Model Output Discussion - 1st February Onwards 12z--->

[mushymanrob]

Winter Over?

 

prectypeuktopoCA3BZO7R.png

 

Maybe not for the Pennines - Mid Wales and Alba?

 

Albeit a week away.

 

Ian

Yeah, wintry showers in early spring is pretty normal. I wouldnt place too much hope on those notoriously inaccurate precip charts.

[Polar Maritime]

The GFS continues this morning to show a cool sometimes cold unsettled Pm flow for the last 1/4 of the Month from the N/W. With fronts driving S/E in off the N/Atlantic pushing the Jet South. Cold uppers of -4/-5 with -8c sometimes touching the far North of Scotland with strong winds will bring Snow to many at elevation as far South as the Midlands at times.. A very seasonal outlook for the UK, As always in these set-ups expect some surprises.

 

Mush.. The chart IAC posted was the 22nd of February, Not Spring, I know it's in sniffing distance..  

 

Edited February 15, 2015 by Polar Maritime

[Daniel*]

Long drawn cold N/W flow perhaps not great for the S but Scotland, Ireland, N England may do well.

[Frosty.]

The GFS continues this morning to show a cool sometimes cold unsettled Pm flow for the last 1/4 of the Month from the N/W. With fronts driving S/E in off the N/Atlantic pushing the Jet South. Cold uppers of -4/-5 with -8c sometimes touching the far North of Scotland with strong winds will bring Snow to many at elevation as far South as the Midlands at times.. A very seasonal outlook for the UK, As always in these set-ups expect some surprises.

 

Mush.. The chart IAC posted was the 22nd of February, Not Spring. 

 

Yes I agree pm, the 6z is very interesting with quite a wintry spell for the north by next weekend and first half of following week followed by another wintry blast later that week spreading south to the rest of the UK..I like the 6z a lot, those in Scotland will love it.

[Frosty.]

The 6z turns into a wintry run in FI, especially for scotland, there would be significant snow at times if this run or anything like it verified.

Edited February 15, 2015 by Frosty.

[West is Best]

Well I've been watching the models regularly. There's a possible polar maritime incursion of sorts right at the end of the month T300+ and perhaps a bit of wintry mix up over the Scottish highlands next weekend as we bump in and out of what is, essentially, showing up as an Atlantic driven setup. We are, in essence, heading into early spring conditions at times over the next week and possibly next fortnight. March and April may yet yield cold spells as is often the case. We watch and wait: things can change fast especially in a mobile pattern.

Edited February 15, 2015 by Polar Maritime
To move discussion on.

[Polar Maritime]

Well I've been watching the models regularly. There's a possible polar maritime incursion of sorts right at the end of the month T300+ and perhaps a bit of wintry mix up over the Scottish highlands next weekend as we bump in and out of what is, essentially, showing up as an Atlantic driven setup. We are, in essence, heading into early spring conditions at times over the next week and possibly next fortnight. March and April may yet yield cold spells as is often the case. We watch and wait: things can change fast especially in a mobile pattern.

 

There is more than 1 possible pm shot showing before T300,  And nothing 'Spring like' on the 6z run. In fact it would feel bitter at times in the wind chill.

Edited February 15, 2015 by Polar Maritime

[Frosty.]

Well I've been watching the models regularly. There's a possible polar maritime incursion of sorts right at the end of the month T300+ and perhaps a bit of wintry mix up over the Scottish highlands next weekend as we bump in and out of what is, essentially, showing up as an Atlantic driven setup. We are, in essence, heading into early spring conditions at times over the next week and possibly next fortnight. March and April may yet yield cold spells as is often the case. We watch and wait: things can change fast especially in a mobile pattern.

The 6z would bring snowmaghedden to scotland, so I don't agree with your bit of a wintry mix description, the 6z brings 3 consecutive days of snow showers to northern UK from next weekend followed by another wintry reload 24 hours later.

[Iceaxecrampon]

There is more than 1 possible pm shot showing before T300,  And nothing 'Spring like' on the 6z run. In fact it would feel bitter at times in the wind chill.

 

It's getting to that time of year it  was very springlike here yesterday - Cumbria ppn records always peak for snow in February courtesy of Mountain Rescue records.

 

Yes 6z a bit on the chilly side - we will see as ever.

 

Ian

[Mucka]

Very much still on course for a progressively more unsettled second half of February with a slow breakdown of high pressure leading to the possibility of a colder/cooler zonal flow last week of Feb. So wintry showers possible at times in the NW later in the period but generally drier and less cool in the Southeast.

This alternating UK trough ridge scenario may give way to a more sustained spell of Northwesterlies as a trough sets up in Europe toward end of Feb.

continuing unsettled into March with high pressure attempting build in once more thereafter - where and how that develop exactly is impossible to know as we are well into deepest FI by now.

The next 10 days are pretty well mapped out though with generally mild settled weather slowly giving way to cooler unsettled regime as low pressure has more and more influence and once we know the extent of the troughing into Europe and how the pattern behind looks we will get a clearer picture of how March may develop (at least early stages) but that is several days off yet.

Also the potential for some storminess increases through the last 3rd of Feb.

Edited February 15, 2015 by Mucka

[polar vortex]

The upstream change back towards the typical winter pattern is now coming into clear NWP focus. Recent posts over the last week or so have continued to use the GWO plots and anticipated next re-initiation of -ve tendency AAM to assess how NWP is likely to evolve.

 

It has also put the longer term anti-cyclonic picture that was suggested by the models as we headed through the first week of this month to continue through much of February, following the previous amplified phase at the turn of the month, into the expected briefer overall context it now looks to be.

 

So, GWO heading out of low signalling this week towards quite high amplitude Phase 1 and on its way to Phase 2 and the models are fully advertising the consequent retrogression of the pattern in the Pacific with the pole ward -EPO ridge.  

 

http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

 

The squeezed effect across the US of the jet stream is primed to assist a temperature fuelled gradient as the frigid cold air from the Canadian arctic spills into the Atlantic to make the weather quite a lot more mobile and the north can expect some more wintry aspects of weather with time. Another aspect we have become familiar with at times this winter.

 

http://www.meteociel.com/modeles/ecmwf/runs/2015021500/ECH0-96.GIF?15-12

 

With the upstream pattern retrogressing, it is a question of how much amplification feeds downstream. The signal stratospherically, whilst conducive to relocating part of the vortex to our side of the pole as previously posted, is not as favourable as it was in late January, with the Canadian chunk of vortex locked in more upstream - but nevertheless, some vorticity energy transport across the pole as the jet stream intensifies is likely to lead afterwards to another Atlantic amplification.

 

I think that suggestions that this amplification will not be as long lasting therefore as the previous one in late January/early Feb are correct. However, beyond this we start to head towards the start of official Spring, and it won't be too long after this before a rather different seasonal interpretation of this -AAM/GWO cycle starts to appear

 

I am very pleased that Vorticity has begun a pinned thread on the topic of AAM/GWO  - and his contribution is very well explained as usual

 

The use of these tools is very valuable in helping to determine extended ensemble clustering and documents daily progress of how well (and how many) members in intra day ensemble suites are picking up on future atmospheric signals.

 

In this respect it should be no surprise that the GEFS has strongly featured the Azores High signal. The atmospheric pattern has been fully supportive of this as a strong feature throughout the last 2 or 3 months. Its apparent over gilding of the High as a dominant mid latitude block through this month has arisen simply because of the 'Bermuda Triangle' period of tropical MJO modelling.

 

However, as the extra tropical GWO atmospheric tendency budget incorporates tropical MJO amplitude and movement in its calculations of AAM tendency, then it is the eventual orbit direction of the GWO itself that can be looked to in trying to determine where NWP will finally head after any incoherent signal period.

 

This orbit direction has consistently shown the next phased re-load cycle of the dominant Pacific pattern - and as now come within the 10 day period, it is set to arrive

Phase 1 is not a high amplified phased state rather the reverse. I see though you have succumbed to the idea of a 

more amplified state going forward rather than the rinse and repeat that you were forecasting. To much faith in one 

teleconnect can lead to failure.

[Mr_Pessimistic]

Phase 1 is not a high amplified phased state rather the reverse. I see though you have succumbed to the idea of a 

more amplified state going forward rather than the rinse and repeat that you were forecasting. To much faith in one 

teleconnect can lead to failure.

Too much faith in all of the teleconnections, and too much faith in any of the computer model output can and usually does lead to failure, however great ones knowledge. Until the knowledgeable ones on here have access to all of the data that the mo does, then it simply is not possible to accurately forecast the weather further than 3-4 days, as shown nearly every year. While the mo, with all their combined knowledge and computing power now seem to have a pretty good grasp on the general long term patterns, as shown over the last several years now. So the conclusion I made years ago, is stick with the met else you will be dissapointed time after time.

[legritter]

Good afternoon all ,well i will certainly take what some of the further outlook is showing today .Ok its possibily going to be an interesting Cold Zonal affair but if we can get the Dice to fall right we could make up  some lost ground late February early March .wouldn,t be surprised to see some active low pressure systems turn up which would also give us some action weather . Its been a long frustrating winter so far for us coldies and for me personally and from an IMBY  thinking a nice covering lasting a couple of days would do me fine .Well lets see what tonights model runs show and lets hope we can see a few more posters say hello by logging in ,some interesting posts ,although thin on the ground ,The Hunt continues   

[Summer Sun]

The low to our west at day 9 is significantly deeper on this run compared to the 06z

 

 

06z

 

 

Gales or maybe even severe gales in the northwest if that low comes off

[igloo]

well there is still no respite for the east coast of america for at least another 10 days or more which means our neck of the woods will see all that energy crossing the atlantic the later part of the GFS has some 935hpa storms smashing there way over its quite unusual to see storms of that depth at the back end of february but with all that energy over NE america it looks highly likely the later part of february will be the stormiest this season

Edited February 15, 2015 by igloo

[IDO]

The low to our west at day 9 is significantly deeper on this run compared to the 06z

 

 

06z

 

 

Gales or maybe even severe gales in the northwest if that low comes off

 

^^^ And of course it shows that what looked like ideal conditions for snow on hills up north can on the next run have the uppers modified and reduced from -6c to -2c. At that range it is likely to change several times again, but this winter we have seen good synoptics fail because of that type of outcome.

 

Anyway nothing really to say on the 12z. Zonal from D4 to D16 on the GFS and the same for GEM D4-10.

Edited February 15, 2015 by IDO

[Cloud 10]

Phase 1 is not a high amplified phased state rather the reverse. I see though you have succumbed to the idea of a 

more amplified state going forward rather than the rinse and repeat that you were forecasting. To much faith in one 

teleconnect can lead to failure.

 

I think you are getting amplified and amplitude mixed up.

 

 

The GWO is indeed forecast to gain more amplitude as Tamara alluded to in her earlier post and follows the same pattern as has been seen all winter.

 

GWO forecast..

 

GWO past 3 months or so..

 

 

The 500 mb anomalies for this winter  are a close match for the ECM ensemble mean day 10 forecast,so very much a rinse&repeat pattern seems likely with some cold Northwesterly shots to come.

 

winter..  ECM..

[knocker]

 

 

The 500 mb anomalies for this winter  are a close match for the ECM ensemble mean day 10 forecast,so very much a rinse&repeat pattern seems likely with some cold Northwesterly shots to come.

 

winter..compday.HaRbJSQ4rU.gif  ECM..EDH101-240 (1).gif

 

I'm not sure I follow that. You are comparing the winter anomaly with the latest ecm ten day and conclude a rar (can't bring myself to say it). because they just happen to coincide. Presumably one could take the same winter anomaly and compare it with the ecm four weeks ago and reach a different conclusion. The periods of NWs have been on the cards for a fair time now.

Edited February 15, 2015 by knocker

[Polar Maritime]

The 12z GFS again continues with cold and stormy conditions especially for the North with Gales & Blizzard conditions at times for the Highlands and over high ground in the North, As Low after Low from the N/W rattle in over the UK from around the 21st, With pretty much good agreement from this mornings ECMWF run. 

 

Charts not in order.. 

 

 

Edited February 15, 2015 by Polar Maritime

[Frosty.]

GFS 12z from T+168 really grabbed my attention with a period of cold zonality and some powerful depressions on a nw/se track with frequent polar maritime incursions bringing a risk of snow at times, especially but not exclusively on hills. I think an exciting and disruptive period is on the way.

[Winter Cold]

It certainly looks like we've gained knowledge on how to handle the new GFS from the runs this week. It has now come into line with ECM and no longer shows high pressure domination. It stuck to high pressure firmly for days and days and has just fliped on todays runs it seems. It does seem to have a new bias for high pressure scenarios!? One to keep an eye on anyway but maybe weve discovered its new quirk!

 

Also, looks to be a victory for the EC32 over GLOSEA5 perhaps, with the regular models including ECM and GFS now displaying a cool/cold NWerly flow into the extended period. I remember Fergie stating the other day that the EC was differing from its counterpart with the colder options further out. They seem to have been consistent with each other through winter from what we hear on this thread, and this seems to be the first time I heard of a difference in the longer range two.

Edited February 15, 2015 by Winter Cold

[Tamara]

Phase 1 is not a high amplified phased state rather the reverse. I see though you have succumbed to the idea of a 

more amplified state going forward rather than the rinse and repeat that you were forecasting. To much faith in one 

teleconnect can lead to failure.

I'm sorry I am not going to let this pass without comment!

 

Cloud 10 has very kindly responded on my behalf, so not much further to add on that matter than he has already said

 

I have previously asked if you might read posts properly before trying to undermine my own or anyone else's. The succumbing to the amplified state going forward (of the Jetstream) is entirely consistent with posts I have been making for some time since, well... the last amplification.

 

Furthermore, if you read properly that post you replied to (which was subsequently deleted to at some stage suitably be re-constituted for the new pinned thread) as well as others made previously to it, you will see it clearly states the GWO is a useful tool for trying to decide how future modelling might evolve.

 

However...that is not saying it is the only tool. I can tell you though, that its value has been proven many times over in recent years by others more knowledgeable than me. So, if you think you know best, you could try and find fault with them rather than me if you wish...

 

Value, btw, does not correlate with 100% accuracy - but I do know that since trying to use the GWO plots it has become possible to see upstream changes in pattern on occasions when they have not been apparent in NWP. Especially because the atmospheric state has been repeating through much of the winter. It has enabled me, at least, to pick out each of the amplifications in this way starting from December - even if the overall pattern has not evolved towards the colder one as expected earlier in the winter. But repeated reasoning has been given about this anyway

 

Any future posts regarding GWO/AAM that might be made in connection with model output will not be posted on here but on the new pinned thread. That new thread is set up as work in progress by Vorticity - and we have exchanged a few posts and varying information on this idea. For anyone who might be interested anyway

 

That leaves this thread clear of unwanted teleconnection material such as this - certainly on my part. Its a big pity that so many posts are critical of the use of these longer range tools - they add an extra dimension to trying to gauge longer range model output in addition to all the other regular data all members have available to them.

 

It seems to be the same every late winter that doesn't meet hoped for wintry potential, the usual posts are made nit-picking and complaining about forecast predictions.

 

We could all just read the Met Office longer range updates and not bother to post at all on here I suppose beyond a certain cut-off period...

Edited February 15, 2015 by Tamara

[mushymanrob]

Im not concened about the possible fi northwesterlies as so far the noaa charts dont support a strong scandinavian trough and without that any pm incursions wont be long nor particually potent.

[Frosty.]

Im not concened about the possible fi northwesterlies as so far the noaa charts dont support a strong scandinavian trough and without that any pm incursions wont be long nor particually potent.

We don't need a strong scandi trough, as we saw from the 6z and now the 12z gfs, as long as the depressions are tracking nw/se then I'm happy because we will have generally cold zonality and a risk of snow at times from next Sunday onwards.

PS..well said Tamara, as you know I think your input on netweather is Fantastic...you have filled the void left by Glacier Point..no higher praise is possible :-)

[Eugene]

There is more than 1 possible pm shot showing before T300,  And nothing 'Spring like' on the 6z run. In fact it would feel bitter at times in the wind chill.

 

 

 

Exactly PM and GFS 12Z further amplifies the cold flow with a very cold WNW'ly flow at times with a snow risk at night almost anywhere, no really cold max's but feeling very chilly esp under showers and once the sun goes down, tiring hearing springlike to describe near average temps, spring to me is calm sunny days with temps of 13C to 15C on a widespread scale.