Stratosphere Temperature Watch 2014/2015

[Recretos]

I was plotting some monthly data, and I came up with the plots of ECM32, from the end of August (Run 20 days ago). 

 

The purpose was to test how well it verifies with current obs.

The ECM32 Control run was actually very decent in its forecast. It forecasted a wave-2ish look, with a high over Asia and North America, and it got surprisingly close to the vortex minimal geopotential height and also the maximum of 314 over North America.

 

 

 

Temperature wise, it was also extremely good for this forecast period, with getting the max/min temp very close if not the same, and generally saw the warmer area of Pacific and Asia.

 

 

 

Its forecast further on is for a not so defined vortex. 

 

 

 

Similar as was the ECM32 ENS mean. it could be just some model bias, or the natural tendency toward climatology.

 

 

 

Another forecasting system I am testing, is the CMA monthly forecast, but it has a bias of developing a too strong vortex on heights and not cold enough.. 

 

 

 

There are also other monthly forecasts I will try to plot, but the data usually gets out with a 10-20 day delay. That is reasonable since we are talking about data which is usually not for free, being available for free under the S2S project. But since some forecasts got to 30 or 60 days, I will be able to get some forecasting power out of it.

 

The fact of the matter is, that if we compare the current model situation with the one about 2 or 3 years ago, its simply phenomenal how much more modelling is now available for the stratosphere, since we only had GFS then and ECM to 240h from berlin. Or actually, the data was there all along, we (I) just wasn't able to plot it yet. But times have changed and my quest to improve stratospheric modelling or at least promote it, is in full swing. I was (and still very much am) really trying to pioneer the modelling and visualisation of the stratosphere, since I do believe that it is being very neglected in this aspect, when compared to its actual potential/importance. 

Edited September 17, 2015 by Recretos

[Snowy L]

Evidence that an E-QBO does not help in the weakening of the vortex when in an El Nino phase. No significant difference in vortex strength in W-QBO or E-QBO when we have an El Nino.

 

http://www.eps.jhu.edu/~cig4/2008JD009920new.pdf

 

"In addition to the affect of ENSO on the polar stratosphere, studies have noted that the vortex is less disturbed under a WQBO at 50hPa than during an EQBO. Recently it's been found in observational data, the vortex is weaker in EQBO as compared to WQBO under CENSO and neutral ENSO but not under WENSO."

 

"A hint that this mechanism cannot fully resolve the question can be seen by comparing the polar cap temperature and geopotential height under WENSO/EQBO to WENSO/noQBO. Throughout the middle and upper stratosphere, the geopotential anomaly from 70°N and poleward is almost twice as large in WENSO/no QBO as in WENSO/EQBO. In the midstratosphere, the polar cap temperature anomaly in WENSO/noQBO approaches 6°C, more than twice the anomaly in WENSO/EQBO. The vortex is actually weaker, albeit not significantly, under WENSO/noQBO than WENSO/EQBO."

 

"The reason that the polar vortex in WENSO/EQBO is not as weak as expected is because WENSO has had different teleconnection patterns during WQBO and neutral QBO than during EQBO. The dominant teleconnection pattern to WENSO under WQBO and neutral QBO is a strengthening of the Aleutian Low, and in particular through the PNA,  WENSO/no QBO not shown), and the dominant teleconnection pattern under WENSO/EQBO is the WP and TNH. Barnston et al. [1991] reached similar conclusions on data from 1951 to 1989; they found that ENSO under WQBO tended to excite the PNA mode, whereas ENSO under EQBO tended to excite the TNH and WP modes."

 

"Thus, the WENSO/EQBO vortex is only slightly weakened as its tropospheric teleconnections do not reinforce the climatological wave 1 in midlatitudes. In contrast, WENSO under WQBO does have tropospheric teleconnections (namely, the PNA) that increase wave 1. Because the midlatitude wave 1 height in the troposphere is greater in WQBO than EQBO under WENSO, the difference between the polar vortex in EQBO and WQBO under WENSO is small despite the QBO’s effect on the vortex."

 

 

 

The W-QBO might not be the hindrance that we think it could be this winter.

Edited October 3, 2015 by Snowy L

[Nouska]

 

"Thus, the WENSO/EQBO vortex is only slightly weakened as its tropospheric teleconnections do not reinforce the climatological wave 1 in midlatitudes. In contrast, WENSO under WQBO does have tropospheric teleconnections (namely, the PNA) that increase wave 1. Because the midlatitude wave 1 height in the troposphere is greater in WQBO than EQBO under WENSO, the difference between the polar vortex in EQBO and WQBO under WENSO is small despite the QBO’s effect on the vortex."

 

 

 

The W-QBO might not be the hindrance that we think it could be this winter.

 

Perhaps the bit I've bolded explains why Dr Cohen was so frustrated by the failure of the waves to pack the punch he expected.

[chionomaniac]

This has to be tempered by the fact that 2009 excepted (ENSO neutral year) there has never been a SSW in winter when the solar flux has been around its current value in a wQBO

 

http://www.swpc.noaa.gov/products/solar-cycle-progression

 

 

from here : http://strat-www.met.fu-berlin.de/labitzke/moreqbo/MZ-Labitzke-et-al-2006.pdf

 

ENSO events that tend to affect the North Atlantic rely on the stratospheric pathway

 

http://www.columbia.edu/~lmp/paps/butler+polvani+deser-ERL-2014.pdf

 

 

What will be the overriding factor this winter - ENSO or the wQBO solar link.

 

A comparison of the 2009 and 2010 SSW's found here and it is a good read:

 

http://onlinelibrary.wiley.com/doi/10.1029/2010JD015023/full

[Interitus]

 

 

Are you sure you have done your research, because 68/69 might not have a major SSW but had major strat influences

 

 

Many researchers consider November 1968 to be a full SSW see eg. Cohen & Jones, Charlton & Polvani, Butler & Polvani etc

 

For the UK at least, the coldest weather in 1962/3 and 2009/10 was before the effects of the SSW.

 

Incidentally, what's the link for the GPH anomaly/ao charts for earlier years (1962/3, 1968/9)?

[Glacier Point]

A couple of observations w/r/t the next few weeks in the stratosphere.

 

Both GEFS and EC EPS depict a deep upper low forming over the NE Pacific around 8th October persisting for several days, followed by sequential +ve 500hPa height anomalies over the North Atlantic and then Scandinavia in the extended range.

 

 

With a 14-21 day lag applied, planetary wave activity over the Pacific low should allow for some moderate Wave 1 activity displacing the upper vortex towards Siberia and Wave 2 activity following end of the month into November. All in all, reasons to think that the stratospheric vortex will be on the weak and slightly displaced end of the spectrum come November.

 

The extended 00z EC EPS has continued to depict a warm 10 hPa layer over the tropics. This is an unusual pattern, not really seen since 2002 for the same period. 1997 was also similar in pattern for date, although warm anomalies slightly further north for these two years - although it highlights the differences this year compared to previous.

 

 

Both these advertise an El Nino type pattern deeply engrained in the atmosphere. Check the correlation between 10 hPa temps and angular momentum>

 

 

All in all, a very different start to the stratospheric season beckons.

Edited October 6, 2015 by Glacier Point

[lorenzo]

GWO tanking..fierce looking orbit, some momentum on frictional torques also..

 

 

Nino gunning for the record books..

 

 

Generally all the Nino analog years feature some form of stratospheric event, bar just a handful of years where dormant until FW in March. 97 is a standout for nothing of note as much as 87 is at the opposite end of the scale. Nice find on the tropics warm layer.

[Recretos]

 

 

Many researchers consider November 1968 to be a full SSW see eg. Cohen & Jones, Charlton & Polvani, Butler & Polvani etc

 

For the UK at least, the coldest weather in 1962/3 and 2009/10 was before the effects of the SSW.

 

Incidentally, what's the link for the GPH anomaly/ao charts for earlier years (1962/3, 1968/9)?

 

They are somewhereon the CPC site, but i have lost the link. I have saved some of the graphics tho, in case I actually lose the link, since the graphics are quite useful. I have it bookmarked somewhere on my old computer, and I will eventually recover it, or at least try to recover it.

 

 

A couple of observations w/r/t the next few weeks in the stratosphere.

 

Both GEFS and EC EPS depict a deep upper low forming over the NE Pacific around 8th October persisting for several days, followed by sequential +ve 500hPa height anomalies over the North Atlantic and then Scandinavia in the extended range.

 

gfs-ens_z500a_sd_nhem_20.jpggfs-ens_z500a_sd_nhem_33.jpggfs-ens_z500a_sd_nhem_51.jpg

 

With a 14-21 day lag applied, planetary wave activity over the Pacific low should allow for some moderate Wave 1 activity displacing the upper vortex towards Siberia and Wave 2 activity following end of the month into November. All in all, reasons to think that the stratospheric vortex will be on the weak and slightly displaced end of the spectrum come November.

 

The extended 00z EC EPS has continued to depict a warm 10 hPa layer over the tropics. This is an unusual pattern, not really seen since 2002 for the same period. 1997 was also similar in pattern for date.

 

compday_coJ4m0Om4A.jpgcompday_1ecwY0jtzS.jpg

 

Both these advertise an El Nino type pattern deeply engrained in the atmosphere. Check the correlation between 10 hPa temps and angular momentum>

 

86_152_19_204_277_5_39_21.jpg

 

All in all, a very different start to the stratospheric season beckons.

 

That is very interesting. 

Also because I just went over GEFS (new one), and it is actually colder than normal over tropics.

 

 

That includes the bias corrected version.

 

 

And the N.Hem (ignoring the south hem. since its going into summer) pattern actually kinda fits (in a very rough sense, since the its just a forecast with some errors) with the 81-14 correlation between ENSO 3.4 and 10mb Temperature. I really prefer to use this period for stratospheric correlations, because the quality of the higher atmospheric assimilated data is much better than in the 50-70 period for example which can create some noise. Besides, a 33 year period of quality data is more than enough (especially since its recent data), and better than 64 years of half-quality data. At least in my amateur opinion of course, I have to emphasise that.

 

 

And using the same correlation as above, the new period sheds a different light. and tropics wise, it looks quite similar if not the same as the ENSO 3.4 correlation, but that is normal since AAM and El Nino do go hand in hand. Also of note is that this graphic is for November, to make it the same as above from GP, and mine above is from October, since it relates to the GEFS forecast. Also of another note is the fact that the actual correlation factors are not that strong at all actually, but its not so important, since we only want to find the "signal" and not to make actual hard correlations. And the signal can be best seen in quality data IMHO.

 

 

And wondering how much bias correction there actually is? Well, not that much, generally the bias corrected version is just a bit warmer in the north hem., or lets say that the normal version is a bit too cold. Of course the bias is not completely removed in the corrected version. Some of the cold bias is probably still left. But i do wonder if the bias would really be so strong to be 6-8 degrees too cold in the tropics? That question will be answered once we get close to this period. I have saved the data files so I can re-plot and subtract data and calculate the potential error for stratospheric forecasts of new GEFS for this period.

 

If we look at the old one, its a bit more stressed out, but still keeps the similar tone. its obvious how it just cant grab onto certain processes, like its new version.

 

 

And since we are talking about 1997 and 2002, lets see how today day stacks up to the same day on those two years. Kinda like an initial conditions check.  But (there is always a but, isn't it) of course we have to understand that the south hemisphere is just coming off its winter dynamics and is in its own story, which can and does affect the overall picture. But lets just focus on N.Hem for now. Analysis data is from GFS high res analysis on 05/10 12z. Temperature data is from ECMWFs ERA Interim, and GPH data is from NCEP R2. I need temperature data in better resolution than 2.5 grid from NCEP R2, so i went for the 1 degree grid reanalysis at ECMWF. Tho for geopotential height it doesnt matter if its 1 or 2.5, since there is some work needed to be done to make the GFS GPH analsyis grid compatible with ECMWF ERA Interim grids, and i dont have the time for it at the moment. Also i will do a whole week to week comparison sometime next time, instead of only day to day, but its ok for starters for now I guess.

 

The temperature pattern is clear, that this year, or today at least, we have a warmer pole the Greenland area and especially Asia/Siberia. Week to week mean comparisons should give a better picture.

 

 

GPH wise, the differences are actually interesting, with the common thing being more cyclonic energy over Greenland area, which is where the vortex actually is today. One more reason why we need at least a 7-day mean to make comparisons, and that should look quite tasty, since I am trying a new "look" of my graphics. 

 

 

 

Till next time. 

 

Regards

 

p.s. to Glacier Point: It is interesting just how different data we got. We are using different datasets in essence, and I do prefer the EPS over GEFS, even the new one, but I really love this, since we get to make a real-time test of the new GEFS.

 

P.s.2:

 

Forgot to add above, GEFS does have the wave2-ish pattern, coming mainly from the Scandi-Atlantic duplex ridge attack and of course the Aleutian low effects that GP has mentioned.

 

    

Edited October 5, 2015 by Recretos

[Interitus]

 

 

They are somewhereon the CPC site, but i have lost the link. I have saved some of the graphics tho, in case I actually lose the link, since the graphics are quite useful. I have it bookmarked somewhere on my old computer, and I will eventually recover it, or at least try to recover it.

 

 

 

That is very interesting. 

Also because I just went over GEFS (new one), and it is actually colder than normal over tropics.

 

 

 

I had trawled the CPC site but without success, thanks anyway.

 

Regarding 10mb temperatures, it depends on definition of tropics or subtropics - if the map projection for 2002 is changed then the cold anomaly over the equator is present - http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/comp.day.pl?var=Air+Temperature&level=10mb&iy%5B1%5D=2002&im%5B1%5D=10&id%5B1%5D=20&iy%5B2%5D=&im%5B2%5D=&id%5B2%5D=&iy%5B3%5D=&im%5B3%5D=&id%5B3%5D=&iy%5B4%5D=&im%5B4%5D=&id%5B4%5D=&iy%5B5%5D=&im%5B5%5D=&id%5B5%5D=&iy%5B6%5D=&im%5B6%5D=&id%5B6%5D=&iy%5B7%5D=&im%5B7%5D=&id%5B7%5D=&iy%5B8%5D=&im%5B8%5D=&id%5B8%5D=&iy%5B9%5D=&im%5B9%5D=&id%5B9%5D=&iy%5B10%5D=&im%5B10%5D=&id%5B10%5D=&iy%5B11%5D=&im%5B11%5D=&id%5B11%5D=&iy%5B12%5D=&im%5B12%5D=&id%5B12%5D=&iy%5B13%5D=&im%5B13%5D=&id%5B13%5D=&iy%5B14%5D=&im%5B14%5D=&id%5B14%5D=&iy%5B15%5D=&im%5B15%5D=&id%5B15%5D=&iy%5B16%5D=&im%5B16%5D=&id%5B16%5D=&iy%5B17%5D=&im%5B17%5D=&id%5B17%5D=&iy%5B18%5D=&im%5B18%5D=&id%5B18%5D=&iy%5B19%5D=&im%5B19%5D=&id%5B19%5D=&iy%5B20%5D=&im%5B20%5D=&id%5B20%5D=&monr1=1&dayr1=1&monr2=1&dayr2=1&iyr%5B1%5D=&filenamein=&plotlabel=&lag=0&labelc=Color&labels=Shaded&type=2&scale=&label=0&cint=&lowr=&highr=&istate=0&proj=ALL&xlat1=&xlat2=&xlon1=&xlon2=&custproj=Cylindrical+Equidistant&level1=1000mb&level2=10mb&Submit=Create+Plot

 

 

It's not clear for 1997 however - http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/comp.day.pl?var=Air+Temperature&level=10mb&iy%5B1%5D=1997&im%5B1%5D=10&id%5B1%5D=20&iy%5B2%5D=&im%5B2%5D=&id%5B2%5D=&iy%5B3%5D=&im%5B3%5D=&id%5B3%5D=&iy%5B4%5D=&im%5B4%5D=&id%5B4%5D=&iy%5B5%5D=&im%5B5%5D=&id%5B5%5D=&iy%5B6%5D=&im%5B6%5D=&id%5B6%5D=&iy%5B7%5D=&im%5B7%5D=&id%5B7%5D=&iy%5B8%5D=&im%5B8%5D=&id%5B8%5D=&iy%5B9%5D=&im%5B9%5D=&id%5B9%5D=&iy%5B10%5D=&im%5B10%5D=&id%5B10%5D=&iy%5B11%5D=&im%5B11%5D=&id%5B11%5D=&iy%5B12%5D=&im%5B12%5D=&id%5B12%5D=&iy%5B13%5D=&im%5B13%5D=&id%5B13%5D=&iy%5B14%5D=&im%5B14%5D=&id%5B14%5D=&iy%5B15%5D=&im%5B15%5D=&id%5B15%5D=&iy%5B16%5D=&im%5B16%5D=&id%5B16%5D=&iy%5B17%5D=&im%5B17%5D=&id%5B17%5D=&iy%5B18%5D=&im%5B18%5D=&id%5B18%5D=&iy%5B19%5D=&im%5B19%5D=&id%5B19%5D=&iy%5B20%5D=&im%5B20%5D=&id%5B20%5D=&monr1=1&dayr1=1&monr2=1&dayr2=1&iyr%5B1%5D=&filenamein=&plotlabel=&lag=0&labelc=Color&labels=Shaded&type=2&scale=&label=0&cint=&lowr=&highr=&istate=0&proj=ALL&xlat1=&xlat2=&xlon1=&xlon2=&custproj=Cylindrical+Equidistant&level1=1000mb&level2=10mb&Submit=Create+Plot

 

Edited October 6, 2015 by Interitus

[Recretos]

Not sure when the definition of the tropics and subtropics changed for the strat, but if there is a seperate official definition, I would love to hear it and use it.

Otherwise I will continue to use the natures own main frame definition of the main strat tropics, via the QBO variability. And by that definition, both 97 and 02 have tropics normal, to colder than normal in 02 on your charts. But certainly not warmer than normal.

[Tamara]

The links that Chiono provided the other day are a very interesting read and a very suitable curtain raiser to the strat/trop pathway questions and answers sessions that are relevent to the factors likely to influence the outcome of the 15/16 winter

Additionally, the post that Lorenzo made recently in the Winter thread which also gave an insight into the external forcing conundrums influencing the Polar Stratospheric pathway this coming winter was equally appropriate and very helpful. The combination on offer last winter, as correctly summarised there, did not add up to the type of vortex destruction envisaged previously at the start of winter by quite a few.

There are also lessons that can be brought forward from last winter in respect of the tropospheric pathway. It is important first and foremost to assess whether the global atmospheric circulation is jiving with the Ocean signal. Connect, or disconnect ,can make quite a difference in outcomes - and last winter it certainly did.

I spent a lot of time on the Model thread after Christmas last winter speaking about the disconnect between the weak El Nino ocean signal, and the atmopsheric circulation which was behaving much closer to a Nina-esque state with a low-ish relative atmosphere and angular momentum state.

This disconnect prevented the extra potential available to perturb the stratopsheric polar vortex this side of the globe and amplify futher the patterns in the Atlantic sector - with a persistent tropical wave train over Indonesia and into the West Pacific. The associated very high SST's in that part of the globe were an overriding factor to the atmospheric circulation pattern engaging and imprinting the developing and warming Nino SST signature in the Central and Eastern Pacific. A good clue was the resistance of the MJO tropical signal to engage Phase 7 - retreat occured through the first two thirds of the winter back to the Indian Ocean which kept AAM supressed and locked the Global Wind Oscillation into a 1,2,3 orbit.

The default pattern of last winter was quite classically Nina-esque with the North East Pacific ridge, SE US ridge, and locked in Canadian/Greenland vortex. There was plenty of Rossby wave activity, but this was mainly centred over the Pacific courtesy of the strong ridge there. As a consequence, the polar vortex was, mostly, being pinched the other side of the pole.

The easterly trades and tropical activity pattern assisted a pattern of pushing the sub tropical ridges northwards and eastwards and hence we saw a strong Azores High and a developed +NAO signature. The failure of the external stratospheric pathway factors further failed to provide required vortex forcing this side of the pole to help what had been a good start to -AO feedbacks over Eurasia last autumn, and the only 'cold shots' available were courtesy of retrogression on the Azores High - when the EPO ridge temporarily retracted.

A lot of re-cap I know, but I think spelling it out synoptically helps to visualise how unfavourable the tropospheric pathway was because it was disconnected, and the factors attributable to making it unfavourable, in addition to the external stratospheric forcings which failed. More lessons learned.

The summer finally brought that atmosphere/ocean coupling and it arrived in spectacular style! There was a record amplitude Phase 7 MJO spike as WWB spread the high SST's in the western Pacific eastwards, finally engaging the atmospheric circulation with AAM laddering up through Phases 4/5 with associated large positive frictional torque and East Asian Mountain torque. A sustained high AAM state has persisted since, as illustrated very clearly in the recent posts - and this bodes well at this stage for a different NH pattern to be starting the short season this year with the tropospheric ENSO pathway being on our side this time.

A continuance of 'constructive interference' in terms of both extratropical (GWO induced) and tropical (MJO induced) forcing through the rest of the autumn and into the winter is important to sustain the Nino circulation and keep AAM solidly high and poleward. Based on ENSO forecasts alone - there is expected to be little change this side of the year.

Changes in poleward flux of AAM are determined by the evolution of momentum flux as a result of transient Rossby waves in the upper and lower stratosphere. Agitation of the trop/strat boundary, as we know, are mechanisms for initiating High Latitude blocking where the polar vortex is highly disturbed at the trop/strat boundary. In this respect, as we saw prior to the SSW in Jan 2010, and later that year in late November and December at the start of the following winter, that a sustained warm and unstable profile at the trop/strat boundary can be enough to create HLB and provide a cold pattern for UK and Europe

With the obvious caveat disclaimer of knowing that the QBO phase is westerly this season and favours at face value a strong(er) vortex, it is conceivable that any SSW that might occur despite this and an uncertain solar situation, and on top of any trop induced interference, might alter the nature of any favourable -AO tropospheric feedback reaction that does manage to become in place - by re-arranging the surface pattern further and eliciting unwanted sibling vortices splinters in the 'wrong' place. Worrying about insufficient forcing is one thing, it is also possible to have too much. Externally there was too much going on last winter.

 

If it aint broke, don't fix it comes to mind.

On an intraseasonal timescale, it is global mountain torque that is the primary generator of AAM. The EAMT of the early summer is a good example of this, as mentioned above, and was part of the game changer in terms of atmosphere circulation changes and consequent tropospheric pattern change we have seen since.

Global frictional torques have a decorrelation time of approx 6 days and are linked to the teleconnective pattern. Within a +AAM framework, in knowing that Nino teleconnects to a classic +PNA pattern we can start to build in the lag times for these torque events and also MT events in terms of anticipating NWP model direction of travel as well as monitoring the stratosphere for consequent lagged effects and changes of temperatures which can create the desired instability, change of shape, re-location and movement of the polar vortex.

Conjecture perhaps, but it is possible that a third spike in solar activity max may occur before the final uninterrupted descent into the next minimum. If this was to occur in symmetry with leading into winter itself, this may prove helpful in terms of mitigating the assistive properties of the +QBO on the seasonal winter time stratospheric vortex. As speculative as it is, an illustration maybe of where opposites attract in the way that too many external cooks last winter spoiled the broth.

Another polar summer is completed and and another low sea ice state observed. The ever more amplified tropospheric patterns we are seeing in association with reduced sea ice concentrations are obviously a greater and greater source for stratospheric polar vortex attack. With the next mimimum a couple of years or so ahead this could prove especially 'beneficial' for cold winter patterns then. This year, at face value with what we know the present situation to be, the solar cycle state is less favourable, and time will tell whether it helps to combine with or detract from the westerly stratospheric gyre. Much as L and C have indicated already.

In this sense, the better organised, robust and sustained the tropospheric Nino pathway and associated coupled high AAM state is the better in terms of setting up a feedback cycle condusive to starting the winter with a NH synoptic pattern in a way that GP hints at, and also one that is robust enough not to then be derailed by the gathering strength of the upcomind seasonal stratospheric vortex. Its precise strength yet to be determined but watched over the coming weeks.

 

P.S @ Recretos: Its great to have your technical skills competing with the super computers once again!

Edited October 6, 2015 by Tamara

[Singularity]

A staggeringly informative post from Tamara... I was in the background last winter and followed the strat. developments every step of the way. I even began to grasp what AAM is and how mountain torque events drive large changes (and frictional torque events smaller ones).

 

 

Reading about the positive QBO, Snowy L's post on the previous page of this thread highlighted the possibility that the westerly QBO could actually correlate with a slightly weaker vortex when occuring within an El Nino configuration. So I wonder how that might interact with solar activity?

 

I do see the low Arctic sea ice as a significant factor this winter, as the high-latitude temps and moisture levels (hence latent heat amounts) are so very much higher than during the strong El Nino events of past. Curiously, I had a glance at years with similar sea ice minimums to this year and they tend to feature a prominent high latitude blocking signal in January, following not much of a signal in December and with February a sort of vague high/mid-lat blocking merger.

 

Here's the January pattern. Not a lot of years behind it of course but interesting nonetheless.

 

Edited October 7, 2015 by Singularity

[chionomaniac]

Tamara, a short one for me but I agree with a lot that you say! I am in winter research mode trying to gather as much info as possible at this time. Here is a paper that I came across last night and mentioned on twitter - it helps with the suggested winter wave pattern ( predominately an increased stationary wave 1 expected over NP/ America this winter) I only have the abstract to link to but you should find it useful.

 

http://link.springer.com/article/10.1007%2Fs00382-015-2797-5

[Singularity]

Here's a question for the big-brains on here;

 

Ex-hurricane Oho is currently on its way to Alaska as what will soon be a powerful ex-tropical system. Next week, another system has the potential to track right up to the high-latitudes as well (again, ex-tropical by that time). Such behaviour was seen last year but before then only once since 1949 (according to Jeff Masters via http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=3150).

 

So my question is, what sort of impacts could this have in the troposphere and, more importantly wrt to this thread, could there be effects on the stratosphere as well? Would I be right in thinking that strat. impacts depend largely on whether the relatively warm air associated with the system encounters high land or some other forcing to lift it upward?

 

Many thanks in advance for your response, I look forward to reading what you have to say 

[mpkio2]

You know you should be getting excited when all of the more knowledgable posters (like Recretos, chino, GP, Tamara, lorenzo, Interitus,) start coming out of thier Summer hibernation really start discussing some informative and well-informed information regarding the Strat and the implications that mmay bode well for our upcoming Winter!

 

Just wated to say thank you to all for the awesome amout of work all you guys put into this forum and all of the invaluable and well-informed informatiion you all post here and share with the community. It means a lot to all of us and we have all learnt so much!

 

Thank you!

 

Lets hope the strat comes well under pressure from Wave 2 annd hopefully an SSW!

[BLAST FROM THE PAST]

Excitement must always be there....but temper expectations

 

BFTP

[sebastiaan1973]

According to the EUROSIP from september a Central Based El Nino will be established this winter. I think Chio you should take this in account

 

Latest EC seasonal

The new ECMWF forecast is basically a Nov to Jan blowtorch type pattern for northern US and Europe. Feb is typical but nothing special From https://twitter.com/antmasiello

Edited October 9, 2015 by sebastiaan1973

[mountain shadow]

According to the EUROSIP from september a Central Based El Nino will be established this winter.

 

Is that Modukoo? Meant to bring colder Winters to NW Europe.

[Cheshire Freeze]

Way out in FI but signs of early attacks on the vortex?

 

[Cheshire Freeze]

According to the EUROSIP from september a Central Based El Nino will be established this winter. I think Chio you should take this in account

 

Latest EC seasonal

The new ECMWF forecast is basically a Nov to Jan blowtorch type pattern for northern US and Europe. Feb is typical but nothing special From https://twitter.com/antmasiello

 

I think it's a given (as much as it possibly can be with weather) that the northern USA will have a warm winter. However, I think the European pattern is less clear cut. It's entirely possible that the European mainland (esp southern and central) has a very mild winter whilst N&NW Europe goes cold. It's hard to say anything without actually seeing the model output.

 

I know the Glosea had a co-existing N Atlantic high and a Med high.....pretty much a slim corridor of NW colder than average.....

 

The more I see/read, the more I'm comfortable with Simon Keeling's idea of a NW/SE split but with the jet slightly further S. Frequent LP incursions with snow on the NW flank of the depressions and the coldest weather found generally to the NW of the UK. As ever time will tell.

Edited October 9, 2015 by CreweCold

[MR EXTREMES]

intresting that the met office are going for a cooler winter.

but plenty of post popping up regarding the enso state being record breaking for many years will this reduce the odds on a warming event ?.

 

are ssw events rare during el nino events ?

 

and could the plumet in solar activity help aid strat warming.

 

and would early wave events help in a less intense vortex and help aid a warming event.

Edited October 9, 2015 by emotional rollercoaster

[Cheshire Freeze]

intresting that the met office are going for a cooler winter.

but plenty of post popping up regarding the enso state being record breaking for many years will this reduce the odds on a warming event ?.

 

are ssw events rare during el nino events ?

 

and could the plumet in solar activity help aid strat warming.

 

and would early wave events help in a less intense vortex and help aid a warming event.

 

We just don't know. Though one thing is for sure, the GFS strat forecasts at present take us into different waters than we've been in over the last few years. The last few years have generally plunged us into average or below average strat temps during November and sure enough we've seen some pretty rampant vortex configurations. I think it was GP that said earlier on in the week that this year looks different stratospherically already...

[Weather-history]

Isn't time for a fresh thread?

The title of the thread at least needs changing to the next season, if not.

Edited October 9, 2015 by Weather-history

[sebastiaan1973]

Please notice the difference between CB El Nino and Eastern Based El Nino.

 

The famous El Nino's of 1982/3 and 1997/1998 were east based El Nino's while 2009/10 was east based El Nino.

 

Seems to me that El Nino is becoming more Central Based in the coming weeks. We have to wait and see, what happens.

[summer blizzard]

Please notice the difference between CB El Nino and Eastern Based El Nino.

 

The famous El Nino's of 1982/3 and 1997/1998 were east based El Nino's while 2009/10 was east based El Nino.

 

Seems to me that El Nino is becoming more Central Based in the coming weeks. We have to wait and see, what happens.

It's possible that the core of the heat will move to region 3.4 from 1.2 however its a near 100% certainty that 1.2 will stay sufficiently warm that its a basin wide rather than west based event.