Stratosphere and Polar Vortex Watch

[Snowman.]

2 hours ago, Weather-history said:

Why is the south polar vortex so active in mid summer?

Imagine this chart in summer in the north polar region?

I believe it's due to the fact that it's over a land rather than the sea.

[chris55]

8 minutes ago, SN0WM4N said:

I believe it's due to the fact that it's over a land rather than the sea.

I thought it was the opposite ? The South Pole is surrounded entirely by ocean! (Away from the land mass in the main) With no topography to slow the vortex it just spins on?

im sure someone with all the info will enlighten us

Edited January 7, 2018 by chris55

[fromey]

At the end of the run I know but it looks nice and warm

[feb1991blizzard]

5 hours ago, Weather-history said:

Why is the south polar vortex so active in mid summer?

Imagine this chart in summer in the north polar region?

Temperature gradient - btw yes I would love that in summer over the North pole.

[Gray-Wolf]

I think we will be seeing some very odd behaviours over the South pole as the Ozone hole mends further and peturbations resonate throughout the Stratosphere from our displaced PV and wayward polar Jet?

I think we had better start to accept that man's impacts on the atmosphere are not restricted to the Trop but , as we saw from the equatorial failed reversal in late 2015 , some of our 'wisdom' may well now be outdated?

I'd caution us to expect the unexpected and not overly rely on B following A any more ( as the failed QBO reversal shows us?).

[booferking]

4 hours ago, chris55 said:

I thought it was the opposite ? The South Pole is surrounded entirely by ocean! (Away from the land mass in the main) With no topography to slow the vortex it just spins on?

im sure someone with all the info will enlighten us

I'm pretty sure it's the opposite Antarctica is land base and arctic is more sea based besides the likes of Greenland etc.

http://mentalfloss.com/article/51435/what-antarctica-looks-under-all-ice

[knocker]

This doesn't mean a great deal to me but I'm sure it will to the more knowledgeable members

 

[chionomaniac]

28 minutes ago, knocker said:

This doesn't mean a great deal to me but I'm sure it will to the more knowledgeable members

 

It's a bit of a technical way of saying that the trop precursors are going to weaken the strat vortex - hence the strat vortex is set to weaken towards the end of the month. Pretty much in line with what we have been saying on here since the start of the month. ( In the meantime as the vortex gets put under pressure the u wind or strength increases but that is all part of the process)

[chionomaniac]

Furthermore, if this is substantial then chances of meridional flow and trop mid latitude cold increases from early feb. Where? well we are in a good as position as any with I suspect increase blocking chances to our north. This is where teleconnective forecasts including joint strat and GWO will give a better chance of verification than those relying on instinct. Still this technique is still in its infancy.

[beng]

I'm going to be a bit negative with regards to us getting lucky here - I'm quite happy though for someone to tell me I'm wrong and why! :-) None of us know for sure how the warming (assuming it happens) will play out for the UK, but I think it's worth having a stab at it based on hopefully logical reasoning.

Although there's every chance that we're going to see the vortex take a battering at the end of the month (looks like a great call from Chio!) with the stratosphere playing ball, it's how that diminshed vortex then interacts with the other teleconnections, SSTs, land temps etc that will then produce the surface level synoptics that we see.  One thing that has been hurting us all winter (IMHO) are the Atlantic SSTs - with a lot of warmth to our SW and colder than normal waters just South of Greenland.  That combination makes it hard to sustain blocking to our NW due to the temperature gradients there.

Let's just take the latest GFS output at face value (of course it won't verify exactly like this) - 

You can see the Arctic playing ball, with the vortex in a bad way, but the Atlantic pattern not really joining in as much as we'd like to give us a sustained block.  I suspect that idea is about right, and if we do finally get a decent block, then it will have taken several attempts to lock in - so that may well eat up the first half of Feb. 

Whatever happens it's fascinating and I'm extremely interested to see how the strat warming plays out and then assuming we get the vortex reduction - am I right about the Atlantic SST hindering its impact in terms of how we'd want for cold?

 

 

 

Edited January 9, 2018 by beng

[Mike Poole]

Looks interesting - from -88C to +4C on this chart at the end of the GFS 6Z!

[Paul_1978]

26 minutes ago, Mike Poole said:

Looks interesting - from -88C to +4C on this chart at the end of the GFS 6Z!

T+384 ..............again.

[bobbydog]

1 hour ago, Paul_1978 said:

T+384 ..............again.

ah, but it starts at +264 and its largely expected that a warming is likely by the latter part the month.

[chionomaniac]

1 hour ago, Paul_1978 said:

T+384 ..............again.

Thje first disturbances at 1hPa are still forecast for the 20th - that's now T+276

[ArHu3]

On 7-1-2018 at 14:30, Dennis said:

yes hope also some good signs - end december we see better warmings in strato - so the runs have started for next weeks

As expected, nearly full rebound 

 

http://www.atmos.albany.edu/student/hattard/realtime/u_60N_10hpa.png

 

(I'm on mobile so you have to click the link else the wrong image will display) 

Edited January 9, 2018 by ArHu3

[karyo]

22 minutes ago, ArHu3 said:

As expected, nearly full rebound 

 

http://www.atmos.albany.edu/student/hattard/realtime/u_60N_10hpa.png

 

(I'm on mobile so you have to click the link else the wrong image will display) 

So the zonal winds are expected to stay above average through January.

[ArHu3]

3 minutes ago, karyo said:

So the zonal winds are expected to stay above average through January.

According to the gfs today... 

[chionomaniac]

Could be the strongest warming forecast yet on this strat run.

[chionomaniac]

Yep and we are reaching 10 hPa. Best angle of attack at 1 hPA see so far. The EP flux looks poleward.

 

I'ts if this can get into the semi reliable (within 10 days) that things will get interesting (wave 1 still projected but wave 2 likely to follow)

Edited January 9, 2018 by chionomaniac

[bluearmy]

Think that’s from the 06z gfs run 

 

[feb1991blizzard]

Looks good towards the end but has anyone got the forecast and observed u-wind actual speed (NOT Anomalies) time series please - don't know if there is one, but the one like this one below but with GFS forecast data added.

preferably for around 60N.

[Singularity]

So if I'm reading things right - the general expectation is for the ridging from Scandinavia to persist for longer, more like ECM/UKMO than GFS, resulting in more of a wave-2 configuration to the stratospheric warming? Or is that expected to trigger results that are delayed such that we see the wave-1 reaching a high peak and then wave-2 coming into play?

TIA 

[feb1991blizzard]

GLOSEA5 saying not a prayer still.

[chris55]

24 minutes ago, feb1991blizzard said:

GLOSEA5 saying not a prayer still.

where and from whom have you got this info? enlighten us with more details please feb.

[feb1991blizzard]

Just now, chris55 said:

where and from whom have you got this info? enlighten us with more details please feb.

Ian Fergusson (BBC points west forecaster), usually (even when we have had these half hearted SSW attempts the past few years), the GLOSEA spots a signal but quickly loses it, this time there isn't one.