Model Output Discussion; into 2015

[Nick F]

I know it's all in the far reaches but both gfs and gfsp both show the majority of the polar,well it doesn't really look like a vortex at that stage completely displaced in half.The models must be picking up on a big change or just got the pattern wrong in the early stages then just continuing to a super cold outlook for us all to be disappointed .Hope not.

I think GFS op maybe following its tendencies to shift through MJO phase 6 over the next 5 days, think it may already have crept into 6 today, before heading to 7/8, hence a pattern change to a strong mid Atlantic ridge toward Greenland from mid month. GFS MJO can be found on Mike Ventrice's page:

http://mikeventrice.weebly.com/mjo.html

CPC probably won't update until tomorrow, so we wait to see if ECM remains less favourable or not.

[SE Blizzards]

I can't see any major pattern change from what we have now up to 19th January.

GEFS ensembles mainly showing a westerly influence.

Anyone thinking SSW will change things is more likely straw clutching at this stage, as same SSW fanatics were disappointed last winter.

 

 

I'm sorry but this is very misleading to newer members.

 

The GEFS for the same time frame of that chart you show are NOT showing a mainly westerly influence. In fact i can only count about 6 or 7 that have!

 

Tut tut!

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=348&size=

Edited January 5, 2015 by SE Blizzards

[Hocus Pocus]

I don't think anyone I've seen on here has come to assumptions like 'psychics'. Those that use tropical oscillations, such as MJO or ENSO forecasts and stratospheric modelling to predict how these may force the pattern in the mid-high latitudes of the northern hemisphere have plenty of empirical evidence to merit a stab at a medium to long range forecast, but with the usual caveats of course.

Predicting the weather will never be an exact science, but there can be some limited success at predicting a few weeks or more on the broad scale patterns, but certainly not with any detail or exact timescale.

Making predictions using well established scientific correlations can be fun, even if it doesn't come to fruition, certainly more fun than going back 50 years ago and with the limited data and science and only able to forecast up to a week or perhaps less with any success.

I kind of agree but there are far too many who get hung up on these teleconnections without really knowing much about them other than reading other people's thoughts based on said teleconnections, how many times do we see posts from posters here writing off chunks of the season because theres no SSW forecasts or the MJO hasn't moved into phase 7. I enjoy reading all the techno babble myself and freely admit I don't understand half of it so rarely comment on these, but yet many who don't see fit to post all sorts of winter is over type posts without any free thinking on their own behalf.

[davehsug]

Hocus Pocus, on 05 Jan 2015 - 00:21, said:

I kind of agree but there are far too many who get hung up on these teleconnections without really knowing much about them other than reading other people's thoughts based on said teleconnections, how many times do we see posts from posters here writing off chunks of the season because theres no SSW forecasts or the MJO hasn't moved into phase 7. I enjoy reading all the techno babble myself and freely admit I don't understand half of it so rarely comment on these, but yet many who don't see fit to post all sorts of winter is over type posts without any free thinking on their own behalf.

Agreed Hocus Pocus, but there are far more who will happily post that we're going back to 62/63 based on the same evidence. The models are teasing, just like they always do, but a tease is all we have to cling to at the moment. The next 7-10 days look pretty poor for coldies at the moment, but hey-ho at least there is some eye candy to dream of!

[Mucka]

Good morning.

 

Still looking good for some snow next weekend, more especially northwestern regions but if the models continue to firm up on this penetrating W/NW flow then I expect showers would push quite far South. It won't be that cold but showers could well be heavy and prolonged so with a bit of favourable timing there could be some lying to low levels for a time though it will melt quickly away from hills.

I know it is too far out to make predictions about ppn type and rate but I am basing the above on the output we have been seeing, it is in the semi reliable time-frame but we will see. I certainly would not want to be caught unawares on the hills though.

 

 

UKMO has a more Northerly component due to the ridge so would likely be colder though the cold air may pass through more quickly than GFS - still likely to bring snow showers to the NW.

 

 

GFS goes for second trough digging South close on the heals of the first above though at the moment it looks as though the cold air may not get as far  South. However it is further out so more subject to change.

 

 

 

In deep FI it is a similar story of building high pressure to the West, this time all but forming an Icelandic high.

 

 

If we do get something along the lines GFS has been modelling lately I still think there is scope for a widespread heavy snowfall in the transition but a long way out yet. From here the run goes off the rails with low pressure forming West of Portugal and reversing back NW into the Atlantic. Seems unlikely and also deepest FI so ignore.

Edited January 5, 2015 by Mucka

[Mucka]

GFS snow forecasts are notoriously unreliable but this is quite a strong snow signal building for next weekend in NW England - will it survive the next few days runs?

 

 

Also right at the end of hi res you will see the warm sector between system is being reduced significantly on this run. Too early to say that is a trend but if it is Northern parts, especially northwest with any elevation could see quite a wintry spell of weather from next weekend even if temps are only a little below average.

Hillier areas could see a lot of snow but of course it is still far enough out for more changes.

 

Ensembles in FI are a mixed bag with the general theme being a toppling ridge with various outcomes. One or two nice runs among them but certainly no solid cold signal. 

For pure eye candy I would go with one of the very few that doesn't topple the ridge, p16

 

 

We can but dream.

 

GFS 00z ensembles(full) probably the coldest set yet but still a long way to go.

 

Central England)

 

Edited January 5, 2015 by Mucka

[knocker]

Yes you can see where the GFS is coming from

Charts weatherbell

http://weather.graphics/gsm/ygfs_t1534_global.php

Edited January 5, 2015 by knocker

[Iceaxecrampon]

I'm going to break with tradition in this thread and actually post a chart to try and provoke some model discussion!

gfs-0-336.png

Now I know this is deep FI, but it would only need a monster low like this to get a little nudge Southwards into undercut territory and we are into some very interesting winter weather!

Despite the recent model runs, I certainly don't buy into some of the posts declaring that we are set for weeks of zonality; it strikes me that some of those declarations are aimed to wind people up, especially as they very rarely come with any charts to back up their proclamations!

...Doubt if you would get much discussion as it is exactly that  - deep FI

 

On the other hand in the shorter term....

 

 

 

Both at T+135 Saturday 10th January

 

....nice

 

Ian

[Captain Shortwave]

Yeah and even then ECM has a tendency to exaggerate the prospects of any blocking in FI so we likely will still be questioning any blocking. Then again that will make it all the more worrying if it shows a flat pattern come the time.

One thing on GFSp (even though it deepest FI) that is a very cold and blocked pattern beginning to set up so no fireworks but a nice slow burner.

Whilst your post is the one I quoted, I think this applies to a few in here.

I could put this hypothetical question.

Consider a situation where the ECM/GEM/UKMO were cold and blocked from day 1 out to the end of their run. Yet the GFS wanted to break this pattern down and bring in more average westerlies at day 12. How do you think this would go down in here? At this point it is only the GFS output that we can actually see going cold at this time. Once we get to the point where the timeframe is such that other models might come on board then we can give this some legs. Until then it's just the GFS low resolution that backs this cold evolution to some degree. The MJO is one factor that we can use to judge whether the GFS is on the right track and it's discrepancy to the other output in terms of the MJO is a definite concern.

If the other models start to back a colder and more blocked pattern in a few days time then it will be time to take it a little more seriously, especially as there have been plenty of runs (parallel in particular) which haven't really got the cold spell going and just settle from surface cold under a mid-latitude block.

Utterly worthless but here are the day 10 charts from the ECM and GEM

ECM

Still westerly and unsettled with alternating air-masses

 

GEM

Similar though differences in the surface pattern. No real sign from either that we will see a change to deep cold conditions.

Edited January 5, 2015 by Captain shortwave

[chris55]

Definitely something brewing for later in the month, tentative signs but when GFS starts continually throwing out a pattern change in FI then I would take note. Details will change massively however the trend is a positive one for a change to colder conditions.

Nice Azores low on the 6z

Overall a much better situation than a raging PV over Greenland. Also signs of the change towards the end if the ECM. Long way to go but the trends are looking ok.

[Jason M]

GEFS are good this morning, but it's interesting to note that the new GFS is having none of it. Also, having looked through GEM ensembles this morning, they are also not having much to do with a big pattern change. It does seem therefore that at present GEFS and its opp remain out on their own.

As captain says, we could do with some support from ECM really. I suppose one plus point has been that GEFS are bringing this forward through the timescales. Let's see if we can get it convincingly through the 10 day barrier as over the last few months and last winter it was this point that never seemed to get breached.

We are still better off than we were a couple of days ago though, so it's certainly not gloom and doom. Just a case of loads of caution as always.

[IDO]

The CFS MJO has improved again this morning, back to what it had been showing consistently, that is it manages to get through phase 7:

 

 

That is from around 18th Jan. That may help the injection of heights build in the Atlantic and give us some longevity. However the picture remains fluid as to whether we are initially likely to get a MLH or a HLH. Split jets, short waves, timing issues re the second wedge of HP exiting the US all make the prognosis very uncertain.

 

Next weekend's possible snow also looks uncertain. The ECM has the cold front pushing SE but the rain has cleared by the time the very cold uppers push in behind. So maybe rain to snow with elevation again favoured, then snow flurries on the NW coast:

 

 

The wind is more of a concern on Fri-Sat, with the low to the north of Scotland and the strongest winds on it's southern flank:

 

 

 

The next 10 days from the GFS suggests milder in the west average in the east: 

 

So this zonal spell from mid-week well sign posted, the next five days model watching will clarify what follows.

 

 

[BlueHedgehog074]

Some good confidence from the models that the UK will get attacked by Atlantic Low Pressure systems this week. The flow mostly being from the West or South-West.The Azores High Pressure system looking to be too tired to try knock out that indestructible Vortex and its army of Atlantic Lows to our North-West. But the Azores High will, at least, hang about close by to our South. This should also mean Southern areas should avoid the worst of the unsettled conditions this week. However, no where will be totally free from rain this week as the Atlantic Lows use their cannon to fire frontal systems at us at times. Some cooler, brighter and, at times, showery interludes will occur between the bands of rain, but with Southern areas benefitting the most from the brighter interludes. Temperatures on the whole, though, most especially towards the South, will be mostly on the mild side.

Today, for example, will see a cold front greeting North-Western areas bringing some heavy rain and winds along with it. This will sink South-Eastwards overnight and clear South-Eastern areas later tomorrow. Brighter conditions following behind for most places tomorrow on a cool Westerly flow with a sprinkling of wintry showers towards the North-West. Another band of rain will then invade the country on Wednesday with the rest of this week continuing on a similar sort of vain - rain, showers (some wintry on hills), cloudy and brighter periods, etc.

[winterof79]

Somethings afoot....

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=300

 

Even at this timescale you sometimes get that feeling when so many members are showing this.

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=360

Interesting to see what IF sees later.

Edited January 5, 2015 by winterof79

[johnholmes]

The latest anomaly charts this morning, showing no marked change and fairly well in line with the NOAA output last evening. Variations of about 20 degrees either side of west is about the only change they have showed in the UK area for several days. Questionable whether any other changes well west are significant on the NOAA output. It is shown on the GFS version this morning, Greenland area and a suggestion of building heights from the north? Too early to be sure of what is happening.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

the NOAA versions for comparison

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

Its 8-14 does not make as much of this feature as the 6-10.

I'll leave it to you to make comments!

[Frosty.]

ECM 00z op run is again showing bursts of cold air and snow showers between spells of milder, wet & windy weather, no two days are the same, lots of variety.

[knocker]

looking at the extended ECM EPS mean anomaly this morning at T360 ( I know).

 

For a start no mid Atlantic ridge.

Essentially it's a picture of LP except for some build up of heights NE North America. The Hudson Bay trough is reorientated SE across Greenland giving a trough to the NW of the UK all linked to another trough NW Europe that stretches south to the Med. This area of  LP sweeps around to another trough Siberia. Another trough eastern Pacific All in all a pretty zonal affair (allowing for the range)

 

So pretty much of the same surface fare with LP to NW and E with HP to south and west  The latter being a modification of the current analysis. Not particularly obvious where any cold incursion would come from on this evidence.

[phil nw.]

Nothing to excite cold seekers in the 00z runs really.

Anything of interest such as Atlantic ridging is again in the later frames of the gefs and as others have said until those scenarios appear closer and are supported by the ECM suite i would be inclined to treat them just as nice charts to look at.

 

The means at day 10 show nothing,not even a faint signal,of anything other than a westerly pattern

http://www.meteociel.fr/modeles/ecmwf/runs/2015010500/EDH1-240.GIF?05-12

http://modeles.meteociel.fr/modeles/gens/runs/2015010500/gensbcnh-21-1-240.png

 

Not to rule out brief shots of colder pm air behind passing lows to the north but any deep or longer lasting cold is as far away as ever on current outputs.

The twin features of the Canadian/Greenland vortex and Azores high simply keep the flow Atlantic based and mobile.

[mushymanrob]

so, a stand off emerging between the anomaly charts which dont appear to support an atlantic ridge ... yet ... (as john and knocker has already mentioned), and some gfs runs which in fi suggest there might be. (even the 00z doesnt make much of it).

itll be interesting to see what happens then, has the gfs picked up on something? will the anomaly charts catch up, or will they yet again prove they are the best indicator of the general pattern upto 2 weeks ahead?...

[Troubleatmill]

looking at the extended ECM EPS mean anomaly this morning at T360 ( I know).

 

For a start no mid Atlantic ridge.

Essentially it's a picture of LP except for some build up of heights NE North America. The Hudson Bay trough is reorientated SE across Greenland giving a trough to the NW of the UK all linked to another trough NW Europe that stretches south to the Med. This area of  LP sweeps around to another trough Siberia. Another trough eastern Pacific All in all a pretty zonal affair (allowing for the range)

 

So pretty much of the same surface fare with LP to NW and E with HP to south and west  The latter being a modification of the current analysis. Not particularly obvious where any cold incursion would come from on this evidence.

 

For sure no definite sign of deep cold heading our way but the GEFS doesn't show what you are saying, with definite blocking around in that time scale

 

  

Edited January 5, 2015 by Nicholas B

[Lord Baltimore]

GFS encouraging coldies something may be along by end of next week. Reality is that it's pie in the sky.

Edited January 5, 2015 by Nick L
Removed unsubstantiated ramp.

[knocker]

For sure no definite sign of deep cold heading our way but the GEFS doesn't show what you are saying, with definite blocking around in that time scale

 

I know i had already posted the GEFS mean anomaly earlier with the Atlantic ridge.

[Great Plum]

I know I'm looking 10 days into the future, but the 0z ECM and 0z GFS looked pretty similar to me considering the long range of those and the 0z evolves into something a lot less zonal!

Latter part of the GFS ensembles still trending cooler...

http://www.wetterzentrale.de/pics/MT8_London_ens.png

Edited January 5, 2015 by Great Plum

[Troubleatmill]

I know i had already posted the GEFS mean anomaly earlier with the Atlantic ridge.

Sorry, yes I did see that earlier, I tend not look at means as it can be a very washed out picture unless they all agree, Like you say we are looking at T360 here which is a bit drastic but definate signs there which has to be better than endless zonal dross we were gearing ourselves up for and a few real belting ensembles for a longer cold spell UK wide

[Captain Shortwave]

A generally mild week to come for many (especially southern areas) with conditions turning much wetter and windier beyond mid-week.

That should change by late Saturday into Sunday with a fairly potent PM shot 

Blustery wintry showers for western areas with sunshine returning for eastern areas.

So western areas may get something wintry over the coming weekend.