Stratosphere Temperature Watch 2014/2015

[Nimbus Nix]

Well the 06z 1mb temperature profile wasn't looking too shabby this morning [1]:

 

That's a top temperature of 35.8C with a temperature gradient across the pole just 4C off a full 100C! Not bad even with the GFS' positive temperature bias. Still, we could do with this increasing and propagating down a bit more over the next few days rather than the flip-flopping about we've been seeing as of late.

 

Also I wondered if anyone could explain the significance of the AAM moving gradually into negative territory and going into Phase 1/2 over the next few weeks. It seems to be really quite significant when compared to the last 3 months which have had a consistently low amplitude GWO (from 00z GFS ENS) [2][3]:

 

 

And the last 3 months [4][5]:

 

Looking back I found a 2008/2009 thread with GP discussing the GWO moving into Phase 1/2/3 and going deeply negative: https://forum.netweather.tv/topic/52083-gwo-and-global-angular-momentum/

 

Could be a promising sign if I'm reading it correctly.

 

[1] http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014121206&var=TMP&lev=1mb&hour=384

[2,3,4,5] http://www.atmos.albany.edu/student/nschiral/gwo.html

 

[feb1991blizzard]

 

Update WSI:

 

 

  WSI_EuroEnergy

Stratospheric polar vortex will still be in place 26th Dec. No SSW yet, although bias stretch toward Siberia. http://t.co/DN10ZhCbux

12/12/2014 13:11

 

 

 

I like that ECM ens mean chart, a) its stretched, b) its the mean of 51 members at 360 hours and c) its not all that long after the warming at the very top of the strat is due to start.

[bluearmy]

Having just delved back to jan 2009 I have to say 'We miss Stewart! '

Berlin should be showing those 1hpa positive temps headed across Asia tomorrow morning.

Edited December 12, 2014 by bluearmy

[feb1991blizzard]

Are these charts as reliable as the other charts?

Or are they as prone as the others to getting it wrong?

 

They have a have a much higher skill score than than the tropospheric and surface charts although don't have any figures to hand, they are pretty accurate within the sub 200 range where as you cant even say that about the H500 charts at T100 sometimes, 300+ is pushing it although even then, you very rarely if ever, go from a significant warming event high up in the strat to nothing at all on the next run, its much smaller changes usually.

 

 

EDIT : some seriously hot temperatures on the 18z GFS, off the scale almost.

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014121218&var=TMP&lev=1mb&hour=384

 

 

IF the trend continues we should see a reversal at 1mb within a few days.

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014121218&var=HGT&lev=1mb&hour=384

 

 

Better downwelling as well, on both the op and the parallel.

 

 

 

Edited December 12, 2014 by feb1991blizzard

[ITSY]

They have a have a much higher skill score than than the tropospheric and surface charts although don't have any figures to hand, they are pretty accurate within the sub 200 range where as you cant even say that about the H500 charts at T100 sometimes, 300+ is pushing it although even then, you very rarely if ever, go from a significant warming event high up in the strat to nothing at all on the next run, its much smaller changes usually.

 

 

EDIT : some seriously hot temperatures on the 18z GFS, off the scale almost.

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014121218&var=TMP&lev=1mb&hour=384

 

 

IF the trend continues we should see a reversal at 1mb within a few days.

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014121218&var=HGT&lev=1mb&hour=384

 

 

Better downwelling as well, on both the op and the parallel.

 

 

 

Must say that to my relatively untrained eye these charts look rather interesting on where we have been recently, which has felt rather stagnant at times given the possibilities on offer. Perhaps not a SSW in the immediate short term, but things certainly seem to be indicating a step in that direction on today's developments. A case of waiting to see how it develops, when and where.

[bluearmy]

Berlin should be showing those 1hpa positive temps headed across Asia tomorrow morning.

the Berlin chart for day 10 is virtually the same as the gfs T384 was for the same date/time. tomorrow is the day because it was the following gfs run (18z) which ramped up the 1hpa warming. Will be interesting to see how overstated the day 16 gfs op was compared to the day 10 ECM for the same point in time. For ECM to compare, we need to see max temps around +15c rather than -1c.

Just looking at current gfs charts for the 23/12 and the day 16 was a pretty good effort and not so far out.

It was the following gfs op which ramped up the 1hpa temps so we would expect to see Berlin showing maxes of 10/15c tomorrow where today it sees -1c.

Not much to report on the Berlin output apart from the beginnings of a wave 1 increase at day 10 up top which I assume is tied in with the warming and will grow larger as the temp ramps up.

Edited December 13, 2014 by bluearmy

[KyleHenry]

Not much to report on the Berlin output apart from the beginnings of a wave 1 increase at day 10 up top which I assume is tied in with the warming and will grow larger as the temp ramps up.

Absolutely agree, to put a correct timing on when wave 1 reaches T0z 10-14 days approximately re Berlin.

The Azores high gets a bad press it's loved in summer for heat but it's loved more in winter when enabling a WAA up Greenland's East Coast.

Anomaly charts have hinted at a Greenland HLB for many months. Omega block c'mon let's be having you.

[Duane S.]

The trend continues for an initial warming (now down to around D10), a slight tailing off of temps and then signs of a bigger warming following in straight behind. I think this is the point where we will see mid Strat temps rising in response. I.e. last few days of 2014 / very early 2015. If it comes to fruition (and so far the initial warming has dropped down from D16 to D10 very well), an early Jan SSW remains fully on the table.

[IDO]

Just looking at Cohen's update as to an SSW and he confirms that December has been poor for wave development and this will delay any SSW, at least for a month. He still expects an SSW sometime this Winter:

 

Longer Term
30–day

With other climate forcing factors (high October Eurasian snow cover, an easterly QBO, and a weak El Niño event), we still anticipate a SSW sometime this winter. However the quiet vertical wave activity for most of December is delaying the onset of a SSW but we still anticipate the wave driving to become more active.   If a large wave pulse event develops just prior to the SSW the AO could trend positive for a while leading up to and immediately following the SSW.  However, soon after the SSW, the AO will trend negative and persist in the negative phase for weeks. Such a transition will increase the chances for cold air outbreaks coming into much of central and eastern North America, Europe, and East Asia.

 

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

[bluearmy]

Will be interesting to see his quickly the zonal flow drops out once the warming begins. It's no co incidence that the AO has gone positive at the same time that the strat flow has pepped up considerably. Question could be whether the strat is following the trop though. We see the zonal flow strengthening now after the AO has gone positive. Are the two influencing each other with the stronger driver in each taking the lead ? ie : the trop AO goes pos and the trop waves drop as a result with less amplification. . Less trop wave forcing into the strat enables the strat zonal flow to ramp up. We then have strong warming up top (anyone care to guess at the catalyst for this?). This should result in the strat zonal flow moderating. Will that encourage the trop AO to head negative as the strat becomes the driver of the whole system?

[karyo]

Just looking at Cohen's update as to an SSW and he confirms that December has been poor for wave development and this will delay any SSW, at least for a month. He still expects an SSW sometime this Winter:

 

Longer Term

30–day

With other climate forcing factors (high October Eurasian snow cover, an easterly QBO, and a weak El Niño event), we still anticipate a SSW sometime this winter. However the quiet vertical wave activity for most of December is delaying the onset of a SSW but we still anticipate the wave driving to become more active.   If a large wave pulse event develops just prior to the SSW the AO could trend positive for a while leading up to and immediately following the SSW.  However, soon after the SSW, the AO will trend negative and persist in the negative phase for weeks. Such a transition will increase the chances for cold air outbreaks coming into much of central and eastern North America, Europe, and East Asia.

 

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

I don't like the sound of this! So we could be looking at a SSW towards the end of January or even February...

[feb1991blizzard]

Just looking at Cohen's update as to an SSW and he confirms that December has been poor for wave development and this will delay any SSW, at least for a month. He still expects an SSW sometime this Winter:

 

Longer Term

30–day

With other climate forcing factors (high October Eurasian snow cover, an easterly QBO, and a weak El Niño event), we still anticipate a SSW sometime this winter. However the quiet vertical wave activity for most of December is delaying the onset of a SSW but we still anticipate the wave driving to become more active.   If a large wave pulse event develops just prior to the SSW the AO could trend positive for a while leading up to and immediately following the SSW.  However, soon after the SSW, the AO will trend negative and persist in the negative phase for weeks. Such a transition will increase the chances for cold air outbreaks coming into much of central and eastern North America, Europe, and East Asia.

 

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

 

 

He does also state this though in the interests of balance.

 

Longer-term prospects for the AO continue to hinge on the state of the stratospheric polar vortex. Vertical wave propagation is extremely weak currently, which has allowed the stratospheric polar vortex to intensify and remain positioned close to the pole - a pattern most common with a positive AO.  The models continue to predict low pressure to dominate the Barents-Kara sea/Northwest Eurasia region.  As long as low pressure persists in this region this will likely inhibit more active wave driving and the stratospheric polar vortex will remain strong.  Still other tropospheric factors such as the retrogression of the Gulf of Alaska low favor a negative trend in the tropospheric AO after week one.

[Duane S.]

I don't like the sound of this! So we could be looking at a SSW towards the end of January or even February...

I don't see where Cohen says it will be delayed at least by a month? No surprises in his latest update, merely following on from the previous where he detailed the main reasons the feedback mechanisms were not in full flow, I.e. the longwave trough sat in NW Asia inhibiting the Siberian high expansion and keeping vertical wave activity lower than was expected a few weeks back.

The NH profile remains in a high wave count/ low amplitude situation. But clearly this is peaking and expectations are a return to a wave 1/2 type as we head towards the end of the year. I think it's safe to say ( and has been for a while) we can rule out an SSW this year but there is nothing saying that one isn't just around the corner, say, by the 2nd week of January

[karyo]

I don't see where Cohen says it will be delayed at least by a month? No surprises in his latest update, merely following on from the previous where he detailed the main reasons the feedback mechanisms were not in full flow, I.e. the longwave trough sat in NW Asia inhibiting the Siberian high expansion and keeping vertical wave activity lower than was expected a few weeks back.

The NH profile remains in a high wave count/ low amplitude situation. But clearly this is peaking and expectations are a return to a wave 1/2 type as we head towards the end of the year. I think it's safe to say ( and has been for a while) we can rule out an SSW this year but there is nothing saying that one isn't just around the corner, say, by the 2nd week of January

I am not saying it is not around the corner. It may well be that it happens in the 2nd week of January as you say but it can easily be the 4th week of January or even February. From what I read in Cohen's previous update, he was not expecting the persistence of the NW Asia low at it doesn't fit with the high snowcover extend that we saw through autumn. This is causing delays and the longer it stays the more delays we are likely to see.

[IDO]

I don't see where Cohen says it will be delayed at least by a month? No surprises in his latest update, merely following on from the previous where he detailed the main reasons the feedback mechanisms were not in full flow, I.e. the longwave trough sat in NW Asia inhibiting the Siberian high expansion and keeping vertical wave activity lower than was expected a few weeks back.

The NH profile remains in a high wave count/ low amplitude situation. But clearly this is peaking and expectations are a return to a wave 1/2 type as we head towards the end of the year. I think it's safe to say ( and has been for a while) we can rule out an SSW this year but there is nothing saying that one isn't just around the corner, say, by the 2nd week of January

i assume because he mentioned the expectation of an SSW in his 30 day plus appraisal that this was when he expected this. i am sure he would have mentioned it in his week 3-4 thoughts otherwise?

He does also state this though in the interests of balance.

 

Longer-term prospects for the AO continue to hinge on the state of the stratospheric polar vortex. Vertical wave propagation is extremely weak currently, which has allowed the stratospheric polar vortex to intensify and remain positioned close to the pole - a pattern most common with a positive AO.  The models continue to predict low pressure to dominate the Barents-Kara sea/Northwest Eurasia region.  As long as low pressure persists in this region this will likely inhibit more active wave driving and the stratospheric polar vortex will remain strong.  Still other tropospheric factors such as the retrogression of the Gulf of Alaska low favor a negative trend in the tropospheric AO after week one.

Yes he did, but that does not guarantee our little island of any prolonged cold, especially with a positive to trending neutral NAO.

[phil nw.]

The striking feature is the development and ongoing +ve ht anomalies over NA which are forcing the main body of the tropospheric vortex towards the Scandinavian/Siberian side.

Thus we see a strong Pacific jet and a +ve nao pattern across into the Atlantic.

http://modeles.meteociel.fr/modeles/gfsp/runs/2014121306/gfsnh-12-72.png?6

 

I would have thought we need further warmings from above to weaken the vortex in order to enable retrogression of the gulf of Alaska low that Cohen refers to above surely or else this pattern could continue unhindered for a while longer until we see a MT or further activity from the  MJO.

We need the re appearance of the E Canadian upper trough to develop any Atlantic WAA and that in turn would come from upstream changes to Alaskan/NE pacific heights.

Just thinking aloud, someone please step in if they can add or correct my thinking here. 

[Snowman.]

Chino said many posts back that we should look at 1mb and then check for downwelling.

 

 

Looking rather tasty up there.

 

 

 

At 10mb we have the warming being fed by bursts of other warmings.

 

 

Burst at the end of the run

 

 

Which amounts to a stronger warming.

 

 

 

 

Also its funny to see how many here take cohen's forecast as fact when its merely just a forecast just like those at the Met who also issued a forecast for it being an slightly above average winter.

 

Maybe if you put less trust in his forecast materialising (which he does seem to be on the right track so far maybe a little delayed) you wouldn't be so disappointed about it not coming in tuition.

 

 

I am not saying it is not around the corner. It may well be that it happens in the 2nd week of January as you say but it can easily be the 4th week of January or even February. From what I read in Cohen's previous update, he was not expecting the persistence of the NW Asia low at it doesn't fit with the high snowcover extend that we saw through autumn. This is causing delays and the longer it stays the more delays we are likely to see.

 

The CFS has hinted for weeks about Feb-April being heavily blocked and PV disrupt so I wouldn't worry about an SSW occurring late in January.

[yellow snow]

I don't get it.

It seems as there will be a temporary pause in the wave activity with the low pushing through scandi inti W Russia. However most models reestablish the high in NW Russia during the 8-15 day period. Also the high west of Greenland and the Aleutian L seem to be there.

Todays ECM is by FAR the most positve this season in the 10 mb anom. The warming is day by day strengthening and coming closer to the pole in the 10-15 day period.

Also the gfs ops are much more positive in the FI after a few days of mainly runs with insufficient warming events.

Also this talk of positive NAO and AO is very strange to me as the latest ECMs are trending more negative in the 8-15 day period.

[Ruben Amsterdam]

Also the gfs ops are much more positive in the FI after a few days of mainly runs with insufficient warming events.

 

 

I also regard the continuous roasting of the upper start in GFS FI a positive thing. At least it is not waning, or disappearing completely. It might be biased, but it is a warming none the less.

 

Does anyone have any info about the performance of GFS-P regarding the stratosphere? Judging by the meteociel 10hpa temp maps it seems a bit too generous. Any other charts available?

Edited December 13, 2014 by Ruben Amsterdam

[karyo]

Chino said many posts back that we should look at 1mb and then check for downwelling.

 

 

Looking rather tasty up there.

 

 

 

 

The CFS has hinted for weeks about Feb-April being heavily blocked and PV disrupt so I wouldn't worry about an SSW occurring late in January.

It is always at the very end of the run though isn't it? 

 

As for the CFS, what can I say, I think most of us would prefer a cold hearted winter as opposed to early spring snow.

[Ruben Amsterdam]

Yes GFS is biased towards the end. Warming is there at +240hr though. I prefer the FI warm, even if we know it is positively biased it is better than no forecast warming at all.

[yellow snow]

Surely we'll get some interesting tweets from wsi in the beginning of next week if the strat trend from today's EC ensm continues

[bluearmy]

Surely we'll get some interesting tweets from wsi in the beginning of next week if the strat trend from today's EC ensm continues

Please can you enlighten us re the ECM strat ens YS.

[Snowman.]

It is always at the very end of the run though isn't it? 

 

As for the CFS, what can I say, I think most of us would prefer a cold hearted winter as opposed to early spring snow.

 

Not really.

 

 

Warmer up there than it is down here that's for sure.

Edited December 13, 2014 by SN0WM4N

[feb1991blizzard]

The warming in terms of temperature actually starts to wane a little at T240 on the ECM compared to T216 and is far less extensive and about 10c at least lower than the corresponding chart from the GFS 0z run today.

 

 

 

 

 

 

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014121400&var=TMP&lev=1mb&hour=228