Model Output Discussion - 18z 31/10/15 onwards

[mountain shadow]

Can someone please explain how one post on this page says the vortex is shredded yet another, presumably using the same nwp output says it is forming strongly. Coming to completely opposite conclusions makes no sense to me. Who is it who has this wrong? It has to be one or the other.

Crewecolds post is referring to the Tropospheric vortex appearing more fragmented. IDOs is about the Stratospheric PV going strength.

If the Stratospheric PV couples with the Tropospheric one a likely windy and wet period will occur with little chance of a sustained cold spell until new year.

[Ravelin]

On the 0Z runs the GFS and ECM are world's apart, at least in UK outcome, at 10 days. Both have ringing into Greenland but the result for us is quite different in each.

http://modeles.meteociel.fr/modeles/gfs/runs/2015110500/gfsnh-0-240.png?0?0

http://www.meteociel.fr/modeles/ecmwf/runs/2015110500/ECH1-240.GIF?05-12

[Summer Sun]

This mornings GFS ens for London shows the Op was coldest run when compared to the mean at the end likewise the control is the warmest

 

 

Differences between GFS and ECM Op's at d10

 

Edited November 5, 2015 by Summer Sun

[terrier]

Well the gfs and ECM at day 10 are pretty much worlds apart. Yes the gfs has been consistent with a colder theme in fi. But isn't the ECM the top performance model out of the two. And with the met not really interested in a colder outlook at the moment I would think that the ECM is closer to the outcome as things stand.

[Paul_1978]

Crewecolds post is referring to the Tropospheric vortex appearing more fragmented. IDOs is about the Stratospheric PV going strength.

If the Stratospheric PV couples with the Tropospheric one a likely windy and wet period will occur with little chance of a sustained cold spell until new year.

Even with the new year being 2 months away?

[MR EXTREMES]

all have heights building into north America gefs most progressive but some consistent runs with last night showing the first signs although we all seen cross model agreement and for it to fail theres certainly always the chance this time round these charts might actually happen.

 

would certainly pee on my fireworks and dampen my trumpet of my ideas of feb being when winter explodes into life...

 

now model watching gets interesting Prozac at the ready.

but some nice cross model agreement,

although each slightly different.

 

but blocking the route of the normal exit from the states with a more southerly tracking of depressions,

as phil explained yesterday morning.

 

 

as is the case of most winters west nao or east nao I think the vortex is already on the ropes and likely to be squeezed over to our side of the pole or perhaps a split with the bigger section over our side!.

 

and north America and Canada being dominated but high pressure although these are just ideas of where the models might be heading.

 

just a quick ramps who knows might get a polar low this winter

Edited November 5, 2015 by emotional rollercoaster

[knocker]

Not much to add concerning this morning's GEFS anomalies excepet that the 11-15 seems to have backed off from the armageddon scenario to something akin to last night's NOAA 8-14.with perhaps slightly more emphasis on the trough. Ergo portending a westerly driven unsettled period, still leaning towards a N/S split. with temps varying around the average.

 

[Nick F]

Well the gfs and ECM at day 10 are pretty much worlds apart. Yes the gfs has been consistent with a colder theme in fi. But isn't the ECM the top performance model out of the two. And with the met not really interested in a colder outlook at the moment I would think that the ECM is closer to the outcome as things stand.

 

I wouldn't say worlds apart, both have trough and ridge alignment similar over Atlantic and eastern Canada day 10, though surface features, as would be expected, a little different in placement at that range:

 

 

EC vs GFS 8-10 day comparison

 

 

00z GEFS and EPS H500 mean/anomaly has the +ve hieghts anomaly over Labrador/Nern Canada at day 10, so a positive signal that this may transfer a little further east if the Atlantic trough does likewise.

 

 

But early days and if there ends up being to much energy beneath the +ve anomaly over NW Atlantic, which is very possible, then cold arctic air may struggle to get far enough south as lows develop to the SW of the UK.

[Summer Sun]

Here are the latest verification stats from Gibby

 

The verification Statistics of GFS, UKMO and ECM show;

 

At 24 hours ECM ahead of UKMO at 99.5 pts to 99.4 pts with GFS closely behind at 99.3 pts.  

 

At 3 days ECM is leading with 97.1 pts to UKMO's 96.7 pts while GFS lags behind at 95.6 pts.

 

At 5 days ECM leads with 87.6 pts to UKMO at 85.5 pts then GFS at 83.3 pts.

 

Then at 8 Days ECM still leads at 55.0 pts over GFS's 45.3 pts.

 

Finally at Day 10 ECM leads GFS at 31.8 pts to 20.0 pts.

[carinthian]

I wouldn't say worlds apart, both have trough and ridge alignment similar over Atlantic and eastern Canada day 10, though surface features, as would be expected, a little different in placement at that range:

 

comparison_gfs-ecm00z.JPG

 

EC vs GFS 8-10 day comparison

 

psu_00z.gif

 

00z GEFS and EPS H500 mean/anomaly has the +ve hieghts anomaly over Labrador/Nern Canada at day 10, so a positive signal that this may transfer a little further east if the Atlantic trough does likewise.

 

gfsens-240.pngecmwfeps-240.png

 

But early days and if there ends up being to much energy beneath the +ve anomaly over NW Atlantic, which is very possible, then cold arctic air may struggle to get far enough south as lows develop to the SW of the UK

Hi Nick thanks for your analysis there, I always like to read. As much as I hate the ECM slug pellet charts for you lot and continued snow drought in the Alpine Region, I do think their present prog is the best route to cold. The high could easily retrogress NW ( post 240hours )  allowing the colder flow down the eastern flank, especially for my location. As you mention the very cold air now developing in the high Arctic could be locked up there with GFS still holding west to east block over Europe with the lows forming to the SW and joining the conveyer belt.

C

[TwisterGirl81]

Here are the latest verification stats from Gibby

 

The verification Statistics of GFS, UKMO and ECM show;

 

At 24 hours ECM ahead of UKMO at 99.5 pts to 99.4 pts with GFS closely behind at 99.3 pts.  

 

At 3 days ECM is leading with 97.1 pts to UKMO's 96.7 pts while GFS lags behind at 95.6 pts.

 

At 5 days ECM leads with 87.6 pts to UKMO at 85.5 pts then GFS at 83.3 pts.

 

Then at 8 Days ECM still leads at 55.0 pts over GFS's 45.3 pts.

 

Finally at Day 10 ECM leads GFS at 31.8 pts to 20.0 pts.

 

Why isn't Gibby posting his model thoughts anymore please?  I used to enjoy the read and it was good for those of us who are not that clued up on what means what.....

Edited November 5, 2015 by TwisterGirl81

[knocker]

The ext ecm this morning maintains the positive heights Labrador and slowly dissipates the HP to the S/SE of the UK. Plus LP Iceland area with a weak trough extending south so all this leads to somewhat benign westerly flow with the south not coming out at all bad.

[Summer Sun]

Why isn't Gibby posting his model thoughts anymore please?  I used to enjoy the read and it was good for those of us who are not that clued up on what means what.....

 

I honestly don't know but you can view his thoughts on his website which he updates just about everyday

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[MR EXTREMES]

if we can get a similar idea to this then game on!.

 

although models at this moment in time are nothing like the chart ive posted this is certainly as possibility as is a mild soggy nightmare.

 

but not all of us wish for that but a slow progression  towards the chart and ideas im posting is as realistic as any.

 

 

 

you cant see the northern hemisphere chart but you can see heights building into the area nick L suggested or should I say the heights are already there on the chart posted.

 

of coarse from the model runs this morning and last night don't really show the azores disrupted to our sw around the azores area!

there for at the moment we don't yet get lows sliding southeast threw the uk.

 

on the chart ive posted we also have higher pressure building to our northeast retrogressing slowly towards Iceland Greenland that also is not showing on current outputs.

 

but I want to be optimistic and believe a similar scenario could arise.

but at least frosty got something to keep the forum spirits up.

 

and certainly more lively in here now unlike the last week.

 

there is an invisible modified chart on my post but ive no reason why I cant see it

Edited November 5, 2015 by emotional rollercoaster

[Ravelin]

Well the gfs and ECM at day 10 are pretty much worlds apart. Yes the gfs has been consistent with a colder theme in fi. But isn't the ECM the top performance model out of the two. And with the met not really interested in a colder outlook at the moment I would think that the ECM is closer to the outcome as things stand.

 

 

Here are the latest verification stats from Gibby

 

The verification Statistics of GFS, UKMO and ECM show;

 

At 24 hours ECM ahead of UKMO at 99.5 pts to 99.4 pts with GFS closely behind at 99.3 pts.  

 

At 3 days ECM is leading with 97.1 pts to UKMO's 96.7 pts while GFS lags behind at 95.6 pts.

 

At 5 days ECM leads with 87.6 pts to UKMO at 85.5 pts then GFS at 83.3 pts.

 

Then at 8 Days ECM still leads at 55.0 pts over GFS's 45.3 pts.

 

Finally at Day 10 ECM leads GFS at 31.8 pts to 20.0 pts.

 

So where we were looking, at day 10, the ECM is quite a bit better than the GFS, but the reality is that both are so bad that neither are likely to be showing the actual outcome.

 

As has been said many times before "more runs needed".

[mountain shadow]

Even with the new year being 2 months away?

Yes.

Given the lag times for the Strat PV impacting at lower levels.

[knocker]

Courtesy MV

 

Week 3 precipitation anomaly map out of the ECMWF Weeklies. Just an El Nino classic. And with the sub-tropical jet roaring out of the southern states next week the Nov. forecast is looking more and more realistic.

Edited November 5, 2015 by knocker

[Daniel*]

As I alluded on the first page of this new thread the eye-candy would start churning out, I'm aware cold charts are some distance out, although there are the building blocks in momentum, some consistency here, and I feel such block in that region is very conceivable. The usual winter shredder monstrous PV setting up shop over Greenland locale with its purple tentacles bottling cold in the poles and preventing any attempt of HP from ridging in - but this does not seem to be necessary the case this time around I feel a great expanse/spillage of very cold arctic air is inevitable exemplified in GFS 18z and morning 6z, really just a moment of when. The PV has not got any footing in outer reaches of FI when you would naturally assume it would gather in size & intensity and I think this is rather fundamental the stratosphere may be colder than average but according to the charts it ain't propagating as far as I can see. I expect the MO are keeping a keen eye - expect by next week onwards for them to start dishing out the hints of possible signs of a much colder second half to November. I think it is rather silly to dismiss, we've seen the MO extended outlook flip a lot in past years. The rollercoasters we've had in here, all I'm saying this a entire different stage to the last 2 winters and for that coldies should rejoice.

ECM +216

[Liam J]

Here are the latest verification stats from Gibby

 

The verification Statistics of GFS, UKMO and ECM show;

 

At 24 hours ECM ahead of UKMO at 99.5 pts to 99.4 pts with GFS closely behind at 99.3 pts.  

 

At 3 days ECM is leading with 97.1 pts to UKMO's 96.7 pts while GFS lags behind at 95.6 pts.

 

At 5 days ECM leads with 87.6 pts to UKMO at 85.5 pts then GFS at 83.3 pts.

 

Then at 8 Days ECM still leads at 55.0 pts over GFS's 45.3 pts.

 

Finally at Day 10 ECM leads GFS at 31.8 pts to 20.0 pts.

No surprise that verification falls sharply after day 7 and both models are pretty poor at day 10, the GFS is abysmal! You could probably guess that by day 14 onward for the GFS that verification would be close to zero? 

[Paul]

Cold snap or no cold snap later in the month, the ensembles today pick out one clearer trend, and that's the end of the east vs west battle we've had raging for what seems like an eternity. 

 

Now

 

End of the run

[A.J]

No surprise that verification falls sharply after day 7 and both models are pretty poor at day 10, the GFS is abysmal! You could probably guess that by day 14 onward for the GFS that verification would be close to zero? 

I guess that's the fun of model watching, especially during the winter months when the output is more volatile......call me 'Mr Cynical' but I look at the GFS in far FI (T240+) ..make a note of what is shown.....then make a broad guess that we'll actually experience the exact opposite of what it's showing.....this method had a good verification percentage.....lol

[Newberryone]

Hi still looking good for cold mid November onwards trending in the right Direction will the ecm start to see this in next few days .

Not I would say if the latter stages of the Ecm 00z come to fruition, for those stubborn heights over the low countries on days 9 and 10 would fend of the worst of any very active frontal activity as well as keeping us trapped in a warm sector. Mother Nature..Bah humbug!! 

[Nouska]

Not I would say if the latter stages of the Ecm 00z come to fruition, for those stubborn heights over the low countries on days 9 and 10 would fend of the worst of any very active frontal activity as well as keeping us trapped in a warm sector. Mother Nature..Bah humbug!! 

 

Not necessarily....

 

On extended ECM output, there is quite a change between the means at 240 and 360 hours.

 

240     312    360 

 

It is all speculative at that range but the model is currently anticipating a mid-month change.

[Nick F]

As I alluded on the first page of this new thread the eye-candy would start churning out, I'm aware cold charts are some distance out, although there are the building blocks in momentum, some consistency here, and I feel such block in that region is very conceivable. The usual winter shredder monstrous PV setting up shop over Greenland locale with its purple tentacles bottling cold in the poles and preventing any attempt of HP from ridging in - but this does not seem to be necessary the case this time around I feel a great expanse/spillage of very cold arctic air is inevitable exemplified in GFS 18z and morning 6z, really just a moment of when. The PV has not got any footing in outer reaches of FI when you would naturally assume it would gather in size & intensity and I think this is rather fundamental the stratosphere may be colder than average but according to the charts it ain't propagating as far as I can see. I expect the MO are keeping a keen eye - expect by next week onwards for them to start dishing out the hints of possible signs of a much colder second half to November. I think it is rather silly to dismiss, we've seen the MO extended outlook flip a lot in past years. The rollercoasters we've had in here, all I'm saying this a entire different stage to the last 2 winters and for that coldies should rejoice.

ECM +216

image.png

Not sure I totally agree based on model output as it stands for now. Yes, there is a signal from ops and ensembles for a +ve height anomaly to develop across Labriador/NE Canada and eventually Greenland. But a look at the upper flow charts suggests that the +ve heights will be undercut by a strong jet coming out of N America.

You see, there is a split flow regime consistently modelled across N America, which is typical of El Nino conditions, alot of energy going into the STJ which will naturally undercut the ridge over Labrador/greenland area as the jet emerges over the N Atlantic and on towards NW Europe - this keeps troughing/low pressure over mid-Atlantic whilst heights are higher over mainland Europe - not ideal for cold arctic air to spill south across the whole of the UK in any potent way. Though there is, I suppose, a chance of colder air getting in across Scotland at times.

Unless the jet weakens and buckles upstream to bring a more meridional flow pattern, the Pacific jet is looking rather strong for a while, I find it difficult atm to see potential for much colder weather as we head into 2nd of November for now.

But, that's not to say that I it won't happen, just can't see it showing for now from the charts. Trying not to get suckered in by GFS FI teases of +ve height anomalies over Labrador and Greenland or even the GFS AO forecasts dipping neutral, but looking at the wider picture

Edited November 5, 2015 by Nick F

[nick sussex]

Looks like a decent call by the GFS for that lobe of high pressure edging out of Canada, the ECM supports that however as to whether this produces a colder snap for the UK is questionable.

 

Generally there are two correlations with colder weather into the UK, pressure falling in central Europe or low pressure over northern Italy.

 

The former suggests lower pressure to the east and se or with the latter high pressure over Scandi, the issue across the operationals aswell as the GEFS is the Euro high whilst weakening remains to the south and se, the GEFS mean keeps that well into FI.

 

We don't see a dig south of troughing into central Europe, the issue therefore remains how far east and south the pattern will get. Of course because of those upstream changes there is an opportunity to get some colder weather so there remains that possibility but its by no means a strong favourite at present.