Model Output Discussion 29th December - Into mid-Winter.

[Dennis]

it goes somewhere.......

[damianslaw]

Keep an eye on the position of the russian heights - forecast to build northwards, these look very robust and as shown by the ECM and GFS this evening place huge forcing on the PV sat over N Canada,aiding alot of warm air advection heading through Greenland and I think therefore preventing spoiler lows from moving in from the NW, hence there is a clear path for the ridge to build quickly and rapidly behind the sinking trough through europe. It is a plausible evolution, so shouldn't be discounted, battle of the russian high vs the canadian PV..

 

[kumquat]

Interesting and pertinent that the start of the evolution of the (current projected) cold output for the UK can be attributed to and tracked back to (on many of the recent model outputs) the High Pressure cell that grows from the Pacific East coast over the next couple of days. (John Holmes caught this first and made a little point about it) as far as I remember.

[radiohead]

18Z GEFS mean at T156 compared to 12Z GEFS mean = Colder uppers over us, more of a northerly angle to the flow, a bit more amplified in the Atlantic.

[stewfox]

I do agree looking at the GFS at 6 hour intervals maybe isn't the best way of model watching (some suggest compare runs 24 hrs apart)

but hey its fun 

GFS 18z 15/1 12pm

GFS 12 Z 15/1 12pm

 We would all like to see the winter end like below

Edited January 6, 2017 by stewfox

[Singularity]

Spectacular feedbacks define the 12z ECM and 18z GFS; such a deep low powering through Greenland yet with the jet angled such as to pass well north of the UK means a large amount of warm upper air is thrown north of the Euro trough, where it acts in-situ to produce a strong height rise. It's an example where you can have a SW-NE orientation to the warm air advection and it works - but such evolutions are notoriously precarious! If the trough doesn't feature a compact low or smaller lows arranged more or less in a line, the WAA falls short and the ridge doesn't build - at least not as much.

Just a note of caution as it seems like 3 in 4 longe-range predicted deep lows these days end up as a disorganised mess yet still tend to flatten ridges south... it is however about time we saw things work out nicely for a change!

[blizzard81]

In order to evaluate the chances of this cold spell developing and in particular whether the easterly can become a reality and not some distant day 10 dream, it would be nice to know what has brought about this possibility in the models. Any thoughts?

[Frosty.]

Let's just enjoy this moment, there will be more drama to come but coldies are in with a fighting chance of seeing some snow later next week and possibly further ahead if the ecm 12z / gfs 18z are anything to go by.night all

[Ice Day]

Just running through the 18z again, I note that the whole country has below 0c uppers from 144 to the end of the run, with the -6c line over at least some of the UK during this time...... that's ten days solid.  Need to see this continue into the 0z but shaping up for something notable.  Time, as always, will tell.

 

[SMU]

GFS 18z control is an even better match to the ECM -- :o

[feb1991blizzard]

Striking changes on the GEFS, these can be seen if you compare the 12z mean and 18z mean at T228(ish), theres a mean trough centred much further south (over france) on the 18z.

Albeit only shallow.

Edited January 6, 2017 by feb1991blizzard

[Allseasons-Si]

Well the models have gone from hangover to sober to frenzy drunk in one day lol

i must admit though we are getting a bit closer to someone seeing snow at the end of next week,but it is still miles away in model/weather terms of being nailed on so everyone should have a sober approach until we get closer because the details will vary quiet a lot from now until then and we know how fickle the models are even +96hrs away,i am on the fence until at least next mon/tue sorry to say

as for the ec ens,there is quiet a bit of consistency upto the 15th then that girl Shannon shows her face

tomorrow of cause will be a step nearer to see if the trend continues,will it be steak with big fat chips

or will the steak be in the shredder

 

[Frosty.]

1 minute ago, Ice Day said:

Just running through the 18z again, I note that the whole country has below 0c uppers from 144 to the end of the run, with the -6c line over at least some of the UK during this time...... that's ten days solid.  Need to see this continue into the 0z but shaping up for something notable.  Time, as always, will tell.

 

And let's not despair if the 00z disappoints, as we have seen today, steady improvement thru 6z / 12z / 18z..plenty of wintry potential for the next 2 / 3 months.

[blizzard81]

So that's ecm op, ecm control, gfs op, gfs control - all going for the easterly. What could possibly go wrong

[Bristawl Si]

Yday eve the posters who put all faith in teleconnections and background signals were saying that nothing was really supporting anything more than a couple of days of cold, snow......SM seemed to be challenging this ........and this evening's runs seem to be hinting at something a bit longer in duration past next w/e...........Discuss.

[weirpig]

2 minutes ago, Bristle boy said:

Yday eve the posters who put all faith in teleconnections and background signals were saying that nothing was really supporting anything more than a couple of days of cold, snow......SM seemed to be challenging this ........and this evening's runs seem to be hinting at something a bit longer in duration past next w/e...........Discuss.

As Matt Hugo said a winter of wild cards  pin the tail on the donkey this year 

[Cheshire Freeze]

2 minutes ago, Bristle boy said:

Yday eve the posters who put all faith in teleconnections and background signals were saying that nothing was really supporting anything more than a couple of days of cold, snow......SM seemed to be challenging this ........and this evening's runs seem to be hinting at something a bit longer in duration past next w/e...........Discuss.

We've been here time and again this winter so far. Each time people fail to learn from the past experience of stellar charts fading back into the status quo. There's nothing to discuss at this range given what we've seen so far. An easterly is a low <10% probability. The bit before that isn't even nailed down yet.

[A.J]

10 minutes ago, TEITS said:

Never agreed with that and its only John Holmes who suggests this. Comparing model runs on data that is 24hrs old is pointless and this is especially true in these rather changeable outputs!

to be fair, this is in your opinion...Over my years on the forum I have seen numerous references from many members advising not reading too much i(ie over analysing) into consecutive runs especially for more than 4 days out,but rather look at the corresponding runs from 12 & 24 hours ago, and with John's many years as a met office forecaster, I wouldn't dismiss anything he advises IMHO

[Nick F]

17 minutes ago, Bristle boy said:

Yday eve the posters who put all faith in teleconnections and background signals were saying that nothing was really supporting anything more than a couple of days of cold, snow......SM seemed to be challenging this ........and this evening's runs seem to be hinting at something a bit longer in duration past next w/e...........Discuss.

No-one can say 'told you so' yet, because the period in question from tail of next week, when the amplification has been on an off, has still yet to be nailed to the mast. 

However, the tropical drivers / global drivers are certainly muted (ENSO, MJO, AAM, GWO) and the strat-trop polar vortex combo are certainly driving the show for now with regards to formation of ridges and troughs in the upper flow around the vortex

Edited January 6, 2017 by Nick F

[karlos1983]

7 minutes ago, Bristle boy said:

Yday eve the posters who put all faith in teleconnections and background signals were saying that nothing was really supporting anything more than a couple of days of cold, snow......SM seemed to be challenging this ........and this evening's runs seem to be hinting at something a bit longer in duration past next w/e...........Discuss.

What I was trying to say before my post disappeared, is looking at the ens, anyone that can predict an outcome in the extended is either lucky if they get it right, or has a crystal ball. 

The future is uncertain to say the least

[TEITS]

1 minute ago, ajpoolshark said:

to be fair, this is in your opinion...Over my years on the forum I have seen numerous references from many members advising not reading too much i(ie over analysing) into consecutive runs especially for more than 4 days out,but rather look at the corresponding runs from 12 & 24 hours ago, and with John's many years as a met office forecaster, I wouldn't dismiss anything he advises IMHO

Not just mine. I have never heard anyone else suggest this in any other weather forum for many years.

The GEFS ensembles are a good example of why its futile to compare with model runs over 24hrs ago. The 18Z GEFS control is identical to the ECM & 18Z GFS and yet the rest of the ensembles are a right mess between W,lys and E,lys. Now obviously something has changed and it's finely poised hence why the Ops/Control runs differ to some of the ensembles. So due to this and the chaotic nature of these forecasting models then data that is 24hrs old is useless.

[Purga]

Some snow to cheer Mr Murr up.

[Cheshire Freeze]

2 minutes ago, TEITS said:

Not just mine. I have never heard anyone else suggest this in any other weather forum for many years.

The GEFS ensembles are a good example of why its futile to compare with model runs over 24hrs ago. The 18Z GEFS control is identical to the ECM & 18Z GFS and yet the rest of the ensembles are a right mess between W,lys and E,lys. Now obviously something has changed and it's finely poised hence why the Ops/Control runs differ to some of the ensembles. So due to this and the chaotic nature of these forecasting models then data that is 24hrs old is useless.

Completely agree. I don't see how 24 hr old initiating data can be of any use whatsoever.

[Bristawl Si]

2 minutes ago, Nick F said:

No-one can claim they told you so yet, because the period in question tail of next week, when the amplification has been on an off, has still yet to be nailed to the mast. 

However, the tropical drivers / global drivers are certainly muted (ENSO, MJO, AAM, GWO) and the strat-trop polar vortex combo are certainly driving the show for now with regards to formation of ridges and troughs in the upper flow around the vortex

Maybe the model 'discrepancies' will turn out to be a good test of the relatively new weather teleconnections science. Just pondering......and watching.

[kumquat]

Euro 4 suggests (for example) 2 degrees dip in Holland over the next 48 hours (2 degrees under what is shown on GFS) 2 Meter temps

Lower pressure further west into the Iberian peninsular (as compared to GFS) over the next 48 hrs by 100 to 200 miles.

All of these trends are in our favour. I'm feeling positive. I know Euro 4 doesn't always pan out just like the NAE didn't but these small increments in our favour. I'll take them.

This is higher res model. It's interesting to see how it compares to the rest.