out is pretty wild and with such consistency. I should be up for the Euro in the morning (I'm 6 hours ahead). If the 00z suite especially the NAM and EURO hold I think it's not absurd to go all in. Still gonna be a million dollar question of where snow/sleet setup is and where ZR happens because that could be very very bad. 

[downeastnc]

8 minutes ago, burgertime said:

Both the 12z and 18z bring a1040 high down to Indiana. We need to keep an eye on that. If we get a stronger high reinforcing that cold air it really is game on for those in NC. 

PGV is 32/18 last frame of the NAM, track kills us though need this thing to stay heading ENE the entire time that turn up the coast is gonna cause problems well inland if it happens....

[BullCityWx]

11 minutes ago, AndyHamachek said:

What about winder ga area and Athens ga area?  What day does the icing start

I do t know much about climo down there but I’d say Athens and NE be in play. 

 

@Lookout

[burgertime]

4 minutes ago, strongwxnc said:

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
As of 240 PM Wed: CAD will take shape across the region Saturday
with strong continental high pressure pushing to the Mid-Atlantic
Coast under strong upper confluence, just as a well-defined trough
(with embedded shortwave) initiates cyclogenesis along the central
Gulf Coast. The low subsequently will move across the Southeast
Coastal Plain in a Miller A-type configuration. Confidence has
increased that with the cold high in place, deep moisture, and
strong dynamic/isentropic forcing, a winter storm will affect a
large portion of the CWFA at the end of the week...

 

 

Wow....just wow. 

[AfewUniversesBelowNormal]

You've got one heck of a storm on the 18z NAM. 

[Brick Tamland]

2 minutes ago, burgertime said:

What the models are putting out is pretty wild and with such consistency. I should be up for the Euro in the morning (I'm 6 hours ahead). If the 00z suite especially the NAM and EURO hold I think it's not absurd to go all in. Still gonna be a million dollar question of where snow/sleet setup is and where ZR happens because that could be very very bad. 

RAH doesn't seem like they believe what the models are showing at all. 

[Cornsnow]

1 minute ago, burgertime said:

What the models are putting out is pretty wild and with such consistency. I should be up for the Euro in the morning (I'm 6 hours ahead). If the 00z suite especially the NAM and EURO hold I think it's not absurd to go all in. Still gonna be a million dollar question of where snow/sleet setup is and where ZR happens because that could be very very bad. 

Hard to get excited, at the same time it is hard not to. Been burned way to many times by that snow/sleet/rain line. Luckily I am now in Mooresville so I at least have that going for me.

[burgertime]

1 minute ago, Cornsnow said:

Hard to get excited, at the same time it is hard not to. Been burned way to many times by that snow/sleet/rain line. Luckily I am now in Mooresville so I at least have that going for me.

GSP knows the warm nose well. What they put out in their AFD is pretty wild. That gives me a lot of faith as well and if the NAM is right about the air aloft it would be all snow. That's some cold air pressing down aloft. 

[BullCityWx]

Can anyone ever remember GSP using the word generational to describe any potential event? I surely can’t.

[sarcean]

Greensboro just updated before they were calling for rain/sleet with only slight snow...

Now

Saturday Night

Snow likely, mainly after 1am. Cloudy, with a low around 30. Chance of precipitation is 60%.

Sunday

Snow before 1pm, then rain. High near 34. Chance of precipitation is 80%.

Sunday Night

A chance of snow before 11pm, then snow and sleet likely between 11pm and 4am, then snow likely after 4am. Cloudy, with a low around 31. Chance of precipitation is 60%.

Monday

Rain and snow likely. Cloudy, with a high near 39. Chance of precipitation is 60%.

Monday Night

A chance of snow. Mostly cloudy, with a low around 27. Chance of precipitation is 40%.

[burgertime]

Well boys and gals I'm off until 00z Euro. See ya on the PBP! 

[burgertime]

Just now, Queencitywx said:

Can anyone ever remember GSP using the word generational to describe any potential event? I surely can’t.

I was thinking the same thing. I'll be crying from my apartment if that happens haha. 

[CLTwx]

5 minutes ago, burgertime said:

What the models are putting out is pretty wild and with such consistency. I should be up for the Euro in the morning (I'm 6 hours ahead). If the 00z suite especially the NAM and EURO hold I think it's not absurd to go all in. Still gonna be a million dollar question of where snow/sleet setup is and where ZR happens because that could be very very bad. 

Dude...you are such a gamer. Homer. Wom back to the Carolinas..you deserve this storm ...for all the contribuition through the years. 

[wxdawg10]

if the big boys hold serve tonight, i think there's gonna be alot of alarm sounding going on tomorrow by mets from GA to VA

[wxdawg10]

2 minutes ago, Queencitywx said:

Can anyone ever remember GSP using the word generational to describe any potential event? I surely can’t.

yeah it's insane.  The crazy part is they're still holding back

[Buddy1987]

2 minutes ago, burgertime said:

Well boys and gals I'm off until 00z Euro. See ya on the PBP! 

Cya man! My parents are actually on vacation in Amsterdam right now. Talk to you soon

[Brick Tamland]

That look reminds me so much of what it looked like the evening before the Carolina Crusher in Jan 2000. I remember looking at the radar before leaving work that night and wondering why the local forecasters and RAH was not calling for much of anything here with regards to snow. I know the technology has improved since then. But now it seems like they don't believe the technology this go around.

[Lookout]

1 minute ago, burgertime said:

This is what I was worried about earlier with the 12z runs. Someone is going to get a bad ice storm out of this. This looks like a strong CAD setup on the models...with a lot of moisture so someone will get the brunt of this in a bad way. 

I've been conflicted  about this due to the lack of low surface dewpoints and the fact that most of our ice/winter storms don't have a long period of just plain rain before hand. (instead just a few hours as we wetbulb down) But every other major indicator i look for is there. Some of it is just general things  i have noticed over the years...like it normally ices here  if the 0c 850mb isotherm starts south of the nc/sc border, Not only does it do that but it touches ne ga as well. 850s never get above a few degrees above freezing, very deep east/northeasterly flow...all the way up to at least 875mb (which is higher than average)......indeed even the 850mb level has that wedge look which is an indicator of a really good one, tight pressure gradient, and strong boundary layer winds.... latest nam is showing 925mb winds at  an impressive 45 to 50 knot across north ga by hour 84. 

The good news for north of 85 is that it might get could enough to make for more sleet than freezing rain because of the cold low levels and mid level temps actually cooling at times. It would be nice if that sleet makes it this far south. Earlier runs of the euro had it very close to doing that but i fear the odds are more likely it's freezing rain for the most part here unless 900 to 975mb temps trend colder or mid levels are a bit cooler. 

[DC2Winston]

Moved to Winston from DC last summer. This thread reminds me of the MA forum vividly. Would love to see us and DC score a big one. I’d cash out 5-7” right now. 

[olafminesaw]

7 minutes ago, Queencitywx said:

Can anyone ever remember GSP using the word generational to describe any potential event? I surely can’t.

Generational or cold rain for the Triad? Maybe the offices should, like, talk to each other every once in a while.

[gman]

This one reminds me of the storm of 1988. 

[burgertime]

2 minutes ago, Lookout said:

I've been conflicted  about this due to the lack of low surface dewpoints and the fact that most of our ice/winter storms don't have a long period of just plain rain before hand. (instead just a few hours as we wetbulb down) But every other major indicator i look for is there. Some of it is just general things  i have noticed over the years...like it normally ices here  if the 0c 850mb isotherm starts south of the nc/sc border, Not only does it do that but it touches ne ga as well. 850s never get above a few degrees above freezing, very deep east/northeasterly flow...all the way up to at least 875mb (which is higher than average)......indeed even the 850mb level has that wedge look which is an indicator of a really good one, tight pressure gradient, and strong boundary layer winds.... latest nam is showing 925mb winds at  an impressive 45 to 50 knot across north ga by hour 84. 

The good news for north of 85 is that it might get could enough to make for more sleet than freezing rain because of the cold low levels and mid level temps actually cooling at times. It would be nice if that sleet makes it this far south. Earlier runs of the euro had it very close to doing that but i fear the odds are more likely it's freezing rain for the most part here unless 900 to 975mb temps trend colder or mid levels are a bit cooler. 

I'm just going on hours and hours of model watching, but it just feels like (not scientific at all here) that whenever you see that signature cad wedge on the surface models it's almost always colder and a lot further south than models predict. It may very well be that you end up with sleet especially if that 540 line can keep pressing south, that's what's really interesting on the NAM and it would make sense given the setup. That sleet line always surprises me with how south it usually goes in storms where WAA becomes a problem on these stout CADs and given what GSP said it would be hard for me to imagine there aren't some big surprises coming close to you. We're talking about a strong CAD with not much of a warm nose (of course easy to say that now). 

[WinstonSalemArlington]

7 minutes ago, CARDC79 said:

Moved to Winston from DC last summer. This thread reminds me of the MA forum vividly. Would love to see us and DC score a big one. I’d cash out 5-7” right now. 

Welcome! 

[FallsLake]

Just had a chance to look at the 18z NAM. If the CAD and dew points are correct, this will be a major storm not just for the western/central folks but for folks into the coastal plain.   

[Brick Tamland]

1 minute ago, FallsLake said:

Just had a chance to look at the 18z NAM. If the CAD and dew points are correct, this will be a major storm not just for the western/central folks but for folks into the coastal plain.   

And I have heard numerous times the CAD is often stronger and harder to erode than the models show. 

[Buddy1987]

Icon is a crush job for foothills and SVA on 18z. Has low sliding by MYR and up toward outer banks. Beginning to think from a consensus standpoint outer banks or just a little south from there will be the track. The Gulf Stream debate could be had for where the lows like to travel when they get to that area.

[Orangeburgwx]

NAM is setting me up for one hell of a nasty ice storm at hr84...

Dew point went from 36 to 32 and surface temp has tanked from 43 to 35

[jburns]

Here's a reason for the difference in GSP and RAL.

GSP

The low subsequently will move across the Southeast
Coastal Plain in a Miller A-type configuration.

RAL

low
tracks along the Gulf coast/S GA/FL Panhandle, likely evolving into
a Miller B configuration 

Sorry, I originally had that backwards.  Fixed now.