Stratosphere temperature watch - 2016/17

[Singularity]

15 hours ago, Catacol said:

Agreed. Very interesting progression. I'm holding off "predicting" the New Year period and beyond yet until the pacific signal is a little more clear. Should that jump be replicated again tomorrow and the forcing comes out of the COD then I think we may have sufficient amplification for a more happy looking profile than the models are tending to display at the moment. If it retreats in the COD and moves away from 6/7/8 then I have a sinking feeling about prospects through the heart of winter.... GLAAM rather inconclusive and vortex profile not showing anything at the moment to help break us out of the current pattern. If the MJO doesnt do it then I'm not sure what will....

Well my friend, it appears we have a very interesting situation on our hands 

Fascinating to see how the models just aren't getting the message for some reason - though it could well drift back into the COD tomorrow, from watching the latest IR loop the convection seems pretty healthy - question is to what extent the wind anomalies will follow suit. 

There's more and more talk developing of a Pacific wave train which implies that the wind anomalies are manifesting and beginning to affect Rossby wave formation - I wonder if this could possibly increase amplification in the Atlantic sector soon enough to allow for a more satisfying behaviour of next week's strong ridge through the UK and N. Europe?

Looking at recent GFS runs I can see the gradual increase in sharpness of the trough in the western N. Atlantic on Monday, which one upon a time was a good sign that the models were underestimating the pattern, but which in recent times has seen too many about-faces in trends to allow any confidence in such interpretations 

[knocker]

 

[Paul_1978]

18 hours ago, Singularity said:

Well my friend, it appears we have a very interesting situation on our hands 

Fascinating to see how the models just aren't getting the message for some reason - though it could well drift back into the COD tomorrow, from watching the latest IR loop the convection seems pretty healthy - question is to what extent the wind anomalies will follow suit. 

There's more and more talk developing of a Pacific wave train which implies that the wind anomalies are manifesting and beginning to affect Rossby wave formation - I wonder if this could possibly increase amplification in the Atlantic sector soon enough to allow for a more satisfying behaviour of next week's strong ridge through the UK and N. Europe?

Looking at recent GFS runs I can see the gradual increase in sharpness of the trough in the western N. Atlantic on Monday, which one upon a time was a good sign that the models were underestimating the pattern, but which in recent times has seen too many about-faces in trends to allow any confidence in such interpretations 

Any update on the MJO situation today?

There are not many straws to clutch at the moment, so I'm trying to keep an eye on this with interest.

[ArHu3]

30 minutes ago, Paul_1978 said:

Any update on the MJO situation today?

There are not many straws to clutch at the moment, so I'm trying to keep an eye on this with interest.

 

Could this be something of interest? I have to admit I don't really understand but I hear people talking about wave 2 activty

[sebastiaan1973]

Not quite sure where to place this research http://onlinelibrary.wiley.com/doi/10.1002/joc.4673/full Greenland blocking index

[Singularity]

5 hours ago, Paul_1978 said:

Any update on the MJO situation today?

There are not many straws to clutch at the moment, so I'm trying to keep an eye on this with interest.

I'm getting into the festive activities so less input from me in the near future - but the ECMF plot sums up the model spread pretty well:

They're all over the place, in fact GEFS heads off into phase 1 far more than any of the ECM ens. while UKME and CANM take it into phase 5!

Also, today's observed MJO is in precisely the same spot as yesterday's which seems pretty strange. I've seen small movements but never zero movement whatsoever.

All the models had this jumping either toward 8/1 or 5 today so they're out of kilter with reality. I daresay this makes their guidance completely undecipherable in terms of which may be correct, if any, over the coming week. Confidence in the model output beyond 4 or 5 days therefore ends up rock-bottom.

I'd at least expect an amplifying trend for next week as long as the MJO continues to hang about outside the COD in phase 6. Should it wander over to phase 7 than HLB will become a serious possibility but for now MLB remains the likely holding pattern.

For this to occur at such a critical juncture - with whatever activity we see potentially determining whether the vortex can be struck down pre-Feb or not - is a right pain in the behind, in fact the holiday period couldn't be better timed as I can take a lighter interest in how things evolve until I return to a full-on state a few days into Jan.

[mountain shadow]

I wouldnt say they were all over the place, they show excellent agreement for the MJO to remain in the COD and we therefore cannot look to the MJO for any support in assisting with ridging in our area.

[Singularity]

12 minutes ago, mountain shadow said:

I wouldnt say they were all over the place, they show excellent agreement for the MJO to remain in the COD and we therefore cannot look to the MJO for any support in assisting with ridging in our area.

You said as much two days ago and it's been out of the COD ever since (and outside the model spread). Perhaps a cruel trick by fate but it shows we can't assume the model spread will capture the true behaviour.

 

I think perhaps one theory for what JMAN and GEFS are showing is that they are seeing eastward progression days 6-16, but adjusting the activity downward due to the negative SST anomalies in the 7-8 region associated with La Nina. Indeed this means I do see progression while in the COD as the more likely outcome - but in recent months we've seen the MJO become active in 7-8 even when the negative SST anomalies were larger, so I hesitate to assume that we won't see at least modest activity this time.

The COD is not actually a cut-off line though, so the MJO point being close to the edges of the circle is still significant enough to encourage some amplification of the pattern. I'm not talking about major developments here - just more resilience to the strong ridge that looks to be right across the UK in 5 days time.

[iapennell]

On 12/21/2016 at 08:15, ArHu3 said:

When looking at model runs from older SSW's it always looked like the isotemperature lines were drawn by someone with a tremor,  I always figured this was because of an artefact of older version of GFS but now see those tremors appearing again, the tremors continue on the gfs para but smooth out on gfs operational later on. Are these tremors a sign of a real SSW, some sort of real wave disturbing the vortex?

 

@ArHu3 If you can make an possibility of anything remotely like a Sudden Stratospheric Warming over the Arctic from that chart you are an absolute genius!

That looks to me like a very strong polewards temperature gradient between the Arctic and mid-latitude stratospheres, a temperature of close to -90C at 10 mb over the central Arctic would be colder than normal even for late December and the stratosphere temperatures (at 10 mb) of -40C in the latitudes of Spain and California are, if anything, a little warmer than usual. This temperature pattern in the Stratosphere would support very strong circumpolar Westerlies at this height on the fringes of the Arctic- as indeed is confirmed by maps of the wind-profile on this very thread; this tends to lock-in the very cold Arctic stratosphere with the strong circumpolar Westerlies inhibiting the penetration of warmer air from lower latitudes. That is the last thing you need if you want SSW's to occur: It is my contention we are unlikely to see anything like that for a month or so (and there is a real likelihood now that they won't happen at all this winter).

Another wet and milder than usual winter overall is on the cards!

[northwestsnow]

Ian, for someone who got the Autumn really pretty badly wrong your last sentence needs a caveat or three ...sorry.

[ArHu3]

10 minutes ago, iapennell said:

@ArHu3 If you can make an possibility of anything remotely like a Sudden Stratospheric Warming over the Arctic from that chart you are an absolute genius!

That looks to me like a very strong polewards temperature gradient between the Arctic and mid-latitude stratospheres, a temperature of close to -90C at 10 mb over the central Arctic would be colder than normal even for late December and the stratosphere temperatures (at 10 mb) of -40C in the latitudes of Spain and California are, if anything, a little warmer than usual. This temperature pattern in the Stratosphere would support very strong circumpolar Westerlies at this height on the fringes of the Arctic- as indeed is confirmed by maps of the wind-profile on this very thread; this tends to lock-in the very cold Arctic stratosphere with the strong circumpolar Westerlies inhibiting the penetration of warmer air from lower latitudes. That is the last thing you need if you want SSW's to occur: It is my contention we are unlikely to see anything like that for a month or so (and there is a real likelihood now that they won't happen at all this winter).

Another wet and milder than usual winter overall is on the cards!

That is not what I said or meant. First figure 2012 (last major midwinter warming, look at how irregular the isotemperature lines look, next one current pv, the isotemperature lines look like they were drawn with a compass, third the forecast for next week, notice the irregularities again. So my question is artefact or real and if so significant

[oligo]

I still think that it's more likely the downward propagation  of the SSC in progress and subsequently affecting the troposhere for quite a long time.

[iapennell]

9 minutes ago, ArHu3 said:

That is not what I said or meant. First figure 2012 (last major midwinter warming, look at how irregular the isotemperature lines look, next one current pv, the isotemperature lines look like they were drawn with a compass, third the forecast for next week, notice the irregularities again. So my question is artefact or real and if so significant

@ArHu3 Indeed I do see some wiggles in the predicted Stratosphere temperature profile for next week. However, I cannot for the life of me see how that translates into any real potential for any SSW and blocking. The 2012 chart shows major irregularities with the zone of Arctic Stratosphere cold less intense and centred somewhere near northern Norway, the forecast chart has an almost perfect circle with the -88C isotherm skirting northernmost Greenland. The stratospheric temperature gradient is also stronger whereas- look at the 2012 chart, the temperature gradient is weaker and very cold Stratospheric air reaches as far south as the central USA with another tongue of very cold upper air reaching the latitude of Japan in the NW Pacific.

The Circumpolar temperature pattern (and the upper wind-pattern this is producing) is more akin to what goes on over and around Antarctica in the Southern Winter. As you will know blocking in winter in high latitudes of the Southern Hemisphere are much rarer than in the North. It is certainly my view that what we have at the moment is not a precursor to anything like Sudden Stratospheric Warmings over the Arctic and this high-latitude blocking remains unlikely.    

[phil nw.]

A number of posts have been removed as they had nothing to do with the Stratosphere monitoring.

[bluearmy]

The vortex seems to shift towards the Siberian side in week 2, presumably in response to some wave 1. Would have thought such a powerful looking fella would resist a bit of wave 1. Is this a sign that it isn't as strong as it looks ??

[mountain shadow]

With the models finally doing away with the pretence of a strong Greenland high, it again vindicates the importance of the teleconnections to see whether what the models show fit what the teleconnections indicate.

With an MJO in the COD and low angular momentum a brief toppler was always the form horse.

[bluearmy]

28 minutes ago, mountain shadow said:

With the models finally doing away with the pretence of a strong Greenland high, it again vindicates the importance of the teleconnections to see whether what the models show fit what the teleconnections indicate.

With an MJO in the COD and low angular momentum a brief toppler was always the form horse.

Be careful about writing history more an a week In advance 'MS. granted the proper greeny ridge is very unlikely but a mid Atlantic ridge could still exist quite happily and ebb/flow as new ridges emerge off the eastern seaboard. 

[bluearmy]

14 hours ago, bluearmy said:

The vortex seems to shift towards the Siberian side in week 2, presumably in response to some wave 1. Would have thought such a powerful looking fella would resist a bit of wave 1. Is this a sign that it isn't as strong as it looks ??

Wave activity on yesterday's 12z ECM run up to reasonable levels and the vortex displaced a little towards Siberia as a result. Would be interesting to see that trop wave three persist but being latter part of a trop run its unlikely. Zonal flow forecast to relax a bit as we head into week 2.

[Paul123]

Tropospheric ridging is oncoming the end of this year. Due to...?

No MJO, no stratosphere, simply tropospheric?

I suspect that the extreme cold over Siberia (and Canada?) has its effect on tropospheric ridging.

However Siberic coldness still is a relict of the stratospheric warmth from November and start of December, especially the Canadian warming.

If this is true, Canadian warmings (also SSW's) not only have direct (dripping down) effect on the tropospheric polar vortex. This way their effect can be stretched beyond the original limits.

March 2013 cold may be another example of this stretching, reaching beyond the 2 month limit after the SSW. I however do not know whether other factors played any role during that time.

Edited December 25, 2016 by Paul123

[bluearmy]

Some wacky charts on offer from today from Berlin but that ECM op run yesterday was also wacky late on so I suggest waiting until tomorrow's output before reviewing the data

[karyo]

14 minutes ago, bluearmy said:

Some wacky charts on offer from today from Berlin but that ECM op run yesterday was also wacky late on so I suggest waiting until tomorrow's output before reviewing the data

Wacky in what sense?

[bluearmy]

32 minutes ago, karyo said:

Wacky in what sense?

Did you not see the hemispheric split?

that will skew the wave 1 big time. Op runs with such a large amplification need be avoided for detailed analysis 

[karyo]

43 minutes ago, bluearmy said:

Did you not see the hemispheric split?

that will skew the wave 1 big time. Op runs with such a large amplification need be avoided for detailed analysis 

Ok I see. I think the 0z was more enthusiastic than the 6z.

[bluearmy]

28 minutes ago, karyo said:

Ok I see. I think the 0z was more enthusiastic than the 6z.

didn't explain clearly - sorry: the Berlin data is derived solely from that days ecm 12z op. So the Berlin charts this morning are the strat part of the op run from yesterday's 12z which was trop hemispherically split completely 

[karyo]

4 minutes ago, bluearmy said:

didn't explain clearly - sorry: the Berlin data is derived solely from that days ecm 12z op. So the Berlin charts this morning are the strat part of the op run from yesterday's 12z which was trop hemispherically split completely 

Do you think there is a problem with the data which makes the split questionable?