Model Output Discussion - 10th Jan Onwards

[bluearmy]

 

Yes because if they're just going on the mean and ensembles then the trough position at T96hrs is pivotal to how those ensembles can develop, f the ensembles have the wrong set up then they're going to be totally wrong later.

 like i said nick, depends how you use them. and the suddenly much revered mogreps-15 is an ensemble product.

[snowking]

Just a quick one from me. All models seem keen once again on MJO phase 7:

 

 

We have to be slightly wary of this once again because we saw this signal before the previous Easterly debacle before the signal slowly waned, but the initial amplitude looks higher this time. This is probably why we are suddenly seeing a projected resurgence in some runs from those Scandinavian heights. A quick reminder below of the MJO phase 7 SLP composite under wQBO and ENSO Neutral conditions:

 

 

We see perhaps why the GEM is reluctant to give us anything interesting right now:

 

 

JMA offering some support though:

 

 

So we now have to wait and see whether this amplified MJO phase 7 signal is overplayed or not. If it ends up being close to reality then expect to see some more interesting runs in the near future.

 

SK

Edited January 14, 2014 by snowking

[MR EXTREMES]

This is the third day in a  row someone has posted a GFS strat chart @..................384 HOURS...............Looks nice but................

to be perfectly honest I think the strat hype in the model output at 384hrs is rather ott no offence but this may not happen and if it does might have very little effect this is only 1 part of a much bigger puzzle.

 

we shall see might need to wait until this weekend to see if the models come to an agreement and I for one am hoping for a more wintry outlook but without the ukmo chef forecasters update to colder solution im firmly discounting any cold or colder air from the east.

 

I think its finely balanced and from what im reading with in the models theres a possibility of alsorts but my punt would be mid lat block after this week and the weekends unsettled spell or a cool northwest flow and remaining slightly cooler than average.

[The PIT]

SS folk can see what you state is wrong for the AO, some of the output shows -ve some show +ve. Had you said there are rather more -ve ideas than +ve then you might find folk more ready to believe you. Please report accurately or simply leave the picture for folk to make their own mind up please?

Eye also the same with NAO some members send it positive as well.

[Summer Sun]

GFS 12z 8 day temperature anomaly shows most of the UK seeing slightly above normal temps the exception to this is parts of Scotland, Northern Ireland, the south west and parts of northern wales

 

Edited January 14, 2014 by Summer Sun

[MrSunshine]

GFS 12z 8 day temperature anomaly shows most of the UK seeing slightly above normal temps the main exception parts of Scotland and Northern Ireland

 

 

You left out North Wales & part of South West England with slightly below average temps.

[fergieweather]

 

All eyes on the ECM tonight. Big test a-coming.

Quite so. The similarities between GFS and UKMO-GM 12z are quite striking (if somewhat meaningless at this range... but...). Of course, as we always bat-on about on this forum and as a UKMO senior colleague rightly was just this moment discussing with me, pretty much any NWP's ensemble mean is almost always set to exhibit bias towards a westerly component (or even full-on zonality), simply because their westerly members will exhibit more 'energy' in the broad sense, e.g. wanting to drag us towards a notion of deeper low pressure to the northwest of the UK (as per, for example EC32 into weeks 3-4 lately). The net result is a skewing of the mean pressure pattern in favour of that outcome... and falsely so, in, certain cases. For this reason, the output today is being watched with very great interest given how EC has maintained various 'nods' towards a quite different outcome next week. Earlier today, Exeter were at pains to stress that despite a 10% easterly prospect on face-value of ENS products, the possibility nonethless needed mentioning. In other words, this ongoing saga / trough disruption mess is by no means a done-deal, at this stage.

[MR EXTREMES]

You left out North Wales & part of South West England with slightly below average temps.

and spain

[Weather-history]

Latest NAO update keeps it at neutral for another 2 weeks at least

 

 

Latest AO update keeps it negative

 

Jus to show the NAO is not the be all end all, if you look at the values for January 1990 and February 1991 on NOAA, they are exactly the same but the two months were totally different in character.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table

It's the AO, where they differ, Jan 1990 was positive and Feb 1991 was negative.

[karlos1983]

This is the third day in a  row someone has posted a GFS strat chart @..................384 HOURS...............Looks nice but................

Yes, however it is showing up in earlier time frames now. One to watch for sure

[nick sussex]

 Quite so. The similarities between GFS and UKMO-GM 12z are quite striking (if somewhat meaningless at this range... but...). Of course, as we always bat-on about on this forum and as a UKMO senior colleague rightly was just this moment discussing with me, pretty much any NWP's ensemble mean is almost always set to exhibit bias towards a westerly component (or even full-on zonality), simply because their westerly members will exhibit more 'energy' in the broad sense, e.g. wanting to drag us towards a notion of deeper low pressure to the northwest of the UK (as per, for example EC32 into weeks 3-4 lately). The net result is a skewing of the mean pressure pattern in favour of that outcome... and falsely so, in, certain cases. For this reason, the output today is being watched with very great interest given how EC has maintained various 'nods' towards a quite different outcome next week. Earlier today, Exeter were at pains to stress that despite a 10% easterly prospect on face-value of ENS products, the possibility nonethless needed mentioning. In other words, this ongoing saga / trough disruption mess is by no means a done-deal, at this stage.

It's a real shame we don't have a similar NCEP model discussion as they do in the USA, where the forecaster discusses the varying solutions and the expected overall pattern.

 

This morning the ECM ensembles at T96hrs had so many different solutions for the troughing near the UK that any mean forecast was really going to be very skewed because some of those ensembles would have no chance of going onto show an east/se or even likely a colder trough disruption near the UK,I find the mean is okay when its a more typical pattern  but in this set up it can be very misleading so I appreciate you coming on to clarify the thoughts at the UKMO.

 

I'd say given the critical nature of the troughing at T96hrs that this will be the decider product if indeed the upstream pattern amplifies as expected by NCEP.

Edited January 14, 2014 by nick sussex

[Bristawl Si]

Quite so. The similarities between GFS and UKMO-GM 12z are quite striking (if somewhat meaningless at this range... but...). Of course, as we always bat-on about on this forum and as a UKMO senior colleague rightly was just this moment discussing with me, pretty much any NWP's ensemble mean is almost always set to exhibit bias towards a westerly component (or even full-on zonality), simply because their westerly members will exhibit more 'energy' in the broad sense, e.g. wanting to drag us towards a notion of deeper low pressure to the northwest of the UK (as per, for example EC32 into weeks 3-4 lately). The net result is a skewing of the mean pressure pattern in favour of that outcome... and falsely so, in, certain cases. For this reason, the output today is being watched with very great interest given how EC has maintained various 'nods' towards a quite different outcome next week. Earlier today, Exeter were at pains to stress that despite a 10% easterly prospect on face-value of ENS products, the possibility nonethless needed mentioning. In other words, this ongoing saga / trough disruption mess is by no means a done-deal, at this stage.

What a great post Ian, in terms of the level and amount of insight you're sharing. Thanks.

[Summer Sun]

GFS 12z London ensemble shows the 850's peaking at a low of around -3 (red line) (the black line was the GFS run red line is the ensemble average) around the 23rd highest snow risk is %15 between the 24th and 25th

 

Edited January 14, 2014 by Summer Sun

[IDO]

GFS 12z 8 day temperature anomaly shows most of the UK seeing slightly above normal temps the exception to this is parts of Scotland, Northern Ireland, the south west and parts of northern wales

 

 

 

Cheers SS. Yes just shows how close we are east and west to cold, but most of the UK stuck in the milder sector. Even with a block you do need a bit of luck, especially if its a transitory pattern.

 

The mean at T180 for 850s highlight this: 

 

Could have picked any from early in the run to deep in FI and it would have been similar.

 

The control from the 12z GEFS more reflective than the op to the mean:

 

Control at T180:    Mean: 

 

Heading in the right direction is the best I can call it.

[Matty M]

ECMWF most advanced eastwards with Scandy high @ 72hrs, of course in the grand scheme of things, not that much difference between MAJOR 3 @ 72hrs

 

[Captain Shortwave]

Nice to see the GFS and UKMO heading towards something a little more blocked. Hopefully the ECM will conjure up something tasty over the next 50 minutes.

[bluearmy]

to follow on from ian's post re appreciation of the ens and their bias - the ecm ens have continued to renew the northern arm of the jet thorugh the uk post day 10 and the gefs post day 8 (these are the points where the resolution of the ens drops away on each model). Interestingly, MOGREPS-15, although running at a resolution between GEFS higher and lower res and lower than ecm's lower res, does not have a drop in resolution during the run. does that help with consistency ????i would still be concerned about using gefs at the moment, given their lack of upper strat visibility and the fact that plenty is going on at the top of the strat at initialisation. its possible that the GEFS are not slowing the zonal winds enough to give them a handle on the ability of the blocking to establish as the impetus from the stronger westerly flow high up drops out.

[Tim Bland]

ECM looks similar to 00z so far

[Stuie]

Ah that mini bit of vortex to the NW wasn`t on the previous run. Maybe a chance of a good blast from there early next week.

[Cloud 10]

Yesterday's 12z ECM was easier on the eye.

 

yesterday..  today..

 

 

Lets see where this one takes us.

[nick sussex]

The GFS is the safer route , the UKMO has less margin for error and the ECM at 120hrs even less because its flatter.The UKMO out of the Euros is better at T96hrs and 120hrs than the ECM.

 

Nerve shredding by the ECM it just about gets there, if the upstream pattern is more amplified in future runs then this increases the margin for error, the GFS is the less cold solution, the Euros more hiding behind the sofa, riskier but colder.

Edited January 14, 2014 by nick sussex

[Long haul to mild]

The GFS is the safer route , the UKMO has less margin for error and the ECM at 120hrs even less because its flatter.The UKMO out of the Euros is better at T96hrs and 120hrs than the ECM.

Looks like we may be in the very unusual position this winter of hoping the GFS is right for once!!

[Purga]

Borderline again with ECM so far

 

We're just on the edge of the block so uncertainty rules

[nick sussex]

Looks like we may be in the very unusual position this winter of hoping the GFS is right for once!!

If you feel lucky go for the Euro trend but with a westwards correction because they would be more likely to bring in deeper cold, if you feel nervous the GFS is the safer option as it clears the shortwave energy, the Euros have very low margin for error.

[Long haul to mild]

Borderline again with ECM so far

 

We're just on the edge of the block so uncertainty rules

 

 

Frustrating that the Azores High seems to want to throw up a ridge and there's a bit too much Atlantic energy to the North, which stops the block backing West.

If you feel lucky go for the Euro trend but with a westwards correction because they would be more likely to bring in deeper cold, if you feel nervous the GFS is the safer option as it clears the shortwave energy, the Euros have very low margin for error.

 

Our luck's been out this winter so far, so I'll hedge my bets and back the GFS!