bluearmy

I have thought about it for all of three seconds and I will stick with ecm/ukmo/gem/gfs 12z + ens over gfs 18z anyway, eps clusters reveal around 30% support for mobile westerly winning out post T300. Other two clusters have undercutting of heights to out ne or north out to day 15 which would prove fairly seasonal ..........

Of all the evenings for the 18z to be sober ............ HNY

When is an easterly not an easterly ??? Mogreps may well show vast majority easterly flow by Sunday but what does that actually mean re sypnotics etc and sustainability ?

How many have you seen that didn’t ? I guess the fact that cfsv2 isn’t churning out warm run after warm run is notable enough though !

Of course they existed andy - we just didn’t realise .......

Just to say that there is little sign that the Atlantic will lessen its strength in the extended period - but with the help of the upper Scandi ridge we could well see it deflected in a sustained fashion to our south - the mean jet at day 10 looks impressive also, three wave hemispheric pattern at same timescale

The eps are pretty good re the op - now that can happen from time to time so it would be prudent to wait for the 00z before digging out the salopettes extended maintains low anomolys (heights and slp) to our south - how the lw trough navigates from the n Atlantic to the med will be the question .......

Look again gavin

Not surprised to see the 12z ec op trend that way, given that the majority of clusters were more amplified days 7/8 but it’s still an uncertain evolution - what really matters is the Atlantic approaching day 10 - to have it undercut into Europe to the south will make this become a proper cold spell. The ec op manages to give us WAA to keep the Scandi ridge in Scandi and then begins an undercut at the end

It was a few years ago - I recall some people saying sunspot activity was responsible for the collapse if it's the one I'm thinking of of course we aren't that close yet as ukmo only just in range of the ridge

They have mogreps which will put the eps into more perspective. the two clusters away from the op one were more amplified and would therefore advect more cold. no one should be surprised about showers being of snow in January when it's cold! we can only interpret what we have access to - as has been said already, no one knows how this will play out but the trend is one of the ridge not bringing notable cold to the uk. However, this could easily reverse as small differences around day 5/6 will have larger consequences later on. With blocking set ups, the orientation of the blocking is everything for our small island.

Yes - but I did edit it to extended. The detail pre day 8 is tough to analyse and as I stated later, may make the extended look rather different if it heads down the more ukmo path

Sorry you've been ill but there was nothing wrong with the way you phrased your post. you were probably posting what quite a few were thinking. Point being that nothing particularly wintry has even appeared yet so those disappointed were probably taking too much notice of the wrong posts - again! Btw - not a good extended gefs for coldies. Worst I've seen for a fair while for anyone wanting a decent wintry outbreak. If could be that changes to the pattern pre day 8 make everything post day 8 fairly redundant- let's hope so!

Less of a bust than the 00z was. Note the development of the low indicating some trough disruption - gfs post day 8 generally takes the jet ne rather than se. Time to see how many eps clusters there are.

Not sure what has yet existed to go 'pear shaped' . we seem to be getting a handle on how the ridging will interact with the various players but detail still fairly sketchy. beyond day 8 and the Atlantic still favoured but is that into Europe or scandi or west of scandi ???

More concentrated pulse of the jet into France would have created a stronger more defined trough which, in turn, would have advected more cold westwards as the ridge intensified - another reason we aren't seeing. The flabby system we see now isn't good for coldies

Whilst the det cannot be used for accurate forecasting post day 7, it does give a broad pattern indicator and also tends to give a heads up to a change from the eps mean/anomoly. A good illustration of this is the digging of the Atlantic trough more to the sw as it heads se next weekend. That has served to push warmer uppers north just to our se and the jet pulse which should have gone into France is more muted as it has been spread around a larger area - tough to explain but the op led the way illustrating this and the eps spreads agreed. if there is a spread and the op sides with the spread then take note! If the gfs continues to trend away from colder uppers next weekend and ukmo follows suit later then sadly, the ecm op will have come out on top. There is still time for it to be wrong though!

Broadly speaking the direction of travel is good with ridging to our east intensifying as the ens come into higher res and the pulses of northern arm have nowhere to go but into Europe to our south. that keeps us on the cold side but the way gfs and ecm orientate the ridge on the ops (and ens ) means that we don't advect any proper cold uppers into nw Europe and when the battleground develops, it's probably going to be nerf guns rather than rpg's. Steve has illustrated the better ukmo in this respect. The outlook remains cool/cold unsettled but with the ridging to our ene thrown in as a wild card it should remain busy on here for the foreseeable.

Surprised you didn't post the 12z from the 2nd steve But then it wouldn't fit your narrative been back and checked very ecm chart from day 9 and two were too progressive without diving/sliding the trough. Gfs was indeed like a dog with a bone but then it overdid the slider too far southwest for several runs within T156. It also overstated the ridging in the n Atlantic. Ecm was never keen on that big area of high heights and that turned out to be much closer to reality. And let's not pretend it was good with the placement of the slider within T84. The stat chart posted above was presumably from Tuesday morning ec run where it was way off to the north. Neither model is ever right post day 7 and whilst I will agree that ecm hasn't been as reliable as it usually is as an indicator in the 7/10 day period, lauding gfs fo being any better isn't right either.

Pointless posting the stats martin because more than 80% of the time the ecm out verifies all the other models. since its last upgrade I'm not sure how it is days 8/10 as before that, gfs used to be about the same stats (both sub 50%)

Nick, I côuldnt understand why people were criticising the ec run as if it was wrong or had made some wierd evolution that was implausible. Surely the point of the thread is to discuss the output. You can say you don't like the evolution from a personal perspective of cold/mild etc but you can't criticise it without providing evidence as to why. At the moment the upstream surge of the northern arm is too strong for any ridge to hold - his the jet splits ne/se against it is the issue.

Criticism of the ec op is bizarre - irrelevant that it IS the best model with the best verification stats, it's 12z op is broadly in line with its eps anomoly output from the 00z suite (which is in reasonable agreement with the gefs). I'm scratching my head reading back the previous couple pages

Not wanting to take the thread away from model discussion but those forecasts from Exeter are broad brushed. Never take any detail from them post day 5. Just use the wording to evaluate whether their in house models are agreeing with what we are seeing on the stuff we have access to. we are seeing a bit of a crossroads post day 7 with the solutions and I expect so are they but the general trend is colder. several days on and that balloon of heights is no closer to being resolved

In which case, why object to a high res decent model like GEM being highlighted? Fwiw, the eps run at 14km out to T240. The gfs op is at 13km. The ec at 9km and the other ops between 15 and 18km so if we are going on resolution alone, the 50 eps members are as useful as the gfs op?? The icelandic view eps clusters are available here : http://brunnur.vedur.is/kort/ec-ens/2017/12/30/00/

but it was supported by the ens ? and I would prefer to see the ens stay with continuity whilst ec det is flitting about days 8/10. If ec det fixes on a solution then I'm rethinking