Model output discussion - 1st December onwards

[gottolovethisweather]

27 minutes ago, CreweCold said:

GFS completely different at 135 hours out East and North East...guess we have our answer Re how the upgrade has affected the ensembles!

Around the 17th December again then CC, certainly intriguing to see the ongoing confusion from that date forward.

That date is consistent with its potential for a pattern change, maybe not a long-term one and potentially just a watered down one but most would take that currently I'm sure. Air Temperatures touching 60f over parts of the South or a Northerly polar influenced short wintry snap anybodies guess right now down at the surface.

The trend is key, the details are much harder to tie down as ever. These types of weather headline are becoming entrenched in my mind of late, even if the cold air isn't. 

First hint of this game-changer here on Monday and then on Wednesday and its still there now Thanks to the GFS pub run. And all of this is simply from quoting my own posts and not those of others.

 

I still believe summats up NH wise and it might not go the way we are currently expecting judging by the model projections. A fascinating second half of December is on the cards for sure. 

Edited December 11, 2015 by gottolovethisweather

[nick sussex]

The only remotely interesting thing on the GFS 18hrs run was that ridge building in from the Pacific towards the Arctic.

This might help to edge the jet further south and put some pressure on the PV. Overall unless Santa reprograms the NWP computers tomorrow then its looking very unlikely we'll see anything colder within the next ten days.

As for Christmas that's too far away to make a call. At this point I think that ridge building in from the Pacific side is the only thing saving the SS White Christmas from sinking without trace.

I need to run now I have a late night Survivor of the Hideous 88/89 Winter Support Group Meeting! Unfortunately recent outputs have caused  a relapse!

[Mucka]

2 hours ago, Costa Del Fal said:

But that signal for change is always at the end of the run!! If I had money for every time the ECM 240 was said to hold promise I would be rich! 

Sorry but it was around now a proper cold spell was due early in December, then it was about the 17th, then about Christmas Day, now it's quite possible it will be 2016 before the pattern truly shifts.

 

It will always be that way though, unless we just ignore any charts beyond the reliable and where is the fun in that?

The problem is that it is very hard to get cold and snow in low lying areas of England even  when there is a strong cold signal a few days out - heck even when we get the cold we don't always get the ppn or there are warm sectors and we get sleet or rain when there is.

It used to frustrate the hell out me, all the let downs, but once you accept any cold and snowy output in FI is more likely than not to fail,  then it is easier to just watch and hope without expecting.

Any cold signals that appear will naturally come in FI first 99/100 times and also they will naturally fail more times than not so it is just a case of hoping the signal strengthens and reaches the more reliable timeframes. It is either that or ignore all FI output if it gets you too frustrated.

 

Edited December 11, 2015 by Mucka

[Captain Shortwave]

The 18z continues in the same vain, predominantly mild for most areas of the UK baring the occasional cold shot from the north west.

Whilst a lot of talk was about changes around day 5/6, temperatures for the end of next week remain unchanged (Mid-teens in the south, low teens in the north).

850 anomaly for next Thursday from the 18z GEFs

8C above normal in the south east, well above elsewhere too, With the ensembles showing a mixed broad south westerly flow then mid teens look likely again in terms of surface temperature. This also quite reflective of the ECM and GEM output (The UKMO throws a secondary feature across the UK at this time frame which gives a different view on the surface conditions).

The theme from the ensembles (GEFs and ECM) is for a potentially very mild week with rain mainly for north western areas with central and eastern areas seeing little in the form of the rain after the issues with this week pass. Beyond that it looks like a strengthening westerly jet stream will take hold with wind and rain for all, though this could be a default signal of course.

ECM ens

GEFs

 

In the end this month was expected to be pretty bad in terms of cold (though I have been  surprised in how bad it has been so far). I am sure this will change come the start of 2016 though.

 

Edited December 11, 2015 by Captain Shortwave

[Mucka]

2 hours ago, Nouska said:

Up thread somebody was mentioning verification stats for Europe - the most recent monthly Z500 from the ECMWF. UKMO looks to be equal top with ECM at T+144.

http://apps.ecmwf.int/wmolcdnv/scores/mean/500_z

What is DWD? That seems to be top?

JMA looks second and then ECM behind with MetO (UKMO 00z) back in the pack (blue dots)

UKMO 12z looks just about bottom. (solid blue line)

Am I reading it wrong?

Edited December 11, 2015 by Mucka

[Costa Del Fal]

4 minutes ago, Mucka said:

What is DWD? That seems to be top?

JMA looks second and then ECM behind with MetO (UKMO 00z) back in the pack (blue dots)

UKMO 12z looks just about bottom.

Am I reading it wrong?

DWD Model here: http://www.meteociel.fr/modeles/icone_cartes.php

[Yarmy]

3 minutes ago, Mucka said:

What is DWD? That seems to be top?

JMA looks second and then ECM behind with MetO back in the pack (blue dots)

Am I reading it wrong?

It's the normalized root mean square error, so lower is better.

[Mucka]

3 minutes ago, Yarmy said:

It's the normalized root mean square error, so lower is better.

Aha I should of looked what the lines actually represented (RMSEFF at top but didn't know what it was)

Thanks.

 

So in that case the question is what is KMA?

Edited December 11, 2015 by Mucka

[Yarmy]

7 minutes ago, Mucka said:

Aha I should of looked what the lines actually represented (RMSEFF at top but didn't know what it was)

Thanks.

 

So in that case the question is what is KMA?

Korean Met, I'd guess.  Looks like we should be following that.

[Mucka]

9 minutes ago, Yarmy said:

Korean Met, I'd guess.  Looks like we should be following that.

 

Yeah. Also fascinating how GFS 12z is comfortably ahead in FI which adds weight to the idea it is good for picking up long range signals and trends.

 

On KMA

there is an interesting article that details its specifications, some of which it has inherited from UKMO (excerpt below)

 

" With the operational supercomputer NEC/SX-5, the KMA could run several numerical models in 1999. Recently, KMA introduced Unified Model (UM) and data assimilation (4DVAR) system from UK Met Office to improve NWP performance. UM-based global and regional NWP system installed on a new supercomputer CRAY/XE6 are being operated since May 2010. "

 

http://web.kma.go.kr/eng/biz/forecast_02.jsp

Edited December 12, 2015 by Mucka

[knocker]

There are only two things of note vis the gfs run this morning. Periods of wet and windy weather are a regular occurrence and temps are above average, particularly in the first ten days. It does feature a cold plunge over the Xmas period although the GEFS isn't quite so keen. Rather academic anyway.

Regarding today the METO has the precipitation heading north bringing rain to most areas but snow on the high ground of Snowdonia, the Peak District and northern England. Some accumulation possible before milder air moves in as the weekend progresses.

Charts weatherbell

Edited December 12, 2015 by knocker

[Iceaxecrampon]

3 minutes ago, knocker said:

There only two things of note vis the gfs run this morning. Periods of wet and windy weather are a regular occurrence and temps are above average, particularly in the first ten days. It does feature a cold plunge over the Xmas period although the GEFS isn't quite so keen. Rather academic anyway.

Charts weatherbell

........meanwhile

00z T+300 Christmas Eve good on FI to break the mild monotony

[Iceaxecrampon]

8 minutes ago, Snowmut said:

You don't very often see this!(snowing everywhere)

As bad as this winter has been so far, some of us just may get lucky for the big day! (would be ironic)

GFS keeps toying with the idea, one way or another. 

Yes! GFS 00z in true FI support

[Polar Maritime]

The GFS shows a much more seasonal pattern as we head towards the Christmas period, Turning more a cool/cold N/Wly Pm flow.

Edited December 12, 2015 by Polar Maritime

[snowangel32]

On 11 December 2015 at 6:42 AM, jvenge said:

 

So if Gfs is correct it could be a case of short term pain for long term gain a number of runs now it shows very cold air around the Christmas period. 00z being the best so far.

 

 

Edited December 12, 2015 by snowangel32

[Liam J]

The air isn't actually that cold hence why the snow risk is much lower away from high ground looking at the above snow risk charts, it would feel more seasonable for a time though, and at the right time for Christmas day and that's assuming the GFS is anywhere near correct, which I wouldn't bet any money on at near two weeks away.... I'd just like to see the demise of the Euro high enter high res! 

 

[snowangel32]

3 minutes ago, *Sub*Zero* said:

The air isn't actually that cold hence why the snow risk is much lower away from high ground looking at the above snow risk charts, it would feel more seasonable for a time though, and at the right time for Christmas day and that's assuming the GFS is anywhere near correct, which I wouldn't bet any money on at near two weeks away.... I'd just like to see the demise of the Euro high enter high res! 

 

Yh that's the big question if the Gfs is correct, obviously caution needed but the fact it's been showing it now the last few days from what I can recall is cause for optimism. Anything has to be better than what we currently have. 

[JoeShmoe]

Can't post the chart but the ECM 0z is noteworthy this morning - yellows and oranges all over the UK out to the end of the run - surely record breaking warmth for Dec if that verifies

[Iceaxecrampon]

4 minutes ago, JoeShmoe said:

Can't post the chart but the ECM 0z is noteworthy this morning - yellows and oranges all over the UK out to the end of the run - surely record breaking warmth for Dec if that verifies

Cumbria ensembles verify - some members will be dusting the BBQ.

[Liam J]

19 minutes ago, Iceaxecrampon said:

Cumbria ensembles verify - some members will be dusting the BBQ.

Hmmmm.....Should we trust the 00z GFS OP when it was an outlier even for tomorrows temps! Typical it wouldn't be when showing temps into double figures... 

[Paul]

2 minutes ago, *Sub*Zero* said:

Hmmmm.....Should we trust the 00z GFS OP when it was an outlier even for tomorrows temps! Typical it wouldn't be when showing temps into double figures... 

Because the operational runs at a higher resolution than the ensembles, it will often be different when it comes to surface temps, as it'll be living up more detail, more accurate heights for each grid point, etc.

[Liam J]

5 minutes ago, Paul said:

Because the operational runs at a higher resolution than the ensembles, it will often be different when it comes to surface temps, as it'll be living up more detail, more accurate heights for each grid point, etc.

GFS can over do minimum temps at times, if it gets that cold tonight then the flooding and water run off will make a nice ice rink! The difference is even more apparent on the 2m minimum graph and it was on the colder side in low res.

[IDO]

No shock the GFS op is an outlier, it is the only member in the GEFS offering snow for London:   

 

Big back track as expected from the UKMO on last night's 12z: 

The ECM op is a beauty of a run for anomalous warm uppers:

Shock, no D10 teaser from the ECM this morning, normal resumption tonight I am sure: 

ECM D10     CFS w3 & W4: 

The CFS w3 and W4 look like they will have a more UK zonal flow by early January so maybe less warm and maybe wetter in the south but no sign of any pattern change (a bit early). The main cluster from the GEFS for Christmas day is 50% for a westerly zonal flow with mild conditions for the south (much like how week 2 is looking):

       2m temps GEFS: 

The 2m temps for London remaining milder than average through to D16 with little sign of anything remotely cool let alone cold. 

The MJO remains in the mild phases (4-5) for a while so nothing there to suggest changes:  

See what January brings?

Edited December 12, 2015 by IDO

[Paul]

18 minutes ago, *Sub*Zero* said:

GFS can over do minimum temps at times, if it gets that cold tonight then the flooding and water run off will make a nice ice rink! The difference is even more apparent on the 2m minimum graph and it was on the colder side in low res.

That's a single grid point in Cumbria though, with low minima as shown there, I'd assume it's a grid point on higher ground, so it's not necessarily overdoing the mins so to speak. It's just a forecast for a colder spot within Cumbria, and that's why the difference between it and the ensembles is exacerbated, as the same grid point on the ensembles is within a bigger grid (ie lower resolution), and will therefore have a lower average height. 

[Snowmad79]

7 minutes ago, IDO said:

No shock the GFS op is an outlier, it is the only member in the GEFS offering snow for London:   

 

Big back track as expected from the UKMO on last night's 12z: 

The ECM op is a beauty of a run for anomalous warm uppers:

Shock, no D10 teaser from the ECM this morning, normal resumption tonight I am sure: 

ECM D10     CFS w3 & W4: 

The CFS w3 and W4 look like they will have a more UK zonal flow by early January so maybe less warm and maybe wetter in the south but no sign of any pattern change (a bit early). The main cluster from the GEFS for Christmas day is 50% for a westerly zonal flow with mild conditions for the south (much like how week 2 is looking):

       2m temps GEFS: 

The 2m temps for London remaining milder than average through to D16 with little sign of anything remotely cool let alone cold. 

The MJO remains in the mild phases (4-5) for a while so nothing there to suggest changes:  

See what January brings?

 

That is all well and good but the OP does actually have quite some support from the other ensemble members according to that Gefs so lets write off the rest of December and start a fresh in January hey ?