Model output discussion - 1st December onwards

[Mucka]

Not bad but a shame the trough phased with the low forcing the pattern east or we could of dragged in some cold polar air.

Gives me hope the ensembles will still show some cold runs though.

 

[January Snowstorm]

The ECM is very close to being an awesome run.

It doesn't make it but does go to show how quick things could change.

Oven to freezer in 24hrs!!  Yes please☺

[Mapantz]

10 minutes ago, January Snowstorm said:

The ECM is very close to being an awesome run.

It doesn't make it but does go to show how quick things could change.

Oven to freezer in 24hrs!!  Yes please☺

Could you explain why, or at least post some charts to show why its awesome?
 

I can see that they don't look too shabby, but, they don't look awesome either. There are plenty of other folks who read this thread, that don't have any idea what you mean, or may take 'oven to freezer' quite literally.

 

Thank you. 

[January Snowstorm]

5 minutes ago, Mapantz said:

Could you explain why, or at least post some charts to show why its awesome?
 

I can see that they don't look too shabby, but, they don't look awesome either. There are plenty of other folks who read this thread, that don't have any idea what you mean, or may take 'oven to freezer' quite literally.

 

Thank you. 

Because a small nudge northwards and the high would settle over Scandi.

This would put us straight in the freezer. It may not happen but the potential is there. Bear in mind some didn't see anything but zonal 2 days ago. These charts have far greater potential of a change of weather type 

We just have to hope that change is a positive one

[gottolovethisweather]

On 18/12/2015 at 7:13 PM, gottolovethisweather said:

 And it is as if tonight's ECM has read the script, my script that is. 

 

Baby steps and tis but only one run, nonetheless the signs are there for something better, colder, drier and sunnier at least post Christmas. Might help keep nature and its pests in check, who knows we might even get a frost for once down in tropical Southern England. My bets for the big day (Christmas Day) now would be for a wet out West, drier towards the East type scenario with mostly average Temperatures, always warmest towards the South and West. As for snow, only on those ole Christmas movies I reckon , Boxing Day might offer more hope for those at elevation.

 

And some 24 hours on, the D7-D10 charts continue to paint a similar picture, the trend to build heights over us and to our NE is definitely the new trend and the trend is our friend.  Slowly slowly catchy monkey but potentially I forsee a more settled spell coming to our shores post Christmas. Boxing Day is the key timeframe for when this Winter might just start to turn around for the better for coldies (well, at least this one who wants some crisp frosty nights if nothing else). No freezingly bitter cold Temperatures on offer yet but watch this space, just give it plenty of time for that aspect. The Christmas period according to the ECM is certainly more festively average to cold feeling with Boxing Day yet again proving the most likely day to see any wintriness up North beyond Northern England. 

Edited December 19, 2015 by gottolovethisweather

[phil nw.]

The concern wrt the expected Scandi.ridging is that we remain on the mild side of the stalling Atlantic trough out west as we approach NY.and we see further transport north of mild air.

They are only a good development from a coldies pov if they go on and really build north and become a separate cell and allow some cold air from N.Russia to move west around the south of the block.Of course this would mean falling pressure in Southern Europe to set up an easterly.The sort of pattern such as from feb 1991 below

That Scandi.high took about 3 attempts before establishing,and it's no coincedence that it was later in the season as the vortex becomes less cold and more prone to succumbing to wave breaking.

Unfortunately current outputs inc. all the ens show we are nowhere near such a setup with the trend to the ridge flattening later and the Euro heights remaining further south.

We have seen this happen so many times over the years where the Scandi.ridging flatters to deceive and the cold remains out to the east.

It is good that we see already some further wave 1 action but from what i can see the pv isn't ready to submit yet,based on all the current data.It's getting a few slaps around the ear but nowhere near a KO blow.

It may well come but more time and wave action needed i think.

[Mucka]

JMA took a  similar path to ECM which adds a little more support and leaves GFS a little out on its own.

What I find interesting is there is good scope for improvement on these runs if the low to our SW is a little faster than JMA or ECM have it.

 

Check JMA 12z progression below.

 

 

See how the low ends up exiting rt our West and phasing with the Atlantic trough. If it were just a little quicker it would be over the UK and toward the NE tip of the ridge/WAA in the Atlantic. What would happen then is that the pattern would end up further East with a more vertical ridge/WAA being pushed poleward and no phasing allowing the low to exit to our East and phase with a Scandi trough which also would be further West and deeper.

This would allow cold polar air to flood down the Eastern flank of our ridge, possibly over the UK and also would be better for cold prospects going forward.

 

ECM 12z may have just about achieved this but it creates a secondary low behind the first low.

 

 

[nick sussex]

Close but no cigar with the ECM.  Those shortwaves near the UK are a worry because they could turn this close but no cigar to nowhere near close.

I think the juries still out until those shortwaves and how and if they phase with the upstream troughing comes into a more reliable timeframe.

In terms of the GFS versus the others some good news on that front, you'll note that the ECM takes low pressure ene from Colorado towards the Great Lakes between T144hrs and T192hrs. This is what WPC expect to happen given the expected pattern. You'll note that the GFS doesn't do this.

A SERIES OF COLD FRONTS WILL AIDE IN DIGGING HEIGHTS THROUGH THE INTERIOR WEST MID-LATE WEEK AND EVENTUALLY PUSH ONE OR A SERIES OF SURFACE LOWS ALONG THE STALLING FRONTAL BOUNDARY IN THE MID-MISSISSIPPI VALLEY NEXT FRI-SAT. PATTERN SHOULD SUPPORT ANOTHER GREAT LAKES TRACK LOW NEXT WEEKEND THOUGH IN WHAT FORM IS UNCLEAR. 06Z GFS/GEFS WERE SUPPRESSED WHICH DOES NOT FIT THE RECENT/EXPECTED PATTERN.

This possible low is important in terms of what sort of ridge is carved ahead of it which then effects the troughing to the west of the UK.

The short ECM De Bilt ensembles are in, the operational and control runs close together but are on the colder side of solutions. I think the main cluster have shortwave phasing problems, the spreads show a large scatter to the west of the UK.

Edited December 19, 2015 by nick sussex

[MJO]

Hi - it seems that the sceuro high is fixed and the trough will go down to turkey and israel

[Swave Snow]

5 minutes ago, MJO said:

Hi - it seems that the sceuro high is fixed and the trough will go down to turkey and israel

 

 

Israel looks like warming up

[MJO]

1 minute ago, Swave Snow said:

 

 

Israel looks like warming up

I mean at the end of the year and At the beginning of the new year.

[Swave Snow]

3 minutes ago, MJO said:

I mean at the end of the year and At the beginning of the new year.

Fair enough a lot can change though before then

[ricey076]

1 hour ago, Mapantz said:

Could you explain why, or at least post some charts to show why its awesome?
 

I can see that they don't look too shabby, but, they don't look awesome either. There are plenty of other folks who read this thread, that don't have any idea what you mean, or may take 'oven to freezer' quite literally.

 

Thank you. 

Could you post some charts also to back up your post ?

[Singularity]

1 hour ago, nick sussex said:

 

In terms of the GFS versus the others some good news on that front, you'll note that the ECM takes low pressure ene from Colorado towards the Great Lakes between T144hrs and T192hrs. This is what WPC expect to happen given the expected pattern. You'll note that the GFS doesn't do this.

A SERIES OF COLD FRONTS WILL AIDE IN DIGGING HEIGHTS THROUGH THE INTERIOR WEST MID-LATE WEEK AND EVENTUALLY PUSH ONE OR A SERIES OF SURFACE LOWS ALONG THE STALLING FRONTAL BOUNDARY IN THE MID-MISSISSIPPI VALLEY NEXT FRI-SAT. PATTERN SHOULD SUPPORT ANOTHER GREAT LAKES TRACK LOW NEXT WEEKEND THOUGH IN WHAT FORM IS UNCLEAR. 06Z GFS/GEFS WERE SUPPRESSED WHICH DOES NOT FIT THE RECENT/EXPECTED PATTERN.

This possible low is important in terms of what sort of ridge is carved ahead of it which then effects the troughing to the west of the UK.

The short ECM De Bilt ensembles are in, the operational and control runs close together but are on the colder side of solutions. I think the main cluster have shortwave phasing problems, the spreads show a large scatter to the west of the UK.

Hi Nick,

I'm fairly sure it was last month that I can recall GFS modelling the upstream pattern differently to the rest of the pack, and having to perform an embarrassing back-down.

It seems there's a significant problem with the model when it comes to handling areas of low pressure over the U.S., one which I believe I've seen noted by the likes of NOAA as a known bias.

That ECM run is fascinating from many standpoints, though it may prove a little over-amplified unless the tropical convection remains prominent beyond phase 5 rather than fading away as yesterday's model runs were suggesting.

Today's runs are more interesting from that perspective, with UKMO again going a bit nuts while ECMF suggests a re-emergence of coherent convection in phase 7 following decay in phase 5.

I've been tracking the changes day to day and the increase in amplification of the MJO 16th-19th has been roughly halfway between the majority vote and the UKMO solution. Similar to what happened back in the summer, funnily enough! Extrapolate that forward and you've got a moderate amplitude signal through phase 6... my fingers are firmly crossed!

[Nick F]

EPS control at day 12 showing a Scandinavia high closing off with Atlantic troughing across Southern Europe. 12z EPS mean not too shabby either, with the Scandi +height anomaly persisting right up to day 15 (03 Jan), the Trop vortex by then pretty much consigned to eastern Siberia and Aleutians, the N Atlantic trough much weakened by then in the means. Even if the Scandi ridge anomaly doesn't favour cold quickly, it will help hasten the weakening of the stratospheric vortex.

12z GFS op quite progressive with flattening any attempt of the Sceuro ridge, but look at the GEFS, impressive +height anomaly in the means at day 13, Atlantic trough anomaly gone. 

So could it be the GFS op is being too progressive? Good possibility looking at the means. Though EC can, at times, be too amplified, but perhaps better at modelling ridging over Europe?

ECM MJO forecast makes it all the way through to phase 8 by 02 Jan, though at low amplitude, so the signal maybe too muted by other factors. But perhaps underestimating amplitude, given UKMO is higher amplitude, UKMO skill, from what I remember from past waves quite good.

certainly looking more encouraging, for now, as we head into early Jan.

 

 

 

Edited December 19, 2015 by Nick F

[Captain Shortwave]

To be honest there isn't much change in the overall picture post Christmas with pressure rising rapidly over a large part of Europe. The trouble continues to be south of the UK in respect to the orientation of the high and the lack of cold air digging into southern Europe.

GEFs

 

ECM ens

 

Whilst there are signs that we could push the jet a little further west with warm air advection pushing north west towards Iceland, the end result at the moment is a Euro/Scandi ridge with winds from a southerly quadrant (this could be very mild or rather chilly depending on several circumstances). There is the chance of a cut off Scandi high developing if the models do increase the effect of this negative tilt occurring around the day 6-8 range to allow a cut of high to develop to our north which will drift east with the jet splitting around this feature.

In the nearer timeframe, there seems to be difficulties telling where a cold front will sit across the UK during the Christmas period, with areas north of this seeing colder and brighter conditions whilst the frontal boundary south would remain mild.

Latest GFS for the big day.

Scotland potentially seeing snow down to modest levels by the afternoon.

ECM

The thermal gradient is a little higher with Scotland still mostly on the chilly side but with the front further north as well. The complication coming from the Atlantic trough quickly sharpening due to the amplifying pattern which is taking place during this period. A lot of runs to get through before this is sorted out.

Edited December 19, 2015 by Captain Shortwave

[legritter]

Just taking our current GFS  run ,its certainly Dire for some places in our island over the coming 6/7 days and possibly beyond with no end in sight from rain wind and possibly now some wintryness over favoured areas especially more northern parts .

Certainly very interesting synoptics and again A significant weather event as taken place across our little island ,when i say weather event i,m talking what we have had now for quite a long time ,on par with late november and december 2010 but of course different weather but certainly headline event .

Looking at the realy further outlook past christmas and beyond a possibility of pressure rising to our east or there abouts but still an active atlantic so what will be around that meteorological horizon ,im pretty sure that we have some interesting weather to get through this winter  lets hope the dice can fall in our favour .

of course what goes on way up in our atmosphere  the upper troposphere and beyond [stratosphere etc ]we are only starting to understand ,things could kick off in the new year so lets enjoy all weather types ,off outside for my last Puff of the night ,i can hear the wind howling so it will be like a hair dryer ,bring me winter , snow and ice ,cheers all .

[lorenzo]

Interesting week, our Wave Activity Flux does semi-damage to the vortex in the current stream - it hits certain parts of the vortex but does not move us over the finishing line for other layers, the other layers not predicated to wave 2 split themes -  experience surf zone warmings and  flux that pirouettes on the periphery.

Again at the core layer and deepest layer, there remains a baroclinic machine, a cold vortex unperturbed by any kind of Nino artefacts and stares down the barrel at wave 2 scandi assistance as if to say - come on then... 

This is referred to in papers in the early 80s as something called stratospheric vacillation, it's a neat idea - essentially is the vortex so mature that it is under it's own control, one naturally then asks - what can then upturn this stratospheric control and create tropospheric control of the vortex.

Thanks for bearing with me, this is where current modelling comes in !

Really is a good battle setting up.

RE - MJO there is no surprise to see differentiation in the plots. This is something that has been ongoing for years. These are my 3 best sources for MJO waves am leaving mr ventrice out as this is a given, Roundy, Schreck and Matthews.

What i will say is that the last one from Adrian Matthew is afaik the only UK based one and the reason I go to this model is as follows, last year, scientific research via paragliders over the indian ocean sought to measure the heating of the diurnal thermocline as part of initiation of MJO waves. Well for me that's as as Jedi as it gets, and advanced on the others so, great work. That examination of the IO region and also the ECM attempted improvements in  parametrization of convective feedback across the tropics would lean me towards watching the ECM and Matthews site tp decide whether we have a coherent MJO propagation.

Either way the slosh in the Pacific means our OLR anomalies mean ' we've already been there'... 

I have see enough this year to conclude that MJO analogs are dicey and the real measure of where we go is within GLAAM, MJO analogs do not have the precision but do yield where GWO will lift and re-assert Nino base state.

I read elsehwere after releasing the winter forecast that ' Ed and I -oh they are strat guys...#.. well yeah we look at that but are foolhardy not to assess everything else. Truth is that #strat guys is probably levelled due to seeing upper trop lower strat guidance either prove or disprove MJO analogs.

Point I am trying to make here is that, back in 08/09 I figured that the spatial pattern which developed via MJO forcing was never succint, unless it had strat support, this was further highlighted by the fact that when the troposphere and stratosphere worked in tandem = predictability could be improved.

Taking as an aside the real 'Jedi' weather algorithm - the GWO or GLAAM, the thought then was that - hey the stratosphere helps predict the troposphere.

Am kinda sad that it's getting kicked a little and folks are like well you are looking at FI etc. Guess what - precursor patterns are FI !! Sorry they are not their sooner, this cold vortex mode Stratospheric Vacillation is quite rare...

Crazy year for weather, crazy december so far.

As far as looking at crazy weather i'll plonk this chart in - this years EN has impacts to the Ionosphere !

Hints and Tips Welcome ! meanwhile -- Go Scandi !!!

 

 

 

Edited December 19, 2015 by lorenzo
fixing first paragraph

[lorenzo]

As for the model thread losing it's spontaneity - that's rubbish, so many good posters on here, so many views, so many angles.

Guess what the mildie vs coldie thing was so last season, this year there is a more mature, educated and clued in bunch of model afficianados, yeah there is the odd mild bias or cold bias but guess what, you are all here to see every single run that churns out of NWP.

ultimately that's what makes stuff fun, and that's why you should all chime in and chat about whats on the charts in front of us.

So, science has removed some of the charm - has it really - we are all surprised , all of the time - hell it was 16C here today, imagine we put a forecast out saying yeah it'll be nearly 20C in some places 4 days before Xmas - LOL !!

Keep on contributing, there are no dark arts in weather, just folks like us that hang on each and every run and love it.

[Nick F]

Well, well, well. 18z GFS op looking a lot more like the 12z EC. A lot more amplified than 12z.

Temp of 850 hPa southerly flow looks quite high as the Sceuro ridge forms toward months end, but SEly surface flow off near continent would be cooling off, perhaps an inversion at night eventually.

[nick sussex]

2 hours ago, Singularity said:

Hi Nick,

I'm fairly sure it was last month that I can recall GFS modelling the upstream pattern differently to the rest of the pack, and having to perform an embarrassing back-down.

It seems there's a significant problem with the model when it comes to handling areas of low pressure over the U.S., one which I believe I've seen noted by the likes of NOAA as a known bias.

That ECM run is fascinating from many standpoints, though it may prove a little over-amplified unless the tropical convection remains prominent beyond phase 5 rather than fading away as yesterday's model runs were suggesting.

Today's runs are more interesting from that perspective, with UKMO again going a bit nuts while ECMF suggests a re-emergence of coherent convection in phase 7 following decay in phase 5.

I've been tracking the changes day to day and the increase in amplification of the MJO 16th-19th has been roughly halfway between the majority vote and the UKMO solution. Similar to what happened back in the summer, funnily enough! Extrapolate that forward and you've got a moderate amplitude signal through phase 6... my fingers are firmly crossed!

Sorry for the delay in getting back, was watching the last 2 episodes of the Bridge 3 ! What a truly fantastic series and Saga is absolutely one of my favourite tv characters ever.

Anyway in terms of the GFS and its upstream bias, yes NOAA have often reported that flat bias in both the GFS operationals and GEFS. You'll see on the 18hrs run the GFS now has that low tracking towards the Great Lakes so its moved to the ECM 12hrs run. This because of that change and associated different pattern helps to sharpen up the troughing to the west of the UK. The issue at the moment is the lack of trough disruption and lack of energy heading into southern Europe although I see Nick F has mentioned the ECM control run does that.

In terms of the MJO I think we'll definitely need it to remain at high amplitude otherwise the strong El Nino could weaken any impacts.

 

[Duane S.]

Fantastic post by Tony above wrt Strat vacillation. This vortex is going to take some taking down that is for sure. As expected it is now a fully mature self propagating absolute beast. Fascinating period of model watching coming up though...

It's always interesting to see what happens next as convection trundles eastwards through the tropics of the SE Asia region. Not only is this phase its greatest test (i.e. not to fizzle out and drop back into the COD) but it is also probably the worst area for accurate readings.

Anyway, my fingers are also firmly crossed we can get into the Pacific at a decent amplitude then we should start to see an increase initially in charts depicting WAA up into Greenland hopefully then followed by some proper Scandi (not Sceuro) High action. 

Edited December 20, 2015 by s4lancia

[mountain shadow]

10 hours ago, January Snowstorm said:

 

It doesn't make it but does go to show how quick things 

Are you going to make reference to every ops run which shows a cold snap "popping " out of no where? 

Bare in mind that sometime in January or February a cold period may appear but it will have been well forecast in advance,  you cannot claim it as being sudden.

[Cheshire Freeze]

GFS 0z trying to build a proper Scandi ridge...

Deep into FI the tropospheric vortex gives in under the pressure and weakens considerably

Things may be changing....

 

Also, isn't this a pre-cursor SSW pattern......?

 

 

Edited December 20, 2015 by CreweCold

[kumquat]

Interest in a swing left into Greeny hasn't abated. Indeed stronger across all models. Most NWP wants to push this East but we shall see.