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

[knocker]

Last nights NOAA anomalies and this mornings GFS and ECM all on the same page (not going into the fine detail) with perhaps the former having more amplification of the HP.  The ext. period out to T360 the HP is still the dominate player with both.

Charts weatherbell

Edited February 5, 2015 by knocker

[Summer Sun]

Unlike the Op the ECM ens keeps high pressure over the UK so temperatures should be around average with the only real risk of some rain in NW Scotland, cloud amounts could be quite high but in any sunshine is should feel quite pleasant under light winds

 

[warrenb]

Well I have to go to India for a week on the 15th and it looks like I will arriving back to the same weather I left, anticyclonic nothingness, quite remarkable, but in these situations in the SE it only takes a slight continental drift for it to be very cold.

[Hotspur62]

Although a little more promise from ECM this morning at day 10 it will have to be the trend setter and as SK has mentioned earlier it hasn't performed very well so far this winter at that stage. Is it me, but since GFS upgrade the performance of this model seems to have improved quite markedly and it was only a year ago the "trend" was to slate this model(for want of a better phrase) and stick to what the ECM was showing.It now seems a role reversal has taken place and confidence in the ECM seems to fallen.Thats just the way I have seen the Model watching since October.

 

Still think the High is the form horse for next 10-14 days with pretty average temps and very little rainfall. All in all pretty good weather for those that work outside for a living like me as this week I have frozen my n--s off!!

[Day 10]

Very good medium to long term ECM this morning, good to see some more optimism again.

 

The UKMO and ECM 144 looks pretty similar so hopefully ECMs later output is onto something and has support.

 

Good start to the day.

 

 

[SMU]

http://modeles.meteociel.fr/modeles/gfs/runs/2015020506/gfsnh-0-114.png?6

 

GFS out to 114 & trending towards the Euros with a slower pattern - should = more amplification towards 168-192

 

s

[mushymanrob]

ignore this



we have seen that before recently, expected for next monday.... whats happening on monday now?

 

this

 

unless that northerly has support in a much closer timeframe its eye candy only.

the anomaly charts are consistent and imho quite clear...



the high sinking to reside at the uks' latitude or south of the uk's latitude.

so a period of high pressure domination is as certain as you can get for the next week and probably longer. dry, calm (by saturday) , cloudy/dirty at first and imho largely cloudy throughout the period UNLESS it taps into the dry continental air. then we will get sunny days/frosty nights. but i suspect cloud will be an issue with some favoured areas getting brighter spells.

no wintry (deep cold/snow), no mobile mild southwesterlies, just a very quiet some would say boring spell.

 

[summer blizzard]

Despite all the excitement about the Euro this morning, i fear some people are chasing crumbs. As with the GFS last night, pressure remains very high (no lower than 1025mb) and it collapses pretty quick so all it does is bring in more frost. 

 

So signs it will stay chilly, yes. Signs that we are getting the cold spell we all dream of, no.

 

[bluearmy]

I think the main issue with the ecm is that we only see the op run in any detail.

That mean far too much faith is placed in the op beyond a range that should be.

The ens are a much better tool but we have to rely on the pros for detail on these.

On that subject, little evidence on the ext ens mean/anomoly that the retrogression signal is growing.

One comment I would make is that the positive anomoly stretches from the eastern seaboard across to nw Europe . Doubtful it would pan out like that so will the high be trimmed at the east or west end or perhaps split in the middle? The East end would be what coldies are looking for. Possibly the middle if the eastern end of the anomoly could be forced a bit to our ne to allow a mean continental flow ahead of any trough dropping to our west.

[johnholmes]

Various interpretations of various charts above which is perhaps confusing to newcomers but is all part of the Net Wx winter discussion, no bad thing.

Here is another.

Much of the post by mushy I agree with and the NOAA outputs are pretty consistent and do not suggest either real mild or real cold nor a bitter easterly nor a rampant Atlantic in the period they are valid for.The charts are as mushy posted above and below the ECMWF-GFS version this morning below

 

No doubt those hoping/searching for a colder outlook may try and seize on the EC version but beware, it does not agree with either the NOAA output nor the GFS idea. Indeed the EC-GFS outputs are not as consistent as the NOAA outputs in this period. Yesterday GFS almost dropped the strong upper ridge in its contours and the +ve anomaly values, today it is back to a view it showed 2 days ago. It is the turn of the EC to show a fairly marked variation from its last 3 or 4 outputs which had agreed by and large with the NOAA outputs at 6-10 days.

So beware jumping to any conclusions from the EC output. IF 48 hours down the line it, GFS and NOAA 6-10 have all decided to follow that route then we could be resonably certain that its idea was about a 60% probability of happening. A further 24 hours for all 3 and it would be near enough 90%.

So for the moment I suggest we are in the weather pattern for an upper ridge with a surface ridge moving about beneath this with its centre of gravity never that far from somewhere over the UK. Watch the sat piccs for how much cloud, take a look at the skew-t predictions on Extra for your location for 24-48 hours ahead for some idea of how much cloud under the inversion or how little. How long this may last-who knows really, 7-10 days perhaps with little marked change and beyond that, see above or guidance from those with a better knowledge on longer term drivers. But remember even those drivers are not infallible.

 

It has for sure been a different winter than for a few years, some things supporting deep cold others not, and most parts, not all, have seen some temporary deepish cold this winter, even some snow in low lying parts (even sunny donny has had more snow already, falling and lying than for several winters), others have been less lucky.

link to EC-GFS, NOAA above in mushy's post

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

Edited February 5, 2015 by johnholmes

[johnholmes]

I think the main issue with the ecm is that we only see the op run in any detail.

That mean far too much faith is placed in the op beyond a range that should be.

The ens are a much better tool but we have to rely on the pros for detail on these.

On that subject, little evidence on the ext ens mean/anomoly that the retrogression signal is growing.

One comment I would make is that the positive anomoly stretches from the eastern seaboard across to nw Europe . Doubtful it would pan out like that so will the high be trimmed at the east or west end or perhaps split in the middle? The East end would be what coldies are looking for. Possibly the middle if the eastern end of the anomoly could be forced a bit to our ne to allow a mean continental flow ahead of any trough dropping to our west.

the part I have bolded is not that different to the GFS 500mb anomaly yesterday, but it only showed it for 1 run. It MIGHT be an indication even on these 'mean' charts that there is some possibility beyond what looks fairly well set using just the NOAA anomaly charts-we simply have to wait and see.

[KyleHenry]

There are a couple of outrageous ensemble runs on GFS 0z

http://www.meteociel.fr/modeles/gefs_cartes.php?code=20&ech=228&mode=1&carte=0

http://www.meteociel.fr/modeles/gefs_cartes.php?code=10&ech=348&mode=1&carte=0

1983 repeat?

https://forum.netweather.tv/topic/34227-january-and-february-1983/

[Nouska]

ignore this

Recm2402.gif

we have seen that before recently, expected for next monday.... whats happening on monday now?

 

this

Recm722.gif

 

unless that northerly has support in a much closer timeframe its eye candy only.

the anomaly charts are consistent and imho quite clear...

610day.03.gif 814day.03.gif

the high sinking to reside at the uks' latitude or south of the uk's latitude.

so a period of high pressure domination is as certain as you can get for the next week and probably longer. dry, calm (by saturday) , cloudy/dirty at first and imho largely cloudy throughout the period UNLESS it taps into the dry continental air. then we will get sunny days/frosty nights. but i suspect cloud will be an issue with some favoured areas getting brighter spells.

no wintry (deep cold/snow), no mobile mild southwesterlies, just a very quiet some would say boring spell.

 

Does the northerly have ensemble support in the longer time frame? - yes it does , but is it normal scatter at that range or is it a valid signal. Quiet anticyclonic conditions up till the 12th and then a scatter to stronger winds on a westerly to northerly vector. Wind direction won't tell much as it is around the high into Holland - wind speed a better indicator of change.

 

 

The GFS ensembles have been signalling some kind of change is possible around mid month. Perhaps the ECM32 being run with the most recent data will give a more coherent signal.

[IDO]

JMA week 2 anomaly suggests the GEFS are on the right track with HP dominating over the UK:

 

With the jet running over the top of the high some dry weather for most.

 

The last week of Feb and the first week of March anomaly:

 

This suggests the repeating Pacific positive height anomaly and the sympathetic trough over Europe. Again the UK on that chart looking at another cold spell. So I would be hopeful of further chances of snow, though based on the current one, we need to have more favourable variables if we are going to get anything more substantial than just snow showers and a quick thaw.

 

Little change in the GFS 06z op, with HP dominant from start to finish:

 

D10:   D16: 

 

It does try to send heights to the N/NW at D11 and D14 but at the moment they have limited success. However early days to say that it won't happen and the signal is what is important and is one to watch going forward.

[Weather-history]

1983 repeat? https://forum.netweather.tv/topic/34227-january-and-february-1983/

A few years ago I wrote an article on do notable February anticyclonic spells end up with some form of retrogression? There are quite a few examples out there but like everything to do with the weather there always exceptions.

[knocker]

Does the northerly have ensemble support in the longer time frame? - yes it does , but is it normal scatter at that range or is it a valid signal. Quiet anticyclonic conditions up till the 12th and then a scatter to stronger winds on a westerly to northerly vector. Wind direction won't tell much as it is around the high into Holland - wind speed a better indicator of change.

 

 

The GFS ensembles have been signalling some kind of change is possible around mid month. Perhaps the ECM32 being run with the most recent data will give a more coherent signal.

 

The GEFs ens mean MSLP anomaly  in the extended period has the high consistently over the UK and then W/SW. This amounts to little wind in England and W/NW up north.

Edited February 5, 2015 by knocker

[Summer Sun]

GFS precip charts suggesting over 2 weeks with very little rain for large parts of the UK again this morning

 

 

This February could end up in the top 10 for the driest Februaries on record if things don't change for the 2nd half of the month

 

 

[Tamara]

The upper anomaly charts are a good guide on the basis that one interprets them in terms of factors that make them liable to change and doesn't take them at face value in the same way as happens with NWP output.

 

For quite some now I have been discussing the atmospheric circulation pattern and the symmetry of the GWO orbits which continue to suggest cyclical amplification phases. This theme is as strong to day as it has been in recent weeks and whilst we can distrust the over amplification tendencies of the ECM (f.e) which cannot and should not ignore the trend it suggests which is entirely in line with expectations.

 

The difficult issue remains timing, and of course, whether the next phase of Pacific retrogression bears fruit for the the UK at all. Neither of these questions can be answered with any degree of certainty at all - but I for one still have high confidence in the macro NH pattern leading us to further polar incursions later this month.

 

GWO as anticipated is creating a second +EAMT which is going to supplement a displaced vortex our side of the pole - as previously mentioned. Large +frictional torques and MT are inevitably going to be followed by corresponding -torque/MT through Phases 8/1 and 2 the other side of the pole which are a high signal for Rossby wave driven Pacific retrogression followed by downstream amplification in the Atlantic. Exactly the same as repeated increasingly through the winter.

 

There should be no surprise if this signal contiunues to wax and wanes in intra day NWP but don't let that fool anyone. I would also ignore the fact that just a small percentage of post 10 day ensemble data reflects this signal..currently.   It is obscured by a rather obfuscated MJO signal - however, the MJO itself comprises a percentage of the AAM/GWO budget and it is this signal which will be a large decider in the behavioural direction of the MJO.  

 

The upcoming MLB quiet period is indeed very much a holding pattern - but I don't personally buy any longer term suggestions that this is any sticking pattern through the remainder of February into March.

 

Stratospheric forecasts support the direction of travel of the vortex our side of the pole. We simply await the trigger for that upstream amplification and the floodgates should open. Its a case, for me at least, of when that happens rather than if it will

 

On that basis, the upper anomaly charts will evolve naturally in response to that signal. What they currently show has no bearing at all on that process.

 

More model output required, as they say, to keep a watching brief over this

 

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

[TEITS]

Im not sure I agree with Mushy comments.

 

Whatever your weather preference & model preference no output should ever be ignored. An open mind should be adopted to all model output. We know the issues the ECM has with regards to over amplifying but the GFS on the other hand tends to be the opposite.

 

At this stage I can see many options.

 

1. As the ECM output brings a very cold N,ly.

 

2. Again like the 0Z ECM but even more amplified with our HP being even further NW bringing an even colder more prolonged spell.

 

3. HP is centred across the UK.

 

4. HP drifts SE of the UK.

 

I can understand Mushy discounting the ECM though because he must be fed up with all these cold spells we nave seen these past 2 winters. :laugh:

 

 

 

The upper anomaly charts are a good guide on the basis that one interprets them in terms of factors that make them liable to change and doesn't take them at face value in the same way as happens with NWP output.

Spot on.

Edited February 5, 2015 by TEITS

[johnholmes]

I have never attempted to predict beyond the 6-15 day time scale so I leave what happens beyond the 15 day scale to yourself Tamara and others who use further links and drivers to suggest what may happen. Note I say may as the drivers for further out are just as susceptible to error as any other model output. If they were not then professional organisations would have found the mix of drivers to predict more than 16-30 days like UK Met currently do.

The fact they have not suggests we all still search for that possibility. My own view is that forecasts beyond about 15 days are still in their infancy and no one understands the complicated data enough to be able to come up with anything more than any of us do on here. Trying to do so is great and is the way forward for any improvement in our understanding of the enormously complex patterns.

The most accurate model predictions I have seen for this winter season do appear to be those issued by UK Met. Just what they based this output on I am not totally sure and they play this game fairly close. But outputs in meteorological scientific journals, of which there are many, I read the R Met Soc ¼’ly journal for some insights, although much of this does go over the top of my head, do show a large number of highly qualified folk doing lots of research. Progress is being made but slowly and will continue in this manner in my view. In the meantime as amateurs we all try to push our understanding forward which is great but I prefer not to knock any views, at least not in public.

Just to add what I should have posted right at the beginning.

Although I usually quote the anomaly charts, I never use them on their own, always prior to posting I will have looked at any available data, both short term and longer term, to see how the anomaly charts fit in with the other outputs.

Edited February 5, 2015 by johnholmes

[johnholmes]

On a totally separate issue, take a look at the 120h Fax chart and where the 528 line is over the eastern med. There is likely to be some very disturbed and cold weather associated with that. For those interested in any weather elsewhere then logging on to web cams in Greece, Turkey then Syria and Lebanon and even Israel may give you a snow fix?

http://www.weathercharts.org/ukmomslp.htm#t120

[Nouska]

The GEFs ens mean MSLP anomaly  in the extended period has the high consistently over the UK and then W/SW. This amounts to little wind in England and W/NW up north.

 

I was comparing like for like ie Holland as it was the ECM ensemble output that was being looked at.

 

There is a scatter in the ensembles for mid month with lowering of 850 temps while increasing winds at that height.

 

 

It is not reflected in the ops or the bulk of the ensemble so will be very muted out on mean charts.

[mountain shadow]

Eh how can it be more likely to verify just because it shows positive NAO is that reverse psychology?...with all due respect the MO went for a positive NAO on their WInter presentation which I posted but we still have had some cold spells...Sorry but saying it shows a positive Nao therefore it's more likely to verify is just not true

It is more likely to verify because it forecasts a +NAO which is the most likely and highly probable outcome during Winter. Therefore any model forcasting a +NAO will be right far more times than it is wrong.

[knocker]

On a totally separate issue, take a look at the 120h Fax chart and where the 528 line is over the eastern med. There is likely to be some very disturbed and cold weather associated with that. For those interested in any weather elsewhere then logging on to web cams in Greece, Turkey then Syria and Lebanon and even Israel may give you a snow fix?

http://www.weathercharts.org/ukmomslp.htm#t120

 

Can also be seen here.

 

http://www.atmos.albany.edu/student/abentley/realtime/atlantic.php

[mountain shadow]

Can also be seen here.

 

http://www.atmos.albany.edu/student/abentley/realtime/atlantic.php

It reminds of the days of yore back in the early noughties when South East Europe used to get frequent cold outbreaks courtesy of a Uk high.

 

Whilst in these islands we pore over the output looking for a Scandi or Greenie High, the Greek and Italiam weather geeks are no doubt salivating at the cold coming their way soon.