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Stratosphere Temperature Watch 2015/2016


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I presume going by what chino said regards the pv that the first month of this winter for starters will have a strong possibility of being a very zonal month?

 

Depends where the vortex decides to set up shop.

 

GFS forecasts it well away from the Greenland death zone at 10mb which perhaps leaves the door open for less zonal options?

 

10mb..post-2839-0-12471200-1446974116_thumb.gi  100mb..post-2839-0-11563000-1446974127_thumb.gi

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Reading this thread, and others, you get the impression winter is over until February at the earliest. That's that then, winter death knell sounded on November 8th? I'd like to think that there is more to this than meets the eye- and of course there is otherwise winter forecasting would be a piece of cake. IMO it's good that so many people are writing the first half/ two thirds of winter off as it keeps expectations low and provides a platform for surprises to pop up.

If you read through the archives the same thing happened around this time in 2009. It's like a inevitable knee jerk reaction to the mild November weather we are having now similar to 2009

It's quite reassuring, from a coldies perspective reading all the "winters over" posts and the bickering that went on in here around this time in 2009 due to the mild November. Little did they know that in a couple of weeks time they were about to experience one of the coldest winters in living memory

post-17869-0-62117000-1446977323_thumb.p

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If you read through the archives the same thing happened around this time in 2009. It's like a inevitable knee jerk reaction to the mild November weather we are having now similar to 2009

It's quite reassuring, from a coldies perspective reading all the "winters over" posts and the bickering that went on in here around this time in 2009 due to the mild November. Little did they know that in a couple of weeks time they were about to experience one of the coldest winters in living memory

attachicon.gifimage.png

Sorry guys but we seem to be drifting off topic....................

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correct me if im wrong but i thought that a strong el nino, plus a westerly QBO favours a stronger strat vortex however it also increases the chances of a SSW

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Depends where the vortex decides to set up shop.

 

GFS forecasts it well away from the Greenland death zone at 10mb which perhaps leaves the door open for less zonal options?

 

10mb..attachicon.gifNH_HGT_10mb_300.gif  100mb..attachicon.gifNH_HGT_100mb_300.gif

 

That's the thing with the El Nino this year. Other years, especially 2013/14 we had an Aleutian high pressure keeping the polar vortex stuck on our side of the North Pole in all levels of the stratosphere which meant a relentless low pressure conveyor belt in the North Atlantic.

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correct me if im wrong but i thought that a strong el nino, plus a westerly QBO favours a stronger strat vortex however it also increases the chances of a SSW

Ref an SSW, I thought solar cycle max / inclining phase of the cycle is also needed for this correlation. We're in the declining phase but perhaps in uncharted waters as in having the exact combo of a strong established El Niño, established W-QBO and declining solar output?

I do think the Strat and consequentially trop vortex is simply going to be too strong for any wave activity to seriously hinder its growth until into 2016 but as others have mentioned, it doesn't automatically mean it will sit slap bang over Greenland for the next 2 months. A vortex centred on the other side of the pole is probably our best realistic chance for some proper cold spells this side of Xmas, so here's hoping for a late December '81 repeat.

Edit: Actually meant December '78! (although 81 not too shabby either)

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gfsgwo_1.pngnpst30.png

 

Is this a -ve  Rockies Mountain Torque event that GFS/GEFS is playing around with?

 

It sure does remind me of the 'wrong kind of warming' that caused us trouble last year by displacing the vortex to Greenland. 

 

Whether there's a Rockies MT being explored or not, it seems we need to keep an eye on the AAM outlook to see if GEFS is overdoing the deviation from the El Nino background in response to the recent anomalous Walker Cell/MJO behaviour in the Indian Ocean (a possible bias). Recently the GEFS seems to have trended toward the MJO type signal spending longer in phase 3 before entering the COD rather than heading toward the Western Hemisphere with significant amplification. This has coincided with the increased amount of predicted strat. warming over the Pacific at the 30 hPa level starting around 12 days from now - hence my pondering over possible wave breaking from East Asia.

 

 

 Edit: I have been assured by Tamara that there is no MT event, rather -ve frictional torque driven by the Indian Ocean convection (interacting with wind patterns). The atmosphere shouldn't end up being fixed in a -ve AAM state by this. I am learning a lot on this forum  :hi:

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Just worth mentioning that we are pretty much seeing the strongest vortex start in the upper strat to a season that we have witnessed here on NW whilst monitoring the strat as can be seen here with the 10 hPa forecast and the 1hPa vortex strength for early November.

 

attachicon.gifScreen Shot 2015-11-06 at 17.23.52.png

 

 

attachicon.gifecmwf1a12.gif

 

 

Now I know that there it is early days and we there will still be a lag betwen upper strat and lower strat but it will be only a matter of time before this transfers down to the lower strat. It would take pretty strong wave activity to disrupt this later this month.

 

The tropospheric raised height anomalies that we are seeing over the east of America towards Greenland  at around day 10 will have to be quite pronounced to break through into Greenland and it is my suspicion that these will be 'squashed out' towards the Atlantic as the strong polar vortex wins the battle. Pm air will likely become entrenched in the flow giving a return to more average conditions temperature wise for a while.

 

Regarding the possible MJO wave - it appears also that this is a non starter, and those of you keeping up with twitter will see that the current MJO wave is in fact an anomaly - moreso of a flare up of walker cell activity in the IO area and is not being pulsed through as a wave of tropical convection. I am unsure of how this correlates to the wavelength patterns traditionally asociated with MJO phases, but it is unlikely to correlate well with these. This is likely to quell any thoughts that this winter may start off in the same vein as 2009, but it will still be worth watching the output stratospherically over the coming weeks.

 

Well as an interesting curiosity, from the MERRA data the closest 30-day 10mb 60°N wind analogues to the current time as calculated by minimum root mean square difference is.... November 2010....not much to say about that, though in strat terms no SSW that winter.

Close behind and soon ahead using forecast data is November 1990...again little needs to be said though again, no full SSW (reverse zonal wind blah) but a substantial minor warming which coupled well to give a typical SSW response.

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To put a bit more meat on the bones, for the 30-days to 9/11/15 the closest match is 19/11/10 - 2010 has been closest since Halloween which shows some potential in forecasting vortex strength.

In third place is 4/11/90, whilst in 4th is 9/11/02 - this winter did have an SSW on 18/1/03.

 

The second closest analogue also had a January SSW - 23/11/08 - and this 'surprise' on 24/1/09 came within days of the winds being at record strength -

 

post-2779-0-43310300-1447060787_thumb.pn

 

If  the forcing is there, any vortex can be brought down.

 

Just to reiterate, these analogues are calculated purely mathematically from the MERRA data without 'cherry-picking', this graph shows the similarity in 10mb windspeed over the past 30 days to today (day 0) and then the subsequent 70 day periods

 

post-2779-0-85450600-1447062185_thumb.jp

 

 

 

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The strengthening of upper level winds to extreme levels as a precursor to warming events was something I came across a few years back. Certainly will be worth keeping an eye on.

 

With the current pattern of little value to wave breaking, some further cooling likely, although the nagging forcing around the east Indian Ocean definitely worth an interest to see if we get some tropical convection in the Western Pacific in the week 2-3 timeframe. Compare forecast for week 2 and most pronounced tendencies in relative angular momentum and you'll understand why that might be of interest, perhaps more tropospherically...

 

post-2478-0-85352800-1447069747_thumb.jppost-2478-0-01645900-1447069758_thumb.jp

 

Southern hemisphere - no sign of the break down of the polar vortex, and we are now nearing summer, so this is extremely late. Strongly positive west QBOs feature this, so a vote for this being a player on our vortex for now.

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Good to see Cohen not discouraged by the unfortunate West QBO/very low solar flux combination. Thing is this is the only factor working against the possibility of an SSW this winter. Sea ice, SAI, El Nino/West QBO combination all in our favour.

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Impressive Siberian Highs showing up on both EC and GEFS extended range modelling right now, which has traceable origins to anomalous snow cover growth during October.

 

This has no direct relevance to the UK or European patterns for now, however, in terms of promoting a first order Wave 1 response in the stratosphere through North Pacific lows, some logical thought process here might suggest battle about to be joined with the cold upper vortex end of November into early December. The caveat is that wave 2 needs to be a player too, as without it the vortex will descend on Greenland (although what we've seen so far and El Nino forcing would trend otherwise).

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 as without it the vortex will descend on Greenland (although what we've seen so far and El Nino forcing would trend otherwise).

 

The lack of deep purples settling over Greenland has been notable. I believe the El Nino driven upper High over the NE States is providing a barrier to the PV settling there. Lets hope this continues.

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I was in contact with Ryan Maue from Weatherbell, discussing the ECM32, or make that ECM45. He accepted my suggestion of adding 10mb Gph+Temp fields to the ECM weeklies model page on Weatherbell, for the ens mean and control run. If it happens, it will be the best ENS support for strat yet. Of course for those subscribed to Weatherbell. It will probably be implemented sometime this month at Weatherbell, till December starts, along with the upgrade to 45 day forecast period, up from current 32 days.

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What are peoples' thoughts on this Asian warming? It is fairly weak and doesn't appear to be getting any stronger but it seems to be enough to disrupt the vortex at the top. Are we looking at a subtle pincer attack on the strat vortex taking place, from the top down and up from the troposphere?

With a lack of any strong wave activity, I wonder if a low level but importantly, sustained, warming would be sufficient to work its way down through the ever growing vortex or will it likely just hit a brick wall? I'm going for the latter as I suppose a bit of vortex disruption at the top is one thing, infiltrating this beast mid level with a W-QBO fuelling it, is likely to be altogether another thing.

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What are peoples' thoughts on this Asian warming? It is fairly weak and doesn't appear to be getting any stronger but it seems to be enough to disrupt the vortex at the top. Are we looking at a subtle pincer attack on the strat vortex taking place, from the top down and up from the troposphere?

With a lack of any strong wave activity, I wonder if a low level but importantly, sustained, warming would be sufficient to work its way down through the ever growing vortex or will it likely just hit a brick wall? I'm going for the latter as I suppose a bit of vortex disruption at the top is one thing, infiltrating this beast mid level with a W-QBO fuelling it, is likely to be altogether another thing.

I'm watching BDO, concentration and it does link geographically to area of the warming at 10 hPa.

post-21685-0-84661600-1447534537_thumb.j

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The stratospheric trough falling through the continent is quite the feature from current output, still we have a few other pieces of output that paint an altogether different picture.

 

 

The classic temp graph illustrates just how anomalously cold the vortex is, on ECM last night up at 10hPa I spotted a ridiculous -91.6

post-7292-0-32254500-1447538357_thumb.jp

 

This temp plot from the NASA suite points towards a relentless cold outlook / u-wind also...

post-7292-0-91346100-1447538507_thumb.pnpost-7292-0-69887900-1447539222_thumb.pn

 

The 475K PV chart ( core of strat) shows the impact of the extreme ECM run last night and WAA, always interesting when you see that shredded gravity wave type image at the edge of the vortex.

post-7292-0-54198500-1447538874_thumb.gipost-7292-0-40669700-1447538903_thumb.gi

 

This image loop is worth a look, plays around 47hPa and shows a vortex core unperturbed by this wave break.

http://acdb-ext.gsfc.nasa.gov/Data_services/arctic/anim_EPV_0600.html

 

Another image worth a look courtesy of Gavin Esler shows the impact of topographical forcing on the vortex.

 

Esler looks at elliptical axis of the vortex, looking at this image think positively tilted trough as we look at entire NH, the opposite of those sliders. The idea being that the vortex stretches across this meridian more than once prior to a split event. Shown here NB Southern Hemisphere.

 

Are we seeing elements now ? Perhaps.. something to search for.

post-7292-0-65268200-1447539705_thumb.pnpost-7292-0-73729700-1447538385_thumb.gi

 

Another aspect of Esler was the conclusion that no topographic forcing was required to achieve a vortex split and these could be a result of internal stratospheric events, this is 'resonant excitation'.

 

This I feel is where the anomalously cold element of the current stratosphere is relevant, whilst we are looking for the wave break, the cold solution may be one of the elements that tips the strat down a different path, intriguing when combined with the Siberian set up. Not going to make a prediction other than this classic VI period is off to a fascinating start.

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The strengthening of upper level winds to extreme levels as a precursor to warming events was something I came across a few years back. Certainly will be worth keeping an eye on.

 

In conjunction with Tony's post above, was this Stewart just thinking out aloud or is he pointing us in a specific direction?

My recollection of this strengthening was that we've seen it after significant wave activity was predicted/ongoing and seemed to be an odd response at the time. Unless Stewart is referring to occasions way back when before 2007/08.

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The gfs op at T372 has the vortex split up to 30 hpa!

Surely not possible for such a strong fella?

Yeah, T372 I know.

Certainly a squeeze on the vortex Blue,

Seems a good connect with the troph.vortex running through the GFS frames.

Seems to favour +ve Atlantic hts and nw-se jet troughing digging further east.

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Certainly a squeeze on the vortex Blue,

Seems a good connect with the troph.vortex running through the GFS frames.

Seems to favour +ve Atlantic hts and nw-se jet troughing digging further east.

Yes Phil, the concern being that it ties in with the trop too much for my liking. we know the trop output will not verify at that range.

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