Model Output Discussion - 10th Jan Onwards

[Captain Shortwave]

The mean is fine from the ECM, even at day 10 you still see a Scandi high, and Atlantic ridge and clear signs of energy going south east into Southern Europe.

You can't expect much at days 8-10 from a mean apart from a broad trend, especially as the uncertainties earlier on can be the difference between a blocking high and zonal westerlies.

[SW Saltire]

I think they back up well, very well, unless I am missing something obvious?

They are all mean charts, the OP had -10 uppers at +192...Still, the mean is not bad at all really. Anyway, +192 etc is miles away. Let's get the +96 building blocks to verify first. Thanks, to Nick for posting the NCEP comments and this would add some credence to the ECM's version of the upstream pattern in the shorter term. Also, as has been mentioned before, if those positively tilted runs with positive uppers are removed (big if obviously) the mean will lower.The problem I have is really margin for error in regard to uppers. We need the good synoptic charts to verify obviously but we also lack a real cold pool. I totally accept the notion that as t-0 cones closer the 850s should become better and we can get our own cold pool as it's mid-January. However, as was mentioned last winter, in general we have a 2/3rds move from GFS and 1/3rd ECM. If on the stellar runs we got -12 uppers for example then we could afford the 1/3rd climb down to say -8 or -9ish but it's far more marginal in the current set up. Anyway, this is all hypothetical. Let's get the building blocks to verify and then we are well and truly 'in the game'

[nick sussex]

If one looks at the ECM De Bilt ensembles the thing to look at is the wind directions, theres very good support for the winds switching round to the se/east around the 18/19th January, the issue I think is whether that flow brings in less cold air from the Med which has been forced nw as the troughing elongates to the west of the UK.

 

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

 

A simple look at the temps will cover up the actual synoptics on the ground, the operational run is towards the colder end but isn't an outright outlier. So as we were before how much cold will be there to draw on if and when an eventual easterly surfaces.

 

We should factor in that the deep cold is held towards northern Denmark at T96hrs, the way the trough disrupts and whether theres any sw corrections will make a difference.

Edited January 13, 2014 by nick sussex

[SMU]

Evening-

 

I feel like im in a time warp today back to around 5 days ago when were at exactly the same juncture with the ECM, no support from the GFS & the UKMO in the middle.

 

A great ECM tonight, not perhaps in the early stages however by day 10 the cold pattern is beginning to crank up- especially for Scotland by then with the -10c line creeping SW - & also the background pattern looking to sustain the cold.

 

Confidence in all outcomes can be perhaps attributed even tonight with all runs having equal probability so we cant stack the odds in favour of the ECM just yet, also interesting is how many runs of the GFS showed the atlantic getting back in- it should be here by now?

 

Anyway finely balanced exciting stuff, the ECM operational bar 1 or 2 runs have never been keen on sinking the high & has generally sent energy south & East across to the continent in the mid term- this is the type of pattern where on the western end of the boundary its 4c & raining & on the eastern side its 1c & snowing, up until 144 we look slightly to far west - however post that things get interesting- also the scandi shortwave will have done the offski by then.

 

A decent run tonight- but not huge support just yet.... Winter needs to get going ASAP!

[fergieweather]

 

If one looks at the ECM De Bilt ensembles the thing to look at is the wind directions, theres very good support for the winds switching round to the se/east around the 18/19th January, the issue I think is whether that flow brings in less cold air from the Med which has been forced nw as the troughing elongates to the west of the UK. http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim A simple look at the temps will cover up the actual synoptics on the ground, the operational run is towards the colder end but isn't an outright outlier. So as we were before how much cold will be there to draw on if and when an eventual easterly surfaces. We should factor in that the deep cold is held towards northern Denmark at T96hrs, the way the trough disrupts and whether theres any sw corrections will make a difference.

Indeed. A (much modified) Mediterranean-sourced flow was the punt from UKMO for any easterly component post next weekend, should it even develop (this was discussed in their 6-15d briefing assessment issued at 11z today). They suggested any tap into the deeper Scandinavian cold reservoir was very unlikely. However, as many have said, anything out at T+192 as per EC DET can't be taken in any literal sense. It's still looking very much the minority outcome, at least as things stand for now. Edited January 13, 2014 by fergieweather

[Snowman.]

18z unlikely to join the ECM yet, but improvements are there.

Edited January 13, 2014 by SN0WM4N

[SnOwFeSt]

Everything seems further west and the block a bit more robust/west based on this run. A very small step in the right direction perhaps?

[damianslaw]

The trigger to a colder pattern developing is most likely to come from developments far to our NW rather than NE - there are signals for an amplified flow to develop over eastern USA/Canada regions and this is what is needed to hold sway the influence of the Greenland vortex which will remain the key driver of our weather for the foreseeable future.

 

Amplification will enable heights to build over mid-west atlantic and lock Greenland PV energy away to our NW which in turn will allow the UK to come under the influence of continental conditions as opposed to atlantic ones- easterlies often develop when we have such a pattern taking hold to our NW - the two go hand in hand - so all eyes on developments over Canada/USA seaboard. Such developments become much more likely as we head through the second half of winter accompanied by the weaker PV - its why February is often a much drier month than Nov-Jan.

[Eskimo]

Anyone for an undercut?

[Matty M]

Low driving southeast into Europe..

Easterly looms large.

Tomorrow could be biggest day Model Watching of winter.

 

The roller coaster is BACK ON

 

(This is a hopecast, not a forecast )

 

Edited January 13, 2014 by Matty M

[Ice Day]

Going under at 132. Could be a good one coming up here!?

 

[Rocheydub]

Doesn't really matter what happens here now on GFS after 132, the position is excellent compared to where we were 2/3 days ago. Discount the actual evolvement, it's the general pattern to look at, and it's excellent.

 

Amazing what taking a few days away from models does for the spirits.

 

Remember, easterlies are notoriously difficult to model, I for one won't get too excited unless it's still there after 96/72 range… And sometimes, they just do this, show up at short notice, and blow us all away! Which will this be? Time will tell, but remember, the weather will do what mother nature wants it to, so don't go ranting at anyone or any model if your weather preference doesn't appear!

[bluearmy]

The 'pub run' has been sober for a long while. It needs to recover its lost status!

[Matty M]

18z moving in right direction, decent correction from the 12z.

 

Indicating the ECMWF Op may have been on to something.

[swfc]

close but the low skuppers things heading north at 156hrs?better run tho and imo moving in the right direction

[Cloud 10]

18z quite an improvement on yesterday's run.

 

yesterday..  today..

 

 

Hopefully this momentum can continue tomorrow.

[Earth Wind and Snow]

18z looked good up to t144 but by t168 its all over - which is the time frame when ECM gets interesting

 

A move in the right direction by GFS - however it may be right in that this could be another 'close but no cigar' situation rather than what the ECM offers

 

A very interesting week of model watching and more twists and turns to come over the next few days I am sure

 

Roll on the 0z

 

night night

 

EWS 

[pdiddy]

I think the GFS is over-cooking the atlantic, having initially got to a similar position to ECM.  Perhaps the middle ground is the safer option...

[john pike]

fax chart at 120 tonight

 

 

ecm at 120

 

 

barring a very subtle difference in the lows

 

these look pretty close at present to me

[Thermohaline Conveyor]

The trigger to a colder pattern developing is most likely to come from developments far to our NW rather than NE - there are signals for an amplified flow to develop over eastern USA/Canada regions and this is what is needed to hold sway the influence of the Greenland vortex which will remain the key driver of our weather for the foreseeable future.

 

Amplification will enable heights to build over mid-west atlantic and lock Greenland PV energy away to our NW which in turn will allow the UK to come under the influence of continental conditions as opposed to atlantic ones- easterlies often develop when we have such a pattern taking hold to our NW - the two go hand in hand - so all eyes on developments over Canada/USA seaboard. Such developments become much more likely as we head through the second half of winter accompanied by the weaker PV - its why February is often a much drier month than Nov-Jan.

 

Developments to our NW are absolutely key.  Ironically the largest deviation in the ensembles spread is immediately around Greenland and into US/Canada territory.  A large-scale amplified long-wave trough dominates conditions across Canada, this likely fuelling the vortex and sending energy toppling over the sub-tropical ridge which is fairly flat at the moment.  Better confidence in heights building across Scandi beyond T+168.  Long-wave trough extends from UK into much of South Western Europe/Iberia and W Europe, but the problem we have at the moment is the energy propelling East from Newfoundland across the North Atlantic/South of Iceland and into the United Kingdom, low pressure systems will continue to topple the high, spin into the United Kingdom, won't be able to go anywhere but either oscillate and fill across the United Kingdom or make slight indentations into Iberia and the W Med.  Short-waves that form within this long-wave trough across W Europe will likely draw in warmer air and may spin back in from the East to affect the United Kingdom, the cold locked away across Scandi.

[damianslaw]

I don't often comment on GFS 18z as it often goes off on one.. but this evenings is very similar to tonights ECM and UKMO outputs at the 96-120hr timeframe i.e. the trough becoming elongated and squeezed by developing pressure rises both to the west and east - the azores high is shown to be ridging northwards - in response to an increased amplified flow off the eastern atlantic seaboard. There is still shown to be residual energy spilling off the Greenland vortex in the vicinity of SW Greenland which is still a spanner in the works for a clean ride to a colder easterly pattern - but certainly it is showing many promising building blocks for tapping into a more colder continental flow next week.

 

Anyhow as others have said we were in similar territory a few days ago - but unlike last Tues/Wed, the models are painting what appears to be a much more plausible outlook retaining heights further to our east as opposed to building to our north - given the strength and position of the PV this was never really likely.

 

A word also on the FAX charts - they too are suggesting an elongated trough developing by end of the week with heights building to the west in response to colder uppers digging down on the western flank.

 

One thing none of the models can predict with accuracy is shortwave activity to the NW - which could still become a spoiler in building strong block over atlantic which is what is needed to make the ride to a colder easterly pattern that much easier.

[karlos1983]

I really don't know why I watch the low res GFS, it just blows that block away with a big 960mb LP.

[Fred Sykes]

Thanks thats very nice of you, its difficult sometimes because I try to keep objective but at heart I'm just a kid who loves snow!

All the happiest people are still kids at heart, so long may it continue!

[Yarmy]

Guys, you aren't going to believe this but the GFS low rez goes Zonal!

 

 

 

Anyway, it's page 51 and I'm out until tomorrow evening so here's my forecast using the page number proxy:

 

60-70: "Back to square 1"

70-90: "Potential"

90+: "Wow, boom, etc"

[nick sussex]

A good start by the GFS 18hrs run which edges towards the Euros but then goes walkabout later.

 

Whatever happens in western Europe the ECM has already led the others upstream, the GFS is much too fast with the energy coming out of the USA and will not verify especially in its lower resolution which is absolute tosh.

 

Overall a decent evening for coldies but some way to go before we can be sure of a change to colder conditions.