Part II, Thanksgiving week transient cold shot and the pattern beyond

[Baroclinic Zone]

I wouldn't hurt... A Sudden Stratospheric Warming event: They originate in the higher altitudes of the stratosphere within the domain of the polar vortex. The key to whether the eruption of a warming in those very high altitudes is whether or not the anomaly begins to propagate downward in altitude.

If so, the warm lobe begins to penetrate the tropopausal depths, causing large scale static stability. This limitation of rising air leads to a middle and upper level geopotential eruption, and the core of the vortex "fills" - blocking emerges at high latitudes.

That model tends to correlate against the presence of the Alaskan and Davis Straight PVs, replacing those regions with positive height anomalies. What this also means is that the main band of the westerlies ring around the NH rosey is suppressed in latitude overall - often in Meteorological parlance this is referred to as "pancaking the polar vortex" et al.

This opens the flood gates and pours cold into the middle latitudes. I began post this correlation of SSW to blocking my self back when this was Eastern ...circa 2005. I'll dig around and see if I can find some of that annotated material.

As far as where the SSWs come from (how), I have heard everything from planetary wave decay at high latitudes (basically the termini of WAA patterns at high altitudes), to interactions with the polarity of the solar wind. One thing I have always found interesting is that the mass of the warming event when it first is introduced to the medium is hugely LESS than the mass of the anomaly once it reaches the much denser 150mb sigma level of the mean tropopause. It's like .5mb where the heating anomaly emerges, yet that is enough to heat an ~ 149.5mb mass differential? Something is continuously injecting heat into the medium as the warm anomaly progates downward in altitude.

Thanks John. I know I've seen the maps posted in the past on theses events. Would you happen to have the link or know where to find it?

As has been said already, it looks as though the day 10 12z Euro kicks the vortex out of AK.

[Tropopause_Fold]

nice ctblizz screaming sou'easter on the euro.

[Typhoon Tip]

Thanks John. I know I've seen the maps posted in the past on theses events. Would you happen to have the link or know where to find it?

As has been said already, it looks as though the day 10 12z Euro kicks the vortex out of AK.

Yeah, well...it if works, bravo! ...lot's of pieces build the foundation of winter...

I'll get something into this thread re SSWs.

[CoastalWx]

Regarding the stratosphere, just looking at the 50mb temps.....man is it cold..lol. It is an elongated egg shaped area that is rotating around the globe with troughs or colder air into the US and on the other side of the pole in nw Siberia. Some warm anomalies show up near Scandinavia and nrn Pacific. These features have been progged to pivot around with no expansion or contraction of either anomaly...both positive or negative. There has been a slow tendency perhaps to get these anomalies into western Canada, but it's also an op run prog near d10. Last year, these temps warmed dramatically...very dramatically.

If you get a chance, roll forward each day and watch that warm pool side into the north pole and grow...pretty cool.

[OSUmetstud]

scott, those links are dynamic and they die after a period of time. It's usually better to just save the image to your computer and then upload it to american.

[Clinch Leatherwood]

nice ctblizz screaming sou'easter on the euro.

Precip bends almost all the way to NW Africa - to a STS SW of the Azores.

[CoastalWx]

scott, those links are dynamic and they die after a period of time. It's usually better to just save the image to your computer and then upload it to american.

Yeah I just saw that. I was hoping it would link to the page. I'll try something.

[Typhoon Tip]

Here is the primer as promised:

Note the behavior for the AO 20 to 40 days after the emergence of the January, 2006 event:

2006 1 1 -1.184

2006 1 2 -0.617

2006 1 3 -0.824

2006 1 4 -1.135

2006 1 5 -1.648

2006 1 6 -1.644

2006 1 7 -1.272

2006 1 8 -0.656

2006 1 9 1.299

2006 1 10 2.884

2006 1 11 3.339

2006 1 12 2.575

2006 1 13 1.473

2006 1 14 0.501

2006 1 15 -0.260

2006 1 16 -0.820

2006 1 17 -0.566

2006 1 18 -0.017

2006 1 19 -0.240

2006 1 20 -0.056

2006 1 21 -0.205

2006 1 22 0.311

2006 1 23 0.450

2006 1 24 -0.572

2006 1 25 -1.409

2006 1 26 -1.389

2006 1 27 -1.144

2006 1 28 -0.584

2006 1 29 -0.208

2006 1 30 -0.415

2006 1 31 -1.068

2006 2 1 -1.550

2006 2 2 -2.201

2006 2 3 -2.729

2006 2 4 -2.522

2006 2 5 -1.950

2006 2 6 -1.357

2006 2 7 -0.542

2006 2 8 -0.061

2006 2 9 -0.498

2006 2 10 -0.563

Here is an even better example; very similar emerging warmth and subsequent propagation took place in January of 2004. Note the marginally negative/positive AO drills later that month:

2004 1 1 -0.523

2004 1 2 -0.186

2004 1 3 0.065

2004 1 4 0.007

2004 1 5 -0.383

2004 1 6 -0.858

2004 1 7 -1.227

2004 1 8 -1.327

2004 1 9 -1.121

2004 1 10 -0.630

2004 1 11 -0.205

2004 1 12 -0.352

2004 1 13 -0.958

2004 1 14 -1.914

2004 1 15 -2.968

2004 1 16 -3.855

2004 1 17 -4.387

2004 1 18 -3.890

2004 1 19 -3.382

2004 1 20 -2.783

2004 1 21 -1.191

[CoastalWx]

1st half of December 2010.

2nd half December 2010

[Typhoon Tip]

Obviously subject to change but that D10 Euro is a prelude to a continental mauler, big time!

[ORH_wxman]

Euro ensembles have that period of a+PNA to start December and even a very brief period where maybe the vortex retrogrades enough to get the EPO toward neutral? But it looks crappy again by the end of the run. But it certainly doesn't rule out a 3-5 days period of some seasonably cold weather with modest negative departures if it works out right.

The goal of course is snow events for many and that can't be ruled out with a western ridge in place. We'd obviously like to see a larger scale pattern change eventually...but this is what we have to work with for now.

[Damage In Tolland]

Euro ensembles have that period of a+PNA to start December and even a very brief period where maybe the vortex retrogrades enough to get the EPO toward neutral? But it looks crappy again by the end of the run. But it certainly doesn't rule out a 3-5 days period of some seasonably cold weather with modest negative departures if it works out right.

The goal of course is snow events for many and that can't be ruled out with a western ridge in place. We'd obviously like to see a larger scale pattern change eventually...but this is what we have to work with for now.

What timeframe is that?

[ORH_wxman]

What timeframe is that?

Maybe Nov 30 to Dec 5 or so...it actually has an initial cold shot around Nov 30-Dec 2 and then it warms up Dec 3-4 and then another decent little cold push Dec 4-6.

This movements are subtle because its an ensemble mean more than 10 days out, but that is what they show right now.

[OSUmetstud]

when do the euro weeklies come out?

[40/70 Benchmark]

CNE weenies saw the NAM and crashed the board.

[40/70 Benchmark]

Euro ensembles have that period of a+PNA to start December and even a very brief period where maybe the vortex retrogrades enough to get the EPO toward neutral? But it looks crappy again by the end of the run. But it certainly doesn't rule out a 3-5 days period of some seasonably cold weather with modest negative departures if it works out right.

The goal of course is snow events for many and that can't be ruled out with a western ridge in place. We'd obviously like to see a larger scale pattern change eventually...but this is what we have to work with for now.

Pretty much on par with what has been expected of that time range for awhile now.....an occasional reach around, but at the end of the night, its "no soup for you"!

[weathafella]

Pretty much on par with what has been expected of that time range for awhile now.....an occasional reach around, but at the end of the night, its "no soup for you"!

But also as expected it's pretty different vs the current regime.

But is it a pattern change you want?

Pattern change begins 12/10 and is complete by 12/25.

[Damage In Tolland]

But also as expected it's pretty different vs the current regime.

But is it a pattern change you want?

Pattern change begins 12/10 and is complete by 12/25.

Yeah it's def a pattern change..It may not be true winter..but it sounds like we'll have a good 5-7 period of winter before a bit of a relaxation before it digs in it's heels for good the following week

[40/70 Benchmark]

But also as expected it's pretty different vs the current regime.

But is it a pattern change you want?

Pattern change begins 12/10 and is complete by 12/25.

I'm sure Ginx is about to answer that question, but most of us would disagree.

[Ginx snewx]

Pretty much on par with what has been expected of that time range for awhile now.....an occasional reach around, but at the end of the night, its "no soup for you"!

That's not true, just three days ago the theme was 10-15 days of above normal with a transient cool shot. Modification of that theme has been occurring since. It is a different animal. I really am intrigued by the massive closed UL all models now show, ultimate positioning and strength will be a huge player.

[Ginx snewx]

I'm sure Ginx is about to answer that question, but most of us would disagree.

Is there a doubt the death vortex is gone first week of Dec?

[40/70 Benchmark]

Is there a doubt the death vortex is gone first week of Dec?

Is it true that it is progged to return...so who cares.

[weathafella]

Is it true that it is progged to return...so who cares.

I would like to see if it's progged to return in the same strength. That would make a huge difference on it's stability.

[40/70 Benchmark]

I would like to see if it's progged to return in the same strength. That would make a huge difference on it's stability.

Prob not.....but I expected the start of the real changes around mid month, so that would work out.

I guess its all semantics, but the bottom line is we are now seeing some chinks progged in that pig's armor.

[Damage In Tolland]

Word from Gibbs Euro weeklies are somewhat colder..but SE biased..makes sense with the cutoff..still a move in the right direction

[CT Rain]

Euro weeklies are hideous through week 4.

Some negative temp departures south of us under that monster cold pool/ULL week 2.

Awesome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Damage In Tolland]

What are thoughts that the period Nov 30-Dec avg 's normal to slightly below? Possible?

[OSUmetstud]

Euro weeklies are hideous through week 4.

Some negative temp departures south of us under that monster cold pool/ULL week 2.

Awesome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

can you give us some details?

[Ji]

What are thoughts that the period Nov 30-Dec avg 's normal to slightly below? Possible?

We Need to forget winter now and check back in 3 weeks. Disaster right now

[CT Rain]

can you give us some details?

Torch, torch, torch.

And that ugly cut-off next week in the OH/TN river valleys.