Model Output Discussion 1200 hrs 15/11/14

[phil nw.]

A new thread then to continue discussion on the overnight models and ready for the evening outputs.

 

We are currently in a slow moving pattern with the 2 main features on this side of the Hemisphere being the SE orientated Atlantic trough and the heights to our east.

 

Compare today with T96hrs and we can see little change

 

which keeps us on the milder side of things with occasional mainly light rain from relatively shallow systems off the Atlantic.

Looking further on, today's runs have trended towards enforcing the block to our east and keeping the Atlantic at bay.

Compare yesterdays ens ht anomalies with today's for the same time.

 

 

so little sign of an end to this en pass until month end.Just an indication of increased blocking for Europe.

Frustrating for cold seekers as we continue with this stand off but at least there are signs of drier weather under some rise in pressure for the UK later on.

 

Just a reminder to please continue to post only views on the model charts and outputs in here so that we can all keep this thread informative for all our members and readers.

 

OK on we go.

 

 

[Mucka]

Seems to me if all goes as some want with the Scandi ridge we will be back where we are now in around another weeks time only with a more powerful jet to contend with.

Looking out to the mean anomaly charts at day 10 and through all the Op output, the suggestion is the stand off will continue, ridge to our East trough to our West, PV close to Greenland. 

 

 

That is no bad thing in November (especially if you have the patience to chase FI Easterlies   ) though of course as long as the pattern is amplified there is always the chance of a diving low sending warm air to higher latitudes where we need it. Currently most of the energy is modelled to go over the top from day 7 or so which means we just get the self sustaining stubborn MLB to our East, neither able to ridge NW or be collapsed due to WAA being fed back in from the Atlantic trough.

 

Personally when I call for low pressure into Scandi rather than the current ridge I am not hoping for a flat jet, I am hoping for the ridge to shunted East and the PV around Greenland to drop and push through to get a shot at building heights to our West. I don't see any typical zonal weather as likely with such a Southerly jet though of course there is always a risk the pattern would flatten. Thing is though, it is impossible for the UK to get cold from here as long as there is an Atlantic trough on our doorstep so the two choices are either undercut or for the trough to push through.

 

That said, as long as the pattern is amplified enough and the current output suggests it will be for the next 7-10 days, then it is  better to keep the ridge in place and hope the upstream pattern favours some undercut. If that is going to develop then around the 144/168 time-frame looks like fertile ground but currently it isn't modelled.

There can be very sudden changes in the output when dealing with blocks to our East in winter, the fickle nature of the beast, especially as we get into winter proper and the jet is less feisty so I wouldn't write off a sudden switch to an Easterly in 8-10 day time-frame but I can't help feeling it is a bit of a wild goose chase we have been embarked on so early in the season. Yes building blocks hit the tick boxes but the time of year and upstream pattern against it at the moment.

 

I don't mind waiting to see if the undercut comes and I would much rather be where we are than in a  zonal rut but I also wouldn't mind the pattern shunted East with a trough over Scandi rather than hoping the pattern can retrogress against an active Atlantic.

 

Every year I say the same thing, much rather high pressure to our W/NW than our E/NE as it is generally a much more secure route to cold though of course should a proper well orientated Scandi high develop I won't be complaining (especially if it gets its passport stamped in Greenland later   )

Edited November 15, 2014 by Mucka

[nick sussex]

If people are hoping for a colder outcome then I've highlighted two key areas to keep an eye on  around the 120 to 144hrs timeframe:

 

 

The more amplified the pattern is over the USA this will result in a more amplified high pressure ahead of this. This will mean a better chance of trough energy splitting se from Greenland, this at least gives a chance of a shortwave ejecting cleanly se.

 

It's still at present a low probability outcome but whilst we have higher pressure to the ne the chance remains. If we see phasing near the UK and a flatter upstream pattern then any route to cold is more difficult and will take much longer.

 

[Robbie Garrett]

I for one cannot understand why the models are struggling so much. It has to be the pattern we currently have going forward, but it's so close yet so far away from developing into strong Northern Blocking.  If that low to our SW digs further SE then we are in, as long as the Azores ridges north.

 

[Polar Maritime]

I for one cannot understand why the models are struggling so much. It has to be the pattern we currently have going forward.

 

Yes Robbie, I don't think the Models are struggling as such, Until we see some changes in the upstream pattern nothing will change on the surface, And with the UK for now at least being stuck in a kind of "no man's land" with the block just to our East i would not expect anything less from the outputs. A very slack pattern indeed for our part of the world, For now at least..

Edited November 15, 2014 by Polar Maritime

[gottolovethisweather]

So far on the GFS 12z into the reliable timeframe. NH Jet diving South with some buckling back towards us by Wednesday as per previous runs. Block holding firm over Northern Europe.

Edited November 15, 2014 by gottolovethisweather

[CanadaAl]

What's good about these runs is that they are sending the lows up the west side of greenland. With each run the lobe is more and more restrained (the euro block keeping it back) Definitely going to make for an interesting couple of weeks 

[gottolovethisweather]

On the face of it, although only one run, this isn't a bad setup from the UKMO 12z as we move into the final third of November. Potentially a blocked Atlantic, a split Jet and part of it having a tendency to dive South, blocked in Northern Europe too.

 

 

 

Building blocks to a more HP influenced pattern than most might have suspected a day or two ago.  The route to deep cold will be very slow but the time of season is on our side and hopefully the nearby continent can also start to cool down as well.

Edited November 15, 2014 by gottolovethisweather

[Barry12]

An interesting day 10 chart on the GFS tonight:

 

 

Nice to see the polar vortex emigrating to the East as well.

 

FI continues on the interest...

 

Edited November 15, 2014 by Barry95

[swfc]

Big changes on the 6z tbh.Looking like the atlantic may not make it as predicted???Fantastic model watching here

[ITSY]

Well GFS op throws up interesting hope shall we say well within +240. Worth watching a) how far the high retrogresses to Greenland and b) where the parallel goes. With Europe not that cold Synoptics need to be 100% at this stage to deliver anything snowy

[nick sussex]

Well the GFS throws the cat amongst the pigeons! Even though its not great initially it develops a big dig south of the jet and more amplification to the west which helps to push the high ne.

 

The UKMO looks more amplified upstream at T144hrs although not so good to the ne.

 

So far GFS good, UKMO could well push that Atlantic high ne afterwards if it digs the departing USA trough further south.

 

All I have to say and a line from a great old movie:

 

Fasten your seat belts its going to be a bumpy night!!!

 

Model drama about to commence!

[Polar Maritime]

GFS shows the block in a more suitable place over Iceland, Very much at odds with GFSP. Yes Nick ^ very much so 

 

Edited November 15, 2014 by Polar Maritime

[Mucka]

If people are hoping for a colder outcome then I've highlighted two key areas to keep an eye on  around the 120 to 144hrs timeframe:

 

UK1.gif

 

The more amplified the pattern is over the USA this will result in a more amplified high pressure ahead of this. This will mean a better chance of trough energy splitting se from Greenland, this at least gives a chance of a shortwave ejecting cleanly se.

 

It's still at present a low probability outcome but whilst we have higher pressure to the ne the chance remains. If we see phasing near the UK and a flatter upstream pattern then any route to cold is more difficult and will take much longer.

 

 

Unless it provides enough energy to get the trough to our East and then the route to cold could in fact be much quicker. There is nothing to suggest a flat zonal pattern would set up IMO though that is admittedly a risk but then there is nothing to really suggest we are going to get the necessary undercut to provide the HLB we need.

 

 

I'm not writing off because I agree with you there is a small window of opportunity but If we can get a trough into central Europe that will always provide much better chances than a MLB to our east with the jet and energy pushing through SW Greenland

 

 

Currently I would rate any kind of quick route to cold from this pattern as very slim and I would much rather move the pattern East and replace the high pressure in Europe with low pressure. Even in mid winter a long fetch Easterly or a nice rounded cut off Scandi high are as rare as hens teeth and while it may be a very good sign for later in Winter to have strong blocking across Europe in mid Nov it doesn't really fill be with optimism for a cold Easterly outbreak in the next 2 to 3 weeks.

 

Of course if it got broke down and we get stuck in a typical zonal pattern then fair enough I was wrong but I just don't see conditions as last year for that to happen.

 

I think what may happen is that we get Azores high ridging in and low pressure pushing over the block, so zonal but with lows on a Northerly track. From there who knows but I would hope the Azroes high would slowly be squeezed West as low pressure rolled down its Eastern flank.

 

I am sticking my neck out here because the prospect of a cold pattern developing from this MLB is still alive but if I were to have a wager it would be that our first cold spell comes from low pressure to our E/NE not high pressure with high pressure to our W/NW not low pressure.

 

Now I have written that expect a stonking Easterly to be modelled within 48 hours. 

Edited November 15, 2014 by Mucka

[gottolovethisweather]

GFS shows the block in a more suitable place over Iceland, Very much at odds with GFSP. Yes Nick ^ very much so 

 

 

Indeed, but with the UKMO and GFS (P) at least during its earlier stages halting an Atlantic onslaught, this might well be a blessing in disguise. Can't have it all but the current timescale was precisely when I believed some changes might start happening in the NWP outputs. No clear signal either way yet but also no continuation of a mild moisture laden SW flow more importantly. Lets shift the troughing and see what's up for grabs as time ticks by. 

Edited November 15, 2014 by gottolovethisweather

[Summer Sun]

After this spell of wet weather we may see a period of high pressure developing later next week bringing a spell of quieter weather with the potential for frost and fog overnight with the latter perhaps lingering well into the day for some of the more prone areas vale of York ect

 

 

Whilst a spell of settled weather won't go down well with some it would help colder air to build across large parts of eastern Europe which in turn could benefit the UK further down the line

[Eugene]

http://www.wetterzentrale.de/pics/Rukm1441.gif

 

 

A very promising chart by UKMO at T+144 hrs IMHO, definitely not looking too shabby and definitely nothing to be despondent over, any cold shot is a slow evolving process, a light SE'ly drift is great to dry the countryside out and build cold across the continent.

[damianslaw]

Its a static slow moving picture as many have said, but the models continue to suggest no sudden atlantic onslaught next week. We have a split jet, and the Jetstream forecast is for energy to transfer more into the southern arm which will help to maintain strong heights to our east and a continuation of a non-fluid atlantic pattern.

 

Interesting GFS 12z beyond reliable timeframe, but it shows a possible route to something much colder if we see an amplified pattern over N America and fuel injected into the southern arm of the split jet - the outcome the polar vortex shifting its core firmly on Siberia which will help pull heights over towards Greenland - its certainly a plausible synoptical evolution, but as ever to get there requires many hurdles.

 

All eyes continue to be on developments over the other side of the atlantic, a more amplified trough formation will help to pump warm air advection up the west side of Greenland weakening the PV lobe currently sat there and killing off energy in the northern arm of the jet. Less amplification will help to keep the current PV position intact and maintain more energy in the northern arm of the jet, the outcome will be more of the same.

 

Despite the rather lacklustre conditions the UK has and will continue to experience over the next few days, its in interesting set up at present with plenty of options none of them likely to deliver a pounding atlantic attack anytime soon.

[blizzard81]

I think model fatigue has set in a little earlier this season, hence the lack of posts. I am wondering what the ECM will throw up tonight. It's interesting that 2 or 3 days ago the ECM 12z threw out a very high pressure dominated run in it's later stages and this seems to be what the GFS and UKMO are picking up on now.

Edited November 15, 2014 by blizzard81

[Eugene]

I think model fatigue has set in a little earlier this season, hence the lack of posts. I am wondering what the ECM will throw up tonight. It's interesting that 2 or 3 days ago the ECM 12z threw out a very high pressure dominated run in it's later stages and this seems to be what the GFS seems to be picking up on now.

 

 

Model fatigue just a few weeks after we hit 23.6C, wow that is just incredible if you are correct  , I didn't even really start looking for cold until today and am raring to go about the next four months of model watching, the endless warm weather did fatigue me though

[bluearmy]

My eyes are taken by the cold arctic high on the Ukmo run. Edging sw out of Siberia and looks odd to see it aside the 'warm' high created from the Alaskan ridge. Cold arctic highs are tricky customers and once moving they take some stopping. the GEM run illustrates how this type of high will often 'suck' a block at our latitude up into the arctic, allowing the cold uppers to flow clockwise on its southern flank. just a sniff of this at the moment but definitely something to keep an eye on as the arctic has not been modelled too well over the past week or so.

Just checking the week 2 gefs and this type of evolution is certainly on the table. split vortex and blocking around us - you just never know. Always a chance.

Edited November 15, 2014 by bluearmy

[SMU]

Afternoon All-

 

So the shift in the models continues & throws more support around the deep cold moving SW on a trajectory to Europe-

 

The GFS & now the GEM becomes alligned to this happening with the 2 slider lows very apparent at 144-

http://www.meteociel.fr/modeles/geme_cartes.php?ech=6&code=0&carte=1&mode=0&archive=0

 

At Day 10 GEM has -28c 850 air from the vortex moving nicely into Eastern Europe driven along on a keen Easterly flow..... Can it make it towards the UK!!!

 

http://modeles.meteociel.fr/modeles/gem/runs/2014111512/gemnh-1-240.png?12

 

Remember the GFS ensembles wont be on board until tomorrow or monday with this solution....

S

[Captain Shortwave]

So we have good consensus developing for next week

GEM now sniffing the ECM southerly. 850s of 14C into the south by the end of the week. Simply incredible for the time of year.

Even more surprising is that the ridge currently over Eastern Europe is relentlessly pushing west despite a big surge of cold air heading in the direction of Europe from the Canadian lobe of the tropospheric vortex. Something is afoot here.

So there is the potential for near record breaking warmth developing next weekend if we get the straight southerly flow from Africa with enough strength to stop an inversion developing. But it's after this point that I think most on here will be more interested in.

So whilst we play with high pressure, maybe we should be keeping an eye out to our east........

I did say that chance of cold will be from the east didn't I 

 

Oh and just for more fun. Here is a GFS ensemble chart for a long way in the future

That Canadian beast turned into a yapping terrier quite quickly didn't it.

Edited November 15, 2014 by Captain shortwave

[Eugene]

So we have good consensus developing for next week

GEM now sniffing the ECM southerly. 850s of 14C into the south by the end of the week. Simply incredible for the time of year.

Even more surprising is that the ridge currently over Eastern Europe is relentlessly pushing west despite a big surge of cold air heading in the direction of Europe from the Canadian lobe of the tropospheric vortex. Something is afoot here.

So there is the potential for near record breaking warmth developing next weekend if we get the straight southerly flow from Africa with enough strength to stop an inversion developing. But it's after this point that I think most on here will be more interested in.

So whilst we play with high pressure, maybe we should be keeping an eye out to our east........

I did say that chance of cold will be from the east didn't I 

 

 

There will be no record breaking warmth for the UK end of the week mark my words, UKMO and GFS don't agree with you at all, the chances are extremely slim and any light southerly will likely produce conditions like today, really give up on the direct southerly warmth until mid February onwards.

[knocker]

Slight difference between the ops and 1534 at T228