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2 minutes ago, WINTRY WALES said:

Fantastic Recretos! So being an absaloute newb...I’m guessing the British Isles in the blue/purple shades is a good thing, at this moment time, for long term forecasted cold for the upcoming winter??

No, the exact opposite I think, given this is a mean (average) chart you'd want as warm temperatures as possible here to signal possibility of cold in the UK with some kind of lag, indicative of a SSW in many runs of the ensemble, if I've read the charts right. The last thing you want is deep purples.

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Some useful tropospheric developments upcoming which are likely to have stratospheric impacts towards the end of November and more particularly into December. A strong convectively coupled tropic

so after many days the GFS & FNMOC & canadian finally now follow the Euro with 44 out 64 Members with a split at day 9- The ECM is day 8. We will call it - SSW & Split for 1st Ja

For all that watch the zonal winds. Let me urge you to look at the geopotential heights more. At least as far as weakening/strengthening trends go. Because as the polar vortex cries for help, you migh

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5 minutes ago, Mike Poole said:

No, the exact opposite I think, given this is a mean (average) chart you'd want as warm temperatures as possible here to signal possibility of cold in the UK with some kind of lag, indicative of a SSW in many runs of the ensemble, if I've read the charts right. The last thing you want is deep purples.

Correct the last thing you want is deep purples, however, this is a monthly mean and the average of Jan in the coldest spot is no lower than -70c, i think that's no worse than average and probably better.

Edited by feb1991blizzard
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7 minutes ago, feb1991blizzard said:

Correct the last thing you want is deep purples, however, this is a monthly mean and the average of Jan in the coldest spot is no lower than -70c, i think that's no worse than average and probably better.

Yes it's a monthly mean but also the mean of 50 runs?  I think we'd need to know actually what is averaged here, it seems to me quite possible that intense cold vortex runs that are in different spatial locations could dilute the peak mean temperature, need to know this before we can interpret what the lowest contours actually mean?

Edited by Mike Poole
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1 minute ago, Mike Poole said:

Yes it's a monthly mean but also the mean of 50 runs?  I think we'd need to know actually what is averaged here, it seems to me quite possible that intense cold vortex runs that are in different spatial locations could dilute the peak mean temperature, need to know this before we can interpret what the lowest contours actually mean?

Yes, i think you wont really deduce much until the timeframe is nearer, i would like to see December charts, personally i don't think we will see a midwinter SSW this year at all but that's just my opinion and too early for sure.

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10 minutes ago, feb1991blizzard said:

Yes, i think you wont really deduce much until the timeframe is nearer, i would like to see December charts, personally i don't think we will see a midwinter SSW this year at all but that's just my opinion and too early for sure.

No, I don't either, mostly down to the increasing strength of the westerly QBO as winter progresses.  Does look to me though at this early stage that the strat and trop vortexes are almost totally disconnected.  Both are reasons why I favour a front loaded winter, a key IMBY question is will the cold be there for the south to tap in to, after the heat of summer?  We'll see.

Edited by Mike Poole
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At 10hpa you wouldn't expect to see much else. Note the 10hpa strat charts in Feb 2018 when we were experiencing our mighty warming and eventual split lower down

archivesnh-2018-2-21-0-4.thumb.png.5e02a3acce5460f810d5bfbc91d4751b.png

The key to the charts Recretos has posted is that we have an ensemble mean signal for a warming over Asia. That is good news if strat disruption is what you want.

Edited by Catacol
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11 minutes ago, Catacol said:

At 10hpa you wouldn't expect to see much else. Note the 10hpa strat charts in Feb 2018 when we were experiencing our mighty warming and eventual split lower down

archivesnh-2018-2-21-0-4.thumb.png.5e02a3acce5460f810d5bfbc91d4751b.png

The key to the charts Recretos has posted is that we have an ensemble mean signal for a warming over Asia. That is good news if strat disruption is what you want.

Not necessarily, look what happened well prior to the blocking lower down in 2009.

archivesnh-2009-1-23-0-4.png

Yes i agree the forecasts posted by recretos are a monthly average and cannot be read into too much but to say you would expect tp see the chart you posted in relation to a split SSW rather than the one i posted isn't necessarily true, it depends on the mechanisms of the split.

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The best news from today is seeing @Recretos back here! 

Per those seasonal 10 hpa mean profiles, I would take the following on board ..... jan and feb are unlikely to be very blocked over n Europe.  The strat vortex seems likely to be around Svalbard/n Scandinavia through jan, slowly retrograding into feb.the chances of a North Pacific ridge west of kamkatchka seem pretty strong.  how big could the strat/trop diconnect be during jan and feb ?  And yet we have seen that the 500hpa charts show high height anomalies to our north where the ec and glosea place the core of  the strat vortex .

ive seen enough today to make me think jan and feb could be anything ....... I’m expecting a pretty blocked December so the idea of a very mobile second half jan and feb seems a reasonable statistical call for the time being. 

Edited by bluearmy
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Thanks guys for the feedback. :)

Yes, these are monthly means and heavily diluted, and also considering its a 50-member weighted average. As far as the vortex core goes, its spatial area is much larger than any area of the potential warming onset from the Asian sector, so the dilution effect is greater on the warming part then on the cold core of the polar vortex. Not to mention that in some individual ens-member cases there likely isn't even any Asian warming occurring, so that is a heavy dilution effect, unlike the polar vortex core which is always present, just spatially shifted by a few 100-1000 kilometres. Now I am not saying that the warming signal on the ENS-mean maps is a given, but we have to consider entire model circumstances when interpreting such ensemble charts. 

That is why anomalies were invented. Yes I have those too. :)  They are from models' own hindcast climatology. It gives a bit better impression what is the actual abnormality in the forecast.

for example from the Glosea5:

ukmogphanom201901.jpg  ukmogphanom201902.jpg   ukmogphanom201903.jpg

ukmotmpanom201901.jpg   ukmotmpanom201902.jpg   ukmotmpanom201903.jpg

And some ECMWF

ecmgphanom201901.jpg  ecmtmpanom201901.jpg

ecmgphanom201902.jpg   ecmtmpanom201902.jpg

 

Edited by Recretos
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I noticed talks of QBO, and decided to look at it via GFS, and it is in the positive values already, so October mean might end up near or at positive values. I made one HD graphic of QBO progress at 10mb and 30mb from GFS data. 

qbo.png

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Todays a record breaker in the strat -

10Mb zonal wind @25.8M/S is a record for the most positive zonal wind in interim ERA data for this date..

 

Lucky it hasnt downwelled!!

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47 minutes ago, Steve Murr said:

Todays a record breaker in the strat -

10Mb zonal wind @25.8M/S is a record for the most positive zonal wind in interim ERA data for this date..

 

Lucky it hasnt downwelled!!

Indeed Steve. Thank heavens for the current strat/trip disconnect.

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52 minutes ago, Steve Murr said:

Todays a record breaker in the strat -

10Mb zonal wind @25.8M/S is a record for the most positive zonal wind in interim ERA data for this date..

 

Lucky it hasnt downwelled!!

I dont understand though steve!!what has made it disconnect to this extent!!with a positive zonal wind to that extent anyone would think the atlantic would be in full control!!

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1 minute ago, shaky said:

I dont understand though steve!!what has made it disconnect to this extent!!with a positive zonal wind to that extent anyone would think the atlantic would be in full control!!

It can take longer into the season to affect the trop, we still might end up zonal later on as a result of this but hopefully not and the seasonal models / LRF's suggest we might be ok with blocking establishing.

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6 hours ago, Recretos said:

As promised, I finally managed to complete the website with ECMWF seasonal forecasts, including the stratosphere. I will add Glosea5 around its November update, so it will be fresh when it goes live.

http://www.severe-weather.eu/ecmwf/

Assuming I am reading those correctly they seem to show the opposite of what many here have suggested will be a front loaded Winter with Nov and Dec looking zonal and Jan and Feb with mid, high lat blocking to the E?

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As far as the stratosphete goes, the Atlantic has not gone wild because there is nothing wild in the strat to begin with. 25m/s is a good start, but in mid winter that speed would be considered a weak/very weak vortex. The vortex core 10mb pressure height dropped below 3000dm just a few days ago, so its not yet that wild beast that we all know and love. :) Or hate, for that matter. :)

In the near future the trop. Atlantic wave will help to push the core around a bit, keeping a lot of the vortex' core energy away from the Atlantic sector, pushing it more into the Siberian region.

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1 minute ago, Recretos said:

As far as the stratosphete goes, the Atlantic has not gone wild because there is nothing wild in the strat to begin with. 25m/s is a good start, but in mid winter that speed would be considered a weak/very weak vortex. The vortex core 10mb pressure height dropped below 3000dm just a few days ago, so its not yet that wild beast that we all know and love. :) Or hate, for that matter. :)

In the near future the trop. Atlantic wave will help to push the core around a bit, keeping a lot of the vortex' core energy away from the Atlantic sector, pushing it more into the Siberian region.

Thankyou for sharing your vast knowledge with us Andrew(same name as me but i'm Andrzej polish version :-)), i'm interested in your final comment, this would be suggestive of an early season cool down across much of central / East Europe into November perhaps.

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6 hours ago, Interitus said:

People are getting too hung up again on the 10hPa zonal wind at this early stage - only a month ago it was looking weak and now it's strong.

The 12z GFS shows how quickly things could change from above average to below throughout the depth of the atmosphere -

819284165_umedel6018101812.thumb.png.56fbbadca57fdf4649187e8639e1f808.png

Looking longer term strongest wind for October 20th in the MERRA2 dataset was 20/10/1981 - this was followed by the very early SSW on December 4th (and the bitter weather that ensued). And it just so happens, 20/10/1981 is the closest 30-day analogue to 18/10/2018 for 10hPa zonal wind -

2018-1981.thumb.png.f34f72ff7f1c878ca5f0adb1f67637e9.png

A couple of days later, the strongest zonal wind for 22nd October was 1998 and is the 3rd closest analogue to 18/10/18 - this year also had an early SSW on 15th December. Not necessarily a prediction for this year but an indication of what can happen.

 

Relevant points ...... I am always happy to see big swings in data within short timeframes ....... big houses need to be built on firm foundations .....

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Welcome back Recretos. The mean charts show a fairly normal picture for the early winter, the "warming signal" over Asia is what would be expected with typical wave 1 forcing of the stratospheric Aleutian high. If anything the ECMWF anomalies show that this could be quite strong which could of course cause a displacement SSW but on the other hand may lead to a strong vortex parked over the Baffin/south Greenland area. The MetO goes for a weak vortex late winter/early spring.

Anyway, it's surprising that more people don't try and view these charts themselves, it is not as difficult as Recretos' impressive DIY approach. There are many GRIB file viewers available which will work with these seasonal forecasts (or other data eg GFS forecasts, reanalysis etc).

A simple one to try is Panoply from NOAA GISS - https://www.giss.nasa.gov/tools/panoply/

The Copernicus site requires a simple registration - https://cds.climate.copernicus.eu/cdsapp#!/home

Once set up, it only takes a couple of minutes to download and produce the chosen charts. So here is the ECMWF Jan anomaly from Recretos above -

On 17/10/2018 at 06:59, Recretos said:

 

ecmgphanom201901.jpg  

 

And here it is rendered by Panoply - default settings, plus added contours -

1010817313_Geopotential_anomaly_isobaricinjan20anom.thumb.png.e892ed05550370ec09d139a719c22489.png

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Yes, the monthly mean of 50-members at a 3-5 month lead time is diluted enough to show near climatological pattern to the untrained eye. Anomalies are needed to reveal actual forecasted deviation, which must be calculated from the model hindcast climatology.

Panoply is a great tool. It needs some getting used to, but its a great begginners tool. I use it on a daily basis for all kinds of plots. It takes some basic trial-and-error, to learn how to optimize the graphics and to create strat-specific plots. Tho it is not for mass production of maps.

I use a whole different beast for that, which is slightly more technically demanding, but enables 3D/4D plotting. :)

Edited by Recretos
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