Model Output Discussion - The Start Of Winter

[karyo]

The NCEP ens is on the same page as the other anomalies. And out to T360

At least the Azores high is looking subdued here with troughing getting into the continent and it should not be overly mild for the UK.

[Weathizard]

For me looking at the models its that wretched azores high causing many of our troubles as is normal with most winters, we've seen many times in winter what an annoying feature this can be especially while there is a portion of the vortex in the vicinity of Greenland it leaves us stuck in the middle, longer term there is some tentative signs the Azores high may sink away but you can't help but wonder how long this could hang around for, hopefully we won't have to bare it for the rest of this month. At this present time the high cannot ridge northwards and it leaves us in an endless cycle of the same pattern, occasional dry dull spells with interspersed periods of rain & rinse and repeat.

 

The PV is a mess right now, and looks to be continuing to be one but its difficult to see any HLB whilst that Azores high and lobe of the vortex play kiss chase.

 

[IDO]

the same models that displayed weeks of mild westerly flow for last 3rd od Nov and early Dec.....yep confidence should be high 2-3 weeks ahead.....not. On another note quite cold for such an inoccuous set up

There is no correlation between the two instances. As I have said on several occasions the GFS got it wrong due to happen stance of a Tropical Storm (Nuri) causing mid latitude disruption along with strat down welling. The nature of these storms mean the outcome may not be known till T-120. To blame a model on that error is rather unforgiving. Well of course yin and yang, and now we pay for the consequences of the PV being delayed it's normal cycle, compounded by the fact we reaped no benefit from the consequential meridional flow. Of course we can discount the models and hope things improve but the models are showing what they are showing and we can only debate that. IMO they look more than reasonable in the great scheme of things, with the usual caveats.

[Frosty.]

A very pleasing Gfs 06z op run again today, just as yesterday, indeed this looks better longer term with wintry potential. November was like watching paint dry model / weather wise but these charts are like a breath of fresh air with frequent cold incursions from the north west and any mild weather very brief and hardly worth a mention at all. Lots of cold, windy and showery weather with a wintry mix at times and cold enough for snow from time to time, especially but not exclusively in the north and on hills, frosty nights at times and I continue to be bemused by the continuing run of the mill, uninspiring comments which are really annoying as I think most coldies will agree that we are in a much better place than we were last month. I hope we see a deepening of the cold in the immediate run up to and during christmas and the way the 6z run finishes, the future could be bright..for the majority on here...cold zonality here we come

 

Mild mush, once again you are the weakest link..GOODBYE

[Summer Sun]

Up-to 10 inches (26cm) of snow looks possible in parts of western Scotland the heaviest falls are likely to occur from around 200m though even lower levels could see some snow at times

 

Edited December 4, 2014 by Summer Sun

[mushymanrob]

For me looking at the models its that wretched azores high causing many of our troubles as is normal with most winters, we've seen many times in winter what an annoying feature this can be especially while there is a portion of the vortex in the vicinity of Greenland it leaves us stuck in the middle, longer term there is some tentative signs the Azores high may sink away but you can't help but wonder how long this could hang around for, hopefully we won't have to bare it for the rest of this month. At this present time the high cannot ridge northwards and it leaves us in an endless cycle of the same pattern, occasional dry dull spells with interspersed periods of rain & rinse and repeat.

 

The PV is a mess right now, and looks to be continuing to be one but its difficult to see any HLB whilst that Azores high and lobe of the vortex play kiss chase.

 

 

indeed the azores high can be troublesome, in summer it keeps us in a westerly unless it displaces.

however, its currently in perhaps the best position it can be for those looking for cold. its latitude in such that we look certain to get several successive polar maritime incursions behind a seriese of cold fronts. it could be milder! and whilst its there, theres always a risk/chance of it ridging north and joining with a greenland high thus thrusting us into a very cold spell.

on the other hand, it might just sink further south and orientate sw/ne ridging towards our south and returning us to mild.

[knocker]

This would have been a grand day on Ocean Station India 59.00N 19.00W. Pretty innocuous really. Hallelujah, hallelujah

Chart courtesy weatherbell

Edited December 4, 2014 by knocker

[Iceaxecrampon]

Good post Frosty.

 

06Z an upgrade -3 days away - some serious totals possible on the tops in Scotland - prolonged lengths of ppn.

 

 

Next weeks storm looks even more vicious on the 06Z

 

 

Ian

 

 

[LomondSnowstorm]

I don't see what's so terrible about the long range ensembles. If you look at the NAEFS height anomaly for +144, around 'peak vortex', you can see a negative anomaly right across the pole, strongest at Greenland and in the Northwestern Pacific:

 

By the end of the run you can see heights over the US starting to transfer northeast towards the mid Atlantic and Western Greenland with basically neutral height anomalies over the pole and the trough to the northwest sinking gradually further south:

This looks broadly in line with expectations of an increasingly -AO as we go into the second half of December with a mean trough over the UK. Of course, at the surface level this pattern could still look similar, at least at first, to what we had last winter, but with the Russian high exerting more influence again and hints of another warming and wave 1 activity in the upper strat., combined with the MJO *potentially* getting into phase 7, I wouldn't necessarily write off the rest of December for more significant cold for all of us (although with an ice warning out tomorrow and a snow warning on Sunday/Monday for Scotland I don't think there's much wrong with the current pattern at all ).

[marksiwnc]

There is no correlation between the two instances. As I have said on several occasions the GFS got it wrong due to happen stance of a Tropical Storm (Nuri) causing mid latitude disruption along with strat down welling. The nature of these storms mean the outcome may not be known till T-120. To blame a model on that error is rather unforgiving. Well of course yin and yang, and now we pay for the consequences of the PV being delayed it's normal cycle, compounded by the fact we reaped no benefit from the consequential meridional flow. Of course we can discount the models and hope things improve but the models are showing what they are showing and we can only debate that. IMO they look more than reasonable in the great scheme of things, with the usual caveats.

Something similar to what I posted earlier regarding this new typhoon and the impact s it has on the next few weeks of model watching. Is this the case?? I am learning btw lol

[IDO]

Something similar to what I posted earlier regarding this new typhoon and the impact s it has on the next few weeks of model watching. Is this the case?? I am learning btw lol

 

Yes. However ECM yesterday spotted that this would not recurve and GFS has now followed suit and it now looks highly unlikely it will head into the mid-latitude. In any case because of the strong jet it was unlikely to disrupt the long wave pattern like Nuri did. So no trigger for a pattern change here unfortunately. 

[bluearmy]

I don't see what's so terrible about the long range ensembles. If you look at the NAEFS height anomaly for +144, around 'peak vortex', you can see a negative anomaly right across the pole, strongest at Greenland and in the Northwestern Pacific:

 

 

By the end of the run you can see heights over the US starting to transfer northeast towards the mid Atlantic and Western Greenland with basically neutral height anomalies over the pole and the trough to the northwest sinking gradually further south:

 

This looks broadly in line with expectations of an increasingly -AO as we go into the second half of December with a mean trough over the UK. Of course, at the surface level this pattern could still look similar, at least at first, to what we had last winter, but with the Russian high exerting more influence again and hints of another warming and wave 1 activity in the upper strat., combined with the MJO *potentially* getting into phase 7, I wouldn't necessarily write off the rest of December for more significant cold for all of us (although with an ice warning out tomorrow and a snow warning on Sunday/Monday for Scotland I don't think there's much wrong with the current pattern at all ).

 

the issue with those anomoly charts is that the trend is to link heights to our south. now any positive anomoly at all over europe is going to represent decent heights. there is no progress to cold in any way with positive anomolys to our south. they can of course, retrogress west or be sucked up ne by amplification up or downstream. that also looks unlikely for the time being but as i said earlier, week 2 output looks unconvincing to me.

[IDO]

Models are only disappointing if you expected a severe Siberian icy blast. Living on our temperate little island we don't get many of those but after the generally warm autumn, a spell of cold zonal weather is just what the doctor ordered..dull, uninspiring, disappointing, run of the mill it ain't..that was October and November in a nutshell. :-)

 

 

Liverpool 2m temps and chances of snow: 

 

So at sea level temps look around average with low probability of snow. That pretty much sums anywhere south of Scotland; with the exceptions being the Pennines, Welsh hills and other hills above 400m.

 

Though as you say miles better than last year with all the good stuff (for cold/snow) keeping us waiting till JFM+.

[IDO]

the issue with those anomoly charts is that the trend is to link heights to our south. now any positive anomoly at all over europe is going to represent decent heights. there is no progress to cold in any way with positive anomolys to our south. they can of course, retrogress west or be sucked up ne by amplification up or downstream. that also looks unlikely for the time being but as i said earlier, week 2 output looks unconvincing to me.

 

Yes I note that the models are not really reading the script, so as you say, if they are miss-handling the background signals then all bets are off in week 2.

 

Highlighted by these composites: https://forum.netweather.tv/topic/81904-netweather-winter-forecast-201415-a-cold-hearted-winter/page-6#entry3080443.

 

That is a big left turn and my untrained eye is struggling to see how this can develop?

Edited December 4, 2014 by i'm dreaming of...

[Frosty.]

What about Reigate hill..?

Anyhow..Models show cold zonal outlook beyond the quieter next few days..some surprise and welcome white stuff on the way and a seasonal feel to things for a change!

[Team Jo]

Moved a couple of posts into Moans/Ramps..if it ain't here, it's gone in there.

[Gibby]

As I have said so many times in the past you can look for cold solutions in the models as much as you like as there will always be some eye candy for coldies somewhere or another in far FI, be it at the Pole the Arctic or Siberia it matters not a jot to the UK as long as that persistent and semi permanent High pressure down to the Azores is maintained and with the Jet strong at the moment rolling over the top it isn't going anywhere fast I'm afraid. Contrary to what some people have been stating here and elsewhere I think the models have changed quite a bit in the last 24-36 hours in as much as gone is the deep Low pressure likely to be at or over the UK towards the early middle part of next week and in it's place is the large High to the SW with pressure hardly falling below 1020mbs across Southern England in the next week to 10 days. That is a big shift in my eyes and this theory is highighted once more on the 6z output. Any cold NW flow in this sort of setup with no deep Low pressure over the UK will be a very watered down affair indeed with bright and dry weather likely in average temperatures alternating with cloudier and milder period as each warm sector passes. On the high ground of Scotland and the North it's a different story of course but unless you live above 400-500mtrs asl of which not many of us do I don't think any excitement can be generated from any output I have seen yet today, but as always with weather in the UK's temperate zone the next set of output released soon might tell a different story...anything's possible.

[winterof79]

Scotland  in the firing line this weekend with accumulating snow not exclusively to higher levels.

 http://www.metoffice.gov.uk/public/data/CoreProductCache/SurfacePressureChart/Item/ProductId/20606726

 

Chaos reigns if you ask me beyond early next week.

https://max.nwstatic.co.uk/ensimages/ens.20141204/06/prmslBerlin.png

https://max.nwstatic.co.uk/ensimages/ens.20141204/06/prmslHelsinki.png

https://max.nwstatic.co.uk/ensimages/ens.20141204/06/prmslReyjavic.png

 

https://max.nwstatic.co.uk/ensimages/ens.20141204/06/prmslWest~Yorkshire.png

[Barry12]

Not sure why theirs so much negativity this morning, not much has changed from last night really. Some people are posting charts way out in FI as proof that things are not looking good, but as others have already said taking FI charts at face value is rather pointless when small changes in the reliable time frame can completely change FI. Some people will never seem to be able to grasp this fact unfortunately, you will also notice that when FI is showing something positive for cold, these people will rarely mention them. It's rather strange, but there you go.

 

Looking at the reliable and semi-reliable time frame on the models it looks like staying below average with snow for the North of the UK, getting to lower levels at times. I can see while people in the south may not be as happy, but at least it's not mild. I see this December finishing below average even if there are some mild days thrown into the mix. The Polar Vortex, especially on recent ECM runs is being beaten up, and while this doesn't guarantee cold to the UK, it significantly improves chances of cold. So it's always a good sign. Over most of the models, the Russian high has continuously been moving further west, which is also a good sign. As this is what Chino and Lorenzo have mentioned they are wanting to see as we progress through December, on the 18z FI last night you could see a block forming to our NE, obviously this needs to move into the reliable time frame to be believed though. But the building west of the Russian high is being shown in the reliable time frame which is why a block forming to our NE again is a possibility.

 

Anyway, looking at the reliable time frame on the GFS 06z we can see that it will feel cold in the coming week, with the exception of temporarily average/mild weather as the Azores High pushes in. The Met Office do seem rather positive in terms of us getting some wintry weather, so maybe they are seeing something more positive in terms of cold and snow that we are. Hopefully Ian Fergusson can give us more information on this.

 

Friday

 

 

As the charts show, there will be highs of 5-6C for most of us, which is slightly below average for the time of year. It's well below average for the time of year for Scotland, and snow should be starting to fall over modest elevations in Scotland.

 

Saturday

 

 

Saturday is less cold as the Azores high moves in, but still around average for the time of year with temperatures ranging from 4-8C. Snow will be accumulating over higher ground in Scotland.

 

Sunday

 

 

Temperatures are around average in the South, but below in the North.This is the day that snow start to accumulate at modest levels, and when the Met Office think snow could fall to lower levels in the North. Over 200m in the North, snow will really be starting to accumulate.

 

Monday

 

 

Monday will have below average temperatures for virtually the whole of the UK, with parts of Scotland well below average, with Ice Day's possible.

 

 

I'm still looking for a pattern change though, and I like most will not be happy to settle with a North Westerly, I want an freezing cold Easterly with drifting snow for the whole of the UK, but how many times has this actually happened during the first half of December. I will certainly be happy to settle with what we have now for the time being, which is mostly below average over the coming week. No point looking in FI and being disappointed at the fact it's not showing anything interesting, when a small change on each run in the reliable will completely change FI. I'd put a lot of money on FI being completely different on the 12z.

[winterof79]

Just for Frosty 

http://modeles.meteociel.fr/modeles/gens/runs/2014120406/graphe3_1000_267_30___.gif

 

70 %.......It may not happen but a heck of a sight better than the whole of last winter which consisted of ONE sof thail thunder shower 

Edited December 4, 2014 by winterof79

[IDO]

As I have said so many times in the past you can look for cold solutions in the models as much as you like as there will always be some eye candy for coldies somewhere or another in far FI, be it at the Pole the Arctic or Siberia it matters not a jot to the UK as long as that persistent and semi permanent High pressure down to the Azores is maintained and with the Jet strong at the moment rolling over the top it isn't going anywhere fast I'm afraid. Contrary to what some people have been stating here and elsewhere I think the models have changed quite a bit in the last 24-36 hours in as much as gone is the deep Low pressure likely to be at or over the UK towards the early middle part of next week and in it's place is the large High to the SW with pressure hardly falling below 1020mbs across Southern England in the next week to 10 days. That is a big shift in my eyes and this theory is highighted once more on the 6z output. Any cold NW flow in this sort of setup with no deep Low pressure over the UK will be a very watered down affair indeed with bright and dry weather likely in average temperatures alternating with cloudier and milder period as each warm sector passes. On the high ground of Scotland and the North it's a different story of course but unless you live above 400-500mtrs asl of which not many of us do I don't think any excitement can be generated from any output I have seen yet today, but as always with weather in the UK's temperate zone the next set of output released soon might tell a different story...anything's possible.

 

I have highlighted before, from similar recent events, that we need to get to around T-120 before we can have any confidence in that deepening LP system next week. The 06z GEFS highlight a cornucopia of different outcomes:

 

 

This could be argued as a trigger to kickstart the mobile PV pattern from week 2.

[Barry12]

I have highlighted before, from similar recent events, that we need to get to around T-120 before we can have any confidence in that deepening LP system next week. The 06z GEFS highlight a cornucopia of different outcomes:

 

Meteociel_-_Panel_GEFS.png

 

This could be argued as a trigger to kickstart the mobile PV pattern from week 2.

 

I wouldn't be confident about what happens at week 2, if you have no confidence past 120  

[BlueHedgehog074]

Just a quick summary from me today: the UK looks to see a cold front slip South-Eastwards from the North-West later on today and into tomorrow as the models show a wave feature track Eastwards from the Low Pressure to the North. Colder, clear, air from the North-West will follow behind accompanied by wintry showers. The -5*C 850mb temperatures over North-Western areas tomorrow could allow wintriness to the showers to fall to some lower levels at times, especially if the showers are heavy enough. Further rain likely to spread in from the West late on Saturday and into Sunday morning with another Polar Maritime flow following behind briniging further snow/wintry showers over hills. Again, with -5*C or colder 850mb spreading through most of the country, we could see some sleet and snow from them get pulled down to some lower levels. Worst of the showers likely in North-West, though some could spread through the North Midlands from the Chesire Gap. The models, generally, show a similar sort of picture next week with Atlantic dominated weather looking quite likely. And changeable too. A mixture of less-cold Westerly flows alternating with further cool North-Westerly Polar Maritime flows (especially if High Pressure amplifies to the West) with ridges and troughs at times. Low Pressure mostly concentrated to North with Higher Pressure mostly concentrated to South/South-West with the windiest and wettest conditions over North-Western areas.

[Frosty.]

The latest MO update shows no downgrade to the cold zonal outlook and is pretty much as the 6z shows with frequent and potent polar maritime incursions during the next few weeks, indeed it's better than the gfs run because there is no hint of anything mild. So we can look forward to cold and windy, showers turning to snow on hills and occasionally down to sea level, gales and heavy rain, sleet & wet snow and frosty nights in quieter interludes..a rather wintry outlook :-)

Edited December 4, 2014 by Frosty.

[Hocus Pocus]

The latest MO update shows no downgrade to the cold zonal outlook and is pretty much as the 6z shows, indeed it's better than the gfs run because there is no hint of anything mild. So we can look forward to cold and windy, showers turning to snow on hills and occasionally down to sea level, gales and heavy rain, sleet & wet snow and frosty nights in quieter interludes..a rather wintry outlook :-)

Indeed it does, I'm still looking for this flatter pattern in the reliable timeframe and if anything we could just as easily get more amplification from the upstream pattern as we move forward this month.