Hi all, can someone direct me to a website that explains what things like:
Outliers
Slack air
Sliders
And other such descriptions/nuances mean??
Thanks in advance!
VSC

Originally Posted by: VIRTUAL STORMCHASER 

The mythical SSW is a consistent feature of GFS, moving closer to the reliable and the strongest of the winter. It's also, setting aside the usual nuances and caveats of weather prediction, positioned nicely to weaken or reverse the zonal flow right over Western Europe.

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=312&mode=10&carte=1

If it verifies. Let's see what the 6Z brings.

So the fat lady should put away her song sheet for now - February has often been our coldest winter month...

Originally Posted by: johnm1976 

hmm, I doubt there is any website that provide answer for Slang terms, but ill give it a go.  Ive Bolded terms which you will find info on the internet.

Outliers

on the ensembles ther tends to be trends to follow, milder or colder, or even stable.  Usually an outlier is unique ensemble that trends very differently to the rest of the ensemble members.

Slack air

My best interpretation of this - would be slack areas of Low pressure- or even High pressure.  Systems either between two larger systems that have all the energy within them... or simply a decaying area of pressure.  Typical weather you would expect is decaying or less severe weather phenomena.  ie Less wind, less intense rainfall, perhaps less intense temperature gradients.

Sliders

When we refer to Slider Lows we usually mean Low pressure which split from the usual course from mid atlantic up to iceland, and rather diverge from the mother low and reconnect with Low pressures usually over the med.  Usually asscociated with Scandinavian based High pressure systems. 

http://rgsweather.com/tag/slider-low/

This gives  diagramatic detail.

These can produce alot of snowfall to the UK (if you remain on the cold side)

Last winter was dominated by such features, with weather systems running up to cold air over the uk stalling then falling south over to France leaving the uk in the colder air, a pretty much perfect weather scenario for widespread snow to the uk.

If you have the time, suggest you have a look at the GFS archives to see them develop and move.

Originally Posted by: VIRTUAL STORMCHASER 

I don't really understand how the strat temps affect the zonal flow, but that chart shows the coldest strat vortex over Greenland and the warmest over Siberia. Is that really a good place for us? I would have thought we would want warming over Greenland?

Originally Posted by: johnm1976 

As in 'bullish in a china shop'?

I'm calling January now and consigning it to the scrap heap.
February, it's over to you.

Originally Posted by: Karl Guille 

THe pattern looks quite well set now. A brief flirt with an easterly around the 20/21st, then another push from the atlantic.

Our next window of opportunity is around the 25th or 26th. Perhaps this strat warming may help us to establish a ridge to greenland.

http://modeles.meteociel.fr/modeles/gfs/runs/2014011506/gfs-0-276.png?6

Originally Posted by: The Beast from the East 

Agrre with your analysis aoart from SSW.Surely HP building over Greenland is not neccessarily down to SSW?I thought SSW took time ie weeks to work through the atmosphere.Last year however I remember Jon Hammond claiming the cold spell which started on  Jan 20th was down to SSW wghuch I think kicked off in late December.

Originally Posted by: roger63 

THe pattern looks quite well set now. A brief flirt with an easterly around the 20/21st, then another push from the atlantic.

Our next window of opportunity is around the 25th or 26th. Perhaps this strat warming may help us to establish a ridge to greenland.

http://modeles.meteociel.fr/modeles/gfs/runs/2014011506/gfs-0-276.png?6

Originally Posted by: The Beast from the East 

I don't really understand how the strat temps affect the zonal flow, but that chart shows the coldest strat vortex over Greenland and the warmest over Siberia. Is that really a good place for us? I would have thought we would want warming over Greenland?

Originally Posted by: johnm1976 

Agrre with your analysis aoart from SSW.Surely HP building over Greenland is not neccessarily down to SSW?I thought SSW took time ie weeks to work through the atmosphere.Last year however I remember Jon Hammond claiming the cold spell which started on  Jan 20th was down to SSW wghuch I think kicked off in late December.

Originally Posted by: The Beast from the East 

Do we know that an area of HP sits over the area where the warming took place?

Originally Posted by: johnm1976 

4-6 weeks as I understand it

Originally Posted by: The Beast from the East 

4-6 weeks as I understand it

Originally Posted by: The Beast from the East 

Chasing phantom easterlies - we just have to accept that this winter has bucked the recent trend of cold ones

I doubt I will be eating humble pie - we might see a bit of cold weather in Feb but as for lying snow for 2 or 3 days on the ground - forget it

Originally Posted by: sriram 

hmm, I doubt there is any website that provide answer for Slang terms, but ill give it a go.  Ive Bolded terms which you will find info on the internet.

Outliers

on the ensembles ther tends to be trends to follow, milder or colder, or even stable.  Usually an outlier is unique ensemble that trends very differently to the rest of the ensemble members.

Slack air

My best interpretation of this - would be slack areas of Low pressure- or even High pressure.  Systems either between two larger systems that have all the energy within them... or simply a decaying area of pressure.  Typical weather you would expect is decaying or less severe weather phenomena.  ie Less wind, less intense rainfall, perhaps less intense temperature gradients.

Sliders

When we refer to Slider Lows we usually mean Low pressure which split from the usual course from mid atlantic up to iceland, and rather diverge from the mother low and reconnect with Low pressures usually over the med.  Usually asscociated with Scandinavian based High pressure systems. 

http://rgsweather.com/tag/slider-low/

This gives  diagramatic detail.

These can produce alot of snowfall to the UK (if you remain on the cold side)

Last winter was dominated by such features, with weather systems running up to cold air over the uk stalling then falling south over to France leaving the uk in the colder air, a pretty much perfect weather scenario for widespread snow to the uk.

If you have the time, suggest you have a look at the GFS archives to see them develop and move.

Originally Posted by: VIRTUAL STORMCHASER 

I don't really understand how the strat temps affect the zonal flow, but that chart shows the coldest strat vortex over Greenland and the warmest over Siberia. Is that really a good place for us? I would have thought we would want warming over Greenland?

Originally Posted by: johnm1976 

If you want warming in the troposphere over Greenland, and consequent high pressure, then I'd reason that you want the stratosphere, which is the layer above the troposphere, to be cold. I'd be surprised if they could both be warm.

On the other hand, I find the jargon of SSWs so baffling that I'm not even enough of an expert to start off SSW posts with "Not An Expert, But ..."

Originally Posted by: johnm1976 

might be worth getting the SSW from last year and its placement to compare the two.

Originally Posted by: johnm1976 

There you go:

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=1&mois=1&annee=2013&heure=6&archive=1&mode=10&ech=6&carte=1

Not massively disimilar from what is appearing at the end of FI right now.

Although some of the GFS runs from t minus 384 would have had us sitting under a completely split stratospheric vortex today (which didn't happen), for example the 6z runof January 1 2014

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=384&mode=10&heure=6&jour=1&mois=1&annee=2014&archive=1&carte=1

so it is important to remember this is still FI so may not verify or any warming pattern may look substantially differnt if it occurs.

Others with access to the strat modelling on ECM and with access to the ensembles state that a warming pattern is backed there also, however, so it does look like some kind of stratospheric warming is likely.

It is also not a simple case that warming leads to blocking or zonal wind reversal directly under the inversion. If warming is strong enough it causes the jet stream to weaken and become unstable, which is conducive to blocked weather patterns in the trop, or for the jet to swoop south allowing an incursion of air from the vortex. There's still alot of research going on to detemine where those incursions are likliest in relation to warming. It would not surprise me if one of the regular posters - Quantum or Nouska for example - knows a lot more about this than me and might be able to follow up with some better thoughts.

What we can say (and to bring this back OT) is that while warming is evident in model output winter most definitely isn't over!!

Originally Posted by: johnm1976