Stratosphere Temperature Watch 2014/2015

[karyo]

It is remarkable how much the GFS has downgraded the warming and split have downgraded at the 30hpa level over the last few days. The GFS P was never keen in the idea so that's something to have in mind next time such promising warming appears.

[Snowman.]

It is remarkable how much the GFS has downgraded the warming and split have downgraded at the 30hpa level over the last few days. The GFS P was never keen in the idea so that's something to have in mind next time such promising warming appears.

 

However they do agree now.

 

 

 

Just getting there is a bit iffy.

 

[karyo]

That's the 10hpa though not the 30hpa which I was referring to.

[KyleHenry]

http://www.meteociel.fr/modeles/ukmo2.php?carte=1021&ech=12&nh=1&archive=0 at 144 hours.

High pressure in Bering Sea, possibilities of Trying to link with Arctic HP via WAA and in sync with wave 2 movements.

It's all conjecture at this point but US to get lobe of PV with -AO coming.

As for British Isles still can't see pattern yet all options still on the table including Greenland/ Scandi Blocking.

[KyleHenry]

ECMWF at 240 hours (cautiously) has a North Pole High showing.

http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=1&type=0&archive=0

If the split PV flows this exact path the Eurasian portion can only go Central Europe bound, deep cold (British Ises included)

[bluearmy]

Yesterday's 12z ECM reversed the flow at 10hpa as far south as 69 degrees. Just 9 short of a technical SSW. interesting that at that timeframe we also saw an arctic high headed toward our side of the NH forcing a sudden -AO drop and pushing the Siberian vortex chunk sw. The ECM strat vortex split from top to bottom.

This very much in line with the gfs forecasts over the past few days. What should be noted is that the gfs has consistently put the split back together again post this timescale. Shame as it looks very promising by day 10. We need some renewed wave activity to appear from somewhere and fast!

Edited December 27, 2014 by bluearmy

[Paul123]

From the Judah Cohen blog:

 

'Possibly the most significant development so far this winter with hemispheric implications is the predicted breakup of the deep polar low in the Barents-Kara seas into two pieces, which will consolidate into the Hudson Bay and East Siberian lows.  This projects more favorably onto the climatological wave pattern necessary for active wave driving that results in sudden stratospheric warmings (SSW).  These conditions are favorable for increased high latitude blocking, a predominantly negative phase of the AO and an increased frequency of Arctic outbreaks for North America and Eurasia.'

 

http://www.aer.com/science-research/climate-weather/arctic-oscillation

 

The troposphere + 144h:

 

 

Here we see something of a split. Hopefully it will be enough for a (minor) ssw.

The stratosphere charts this morning are somewhat better again.

 

 

 

Some significant warming forecasted again, can be totally different in the coming runs.

 

[GrangemouthBairn]

https://twitter.com/_chrisfawkes/status/548808658499674112

 

https://twitter.com/_chrisfawkes/status/548809326732013568

 

Good news

[snowking]

Unfortunately we are still looking towards the tail end of runs, but this is much more promising from the last few runs of the GFS(P) - it should be noted the Parallel was pretty adamant on not supporting the brief Greenland warming suggestion of the Det.

 

 

Try to think of Ed's analogies of the vortex being like a balloon. Up until now our warming waves have come almost exclusively from the Pacific sector in the form of a Wave 1 pattern. Whilst this is placing a considerable strain on the vortex (and a follow up Wave 2 attack causes the split in the mid-term), it is also having the effect of displacing much of the vortex energy over to the Atlantic sector, and we just can't quite manage, in current NWP at least, to see the Northern arm of the jet stream relent for long enough to build any meaningful blocking in the right position for long enough.

 

So suggestions of a temperature wave from the Atlantic sector may provide a little more interest towards the middle of this month. There is no doubt the vortex is staggering around and just waiting for that final jab....coming back to the balloon, perhaps it needs that final jab from the opposite side this time. If somebody is pressing at the balloon from one side, if somebody can come around to the other side and jab at it there is a greater chance of it bursting. It may not necessarily be a Wave 2 attack, but it may just be enough to tip us over the edge.

 

Let's hope so because I saw my first few flakes this morning and none of them settled...

 

SK

[bluearmy]

https://twitter.com/_chrisfawkes/status/548808658499674112

 

https://twitter.com/_chrisfawkes/status/548809326732013568

 

Good news

It's nothing we don't already know but it's not technically a SSW (it's bad enough when the media peddle untruths but the pros.......).

However, Chris should have more info than us and that obviously doesn't put humpty together again in the same way that week 2 gfs does.

If the warming and split generated the type of ECM op run we saw on yesterday's 12z then the pedantic view that it isn't an actual SSW wouldn't really matter

[MattH]

Afternoon all..

 

Firstly that tweet from Chris Fawkes is a bit misleading as clearly there is a specific definition for a SSW and one isn't or will be occurring any time soon. The vortex does split but again this isn't an official SSW...

 

My comments today sort of follow on from the last few above but highlight the current and upcoming state of the split and how this, unfortunately, is bad news when it comes to cold weather in the UK, at least within the next 7 to 14 days.

 

There's a lot of charts out there but using the ECMWF as a basis for my comments;

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=all&forecast=f192&lng=eng

 

Clearly from the bottom of the strat up to essentially 'the top' there is a split forecast. However, what the bad news is that the split has clearly left a significant 'lobe' of the vortex over NE Canada and into Greenland which really doesn't help our situation at all in terms of northern blocking and is a good example of how splits don't necessarily mean cold weather and blocking for the UK. It comes as no surprised that there is a consistent theme within the tropospheric models for the 'deep blues and purples' to be in evidence over the same regions, as below...

 

http://www.wetterzentrale.de/pics/Recm2161.gif

 

In essence the thermal gradient across the W Atlantic will now increase and thus increase the organisation and intensity of the PFJ that will really get going into the New Year, hence the outlook, primarily is a zonal one. Whilst clearly not a repeat setup of this time last year, the principles are the same in that with the main (or one primary region) of the PV over NE Canada and Greenland then deep cold arctic air will feed off Canada into the W Atlantic and hence increase the activity of the jet stream (baroclinic environment).

 

In essence it looks like a waiting game once again. The end of the year has and will provide some seasonal weather and cold Tmin's in particularly will help pull the CET for December probably near to average, which, compared with last year, is far more respectable. The start vortex really will be waiting for that 'killer blow' now as we progress through January but my money is on the first half of January (at least) potentially being very similar to the early part of December with temporary incursions of Tm air mass from the SW but then these being quickly followed by Pm air masses from the NW etc. I still believe the 'true winter goodies' will arrive, but it's looking like it will be mid to late winter now if you ask me, which as we would even in late March of 2013 isn't a bad thing as under the 'right' setup deep cold will no doubt be just waiting in the wings to flood into the UK, but those hoping for a rapid amount of northern blocking because of this split within early January will be disappointed.

 

Cheers, Matt.

[GrangemouthBairn]

It's nothing we don't already know but it's not technically a SSW (it's bad enough when the media peddle untruths but the pros.......).

However, Chris should have more info than us and that obviously doesn't put humpty together again in the same way that week 2 gfs does.

If the warming and split generated the type of ECM op run we saw on yesterday's 12z then the pedantic view that it isn't an actual SSW wouldn't really matter

Yeah, I was thinking since he was a pro, then he surely wouldn't just say it was a SSW if it wasn't actually one, despite the fact that the talk on here was just about wave 1 and 2 attacks rather than a full on SSW. It's actually in contrast to what Ian Fergusson said on the MO thread last night where he said that a SSW didn't look likely in the forseeable

[feb1991blizzard]

https://twitter.com/_chrisfawkes/status/548808658499674112

 

https://twitter.com/_chrisfawkes/status/548809326732013568

 

Good news

 

A word of caution on that, I cant see an SSW forecast anywhere, this is close(ish).

 

 

 

Plus I remember a BBC forecaster 2 years ago (I cant remember who) actually admitting that they didn't know that much about SSW's and that they were only just beginning to get to grips and that they remain under study, this is in no way intending as a criticism of any Met forecaster but I would hazard a guess that Dr Cohen (who most on this thread seem to reference), is more qualified than anyone on this subject, the good news is that he still thinks we will get one at a later stage.

 

 

Beaten to it by quite a few - thought I might!

Edited December 27, 2014 by feb1991blizzard

[karyo]

Afternoon all..

 

Firstly that tweet from Chris Fawkes is a bit misleading as clearly there is a specific definition for a SSW and one isn't or will be occurring any time soon. The vortex does split but again this isn't an official SSW...

 

My comments today sort of follow on from the last few above but highlight the current and upcoming state of the split and how this, unfortunately, is bad news when it comes to cold weather in the UK, at least within the next 7 to 14 days.

 

There's a lot of charts out there but using the ECMWF as a basis for my comments;

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=all&forecast=f192&lng=eng

 

Clearly from the bottom of the strat up to essentially 'the top' there is a split forecast. However, what the bad news is that the split has clearly left a significant 'lobe' of the vortex over NE Canada and into Greenland which really doesn't help our situation at all in terms of northern blocking and is a good example of how splits don't necessarily mean cold weather and blocking for the UK. It comes as no surprised that there is a consistent theme within the tropospheric models for the 'deep blues and purples' to be in evidence over the same regions, as below...

 

http://www.wetterzentrale.de/pics/Recm2161.gif

 

In essence the thermal gradient across the W Atlantic will now increase and thus increase the organisation and intensity of the PFJ that will really get going into the New Year, hence the outlook, primarily is a zonal one. Whilst clearly not a repeat setup of this time last year, the principles are the same in that with the main (or one primary region) of the PV over NE Canada and Greenland then deep cold arctic air will feed off Canada into the W Atlantic and hence increase the activity of the jet stream (baroclinic environment).

 

In essence it looks like a waiting game once again. The end of the year has and will provide some seasonal weather and cold Tmin's in particularly will help pull the CET for December probably near to average, which, compared with last year, is far more respectable. The start vortex really will be waiting for that 'killer blow' now as we progress through January but my money is on the first half of January (at least) potentially being very similar to the early part of December with temporary incursions of Tm air mass from the SW but then these being quickly followed by Pm air masses from the NW etc. I still believe the 'true winter goodies' will arrive, but it's looking like it will be mid to late winter now if you ask me, which as we would even in late March of 2013 isn't a bad thing as under the 'right' setup deep cold will no doubt be just waiting in the wings to flood into the UK, but those hoping for a rapid amount of northern blocking because of this split within early January will be disappointed.

 

Cheers, Matt.

Thank you Matt, your post summarises perfectly where we are going. A bit depressing to read but it is better to know.

[KyleHenry]

A word of caution on that, I cant see an SSW forecast anywhere, this is close(ish).

 

 

 

Plus I remember a BBC forecaster 2 years ago (I cant remember who) actually admitting that they didn't know that much about SSW's and that they were only just beginning to get to grips and that they remain under study, this is in no way intending as a criticism of any Met forecaster but I would hazard a guess that Dr Cohen (who most on this thread seem to reference), is more qualified than anyone on this subject, the good news is that he still thinks we will get one at a later stage.

 

 

Beaten to it by quite a few - thought I might!

There's no doubt about it Judah Cohen's work is outstanding and precise.

For his own reputation he was willing away the limpet Aleutian low pressure system and at last it does go.

I'm looking at current warming at 1 hPa level on ECMWF if the warming stays at current temperatures 25C for next few days then the ongoing Asian MT event will result in SSW within 14 days.

MT events always needs to be revised after event has concluded to see that it did cause the SSW. Which it mostly does.

As Matt Hugo States the timing of all events is following 2012/13 to a tee.

Where the PV goes is the $64,000 question.

[bluearmy]

Ecm ens strat shows the warming in week 2 to become centred on our side of the NH (as per gfsp).

[John Badrick]

Thank you Matt, your post summarises perfectly where we are going. A bit depressing to read but it is better to know.

Yes but a lot of the coldest winters occurred without the aid of a SSW, so to write off half of the winters is a bit premature

[feb1991blizzard]

There's no doubt about it Judah Cohen's work is outstanding and precise.

For his own reputation he was willing away the limpet Aleutian low pressure system and at last it does go.

I'm looking at current warming at 1 hPa level on ECMWF if the warming stays at current temperatures 25C for next few days then the ongoing Asian MT event will result in SSW within 14 days.

MT events always needs to be revised after event has concluded to see that it did cause the SSW. Which it mostly does.

As Matt Hugo States the timing of all events is following 2012/13 to a tee.

Where the PV goes is the $64,000 question.

 

I have been think along the lines of as long as we can keep the 1hpa warming going then there always would be a chance further down the line of an SSW, I have been concentrating on the top more than any other area, Unfortunately it wanes from now on into the foreseeable though.

[karyo]

Yes but a lot of the coldest winters occurred without the aid of a SSW, so to write off half of the winters is a bit premature

1/3 of the winter is gone and with the forecasts we are looking well into January now. So there's the half winter.

[Woollymummy]

I am only just trying to understand things about the stratosphere but am interested so forgive my ignorance; is this image showing an "attack" on the polar vortex, and if so, what kind, and is the time scale (a week from now) too far away to usually prove "true" ;are the forecasts for patterns in the upper atmosphere easier or more difficult to model than the lower down snowy ones that everyone obsesses about, and finally, on one of the charts for the middle of the atmosphere , it seemed to show air moving from a low pressure region in the Pacific this week, in a system of swirls that remind me of cogs, so that the air would then pop straight over the North Pole and appear in Scandinavia and Europe in the near future; is that normal, or unusual/unlikely, and if it has a name, what do you call it? Many thanks :-)

[bluearmy]

Heights are back on the weatherbell output and we see the split retained at day 10. Gfs has dispensed with the split just beyond T216. Whether ECM wold retain the split much beyond day 10 looks 50/50 to me and given gfs's consistent output in week 2, I expect it wouldn't.

Still wondering if the week 2 trop output is reflecting the strat split effectively yet. Seems to try and put the vortex back together fairly quickly into low res.

[Skin]

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ts.php?plot=temps&alert=1&lng=eng

The temperature spike is pretty significant, to me should be enough to be a sudden stratosphere WARMING event. 25° difference in a matter of days. Do we even have a clear definition of a SSW yet?

Edited December 28, 2014 by Skin

[feb1991blizzard]

Warming seems slightly more pronounced on ECM than GFS, there looks a much bigger wedge of heights in between the daughter vortices, especially right up top.

 

Edited December 28, 2014 by feb1991blizzard

[MattH]

Further to the last post (feb1991blizzard) that is a good spot and at this juncture I'll add that this could be a case of being an outlier run from one model run, just like any forecast model but bear that in mind...

 

However, whilst not at the right position within the stratosphere we almost get a wind reversal at 1hpa to start with...

 

What's important here from yesterday's 12Z is the warming which seems to be in evidence, but this time to the NW of the UK over Greenland. Whilst not evident within the lower strat, from approx 10hpa upwards you'll notice the warming and again this ties in with the images post above too...

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=all&forecast=f216&lng=eng#fig6

 

A warming developing in this area can only be a good thing for longer term blocking within the troposphere. I may be incorrect here, but it certainly doesn't look like being a trop lead upwelling event as the warming is clearly not at lower levels within the stratosphere, it seems to occur higher up, hence the wind reversal (almost) at the top of the strat. This looks like it would be all tied in with further wave 2 activity rather than a wave 1 activity, where and exactly how the 12Z ECMWF model wants to show this I'm not sure. Once again this may all have gone tomorrow, but in terms of really killing off the vortex seeing this warming over NE Canada and over Greenland later on in the ECMWF run is particularly noteworthy.

 

Just as I type this this I remembered about the new (excellent!) ECMWF charts over on WxBell which are clearly updated twice a day and the 00Z run of the ECMWF maintains this warming signal to the NW of the UK, especially at 10hPa, as the below image highlights. I know Ed (Chino) will be knocking about in the next few days so no doubt he'll post some thoughts along with Lorenzo (Tony) as well regarding this.

 

 

Regards, Matt.

[lorenzo]

Some better looking charts around this morning.

 

Start with the Wave activity that leads from a solid vortex and seemingly impenetrable core.

Wave 1 today and D10

 

Wave 2 mid run

 

Cumulative effects deliver the split we have been talking about. Wave 1 and Wave 2 culminate in actual vortex separation, yesterday the pair of daughter vortices were still hanging together by a filament. 

 

As per the wave 1 plot and also this heat flux chart you can see the warming at the very top of the stratosphere burrowing down through the layers.

 

1hPa pressure on the vortex

 

Gaining traction at 5hPa and first signs of 'wraparound' and the Greenland warming.

 

Down we continue and at 10hPa again the solid vortex, the internal wave and eventual split.

 

 

Leading to a u wind projection of just -6ms, not far off technical SSW.

 

Days 5 -7 appear to be where the 'action' really is on this run and the most dynamic changes take place in the core of the stratosphere. Hopefully these side by side show the dramatic changes within 48 hrs.

 

20hPa

 

30hPa

 

A good time to keep track of things as it appears the wave 1 that is the catalyst for these events has gained impetus on the modelling over the last 48 hrs, maybe more changes toward verification as the main action is only at day 6 or so and potentially more 'upgrades' in split activity as we head toward verification.