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Model Output Discussion - 10th Jan Onwards


Paul

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Posted
  • Location: Eshaness, Shetland Islands
  • Weather Preferences: Cool and Stormy
  • Location: Eshaness, Shetland Islands
Posted · Hidden by Osbourne One-Nil, January 10, 2014 - Interesting, but not model discussion!
Hidden by Osbourne One-Nil, January 10, 2014 - Interesting, but not model discussion!

A BBC weather presenter was on the radio this morning (Shetland) explaining the recent flooding and what is likely to come over the next few weeks. She explained that the strong jet stream was responsible for the recent storms and flooding and that the deep cold in the US was providing additional energy to the jet stream over the UK and NW Europe.As for what is to come, she stated that it is very difficult to predict the weather, at this time of year, from 4-5 days out. However, in her opinion, she said that it was unlikely that the UK would see sustained periods of deep cold now this winter, but shorter cold spell were a distinct possibility. So far this winter, it has been one of the mildest since the early 2000's, which is a change from recent years. Any significant snowfall is likely to be short lived or limited to Scotland and the Northern Isles over the next week, at least.

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Posted
  • Location: Kings Norton, West Midlands
  • Weather Preferences: Thunderstorms, Cold & Snowy
  • Location: Kings Norton, West Midlands

A BBC weather presenter was on the radio this morning (Shetland) explaining the recent flooding and what is likely to come over the next few weeks. She explained that the strong jet stream was responsible for the recent storms and flooding and that the deep cold in the US was providing additional energy to the jet stream over the UK and NW Europe. As for what is to come, she stated that it is very difficult to predict the weather, at this time of year, from 4-5 days out. However, in her opinion, she said that it was unlikely that the UK would see sustained periods of deep cold now this winter, but shorter cold spell were a distinct possibility. So far this winter, it has been one of the mildest since the early 2000's, which is a change from recent years. Any significant snowfall is likely to be short lived or limited to Scotland and the Northern Isles over the next week, at least.

As the saying goes, she can tell me the winning lottery numbers. 

+120h is the critical point now. 

Posted Image

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

All things considered, the latest met office update sounds wintry for the far north and east with hill snow and then an increase risk of frost and ice, and the Ecm 00z ensemble mean is still full of potential, there is still a ways to run with this in terms of how cold it could become and ppn type, especially with elevation. It's sounding more encouraging than what we have endured so far IMO.

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Posted
  • Location: Penwortham nr Preston, Lancashire
  • Weather Preferences: Severe frosts, warm sunny summers,
  • Location: Penwortham nr Preston, Lancashire

One thing that has struck me in since the onset of the internet and accessible models to go through is that the PV seems to be a semi permanant feature over NE Canada/Baffin area most winters rather than around Scandi, does anyone know why this is? is it because of the North Pacific ridge being semi perm or siberian section of the vortex being semi perm :s knee bone before the thigh bone?

Edited by Arron B
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Posted
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Weather Preferences: Sunshine and 15-25c
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)

Looking at the NH set up as a whole i dont see a pattern that would favour any cold outbreak across Western Europe in the foreseeable. Things are changing across N.America to a much milder set up and a eventual weakening jet over here..which would encourage a slowing of the Atlantic train towards the end of the month...overall a poor outlook for cold across both continents.

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Posted
  • Location: hertfordshire
  • Location: hertfordshire

All things considered, the latest met office update sounds wintry for the far north and east with hill snow and then an increase risk of frost and ice, and the Ecm 00z ensemble mean is still full of potential, there is still a ways to run with this in terms of how cold it could become and ppn type, especially with elevation. It's sounding more encouraging than what we have endured so far IMO.

The way the update reads it sounds as though the colder air to the east will be a bit further

west than what the models are showing although nothing really cold hence the snow on

hills.

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

HI Nick,

 

what time frame do you think renewed amplification over the USA might take place?

Sorry for the delay in replying, the amplification is beginning over the eastern Pacific west coast as we speak,  this helps to slow the eastwards progress of low pressure etc, and will impact on the pattern in Europe.

 

In response to JH in terms of the overall upper air pattern well the NOAA maps which I know you like to use suggest a cold pattern for Europe with where the negative and positive anomalies are shown however this can cover up the detail on the ground which is always crucial for the UK because of the nature of it often being at the periphery of cold.

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Posted
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Weather Preferences: Sunshine and 15-25c
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)

1947 had record cold in the USA in fact i believe their all time low temp was recorded then. No comment needed on what happen here!

The worst recorded cold outbreak in US history was February 1899..when a low of -19c was recorded in Florida of all places!

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Posted
  • Location: hertfordshire
  • Location: hertfordshire

Looking at the NH set up as a whole i dont see a pattern that would favour any cold outbreak across Western Europe in the foreseeable. Things are changing across N.America to a much milder set up and a eventual weakening jet over here..which would encourage a slowing of the Atlantic train towards the end of the month...overall a poor outlook for cold across both continents.

I would say that this would be a positive pattern change towards a colder outlook for

the UK and Europe towards the end of January and onwards into February unless a

big southeast ridge forms which I think is unlikely.

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Posted
  • Location: South Gloucestershire BS35
  • Weather Preferences: Severe weather enthusiast
  • Location: South Gloucestershire BS35

One thing that has struck me in since the onset of the internet and accessible models to go through is that the PV seems to be a semi permanant feature over NE Canada/Baffin area most winters rather than around Scandi, does anyone know why this is? is it because of the North Pacific ridge being semi perm or siberian section of the vortex being semi perm :s knee bone before the thigh bone?

 

I have just posted some info in a different thread - Hope it answers your question, if somewhat briefly.

 

http://forum.netweather.tv/topic/78799-talking-about-the-polar-vortex/?p=2891848

 

If you haven't aleady, well worth reading chio's post #1 on the Strat temp watch thread for more detail, as well as following other posters in there Posted Image

 

http://forum.netweather.tv/topic/78161-stratosphere-temperature-watch-20132014/?p=2806808

Edited by Chris K
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Posted
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Weather Preferences: Sunshine and 15-25c
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)

I would say that this would be a positive pattern change towards a colder outlook for

the UK and Europe towards the end of January and onwards into February unless a

big southeast ridge forms which I think is unlikely.

Yes the potential is there towards the end of the month more scope for high pressure to build...but where is the question?

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

 

 

In response to JH in terms of the overall upper air pattern well the NOAA maps which I know you like to use suggest a cold pattern for Europe with where the negative and positive anomalies are shown however this can cover up the detail on the ground which is always crucial for the UK because of the nature of it often being at the periphery of cold.

those charts have never been suggested as being able to predict detail on the surface. What they do is enable some predictions to be made as to what can and cannot occur due to the upper air pattern. if the upper air pattern is not correct there is absolutely no chance of any surface prediction being correct. Detail must always come from synoptic models. It is how folk use that data that is so often the problem on here. No one no model can accurately predict the surface detail more than about 120-144 hours ahead for the UK or any other small portion of the earth. Don't believe me ask the current weather forecasters currently giving out BBC weather forecasts. They are very approachable if anyone wants to  e mail any of them-honest.

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Posted
  • Location: Seaview - Isle of Wight
  • Location: Seaview - Isle of Wight

Surely the gradually increasing solar output needs to be taken into account. By the time February arrives and any cold would this not be a factor?

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Posted
  • Location: York
  • Weather Preferences: Long warm summer evenings. Cold frosty sunny winter days.
  • Location: York

Surely the gradually increasing solar output needs to be taken into account. By the time February arrives and any cold would this not be a factor?

 If anything we have seen the peak now and are about to see a return to a quieter phase

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

those charts have never been suggested as being able to predict detail on the surface. What they do is enable some predictions to be made as to what can and cannot occur due to the upper air pattern. if the upper air pattern is not correct there is absolutely no chance of any surface prediction being correct. Detail must always come from synoptic models. It is how folk use that data that is so often the problem on here. No one no model can accurately predict the surface detail more than about 120-144 hours ahead for the UK or any other small portion of the earth. Don't believe me ask the current weather forecasters currently giving out BBC weather forecasts. They are very approachable if anyone wants to  e mail any of them-honest.

I'm not disagreeing with you re those charts. However most people in here at this time of year want to see some cold and snow and those maps whilst illustrative in one sense aren't a lot of good in terms of the detail.

 

And its this detail which at the moment is proving hard to find, so the maps show that the UK could get cold but the actual orientation of low pressure and possible trough disruption and how far west the cold might come is still a big question mark.

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Posted
  • Location: Royston, Herts 76m asl
  • Location: Royston, Herts 76m asl

No doom and gloom from me. The pattern shift is pretty much bang on schedule - mid Jan - and we have decent slowing zonal winds, renewed wave 1 warming forecast today and much more likelihood of HLB than at any time so far this winter. It would have been an enormous bonus to achieve proper cold at the first attempt... but I think within 10 days we will have a much colder continent, stalling low pressure in the atlantic and (hopefully) a signal for substantial vortex disruption that might lead to a reversal. I have been mulling over whether strong solar activity is desirable: normally we would say no. But I am mindful of spells in recent winters where the block as been so damn strong that low pressure has simply not got here, or the azores high has built NE and spoiled our setup. Stronger solar activity may maintain a bit of atlantic push while stratospheric chaos helps build a decent Scandy or perhaps Greenland block. With a bit of luck this could possibly produce at least one spell of special winter weather.

 

Fingers crossed.

 

Good post.  Barring a reversal of the models (which could happen, it's not too late) it seems that we are not going to get any serious cold at the first attempt, at least not outside Scotland. Even GEM retreating I notice, given chilly rather than deep cold charts, with SE flow.

 

But hey-ho, no doom and gloom is justified at all.  TEITS said way back that his instinct was that the first attempt will fail, and it looks like he was right.  But the important thing, as Tamara says above, is that there is abot to be a massive and (even for non-coldies surely) welcome pattern change.  That is, to use the cliche, "nailed".

 

There will be bags of opportunities in the futre and I for one will be amazed if we don't get some interesting cold weather at some point, probably before the month is out.  Winter of 88/89, this aint gonna be, in my opinion.

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Posted
  • Location: Bristol
  • Location: Bristol

Nothing is cast in stone yet and never will be :)

That is true, but imo, the mid term does not not appear favourable for cold. Obviously there is a window next week, but this still appears temporary. And that's what the models suggest this morning.

If we look at the Teleconnections, the NAO is reluctant to turn negative through its forecast period, with the ens trending weak positive (taken as a mean). The PNA is forecast to move back to neutral into last third of month.

Posted Image

The AO looks better, with a negative state for a while, but turns positive as we head into latter stages of the month!

Posted Image

NAEFS shows troughing to our NW within the 11-15 day range, indicating average temps for the UK.

Posted Image

While GEFS, shows much of Europe returning to more average conditions to slightly below, with the colder air towards the east & ne. Also, southern Europe sees a split, with the se positive, the sw into Spain and Portugal seeing cooler than average.

Posted Image

11-15 day mean surface temps

Taking into consideration the latest meto update 30d, ec32.. It does appear we are edging towards a rather average medium term, in terms of temperature. But obviously, this is a fluid situation with many changes ahead. But i do think we need to temper expectations.

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Posted
  • Location: Solihull, Midlands. (Formerly DRL)
  • Weather Preferences: Sunshine, thunder, hail & heavy snow
  • Location: Solihull, Midlands. (Formerly DRL)

We should not be peturbed at all by the apparent model stalemate of the heights to the NE and the 'static' stalemate of atlantic trough disruption. In other words the suggestions that it might well refuse to align favourably into europe for a cold easterly to be backed over the UK.

 

First up, stalemate or not, we should welcome the pattern change with open arms after enduring raging +AO tram-like gradient fuelled zonality for several weeks. It is imo actually quite an achievement and turnaround, in relative terms, just to get to this position after the awful set-up in our part of the NH that we are only just in the process of leaving. So the first blow has been dealt to the  vortex, even if there is more to do.

 

Next, as a consequence of the changes we see, we have the advantage of having big uncertainty on our side for the first time this winter. The models indulge in a dogs breakfast with these sort of winter time blocking patterns, much as stated yesterday, and will not only be hard pressed to calculate energy equations in terms of trough disruption and play catch up with upstream amplification conundrums over the Pacific as nick s has been rightly suggesting, but they will also be far too progressive in trying to break down the blocking pattern over the medium/longer term too

 

There is still a massive amount of uncertainty in terms of how trough disruption might work next week with both football and rugby ball shaped lows still suggested to approach us from the atlantic. As depicted by the EPS ensembles at day 5

 

Posted Image

A complete pick and mix still evident..and as well as the positively tilted solutions, there are still actually some rather nice incoming easterlies suggested amongst them as well...Posted Image

 

I've stated often through recent weeks that this was always a long game this winter and am happy enough (in the circumstances!!) with that proving to be the case, even though patience is being tested for many of us for sure. 

 

So, if we assume for one moment that nothing favourable in terms of a cold easterly occurs in the next week or so - a rather nice quandary develops regardless anyway from the suggestion (at current face value) by the models of this 'static set-up' in terms of the significant cold anomalies that are indicated to build over Eurasia (irrespective of whether we in the UK tap in the short to medium term into that cold or not).

 

Posted Image

 

Could it be that the flip in wave activity forcing, as suggested by stratospheric forecasts down the line, might help us tap into a cross-polar flow - this feedback initiated by the developed cold pool to the NE, to force that cold air southwards to us instead of west or south westwards? I'm speaking here on the basis if the latter (more immediate) route doesn't materialise.

 

Recent ensemble data, although open to question in this messy pattern, has appeared to back off any early suggestion of deep cold as indicated the other day, but it has also been hinting at the possibility of cross polar ridging down the line too. It could simply be that this signal is too premature, but it could be that a change of troposphere/stratosphere attack focus on the vortex might open up the door for this, even if it also presents possible downside risks too if the tropospheric cards don't fall right. These risks depend entirely on how strong this attack might be.

 

There are good suggestions that the Scandi High will stay around long enough to find us in the scenario later this month for hopefully at least a displaced vortex to then be forced east towards Siberia and pressure to rise towards southern Greenland in the wake of a trough migrating and sinking into Europe. Yes, we would prefer a split, and there are always risks with vortex transport, but I'm going to follow the best case scenario possibility here and take into account the cold build up to our NE forcing any 'zonal' attempted route, as energy is attempted to be transported briefly across the pole, to be the continued disrupted southerly tracking variety. Especially as assisted by a continued amplified Pacfic pattern with energy splitting the jet stream. Indeed, this might prove the catalyst even to kick start the stalemate and send low pressure properly into Europe

 

So, if we don't get the immediate trough disruption into Europe and we have chillier SE'erly winds rather than a cold easterly backing the cold westwards over the next week to ten days, then there is an opportunity for the Eurasian cold pooling feedbacks and renewed wave activity, as mentioned above, producing cross polar ridging to force the cold from the north instead.

 

With wavelengths changing as we head through the second half of winter and the polar westerly signal waning in tandem, and the reasonable chance that subsequent wave activity follow-up could be big enough to deal the vortex a real blow before re-organising to any extent,then the glass full solution is there to be looked at as much as any pessimistic solution. Such an unfavourable other scenario is whereby any less effective vortex attack and greater subsequent transportation of energy across the pole, uproots out cold pool to tap into, and leaves us with residual parcels of energy over Greenland instead.

 

But enough of that talk - maybe there are reasons behind my fascination with this pattern as stated yesterday evening, and the subsequent reply to it in terms of late month surprises might hold some water afterallPosted Image ..time will tellPosted Image

That's a pretty sick post Tamara. Very informative and enlightening. Posted Image

 

I think you made a good point their regarding the upcoming pattern change we're likely to undertake, and how it almost feels like a miracle getting to this stage considering the dominance of the Vortex to our North and North-West helping to drive that mobile Westerly setup we've faced in the last few weeks or so (albiet obviously with some odd instances of amplified Highs out West providing the odd Northerly-like toppler here and there). I do begin to wonder that it might turn out to be that possible 'second bite of the chocolate muffin [or cherry ;-)]' to perhaps see some very chilly and wintry weather over the UK. As you say, even if the first attempt of cold, or deep cold, doesn't deliver for the UK, then other developments, such as those Wave activities and/or other type of Stratosphere/Troposphere warming events could still help get that cold from the North-East or North to drain down over the UK. I guess providing we see those Vortex pieces knocked about towards favourable places for cold, and as you mention, not seeing too much cyclonicness/energy left over Greenland, or any other places that would be unfavourable for cold for the UK. But it's true that the cold, possible, continental flow outlook next week probably shouldn't be discounted completely with those varied solutions on offer, which I think shows that the models still haven't got a complete handle on this (even though it's possible the Lows may struggle to push far enough East or South-East under the block, or end up tracking straight through the UK). I can certainly imagine it must be very hard for the models to handle Easterly patterns as previous events in the past will prove how difficult it can be, and how these modelled Easterly flows can sometimes just suddenly become 'stamped-out' on the models.

 

It's just like a game of Mario Kart. You get off to a bad start in last place, but various items and elements get you further and further ahead in the race until, before you know it, you've won the race. And I think that's probably how this Winter may indeed end up turning out for the cold and snow fans. If, let's say, the pieces of the jigsaw do not fit into place for chilly weather next week, then other pieces of the jigsaw (whether it's the Vortex disruption/relocating, that upstream amplification you and nick sussex mentioned and/or the blocking to the North-East still helping the cold and snow fans out) could fit together for chilly weather.

 

One thing for sure is that there are lots of changes coming our way... ;-)

Edited by DiagonalRedLine
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Posted
  • Location: Orpington Kent.
  • Location: Orpington Kent.

Eyes down folks.. The brilliant post earlier this Afternoon from Lady T has given me renewed hope that although the models on the face of them have backed off a long way since Wednesday we are still in with a chance of something the end next week and if not there is plenty going in our favour for later on in month.

We're an impatient lot here, but if nothing shows up on this set of 12z then I feel it won't be long..

Good luck folks, I,m settled down with a cup of tea waiting for the next instalment.

18 hous in no change ;)

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Posted
  • Location: Lytchett Matravers - 301 ft ASL
  • Weather Preferences: Snowy Winters, Torrential Storm Summers
  • Location: Lytchett Matravers - 301 ft ASL

Heights look better to me at +66 to the NE

Posted Image

All eyes on the jet for me and how far south it digs!

 

Posted Image

Edited by karlos1983
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Posted
  • Location: Kings Norton, West Midlands
  • Weather Preferences: Thunderstorms, Cold & Snowy
  • Location: Kings Norton, West Midlands

I know a lot of people tell others not to look too closely into the model run but the 12z certainly has more of a negative tilt towards the SE on that low which is a good sign at least! (Slight differences make all the difference!)
 

6z

 

Posted Image

 

12z

Posted Image

 

Edited by PerfectStorm
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