phil nw.

The euro ridging in some later charts is not without support.The day 10 ecm clusters do show some form of ridging The Scandinavian high is in the minority cluster but there is good support overall for some heights around Europe in week 2. It's whether these gain enough traction to bring something of interest. Day 15 clusterings increase to 5 so a lot of options remain on any development of these and on any different pattern around nw Europe later on. Certainly at this stage there's nothing to raise much cold interest and I think it's a waiting game for the next week or so whilst this zonal pattern remains.

Hi all,i hope you all had a nice Christmas. Just skipping through the thread i sense some despondency over the prospects for the coming weeks which i understand given the current nwp outputs. I try to keep upbeat knowing that there are factors that may see a pattern change and a way out of this zonal spell but i am also aware of some uncertainties. Both gefs and ecm suites show a reduction in the zonal winds by the second week of January at the top of the stratosphere .It.s clear from the daily 10hPa charts that the vortex comes under pressure from another wave attack as it is squeezed and eventually displaced from the pole in week 2. A couple of unknowns is that although the MJO has begun another cycle towards the more favourable phases it does look to be a weaker version this time.The other uncertainty is how effectively we see the weaker zonal winds down well. Signs in the clusters and ens of a pressure rise around w.Europe in the medium term which will slow and maybe divert the Atlantic,again it's all down to how much the overall pattern can amplify and encourage a euro high further north. We have no certainty on this,do we ever with the weather?,but i think there is enough going on in the background to keep an open mind whilst we experience this Atlantic spell.

Here you go https://www.wetterzentrale.de/en/reanalysis.php?map= Just choose your date options on the left hand side of the page. This is the date to start. An Arctic northerly was on it's way bringing extensive snowfall right down to the south by Boxing day. There was a brief thaw late January for a day or so before Winter was back as cold as ever. It never thawed away completely until early March.

Here we go then after an exciting start to Winter on here,for coldies,we have to see through this period of mobile westerlies,probably for at least the next couple of weeks. Looking forward beyond this period for signals we can see both the ecm and gfs suites are forecasting a weaker vortex from the bottom up as we go towards mid-January.Charts and graphs posted by myself and others both in the Strat.thread and here show this trend. Forecasted mjo movement into favourable phases is on the cards but there is some uncertainty on it's amplitude as can be seen by the spread of members,so something to monitor. Anyway promising signs of a pattern change are showing as can be seen by the later ens gefs showing the Atlantic pattern weakening and heights building over nw Europe. A thought has just occurred to me-it's 60 years ago that we were on the verge of that historic 62/3 Winter-something i remember so well as a schoolboy.To any younger members i would say have a look through the archive charts it was quite something unlikely to be repeated for longevity. Anyway to coin a phrase- whatever the weather- I must say i appreciate the excellent posts by so many members both the older and newer ones.The amount of knowledge increasingly shown by so many recently is quite impressive and enriches the thread. I will finish my ramblings now by wishing you all a safe and very happy Christmas.

Nice little trend also from the ecm zonal winds forecast as we go into January Comparing the earlier chart with today's it shows a wide spread in the forecast yes,but also a greater number of members showing a reversal.Early days but following on from the post above by squeakheart forecasts from the gefs are also encouraging . zonal winds forecasted to decrease from the bottom up as we go into week 2.Just the first signs of the spv becoming weaker with a more pronounced disconnect from the strong westerly flow at the top.

Yes i noticed the switch back on the gefs forecasts from yesterday blue.Signs of wave 1 action picking up in week 2 as well. This could well be effects of a forecasted re emergence of the MJO moving eastwards into the Pacific showing it's hand in a few days,although amplification of this not forecasted as strong as the previous effort as yet. Later GFS frames also showing some warming picking up again at 10hPa with a push on the spv. Looking back whilst we were experiencing the cold last week the previous mjo cycle had just finished and with the time lag the blocking signal was bound to wane around now,indeed we could see the trend in the falling AAM and NWP days ago. The current cold over NA just gives a temporary kick to the Jet,the cards were already falling against our pattern before this. Just my thoughts on what i could see.In the meantime for coldies it is grit your teeth time until at least early January. In this current setup it won't always be mild with the jet running across us there will be colder snaps but i know it/s not what we hope for.We do have those little background forecasts looking into January to give us some hope of a pattern change into more in our favour.

As expected we now are starting to see the results of the downwelling of stronger zonal winds however maybe there is a light at the end of the tunnel and this expected period of mobility. Signs in the extended gefs that early in January the lower strat winds again fall away. The blues(negative anomalies reappearing as it looks like they upwell into mid-layers. The nice rounded shape that the upper strat is now showing at 10hPa isn't expected to last too long as it becomes squeezed by further warmings. It looks like a displacement of the upper strat pushes it off it's polar perch in the new year.We just need a bit of luck that this impinges on the 500hPa pattern in a favourable way. I wish we still had access to the ecm suite to double check but if the gefs is correct then chances of northern blocking will increase in a couple of weeks.

Latest fax t72 Now that is a complex area of low pressure.Arctic air from the north east meeting the sub tropical Atlantic air out west.Sort that lot out models.We can see the early skirmish developing around the Scottish north coast. At this stage (day 3) we are nearly all south of the divide but where will this end up on the big day? Later fax's are usually issued around 11pm for days 4 and 5,will be interesting to follow these now as well as other models to see how things develop leading into Christmas.

The 2 mean charts at t168 show the 850hPa forecasts NH view. Interesting to see how the deep cold trough over N.America meets the mild sub tropical air to it's east and creates the WAA up to Greenland.The jet splits and the northern arm goes over the top of Greenland and this sends a cold trough south towards the UK. Meanwhile the Iberian high is doing it's best to stall the cold over the UK.This creates the battlezone of lows around our latitude .The models are still to agree on the development and movement so i think it could be as late as Wednesday before we get a better handle on this. The main point being there is pretty decent agreement on the overall NH pattern over Christmas but the devil is now in the detail over the UK and where the 2 airmasses battle it out.

Quite an interesting turn of events with the possibility of an Atlantic ridge becoming a Greenland high. A few runs ago we were relying on wedges to get some cold south. We still have the villain Iberian ridge to overcome but perhaps the stronger heights further north will tip the balance eventually. Meanwhile the wavering boundary over the UK is likely to create some snow interest over the coming days. The move to mild or cold is equally possible and it's easy to see why we are seeing so much uncertainty and wide spreads in the ensembles. Fascinating stuff.

GFS determined to develop that Atlantic ridge again. A full blown Greenland high would be a game changer and put us into another decent cold spell. The main development comes after Christmas so too soon to hang your hat on yet.

Yes we seem to be evolving into a ridge/trough setup. A result of a wavering jet running across our latitude.

The latest 850hPa ens graph incl some of the ops from different models . Just to show the wide spread from Christmas and beyond-these are for Warks. Pick the bones out of them.This underlines that the UK is very much on the boundary of cold and mild,small developments in the track/development of the lows running across still to be pinned down.

Yes there is evidence of a more typical pattern coming at least for a while. I posted in the Strat thread a couple of days ago of the warning signs .

It's clear that fading heights to our north west is enabling the mean jet path to edge northwards in the next few days which leaves us in the UK very much on the boundary. A look at tonight's ecm mean comparing today with expected day 10 NH pattern makes the point A disappointing trend and leaves us relying on the an Atlantic ridge to hopefully move our trough enough to bring the colder air back.The Iberian high is just part of the picture really and it wouldn't affect us if the strong Greenland high of recent times had held. Unfortunately weather doesn't work like that as it's always evolving. The low pressure coming from upstream a couple of days before Christmas is the one to focus on .As it comes across the Atlantic it 's heading east at around 50n and could turn out to become a complex area so at this stage not easy to forecast where the polar front will lie around the Uk. Gfs gives a reasonable idea. Hopes of a seasonal Christmas for some of us at least are still there as the cold air is tantalisingly close to the north but we need that bit of luck.

Yes Winter is the best for this hobby and at 74 yo I am just as keen on this hobby since I got interested in the 62/3 winter. Anyway enough of my rambling let's hope for a decent 18 z set to continue the better trend.

The switch to a colder trend again on the 12's is mainly down to somewhat stronger northern heights- enough to push our pattern south just enough to get that lee northerly. As we all realise we really are on the margins and a nudge either way will spell cold or mild.Let's hope that the 12z runs around day 6/7 is the trend we can maintain by slowing that upstream low. In this situation it is even more important not to focus too far ahead other than give the later frames a cursory glance. Edge of the seat stuff and so addictive,every run is eagerly awaited.

Better from ecm.at t168.The cold air just makes it before the next low phases with our trough. Close though! Such fine margins when the uk is on the boundary.

It looks like it is down to the phasing or not of the next low around days 6/7.Gfs holds this back and hey presto the Northerly gets in and then we see our cold pattern retained until Christmas. We saw what happened this morning when this delay didn't happen and the trough over the uk was pulled north.It's the different moving parts again.A strong mid-Atlantic ridge will slow the phasing or send it further south keeping us on the colder side of the boundary.

Interesting seeing the boundaries of the polar and milder air around the Uk next week.Maybe better for the many locations that haven't seen snowfall yet. That northerly has some bite to it.

Just signs that increasing zonal wind speeds will be filtering lower down towards month end. The Upper Strat. zonal winds continue apace with the latest gefs forecasts for further increases in the next couple of weeks. Up to now the ongoing wave action has been battering the lower strat vortex and keeping it weak and split creating a protracted and unusual December period of Arctic blocking and thus a disconnect from the strong westerly winds high up..It does look like something of a change is underway. Post Christmas forecasted speeds lower down look like gaining some westerly momentum as some filtering down of westerly zonal winds is shown. Expected speeds around 10/15 m/s after this current period of negative readings This would indicate a reduction of potential blocking at higher latitudes as the westerly momentum picks up. Another indication perhaps of a change to something more typical for a while. as we see a trend to lose our current blocked pattern and gradually move the mean jet stream path north from around 45N towards 55N bringing the UK into the boundary of the polar and sub-tropical airmasses. Hopefully we see another round of warmings before too long to keep the SPV on it's toes.

Certainly a better set of runs this morning for returning the cold .A couple of days ago it looked like the UK model was almost a lone voice in minimising the mild incursion. The general consensus now seems to be milder for around 36/48hrs and a forward looking shredded trop.vortex. Again this morning the uk model continues with it's trend at t168 The Arctic air coming back south.I wouldn't be surprised to see that front develop a feature which could produce a rain to snow event with a sharp temperature drop as it comes through. Comparing the 850 ens.from the latest ops and ens means runs we can see the brief uptick in the upper temps before the trend down next week.Of course lots of spread later on but generally it looks like a return to a colder setup it's just a matter of how cold. I do like the overall NH pattern though that's got to be ripe for plenty of interesting charts in the coming weeks . This time from the ecm t168 Very un-December like.

We are indeed seeing some signs of the cold relaxing in a few days but will it only be for a short time? I have been looking through a bit of data to try and see where we are and where we might go. A view of some combined graphs from the different model runs and some of the ensembles show the spread of possibilities rising sharply towards next weekend. Just at the point where the northern blocking signal fades and we see the push from the Azores with a small ridge.Nothing dramatic but enough to send a bit of a warmer air into the south at least. Later eps/gefs guidance still favour +ve arctic ht anomalies and our temperatures still generally below normal. It looks like overall we remain generally on the colder side of the jet ,allowing for the odd push close to the south.It's a case of whether the blocking re-asserts whilst we remain in this unusual pattern. As ever the often used observation of much uncertainy beyond the next 5/6 days seems the right phrase.At least there is no strong signal for a return to our usual zonality. Original post: https://community.netweather.tv/topic/98087-model-output-discussion-the-cold-has-arrived/?do=findComment&comment=4760655

Just a reminder folks any discussion on the Met.office/BBC outlooks please post in the relevant thread link Just so we don't clog this thread up. Thanks everyone.

A big move south of the cold at day 7 on the gfs yes if you are comparing the last run although was referring to the UK run. All good though the gfs moving the right way as it get's closer ,often happens.