GFS was actually faster with the extremely cold stuff then last run….
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Pattern Dazzling December
- Thread starter Rain Cold
- Start date
Not a bad trend on the speed of the Arctic airmass moving in 
That would be a high quality cold front right there
Avalanche
Member
Would their be some narrow convective fropa with that?
Now we look behind to see if a storm rides into this air mass .. usually so the big cold shots like this you look for snow on the front end, a little after it’s established and on the backend for winter potentials.. this though is absolute plenty of cold air to support a winter storm .. almost too cold ?
Dry as a bone if I had to guess with air that cold.
It wouldn't surprise me, but I'm lazy and haven't looked at parameters.
Cary_Snow95
Member
Lol OP gonna trend better and ensembles going to go the other way
Kind of looks like that one in Dec 2000. Tornadoes followed by a dusting of snow. I think my high was 17 that day.
Met1985
Member
So far the GEFS has a better cold push at the beginning of this whole change. I like it.
this gefs run catching my interest in day 7 system, 50/50 low and energy with a suppressed height field, cold would be biggest issue imo, need stronger 50/50 low or more Arctic injection into it 
That one has potential.. biggest question will be whether or not we can manage to get cold enough air for winter weather, either at the surface in the form of ZR or otherwise in the form of SN.. the upper air setup almost looks like a classic ZR storm across the southeast.
accu35
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Little more north and maybe a little faster then this southeast would be rockin. Fro, this is catching my interest also.
Cary_Snow95
Member
Clear trend on GEFS towards dumping in the west
Some of the GEFS are trying to quickly phase this system with the northern JET .. interesting
Snowlove33
Member
On a positive note I wonder what would happen if everyone in the southeast on the board was to get 30 inches of snow in one storm then would y’all be satisfied or would y’all still track snow afterwards???
rburrel2
Member
7 day system is plenty cold enough for snow on most models for the upstate and Western NC if we get enough precip to saturate the column. Surface temps are a little iffy, but decent rates would get us to 32. Hi-Res models will look really good when they get in range,(if we can trend towards there being measurable precip Tuesday morning.)
This system definitely has potential.
Here's a sounding from the GFS, we have well below freezing wetbulbs through the column. Just need enough precip to saturate.
This system definitely has potential.
Here's a sounding from the GFS, we have well below freezing wetbulbs through the column. Just need enough precip to saturate.
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Met1985
Member
Really because im out to hour 168 and I don't see that.
SASQUATCH
Mobile, AL: Snow Capital of the South
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We track err-thang
One thing that I've noticed is too much focus on where the TPV sets up and how much it phases over the Great Lakes. Look at the CMC vs. the ECM, you notice that both have the wave cutting off and separating from the main TPV around day 7. Both get them stuck in the NW. However, the main difference between the two is the heights South of Alaska. The CMC phases with the Aleutian low while the ECM has a strong Aleutian ridge that keeps the energy west and pumps a -PNA.
When you look at the historic major storms that have hit NC, the height axis has a trough touching the west coast, pumping the western ridge. People often cite December 2010 as being the exception that a snowstorm can happen during a -PNA. However, when you look at that storm, it really has the same orientation as a +PNA. It was likely recorded as a -PNA due to the higher heights to the west of the trough.
At the moment, I don't think we're quite there yet with a pattern that supports a major snowstorm around Christmas. We need an Aleutian trough off the west coast of the CONUS. The 18z GEFS was a major step in the right direction in terms of seeing that change. We shall see how things progress!
When you look at the historic major storms that have hit NC, the height axis has a trough touching the west coast, pumping the western ridge. People often cite December 2010 as being the exception that a snowstorm can happen during a -PNA. However, when you look at that storm, it really has the same orientation as a +PNA. It was likely recorded as a -PNA due to the higher heights to the west of the trough.
At the moment, I don't think we're quite there yet with a pattern that supports a major snowstorm around Christmas. We need an Aleutian trough off the west coast of the CONUS. The 18z GEFS was a major step in the right direction in terms of seeing that change. We shall see how things progress!
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Cary_Snow95
Member
Interesting, the gefs has way less top heavy ridging, but way more western ridging, might be some members that pull a CMC or overextend the jet. Personally, I’m Happier with a western ridge (this change)…. 
I don't see that as a potential west dump. Ridging in conus west as myfro pointed out
Don't focus so much on the "blue" focus more so on the "red". The 2 run trend was to more Western ridging, which is good.
Getting some high ratio clippers on the GEFS lol we are far from knowing what we’re getting out of this pattern .. all I know is the cold will come
Met1985
Member
Yes sir! Great post.
Agreed. Cold dropping into the PNW does not mean that it’s going to completely dump all out west. Personally I prefer some of it dropping out there and then spreading east and south because if it all drops east of the Rockies at once, you end up with what the GFS just did…. Bone dry cold and everything piece of energy squashed to the southern Gulf.
This is much much improved, air coming down is only a little less colder, but this means a more progressive pattern meaning it actually makes it here, still would be plenty cold 
NCSNOW
Member
We track anything deeper than frost. Heck we even track Mega Frost. Priorities!
Euro is probably over amplified and too slow but the clear trend is to tilt the see saw enough that we potentially warm, cut, rain. That said we could sneak something through before this happens and I wouldn't sleep on something on the back end near or shortly after Christmas when the vortex lifts
That’s that 2021 western ridge type of trend
I put together a composite map of the best snow events in Metro Atlanta since 1960 and here's what the average 500mb height anomaly and MSLP look like.. so an "ideal":
thing you like to see . This 
NCSNOW
Member
If that moisture would hurry up off table setter storm tonight, we might have gott an icicle
This gefs run is way colder and moves the cold in way quicker then any other run. thanks to a way more +PNA. these means gonna be insane and temp spreads about to be below 0 in some spots 
