2013 Polar Vortex Collapsing; Complete Disintegration Possible!!! US, North Europe, Midle East Hit!!!

MattHugo81Matthew Hugo 7 m


EC ENS mean N Atlantic 850mb temp anom with a text-book distribution that highlights blocking to the N or NW of the UK [link to twitter.com]

Posted A minute ago

An interesting read for SSW enthusiasts;

[link to curriculum.pmartineau.webfactional.com]

Animations of all previously known SSW's. [link to forum.netweather.tv]

[link to www.youtube.com]

And now we can sing all together the song of the "Sudden Stratospheric Warming" aka SSW

Posted 17 minutes ago

Thanks BA, TEITS et al.

So SSW day today, pretty much bang on with the Dec 9th forecast. ( Let's not mention CW forecasts).

However, I suspect I was beaten to this forecast by GP who ultimately has suggested a chain of events even before winter started.

And let's not forget Cohen's work- [link to web.mit.edu]

The increased wave activity from the snow cover gain during October helps us to have more confidence with this type of forecast. Here's hoping that we see those Greenland height rises now that would fit in with the Cohen climatology - if anything I think that the split following the displacement makes this even more likely.

We shall see soon enough! [link to forum.netweather.tv]

#1852 Recretos

Posted Today, 03:25
About the propagation forecasts.

I plotted some GFS meteograms. I think it should be interesting. Let me point out that this is not really that "straightforward" as it might seem, but I think these meteograms can show at least some idea of the trop/strat coupled activity. And let me say at the start, that the colour of the lines ( I drew in MS Paint) is basically random and doesn't have a specific meaning. A problem with these meteograms is, that it is a point forecast. So basically the activity in the atmosphere is not really straight vertical, so we would have to make meteograms through more points to see more of a 3D picture where certain activity "comes from". I am not really going to present anything new here, but I think it might be interesting for some at least.
And these first meteograms go only till 192h, where there is not really that much going on up there, when compared to the 200-284h period. Not to mention that the tropospheric responses and signals start to lose reliability after 144h, and especially after 192h.

This is a GPH meteogram for Greenland (more E Greenland). I chose Greenland, because it is a "point of interest" regarding to post-SSW activity. There is a response from mid down to lower stratosphere with one part of the split vortex hanging over Canada, and heights rising in over Greenland. Heights start to drop off again, with the Canadian vortex moving slowly N/NE.

What is interesting, is the activity in the mid and upper troposphere. On a time scale, it kinda fits in with the wave 2 forecast, touching down into mid troposphere, and peaking around 8-10th. Now the ECM chart is a zonal mean and averaged out on a daily scale. So we don't really have a spatial presentation where exactly is the max. But we have the mid-troposphere "touch" between 70N and 80N, which is around the location of the meteogram plot. But of course the meteogram is only one single point. As we see on the chart, the activity kinda retrogrades with height. So I made a meteogram of a point more south, in north Atlantic. It is more SE of the Greenland point. And basically, while the "tropospheric wave" on the meteogram is not so strong as more north over Greenland, it is stronger in the lower and mid stratosphere. The problem is of course, that we dont really have a good enough spatial presentation from these cross-sections, where exactly the main activity lies. So basically that's where the good old charts come into play. Especially the isentropic "heights" prove useful in this case.


Looking at the pole, the dynamics are not so intense, and there is some propagation from both sides, basically showing that the strat-trop interaction is not really that "straightforward" as it might seem. But of course nothing new here.


Looking over to north of Alaska, thing are a bit more straightforward with less dynamics. A tropospheric response "look alike" of a stratospheric "height wave", with troposphere having a shorter wave response.

Looking at the 192-384 period is a bit more tricky, because the tropospheric dynamics are much less reliable do to all the know issues with NWP's. Some propagation look alike over the pole, while nothing reliable over Greenland.

I combined all the periods in MS Paint, for Greenland. There is propagation, but the tropospheric signals have a low reliability.

Basically the main problem is that this is vertical representation of a single point. With all the strong and intense dynamics, we should be looking in 3D. Because when looking at a single point, you can easily overshoot or undershoot important trends. For example, where it looks like upward propagation, it might actually be downward, but in a tilted manner. So these meteograms do show a certain degree of dynamics, but cant represent dynamics which are tilted in nature.

Lets shift to 2D from the top now.

Now matter how I look at it, the tropospheric and stratospheric vortex split are basically simultaneous, with troposphere slightly in the lead, as shown up on the meteograms and the wave 2 graph. And what a split it is! It is in the same "spirit" as the late Nov./early Dec. split.
ECM operational is really pushing the power of the Greenland blocking up to the max!

The ensembles are following nicely, having a 350m anomaly on a 240h range. That tells a lot about the consistency of the ensembles and a not so bad deviation.

With the ECM operational forcing such a strong block into Greenland, that of course means a strong WAA into the polar region and strong CAA from the pole, down the southern latitudes.

GEFS following, or walking shoulder to shoulder with ECM. But there are some differences, as it was already pointed out a few posts back.

chionomaniac, on 04 January 2013 - 17:53 , said:

In reality, the cross polar flow and -ve AO are from a direct result of the splitting stratospheric vortex. To try and give them their own identity as if they would have occurred without the split is a nonsense.

I couldn't agree more. Now the way I see it, is that this split would not have happened in this magnitude if it weren't for the SSW and the severe vortex weakening. With the vortex getting displaced and starting to weaken, the not really so strong wave 2 will begin to take it apart. And with the simultaneous or precursing tropospheric split and height rises connecting from troposphere and stratosphere, the polar vortex vortex is looking at its doom, and tropospheric higher latitudes are looking at blockings. Shall the subsequent warmings continue, the vortex will not be able to reform or restrengthen to its previous state, before the final warming onsets.

Another thing worth pointing out is the EP-Flux. Just saw the reanalysis on the JMA site, and I just have to add it. Given the look on the meteograms, the ECM forecast for EP-Flux should eventually start to became more favourable.


Maybe I should also add MJO, to make this post a bit more colourful.

We are in a phase 4 which is promotive for Atlantic and Pacific ridging.

Now basically phases 5 and 6 are also promotive mainly for Atlantic and Aleutian ridging, with lower pressure being promoted over Scandinavia. And phase 7 is more or less the best looking one for January.

So as far as MJO goes, it might have looked unfavourable with its recent and current phases, but when looking at the bigger picture and stratospherically, Atlantic and Pacific ridging is all we could hope fore at this stage.

A cold shot is in the "model works", and I think we could easily link it with the stratosphere and its activities, of course coupled with troposphere.

This post is just as dynamic and versatile as the current atmospheric activities, but I wasn't really writing much recently, so I had to cover more topic in this one.

And I admit that I still haven't read the papers on stratosphere and SSW's, especially the ones where MJO linkage is being mentioned. So I apologise if I wrote some stuff that have already been mentioned here, or in some other thread. I only follow this thread, so I apologise for that too.. And I just had to add some model chars, not to make this thread look like "model discussion", but to make sure that when we look back at this thread in some time, there will be some troposphere model output in here too, not just stratosphere charts.

Barely awake right now, but really glad I finally finished the post and got all of this of my chest. Just couldn't find enough time earlier.

Best regards [link to forum.netweather.tv]

Ian Fergusson‏@fergieweather

Latest forecast models continue to focus an increasingly cold easterly flow across UK into next weekend... major change on way #SSW

Matthew Hugo‏@MattHugo81

EC Op run - [link to www.wetterzentrale.de] … | EC ENS mean - [link to www.wetterzentrale.de] … Distinct similarities once again...

Nice!

yay, we may get snow here next weekend WOOHOO !!!!

Really interesting

Matthew Hugo‏@MattHugo81

Well it's quite a drop in 850mb temps from the 06Z GFS ENS that's for sure - [link to www.wetterzentrale.de] …

Matthew Hugo‏@MattHugo81

Last nights 120hr FAX for Thu sums up the complexities for the end of the week - [link to www.wetterzentrale.de] - Getting that detail is a tough one!

Sunday, January 6, 2013What Will Happen After The Polar Vortex Collapse?
By Andrew at 9:12 AM
I have been heralding the collapse of the polar vortex for days now, and have written several detailed explanations on how the collapse will happen. But what will happen after the collapse? What will be the effects of a collapse of the polar vortex?

We'll start with observed conditions. The graph above shows North Hemisphere snow cover anomalies. There is a proven correlation between the anomalies of snow cover in the North Hemisphere in October and the Arctic Oscillation's phase in the following winter. As you can see, the first half of October brought below normal snow cover, and the month of December brought warmer than normal conditions across much of the nation. Now we're looking to the second half of October to predict what temperatures will be like for the rest of winter. The second half of October looks to have above normal to very above normal snow cover, meaning we could see the Arctic Oscillation blow its bottom out later on in winter. This bodes well for the predicted collapse of the polar vortex and the effects being felt in late January and through February.

Speaking of the Arctic Oscillation, let's look at the forecasts for the AO and the North Atlantic Oscillation (NAO) from a couple of big models.

The Arctic Oscillation's forecast from the GFS model shows the index bombing out into extreme negative territory- and that doesn't even cover the full extent of how negative the AO could get. When the AO goes negative, the polar vortex is naturally weakened and cold air will make a good push to go into the US. However, in cooperation with the multiple sudden stratospheric warmings (whose effects will be seen in late January), the Arctic Oscillation has a good chance to be tanking to an extremely negative area. That would most likely happen beyond January 20th. Again, Siberia supports a tanking Arctic Oscillation, meaning this forecast of a strong negative AO is not nearly off the table.

This is the ECMWF's forecast for the North Atlantic Oscillation (NAO). The model is projecting the NAO to be in a very deep negative phase, below the -4 value, which is extremely negative. In the negative phase of the North Atlantic Oscillation, the jet stream buckles to bring cold and storms specifically into the Northeast US and New England regions. Such a negative NAO would indicate that cold and snow would be provoked to move east as soon as the negative PNA relaxes and the high pressure commanding the East US leaves the region. If such a strong negative NAO is still around post-January 20, some serious cold could bleed east into the East US, whereas a negative PNA could pose a significant barricade to the cold getting to the East right away. It will certainly get there, but it could be held back a few days due to the persistent negative PNA.

The ECMWF above is projecting potential vorticity (PV) values for the Day 10 forecast timeframe. Raised PV values suggest the presence of lower pressure, in this case the polar vortex. The polar vortex has split into two pieces at this point, with one over southwest Canada and the other in Eurasia. The polar vortex is severely decimated at this point, meaning a large amount of the cold previously held by the polar vortex must now be released, because it cannot be held by two smaller and weaker polar vortices. Furthermore, a third sudden stratospheric warming is in the forecast, and if such a warming strikes in the perfect place, I find it likely that both vortices will be unable to sustain themselves and may dissipate completely, flooding the lower latitudes with Arctic air.

Models agree that the long range includes good chances for strong cold entering the nation, as shown in the GFS Ensemble temperature departure forecast in the first image below, and the CFS weekly forecast in the second image below.

After the polar vortex collapse, it's looking very cold for the end of January, supported by Siberia, the forecast models, and the stratosphere itself. When the end of January does come around and the US does not experience anomalous cold, I will be extremely surprised. I highly doubt the cold will miss the US; things are looking positive for a sharp Arctic outbreak in the nation, possibly persisting through February.

Andrew [link to theweathercentre.blogspot.de]

feb1991blizzard
Posted 4 minutes ago

12z GFS has the vortex trying to relocate towards Greenland again at 100mb, is this anything to worry about and could this be responsible for the ramped up PV at 500mb on the last few runs?, i am slightly concerned. [link to forum.netweather.tv]

Matthew Hugo‏@MattHugo81

Mixed views from the 12z UKMO and GFS. Neither backing the potency of the E'ly from previous ECM runs. Plenty of uncertainty...

Ian Fergusson‏@fergieweather

Ongoing model uncertainty re evolution of colder spell later this week. A real headache in med-range f'casts. But for sure, turning chilly..

Don't worry Luisport your Tropical kinda weather will carry on as forecasted

I just hope so... we are not prepared for cold below -10C.

Ryan Maue‏@RyanMaue

For an ensemble mean, ECMWF 00z EPS was frigid for W. half of USA for 10-15 day extended range, e.g. [link to twitter.com]

Matthew Hugo‏@MattHugo81

850mb temps like on this graph don't always tell the story of temps nearer the surface - [link to www.wetterzentrale.de] …

Matthew Hugo‏@MattHugo81

ECM 12z model definitely a downgrade from previous runs but does match some of the previous ensemble members. Masses of uncertainty...

12z ECMWF has a monster -EPO ridge in Canada at 240 hours. [link to i47.tinypic.com]

Matthew Hugo‏@MattHugo81

@_chrisfawkes - The model volatility is a major headache. 12Z GFS ENS clearly cold but the lack of model consistency is clearly evident.

Matthew Hugo‏@MattHugo81

Here's the 2m GFS ENS for N Eng - [link to www.meteociel.com] … - Clearly far from a mild outlook...

Matthew Hugo‏@MattHugo81

From 168hrs the EC ENS mean is colder than the EC Op run & still has a block to the NW more dominant than the Op. 12Z EC run looks mild run.

snowking
Posted 3 minutes ago

Have I just been missing it all this time, or have a heck of a lot more models suddenly been given 10mb temperature outputs on Meteociel?!

[link to www.meteociel...rte=1&archive=0]

[link to www.meteociel...&nh=1&archive=0]

[link to www.meteociel...rte=1&archive=0]

[link to www.meteociel...de=10&archive=0]

Thats now JMA, NOGAPS, CMA (China) and NCMRWF (India)

Gives us a lot more data going forward!

SK [link to forum.netweather.tv]

Joe Bastardi‏@BigJoeBastardi

No End to Coldest China Winter in 28 Years, Forecaster Says [link to bloom.bg] via @BloombergNews EUROPE,US NEXT IN 10 DAYS

Joe Bastardi‏@BigJoeBastardi

Severe Cold is taking over much of the Nhem land masses in 8-16 day period [link to twitter.com]