Model Output Discussions 06z 04/11/16

[bluearmy]

11 minutes ago, feb1991blizzard said:

Just wondering how strong the Atlantic ridge at the end of the eps mean and how far North does it get, I take it you haven't seen the clusters.

 No to the clusters

the mean is strong no higher than the latitude of Scotland. The high anomoly is strong sw of Greenland across to hudsons.

looks like a reasonable flow from the nw into the broad sceuro trough at that stage which is why I'm not convinced that there will be a strong greeny ridge. Plenty can change on that front but the sceuro trough looks solid. 

[Frosty.]

The GEFS 6z mean continues to show growing scandi / euro trough influence with height rises to the w / nw with below average temps for the uk  (cold cyclonic) with potential for much colder weather late Nov / early Dec onwards from a Nor'easter or Northerly..very interesting extended outlook watching it all hopefully come together.

Edited November 18, 2016 by Frosty.

[Ali1977]

If a Scandi trough is the way we do go I'm wondering what potential this could bring in December. We would still need some luck to get some proper cold to the UK but with this setup atleast we'd get some frigid air back into Scandinavia, it just depends on where it drops to see if we can tap into it. If it drops slightly further east than shown so far we should be able to get some WAA back into greenland which could prolong anything from the North or North East. The Op has potential but doesn't get the cold 850s in, this could change of course.

[jvenge]

Quite far out, but the temperature anomaly is impressing for large parts of Europe.

[feb1991blizzard]

2 minutes ago, jvenge said:

Quite far out, but the temperature anomaly is impressing for large parts of Europe.

Tease!!!!!,   I thought that was ensemble mean for a minute then, nearly jumped up,

[Singularity]

I believe if we're going to see a major trough turn up to our east, it will be very helpful if the negative AO state can facilitate some height rises in the Svalbard region to help advect the deeply cold air in our direction.

Get enough of that across, and the threat of Atlantic intrusions can potentially be overcome as such systems disrupt with the resultant secondary low sliding along the southern edge of the cold airmass, much like yesterday's GFS 12z showed for a time. Shame the following three runs have failed to produce this mechanism - they've not been very kind, regardless of the long-term trend.

A less broad trough imported from near Greenland that drops further south through Scandinavia and allows a ridge over the top, is a (large?) variant on the theme which I suppose the 00z ECM det. was a bit too keen on in light of the EPS.

[Zakos]

12 hours ago, jvenge said:

Quite far out, but the temperature anomaly is impressing for large parts of Europe.

 

Deep cold continuing to edge closer!

GFS ensemble mean showing blocking remaining solid in this area right through into December, also now indicating the atlantic will remain blocked.

Surely this cold pool will move west with time aslong as the atlantic remains blocked?

Edited November 19, 2016 by Zakos

[nick sussex]

A good easy way to keep a check on the ECM ensembles is on this chart, we can track the colder solutions over the next few runs to see if these increase:

It's a shame they don't have one for a UK location but given the set up if the models do stick with higher pressure to the n/ne then De Bilt can be a useful guide.

 

 

[Nouska]

This will give a flavour of the ECM means at 360.

                            T850  = Cold.

                             Z500   = cold

Week 4 of the EC 32     = cold

[jvenge]

1 minute ago, Nouska said:

This will give a flavour of the ECM means at 360.

                            T850  = Cold.

                             Z500   = cold

Week 4 of the EC 32     = cold

I better make sure my mother in law has enough wood, heh.

Any words from the pros in when we can consider the models to be more trustworthy? I remember Ian saying anything past 6 days was suspect. Can we extent that to 10 days yet?

I'd personally have thought more of the same would be expected with a reload coming, but of course, who knows where the cold drops.

[Blessed Weather]

Very encouraging tweet from Weather Co Europe. The latest ECMWF weekly showing a strengthening of the -NAO and colder Europe to mid-December.

[Methuselah]

All the model-runs have induced me to clean my windies...Don't want to obscure the view, now?

That said, things look rather more 2012 than 2009, to me; but, given the right relative orientation (between Scandi trough and Atlantic ridge) thundersnow might well be on the cards for eastern coastal counties?

[jvenge]

2 minutes ago, Ed Stone said:

All the model-runs have induced me to clean my windies...Don't want to obscure the view, now?

That said, things look rather more 2012 than 2009, to me; but, given the right relative orientation (between Scandi trough and Atlantic ridge) thundersnow might well be on the cards for eastern coastal counties?

Do we not have a resident who can look back through previous years? I'd have thought to look for weak La Nina or neutral, looking at where the cold has dropped so far and seeing what came of the years as potential clues as to what might be likely. There can't be too many winters that match all of those criteria.

 

[weatherguy]

3 minutes ago, Ed Stone said:

All the model-runs have induced me to clean my windies...Don't want to obscure the view, now?

That said, things look rather more 2012 than 2009, to me; but, given the right relative orientation (between Scandi trough and Atlantic ridge) thundersnow might well be on the cards for eastern coastal counties?

Was it 2012 which was the year of that tiny region of HLB which refused to budge between Iceland-Scandy through March?  Kept forcing slider lows and a near-endless stream of blizzards if I remember correctly.

[blizzard81]

16 minutes ago, Nouska said:

This will give a flavour of the ECM means at 360.

                            T850  = Cold.

                             Z500   = cold

Week 4 of the EC 32     = cold

Is that week 4 E C a map of southern europe?

[Snowman.]

9 minutes ago, weatherguy said:

Was it 2012 which was the year of that tiny region of HLB which refused to budge between Iceland-Scandy through March?  Kept forcing slider lows and a near-endless stream of blizzards if I remember correctly.

We had an Easterly teaser for December. Some of you may remember 'That ECM run' which caused the NW servers to crash.

http://www.meteociel.fr/modeles/ecmwf.php?jour=5&mois=12&annee=2012&heure=12&archive=1&mode=1&ech=72&map=0&type=0

It failed but disruption to Atlantic weather remained for most of the month till later in the month when the Atlantic finally got moving but was a short lived affair due the January 2013 SSW which lead to various slider scenarios.

 

Edited November 18, 2016 by SN0WM4N

[Ali1977]

All these great signs for Dec, then we have the chance of a SSW event on the cards....Not to shabby !! White Xmas is Defo a possibilty this year I'd say!! 

[Nouska]

2 hours ago, blizzard81 said:

Is that week 4 E C a map of southern europe?

Yes, from an E. European weather agency so focus on their region.

 

2 hours ago, jvenge said:

Do we not have a resident who can look back through previous years? I'd have thought to look for weak La Nina or neutral, looking at where the cold has dropped so far and seeing what came of the years as potential clues as to what might be likely. There can't be too many winters that match all of those criteria.

 

You'll be struggling to find an analogue for this year - so many anomalous factors.

I've been through old charts and nothing similar to current N. America/Arctic/Siberian anomalies.

Just to expand on this - below is the 925mb temp anomaly for the first fifteen days of November - all the negative anomalies are outwith the arctic circle and mostly in the eastern arc of the NH - nothing* of this pronounced nature in the modern ESRL record going back to 1948.

 * Only one other year with a similar, but weaker, profile.

Edited November 18, 2016 by Nouska

[weatherguy]

25 minutes ago, SN0WM4N said:

We had an Easterly teaser for December. Some of you may remember 'That ECM run' which caused the NW servers to crash.

http://www.meteociel.fr/modeles/ecmwf.php?jour=5&mois=12&annee=2012&heure=12&archive=1&mode=1&ech=72&map=0&type=0

It failed but disruption to Atlantic weather remained for most of the month till later in the month when the Atlantic finally got moving but was a short lived affair due the January 2013 SSW which lead to various slider scenarios.

 

Ah yes thank you! That was absolutely bonkers on here haha, oh what could have been.

Sorry mods for the semi-offtopicness - But that situation back then shows what can happen out the blue amidst a background of an extremely weak Jet coming up against a fairly modest block if its orientation is favourable.

Edited November 18, 2016 by weatherguy

[ArHu3]

2 hours ago, jvenge said:

Do we not have a resident who can look back through previous years? I'd have thought to look for weak La Nina or neutral, looking at where the cold has dropped so far and seeing what came of the years as potential clues as to what might be likely. There can't be too many winters that match all of those criteria.

 

I checked this for the Netherlands,  the best winters here were in neutral to moderate enso events, strong and very strong enso events always lead to mild winters

[Mucka]

No change of thoughts for me. I still believe ECM leading the way here as GFS looks to pick up the new signal.

I would much prefer GFS ensembles jump on board sooner rather than later but again, they are just showing noise at the moment for the same period and not a contrary signal to ECM which is an important distinction.

Blue posted the ECM ensembles but here they are again for London.

A notable cluster going cold end of November into December with the signal strengthened from when I mentioned it last night.

 

[chrisbell-nottheweatherman]

2 hours ago, Blessed Weather said:

Very encouraging tweet from Weather Co Europe. The latest ECMWF weekly showing a strengthening of the -NAO and colder Europe to mid-December.

What is also noticeable on the upper right chart (NH view) is that the +ve height anomaly is centred south of Greenland, which would suggest that this isn't a west-based -ve NAO.

Edited November 18, 2016 by chrisbell-nottheweatherman

[bluearmy]

Para ec46 in and it's colder than the op

uk looks to be surface cold throughout December - the last week around the new year shows an easing off but that's the far range of the product

broadly aligned with the op but low sceuro anomoly closer to us which keeps us cooler. 

[feb1991blizzard]

Just now, bluearmy said:

Para ec46 in and it's colder than the op

uk looks to be surface cold throughout December - the last week around the new year shows an easing off but that's the far range of the product

broadly aligned with the op but low sceuro anomoly closer to us which keeps us cooler. 

Recurring theme that there doesn't seem to be any cold uppers on these runs.

[bluearmy]

Just now, feb1991blizzard said:

Recurring theme that there doesn't seem to be any cold uppers on these runs.

Is that what I said?

uppers are also below average throughout apart from a couple of days around day 20 and after xmas

 And any west based NAO becomes less likely after week 3 as height anomolys rise more notably around Greenland. Weekly Mean anomolys are not too details at his range though