Model Output Discussion - January 12th.

[Osbourne One-Nil]

If you thought the last 24 hours lead to some world-class discussion between the finest meteorologists in the land....well, this will be something else.

As before, if your post is not related directly to the output of the various models, then please don't post in this thread. There is a parallel Model Mood Thread where you can post any general comments, moans, hopes, or gut feelings. There is also The Models: Summed Up, where twice a day you own 100 word update on how you think things are looking. You don't have to be an expert. Bit like this thread then it would seem.

For those wanting a good summary of where we stand, may I suggest the venerable John Holmes's offering?

[kold weather]

12z GFS has just started rolling. Will the GFS continue to strengthen the high like it did with its 06z run or will it be the more zonal run that it typically is...we will have to wait and see!

[johnholmes]

If you thought the last 24 hours lead to some world-class discussion between the finest meteorologists in the land....well, this will be something else.

As before, if your post is not related directly to the output of the various models, then please don't post in this thread. There is a parallel Model Mood Thread where you can post any general comments, moans, hopes, or gut feelings. There is also The Models: Summed Up, where twice a day you own 100 word update on how you think things are looking. You don't have to be an expert. Bit like this thread then it would seem.

For those wanting a good summary of where we stand, may I suggest the venerable John Holmes's offering?

how kind young man

[Timbo]

afternoon all, whilst we are waiting for the 12z, who thinks we will see a major swing back to v cold easterlies and snow???

I have a gut feeling that by next weekend we will be ready for some serious snow and cold...

[Osbourne One-Nil]

Model Mood Thread - don't forget!

[Paceyboy]

http://raleighwx.ame...comparison.html

GFS seems to 'off on one' when one considers how long it showed a strong negative AO until today!

SIGNIFICANT upstream uncertainty here, even though there may be agreement to 144hrs, events in the arctic are always changing run to run

i.e small changes= large changes/uncertainty for our part of the North Atlantic.

[kold weather]

http://raleighwx.ame...comparison.html

GFS seems to 'off on one' when one considers how long it showed a strong negative AO until today!

SIGNIFICANT upstream uncertainty here, even though there may be agreement to 144hrs, events in the arctic are always changing run to run

i.e small changes= large changes/uncertainty for our part of the North Atlantic.

It does seem to be an odd thing, i remember saying a week ago that until the models get a good grip on the Arctic pattern that they can be forgotten about past 144hrs. It seems they are still struggling with this aspect even now thus they are still very prone to shifts and changes.

[Summer Sun]

Well the 12z is underway out to 60h and there is little change from the 06z. Will this run deliver snow and cold or not? Only time will tell

[Backtrack]

Well the 12z is underway out to 60h and there is little change from the 06z. Will this run deliver snow and cold or not? Only time will tell

Likely to be firm agreement between the major models at all time intervals of the day at T+60hrs though, Gav.

[Radiating Dendrite]

Subtle differences already on the 12z compared to the 6z at 60hrs out.

The jet has a slightly different angle of attack. I think this may end up being a better run for earlier cold, more like the UKMO and ECM, we shall see.

[ukpaul]

By 84h though the GFS appears to have a difference from both ECM and UKMO over Scandinavia and that's one of the areas where I think they are sowing the seeds of their differing evolution further down the line.

[Paceyboy]

Subtle differences already on the 12z compared to the 6z at 60hrs out.

The jet has a slightly different angle of attack. I think this may end up being a better run for earlier cold, more like the UKMO and ECM, we shall see.

Yh the low near portugal is 100miles further northeast than the 06z.

And its only t87

[nick sussex]

Some key differences showing up at only 72hrs between the GFS and UKMO over Scandi which manifest themselves into total disagreement at 120hrs!

Here we go again!

UKMO

http://www.meteociel.fr/modeles/ukmo2.php?nh=1&ech=120&carte=1021

GFS

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=120&mode=0&carte=1

[Paceyboy]

Some key differences showing up at only 72hrs between the GFS and UKMO over Scandi which manifest themselves into total disagreement at 120hrs!

Here we go again!

UKMO

http://www.meteociel...=120&carte=1021

GFS

http://www.meteociel...&mode=0&carte=1

Yes they are poles apart Nick. Too much uncertainty!

[Jimmyh]

Some key differences showing up at only 72hrs between the GFS and UKMO over Scandi which manifest themselves into total disagreement at 120hrs!

Here we go again!

UKMO

http://www.meteociel...=120&carte=1021

GFS

http://www.meteociel...&mode=0&carte=1

That is quite a difference on the UKMO and GFS who will be the winner i wonder!!!

[trisnow]

Oops, sorry on my phone. Meant to ask Nick, for the noobs, what do the differences show us please?

[Radiating Dendrite]

Well the 12z is now going the way of the 6z. I hope the ECM sticks to its guns and does not fall in line with the GFS later.

The GFS seems to have heights to the south, lows to the north disease!

[Osbourne One-Nil]

It hasn't been the best opening page or two to a thread - can we just discuss the model output?

[Andy_]

GFS 12z and ECM 0Z T216 completely abstract...

When are we going to see some agreement?! I suppose only time can bring certainty closer, hopefully it will be the GFS that jumps on board at the last moment, rather than the ECM jump on board the Mild Express...

[nick sussex]

Oops, sorry on my phone. Meant to ask Nick, for the noobs, what do the differences show us please?

The UKMO has a more amplified pattern upstream and begins to elongate the PV, the GFS is as flat as a pancake and brings much more energy east off the PV.

In a nutshell to get to cold from the GFS is a very long slog and hard to see without getting the Hollywood script writers in! The UKMO is still not great but doesn't need such a dose of fiction to get there.

Because of a renewed jet out of the USA you must have some of this energy splitting and heading se in tandem with a more amplified jet, if you don't get this you could well miss the boat as the Arctic high and ridge to the east are in a favourable location.

Once energy from the jet pushes everything east it will take so much more time to wait for another opportunity, certainly the UKMO is passable, the GFS to be honest from a cold perspective is dire, regardless of whether it comes up with some ridiculous tease in its lower resolution output.

[KTtom]

Sorry OON, once again you tempted fate by your opening statement..

Looks like @ 204hrs the trough exiting the US is perfectly aligned to head west up to Greenland and alow the Atlantic high to ridge...potent northerly on the way

Edit: Gets there in the end but its blumin painful!

http://www.wetterzentrale.de/pics/Rtavn3241.png

[CreweCold]

The UKMO has a more amplified pattern upstream and begins to elongate the PV, the GFS is as flat as a pancake and brings much more energy east off the PV.

In a nutshell to get to cold from the GFS is a very long slog and hard to see without getting the Hollywood script writers in! The UKMO is still not great but doesn't need such a dose of fiction to get there.

Because of a renewed jet out of the USA you must have some of this energy splitting and heading se in tandem with a more amplified jet, if you don't get this you could well miss the boat as the Arctic high and ridge to the east are in a favourable location.

Once energy from the jet pushes everything east it will take so much more time to wait for another opportunity, certainly the UKMO is passable, the GFS to be honest from a cold perspective is dire, regardless of whether it comes up with some ridiculous tease in its lower resolution output.

Yes GFS is horrible but TBH Nick I have a feeling it has had this one correct for a couple of days now. The ECM has been much more prone to swings for a while now IMO.

[nick sussex]

In an effort to lighten the mood the NOGAPS backs the trend of this mornings ECM run.

http://www.meteociel...&mode=0&carte=1

I only link to this in times of emergency! But so far we have one passable the UKMO, one dire the GFS and one good output the NOGAPS.

[ukpaul]

Yes GFS is horrible but TBH Nick I have a feeling it has had this one correct for a couple of days now. The ECM has been much more prone to swings for a while now IMO.

Are you sure you have that the right way round? The ECM is the model that has picked a pattern and stuck with it for the last couple of days, the GFS has given differing results for the op and a much more variable output from its ensembles as opposed to the ECM. I'm looking fr consistency as things move into a more reliable timeframe and, so far, it's provided that (now, having said that, it's bound to flip totally for the next run!)

[Radiating Dendrite]

In an effort to lighten the mood the NOGAPS backs the trend of this mornings ECM run.

http://www.meteociel...&mode=0&carte=1

I only link to this in times of emergency! But so far we have one passable the UKMO, one dire the GFS and one good output the NOGAPS.

NOGAPS, bringing out the big guns now Nick.

That is a nice looking run from the NOGAPS though.

The thing that confuses me is I thought the PV was meant to be moving over Baffin? Why is the GFS trying to shunt it over the North Pole and then the North Atlantic?