Stratosphere and Polar Vortex Watch 2020

[Mucka]

Frigid yet toasty GFS 00z run

[Griff]

 

[Vikos]

For the records

Let see what the updated 10hpa windcharts will say.

[lorenzo]

[bluearmy]

25 minutes ago, lorenzo said:

Going to get busy in here today methinks .... 

[TSNWK]

30 minutes ago, lorenzo said:

Hello, what is that chart indicating please?

[ICE COLD]

15 minutes ago, bluearmy said:

Going to get busy in here today methinks .... 

what does that chart show/mean please Nick ? 

[Vikos]

AO Blog Update | AER | Weather Risk Assessment

WWW.AER.COM

---

December 14, 2020 - Dr. Judah Cohen from Atmospheric and Environmental Research (AER) embarked on an experimental process of regular research, review, and analysis of...

 

Edited December 18, 2020 by Vikos

[Paul_1978]

4 hours ago, Mucka said:

Frigid yet toasty GFS 00z run

At least these charts are within a reasonable timescale. People normally only post stuff like this at T +384. I get the impression something is afoot?

Edited December 18, 2020 by Paul_1978

[mountain shadow]

6 minutes ago, Paul_1978 said:

At least these charts are within a reasonable timescale. People normally only post stuff like this at T +384. I get the impression something is afoot?

Yes. We're told forecasting in the Strat is less volatile so let the countdown commence!

[SqueakheartLW]

4 hours ago, Mucka said:

Frigid yet toasty GFS 00z run

Wave 1 warming but at the end it appears Atlantic side wants to join in too

Possible wave 2 to finish the vortex off after the big weakening from the first go

 

Even the wind chart from weather is cool looks good later on at all levels

This is an interesting chart at 150hpa from ECM for 10 days time

Notice the vortex is in pieces here. I can make out 4 distinct mini vortexes

Latest                                                         Day 10

I've noticed the prediction for the EQBO to really strengthen in the next 10 days along with the weakening of the WQBO lower down. Also if you look at the northern hemisphere prediction winds high up are not really strengthening at all. Also where is the polar jet stream on these charts. I can easily see the tropical jet but there's no sign of the polar jet

 

 

 

[ghoneym]

38 minutes ago, ICE COLD said:

what does that chart show/mean please Nick ? 

I use the nasa ozone website to better visualise what these plots look like. It's a great snapshot that gives you an overall picture of all layers of atmosphere and where anomalies are situated. 

Once you are on the nasa ozone site click on the tab top right that will say Northern hemisphere. Then click the meteorology tab from the top bar also.  You will be taken to a page that looks like the one above.  Then scroll down to the bottom of the page and you will see 3 li ks at the bottom of the page, like in the image below. Click on artic forecast maps. 

You will arrive at a page that looks like this.... 

You will see the different options from the blue collum on the left. Look for the different hpa charts and select from 1hpa down to 700hpa. Each one has a little + sign on the far right collum. Select that and you will be taken to a page like this... 

Click the start/stop button and you will see an animated version moving through the forecast. Try and visualise where 30 to 80N would be on the hemisphere and where you see the higher temperature anomalies coming into play in relation to the chart Lorenzo displayed. 

 

 

 

Edited December 18, 2020 by ghoneym
.

[Anthony Burden]

The plot continues will it  remain cold and dry after Christmas or cold and unsettled with

dare I say it snow.The key word being cold for both scenarios hopefully.

[snowking]

Very impressed with this as an ensemble mean:

A slight note of caution re: Strat forecasts being more accurate - to a certain extent, yes, mostly because in the stratosphere you don't have to put up with the unpredictable pitfalls of great big mountains sticking out from a flat surface, or vast oceans interacting with the air aloft. However of course the stratosphere forecasts from NWP modelling aren't just a standalone forecast at a single layer of the atmosphere, they're entirely coupled to the forecast through the troposphere too - and given this latest warming is likely triggered by a +EAMT in the main, caution should still be taken even at these timeframes (although as @chionomaniac alluded to over in the mod thread yesterday, it's always encouraging to see these warmings counting down with the days, rather than staying stuck out at T360+). So whilst the overall dynamics are easier to predict in the stratosphere, you still have to account for the entropy below.

And whilst the temperature profile looks impressive overall, remember temperature alone will not show you the state of the vortex:

By the end of the 0z op, the vortex is disturbed, but not entirely defeated. Further disruption will be needed, but fortunately the warmings look set to continue for the foreseeable

[ICE COLD]

19 minutes ago, ghoneym said:

I use the nasa ozone website to better visualise what these plots look like. It's a great snapshot that gives you an overall picture of all layers of atmosphere and where anomalies are situated. 

Once you are on the nasa ozone site click on the tab top right that will say Northern hemisphere. Then click the meteorology tab from the top bar also.  You will be taken to a page that looks like the one above.  Then scroll down to the bottom of the page and you will see 3 li ks at the bottom of the page, like in the image below. Click on artic forecast maps. 

You will arrive at a page that looks like this.... 

You will see the different options from the blue collum on the left. Look for the different hpa charts and select from 1hpa down to 700hpa. Each one has a little + sign on the far right collum. Select that and you will be taken to a page like this... 

Click the start/stop button and you will see an animated version moving through the forecast. Try and visualise where 30 to 80N would be on the hemisphere and where you see the higher temperature anomalies coming into play in relation to the chart Lorenzo displayed. 

 

 

 

Thank you for that much appreciated

[northwestsnow]

Thanks Kris...

Certainly lots to be watching !

[Singularity]

Even in the stratosphere, posting +384 hour charts is a fool's game - but I thought these two were worth saving for the heck of it. Two strong areas of warming and three ridges at 10 hPa. Not bad, GFS.

The tough questions:

Will we see the usual delay of up to a fortnight to how quickly the assault on the polar vortex advances? Seen often... but not always.
Will the troposphere pattern orientate in the right way for a sufficiently strong wave-2 or are we looking at a wave-1 dominated event like in early 2019... which went well (!).

The first one depends on the model dynamics and how they compare to older versions of the model.
The second is highly sensitive to model fluctuations during this time of poor polar vortex organisation. We're seeing blocking highs all over the place with not a lot of consistency. One key exception is over East Asia where a strong high is has very good support - this being the key to the huge wave-1 warming we keep seeing modelled.

[chionomaniac]

Busy at work today. The way this warming is reeling in with consistency is giving me stronger confidence that it will occur. I have watched a few, and this is as strong a signal as any of them. 

[sebastiaan1973]

http://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2018GL077098

Plain Language Summary

The stratosphere is a layer of the atmosphere far from the Earth’ssurface (10–50 km above the surface), but changes in stratospheric circulation, particularly events knownas sudden stratospheric warmings, affect the weather and climate at the surface. By flattening individualmountain regions in a climate model that extends from the Earth’s surface far past the stratosphere, westudy the effects of mountains on stratospheric circulation and the frequency of sudden stratosphericwarming events. We find that the presence of the Mongolian mountains weakens the stratospheric jet by athird of its strength and creates 6 times more warming events as there would be without these mountains.The impact of the Mongolian mountains is about twice as large as the impact of the larger and moreexpansive Tibetan plateau and Himalaya. Mountains are a source of planetary-scale atmospheric wavesthat propagate upward into the stratosphere; we findthat the mountain effect on the stratosphere is largelybecause the mountains alter the pathway that all waves take as they propagate toward the stratosphere,through the influence the mountains have on circulation lower down in the atmosphere. We find similaranomalous wave propagation during sudden warming events in the model and observation

[ALL ABOARD]

8 degrees hotter this run. 

 

Time for the sunscreen?? 

 

[snowking]

Lots going both from the bottom up and the top down.

I would usually caveat this by saying single operational run at long lead time, etc. but checking back through recent runs this really is pretty consistent

Absolutely enormous warming up at 1mb, that's +35c you can see in there (remember, this not an anomaly chart, that is actual temperature) from about day 11 onwards. Warming is still ongoing by the end of the run:

Seeping down into the levels below too:

Back at the very top, this leads to what looks to be a Wave 2 attack by the end of the run, but I could be seeing things there and it may instead be an all-encompassing Wave 1 - difficult to tell whether that is two distinct waves:

We then seem to have the more widely advertised bottom-up pressure which leads to at least a partial split from 100mb:

All the way up to 20mb by the end of the run:

The Wave 1 pressure pretty apparent there too at 20mb.

So we have a situation where we have top-down warming absolutely battering the vortex from the top, and tropospheric forcing causing some fairly significant bruising to the vortex from the bottom. Assuming that current forecasts are correct, the question really must become when, not if, the vortex falls entirely to its knees. I'll leave that to someone far braver than me.

 

 

 

[sebastiaan1973]

ResearchGate - Temporarily Unavailable

WWW.RESEARCHGATE.NET

 

[bluearmy]

That saved me a post kris!

but as you say the stuff coming from low down may be unreliable if it is predicated on the gfs output post day 7/8 .... the ridge that drives the wave may not actually verify ....

[Vikos]

Ozone concetration might be far to low for a strong SSW (by now), forecast only goes to +120h

  Forecast--->

Winds still in the gray range, nothing to see (yet)

COPERNICUS

EC: UKMO:

[snowking]

11 minutes ago, Vikos said:

Ozone concetration might be far to low for a strong SSW (by now), forecast only goes to +120h

  Forecast--->

 

Nothing too substantial specifically at 10mb perhaps, though in fairness when looking at total ozone so far in December:

Signs there of decent transport via BDC poleward to suggest that ozone concentration is not too detached from the (very colourful) picture being painted in the stratosphere by modelling at present.