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Pattern December - Deal or No Deal?

The overall pattern looks favorable leading up to late December for a potential Sudden Stratospheric Warming Event in the form of a wave 1/displacement event with troughing dominating the Bering Strait & Eastern Siberia and a huge high over Scandinavia, both of which are projected onto the standing planetary wave pattern and will increase wave forcing onto the polar vortex, decelerating the polar night jet, and leading to considerable warming in the polar stratosphere.

The question becomes how significant is this warming, does it actually perturb the tropospheric vortex enough to give us a prolonged period of high-latitude blocking in January & even February, and how will tropical forcing (the MJO esp) evolve in tandem w/ this potential SSWE?

The answers to all these questions are still in the air atm, the MJO's amplitude may increase in a few weeks time though given the polar stratospheric warming that leads to acceleration of the Brewer-Dobson Circulation, ultimately affecting the shear & static stability of the tropical tropopause (in this case, cooling it and thus being more conducive to near-equatorial convection), and typically it takes a few weeks for the tropospheric vortex to significantly respond to a sudden stratospheric warming event like this unless the warming is initiated in the troposphere first, thus I wouldn't anticipate this to really have much of an effect on our pattern until early-mid January.

Until then, the tropospheric vortex will leave North America and migrate towards Siberia, temporarily exhausting the North American continent of cold air. However, as the vortex digs towards Siberia, it will induce downstream ridging in the NE Pacific and Alaska, (-EPO), which will then reload the continent with cold air and create a pattern we've come to all know & love the last several years in the southern US, giving us a favorable look for wintry weather in the southern US yet again as early as the last week of December, with the SSWE potentially influencing our chances in January & beyond perhaps.



I’m not sure what you mean “the tropospheric vortex will leave North America” What do you mean? What would cause that to happen? I don’t see nothing that would suggest that?




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FV3 already brewing up another heartbreaker for the SE of RDU folks.

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What’s great about this particular map. I know it won’t really pan out this way. But it shows snow for Pickens and Oconee counties in sc. and gives everyone else rain. Usually what happens is Greenville Spartanburg Cherokee county’s sc see more snow then Pickens and Oconee counties


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What’s great about this particular map. I know it won’t really pan out this way. But it shows snow for Pickens and Oconee counties in sc. and gives everyone else rain. Usually what happens is Greenville Spartanburg Cherokee county’s sc see more snow then Pickens and Oconee counties


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I agree FV3 will probably if it keeps this storm trend further south just like the last storm. As of now it looks to amped and juicy.


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Two things about that run of the FV3:

1: to get snow in central AL with that low track is very impressive. Normally a hundred miles to far north for that. Shows very deep cold air. But it's very iffy with the fact that I'd reason the WAA at 850mb is under done.

2: Very dangerous game at 500mb. A phase there changes everything and many people cry. Or a farther south track with the southern wave and a deeper northern stream track and everyone except NC/SC rejoices.

One thing I have to hand to the models is the southern stream waves have been decently modeled in the very long range. The northern stream however is drawn each run by a two year old.
 

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High clouds developing off the nc mountains from a inversion at around 850mb, temperatures will bust
 
I’m not sure what you mean “the tropospheric vortex will leave North America” What do you mean? What would cause that to happen? I don’t see nothing that would suggest that?
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Ongoing poleward heat flux over the coming two weeks will continue to disrupt the polar vortex, sending it towards Siberia.

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Granted, this is the stratospheric PV, but it makes it easier to see what @Webberweather53 was referring to.

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With the pattern we got this winter an epic board wide storm is pretty much a guarantee.


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The last storm which would in retrospect have been active member boardwide (which includes @pcbjr who should never be ignored) was way back in Feb of 1899. If you were to for some reason exclude Phil, I believe you’d still need to go back to Feb of 1914 to get boardwide among active SE US members.
 
I was looking at the 23-30 time period last week and it still looks promising.

Everyone looks at that period . We all want the hallmark movie of snow falling Christmas morning opening gifts with our loving families . Problem is , normally it’s a brown ground and we are with family members we can’t stand


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Everyone looks at that period . We all want the hallmark movie of snow falling Christmas morning opening gifts with our loving families . Problem is , normally it’s a brown ground and we are with family members we can’t stand


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Omg, you made me bust laughing when I saw this.
And the most famous line is. “It’s so good to see you”??
 
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