Model Output Discussion 17th Dec.2013-12z onwards.

[SMU]

GFS backing west again over the states-

http://modeles.meteociel.fr/modeles/gfs/runs/2013123112/gfsnh-0-120.png?12

Awaiting for the low to develop @ 140

 

S

[shedhead]

Well if there is one straw to clutch for coldies it is that Winter - which didn't properly get going until the 21st January.

 

Today in 1946

 

 

Today

 

Never been a huge fan of pattern matching, but for the record Dec 46 was nowhere near as cyclonic as this month has been, indeed HP was often on the scene....as were E'erlies. 

 

[TSNWK]

At 120 I think the GFS is more amplified over the north western Atlantic, if my understanding is correct then that's better for later in the run.

Edited December 31, 2013 by TSNWK

[Gaz1985]

Never been a huge fan of pattern matching, but for the record Dec 46 was nowhere near as cyclonic as this month has been, indeed HP was often on the scene....as were E'erlies. 

 

 

Actually Shed that chart does not show an easterly, it shows a northerly across some parts of the UK, Ireland a more SW tilt to the wind. But the following days the wind becomes more a NE, still it wasn't a lengthy cold spell until late January

 

Edited December 31, 2013 by Gaz1985

[Captain Shortwave]

The Pacific and Scandi ridges look like meeting over Svalbard, probably means the trough will stall over the UK

not much consistency from the GFS but more akin to the ECM output.

[TSNWK]

GFS backing west again over the states-http://modeles.meteociel.fr/modeles/gfs/runs/2013123112/gfsnh-0-120.png?12Awaiting for the low to develop @ 140S

Bang on que the low started to develope at 144 and maybe just a tad further south west at 162, which I think again is the trend we would like to see... Edited December 31, 2013 by TSNWK

[nick sussex]

Interesting trend from the GFS 12hrs run, bearing in mind that the 00hrs run had no low at all, also more uncertainty over the Arctic with that lobe of high pressure extending se towards Russia.

 

If you followed this amplified wave as it worked its way across from the west coast of the USA it was more amplified than the 06hrs run, because it was late to develop this the initial mid part of the USA was flatter.

 

Overall given the 00hrs run from the GFS this is a step forward especially with high pressure now appearing to the ne but its hard to have too much faith in the pattern over the Arctic because of the constant chopping and changing between outputs.

[Methuselah]

Actually Shed that chart does not show an easterly, it shows a northerly across some parts of the UK, Ireland a more SW tilt to the wind. But the following days the wind becomes more a NE, still it wasn't a lenghthy cold spell until late janaury

 

 

No; I think Shed's right: an easterly in the south, a southerly in the north?

 

http://www.wetterzentrale.de/pics/archive/ra/1946/Rrea00119461215.gif

Edited December 31, 2013 by No-Time Toulouse

[Purga]

12z  looking very cyclonic with another train of exceptionally vigorous Low Pressure syatems ready to steam across the Atlantic towards our shores at break neck speed

No sign at all so far of any amplification.

[damianslaw]

Models continue to paint a very unsettled outlook for the foreseeable future with further bouts of heavy rain and strong winds associated with the very active atlantic. Low pressure firmly in control languishing to our NW. Temperatures around average in the north, above average in the south.

 

The models yesterday were showing signal of heights developing to our NE as we approach middle of January, they have backed away from this scenario today.

 

In zonal set ups the form horse is always a continuation of the same, however, I would keep an eye on the stratosphere thread, the polar vortex is anomanously cold at the moment unusually so - hence the wild atlantic- and there are stirrings of a major warm up in the upper atmosphere ready to hit the vortex... mother nature has a habit of balancing herself out from warm to cold and vice versa maintaining an equilibrium..  the models however, won't easily pick up on such developments.

[Tamara]

 

 

The upshot of this,as far as can be gleaned at present, is that the New Year holds the prospect of a colder form of zonal conditions gradually becoming established - but then something of a crossroads to follow. Much will depend on the continued attacks on the vortex from the wave activity and much will also therefore depend on how the models interpret these. In the unlikely event of any full blown SSW (Sudden Stratospheric Warming)  until later in the winter (which is as anticipated anyway for some time in the other thread)  and with the current entrenched and very hostile polar profile, I do think that any changes are going to be slow, most especially further south and that true blocking (at least in the sense that it clearly influences our weather from a

deeply cold viewpoint) remains a thing of further continued patience.

 

 

 Clarity appearing about the nature of how the cyclonic pattern evolves with a little micro amplification in the pattern suggested to provide some lower temperatures (nothing especially cold though) . The ECM ensemble mean looks quite realistic for this stage of proceedings imo

 

 

I do think that this time period up to mid month is best not analysed too much in terms of expectations beyond something of a slowing down of the frequency of the zonal train of depressions and perhaps the prospect of some polar maritime incursions behind the weather fronts as the pattern becomes just a little less flat for a time. But I won't personally be checking outputs for surprises in terms of this atlantic ridge

 

The crossroads as mentioned then is based on the solid omni-presence of the Canadian sector of the vortex in the lead up to the FI forecasts of a stratospheric attack after mid month. We simply cannot comment on this with any confidence at this time, obviously, other than clearly without sustained two pronged vortex wave activity, the pattern profile will quickly flatten out again and fast, furious and flat service will resume once more which is probably what is the gist of the current METO suggestons as posted on here.

 

The much more appealing scenario is that if stratospheric activity means a proper split and downwelling can be achieved in this further outlook period then this would be the key mechanism to finally moving that bothersome lump of concrete westwards away from Canada and Greenland and change the distant prospects considerably.

 

However, this gives some idea of just how far away we remain at present from any hope of a proper end to this extended zonal period and in the meantime this coming week and into the first full working week of 2014 holds the prospect of yet more flood and wind associated hazards.

 

Happy New Year, despite the weather x

[Gaz1985]

No; I think Shed's right: an easterly in the south, a southerly in the north?

 

http://www.wetterzentrale.de/pics/archive/ra/1946/Rrea00119461215.gif

 

Nope, but a couple days or so later all the country has an easterly or north easterly 

 

[A.J]

Actually Shed that chart does not show an easterly, it shows a northerly across some parts of the UK, Ireland a more SW tilt to the wind. But the following days the wind becomes more a NE, still it wasn't a lengthy cold spell until late January

 

Erm, only shows a northerly if you turn the chart upside down...lol

 

winds flow clockwise around a HP, anti clockwise around a LP 

[Methuselah]

Nope, but a couple days or so later all the country has an easterly or north easterly 

 

But that's 2 days' later...

[Purga]

Temps down to 40 below in Central Canada  widely sub 30 below in the Maritimes

 

With NW Atlantic at above normal SST nothing is going to stop them LP systems developing and riding a super jet streak.

GB of course, mild.

Edited December 31, 2013 by Purga

[nick sussex]

If the ECM sticks to its output and develops that high pressure lobe to the ne then it could get interesting, that lobe to the ne could force some energy away from the troughing near the UK, essentially the problem this morning with the ECM wasn't upstream but downstream over the UK.

 

Because the GFS is flatter over the mid USA by the time the amplified wave has worked through its later to pick up that Gulf moisture, we want the low to develop much earlier and further west.

[SMU]

http://modeles.meteociel.fr/modeles/gfs/runs/2013123112/gfsnh-0-228.png?12

 

3 runs successive the GFS has moved back to the ECM- this final run still a way to go but now for the first time come scandi heights appearing- sure they will be brushed away on the 12z, but a few more runs of that inland running moving back west & the whole pattern changes-

 

Remember any further west on that low & it starts to phase with the low dropping in from Canada which will tug it further north...

 

S

[Mucka]

 Clarity appearing about the nature of how the cyclonic pattern evolves with a little micro amplification in the pattern suggested to provide some lower temperatures (nothing especially cold though) . The ECM ensemble mean looks quite realistic for this stage of proceedings imo

 

 

I do think that this time period up to mid month is best not analysed too much in terms of expectations beyond something of a slowing down of the frequency of the zonal train of depressions and perhaps the prospect of some polar maritime incursions behind the weather fronts as the pattern becomes just a little less flat for a time. But I won't personally be checking outputs for surprises in terms of this atlantic ridge

 

The crossroads as mentioned then is based on the solid omni-presence of the Canadian sector of the vortex in the lead up to the FI forecasts of a stratospheric attack after mid month. We simply cannot comment on this with any confidence at this time, obviously, other than clearly without sustained two pronged vortex wave activity, the pattern profile will quickly flatten out again and fast, furious and flat service will resume once more which is probably what is the gist of the current METO suggestons as posted on here.

 

The much more appealing scenario is that if stratospheric activity means a proper split and downwelling can be achieved in this further outlook period then this would be the key mechanism to finally moving that bothersome lump of concrete westwards away from Canada and Greenland and change the distant prospects considerably.

 

However, this gives some idea of just how far away we remain at present from any hope of a proper end to this extended zonal period and in the meantime this coming week and into the first full working week of 2014 holds the prospect of yet more flood and wind associated hazards.

 

Happy New Year, despite the weather x

 

He, he, More like an Atlantic bump at the moment 

 

But don't worry, I and a few others will be watching, patiently awaiting our Xmas gifts yet undelivered in the shape of a surprise Atlantic ridge. 

We will let you know if it materialises against the odds

Edited December 31, 2013 by Mucka

[That ECM]

IF the GFS is correct then the low at T126 is till there at t186 and will have only moved a few hundred miles in that time. Every other low has moved quicker across the uk. I would question the time it takes to move away. Couple this with it building heights to the ne. I think we maybe seeing a start to a change.

[Purga]

GFS 12z finishes in familiar form

 

Zonal Groundhog Day - LOL!

[jvenge]

IF the GFS is correct then the low at T126 is till there at t186 and will have only moved a few hundred miles in that time. Every other low has moved quicker across the uk. I would question the time it takes to move away. Couple this with it building heights to the ne. I think we maybe seeing a start to a change.

 

I'm sure someone will correct me if I'm wrong, but the speed of this one might be related to the NAO going negative as compared to positive earlier in the month? Some uncertainty on if it stays negative or goes back positive at this stage.

[SMU]

http://modeles.meteociel.fr/modeles/gem/runs/2013123112/gemnh-0-138.png?12

 

GEM @ 138 pulls the inland track...

 

S

[Mucka]

UKMO 144 doesn't look up to much on the face of it

 

[fergieweather]

Agreed, I currently cannot see anything to suggest what Ian has indicated should not be the most likely outcome for Jan, but as I'm sure he would agree it must come with the usual caveats given the timeframe involved.

Absolutely & undeniably so. We can merely represent what NWP *currently* indicates, safe in the knowledge it can so easily undertake all manner of chicanery further down the line...!!

[Mucka]

Interesting new trend in GFS ensembles?