Model Output Discussion 29th December - Into mid-Winter.

[Cheshire Freeze]

9 minutes ago, Mucka said:

Yeah looks good, all about how the Atlantic trough disrupts.

GEM 144 for what it is worth.

Not great...however, ECM and GFS are now very similar around 216 hours with the retrogression signal and Atlantic troughing sliding underneath

So close to a lovely 'Griceland' HP...just need that trough to cut down from the NNE

Also..an observation- this run sees trop vortex continuously draining to the Siberian side. Potential for an epic low res.

Edited January 12, 2017 by CreweCold

[Mucka]

14 minutes ago, CreweCold said:

Not great...however, ECM and GFS are now very similar around 216 hours with the retrogression signal and Atlantic troughing sliding underneath

So close to a lovely 'Griceland' HP...just need that trough to cut down from the NNE

 

Yeah the possibility of a retrogressing high was something I spoke about a couple of days ago as the upstream modeling started to become more favourable but I think people were quite rightly more interested in the Northerly and possible Easterly at the time to take much notice. Well that or a lot of people aren't interested in my FI ramblings. 

 

Actually getting the high pressure to our NW and pulling in a N/Northeasterly is like pulling hens teeth so far though.

I wonder if the models begin to firm up on this if we might not see a cleaner evolution? Hope so.

Edited January 12, 2017 by Mucka

[Cheshire Freeze]

>20C temperature anomalies at 850 level approaching Greenland

[Cheshire Freeze]

2 minutes ago, Mucka said:

 

Yeah the possibility of a retrogressing high was something I spoke about a couple of days ago as the upstream modeling started to become more favourable but I think people were quite rightly more interested in the Northerly and possible Easterly at the time to take much notice. Well that or a lot of people aren't interested in my FI ramblings. 

 

Actually getting the high pressure to our NW and pulling in a N/Northeasterly is like pulling hens teeth so far though.

I wonder if the models begin to firm up on this if we might not see a cleaner evolution? Hope so.

The whole Canadian side of the vortex is disintegrating, which has been a common theme in the extended for a fair few runs now

Looking at some of the strat charts further out, it could be coming close to RIP vortex 2016/17

[Captain Shortwave]

Whilst not comparable to the ECM, the UKMO has at least offered some give and produces a better morning run.

So good agreement on a continental flow at least with the chance of that cold pool over Europe back west into the UK which will really add to the chill.

Promising signs in the short to mid range. I expect there will be some epic low resolution runs soon than later given the retrogression signal.

[Mucka]

GFS ensembles look very good out to 144 with most of them bringing the cold back in from the SE 

[Cheshire Freeze]

1 minute ago, Mucka said:

GFS ensembles look very good out to 144 with most of them bringing the cold back in from the SE 

Not a bad ensemble mean to have, seen worse

[Cheshire Freeze]

How's this for a 240 hour pressure anomaly 

This is the ensemble MEAN

Edited January 12, 2017 by CreweCold

[Mucka]

4 minutes ago, CreweCold said:

How's this for a 240 hour pressure anomaly 

This is the ensemble MEAN

Good but hints of a West based -NAO

[Cheshire Freeze]

1 minute ago, Mucka said:

Good but hints of a West based -NAO

Indeed, but an evolving situation..will have to monitor how it develops in future runs. Plenty to keep us engaged though.

[SMU]

A bit low key in here this morn ??

UKMO moving all the way to the GFS mean @144 delivering an Easterly was the     Last model to do so-

The GFS mean has now dropped to -8c @144 off the continent.. the lowest yet-

Thats sub 2c maxima for england probably for 5-6 days on the cards- far colder than a Northerly will ever be !!

PS a west based NAO doesnt matter as long as the main trough drops to our east which it should....

Edited January 12, 2017 by Steve Murr

[metaltron]

The GFS control run is more amplified than the OP this morning. I read here a few days ago that the control has the same starting data as the op but with lower resolution. So is the control meant to point out possible errors in low resolution? For example today the low resolution version of the same starting data is more amplified, so should we expect the ensembles to be biased towards amplification this morning?

Edited January 12, 2017 by metaltron

[Mucka]

Best set of GFS ensembles for a while. Any "warm up" very brief indeed. 

Not sure MetO's forecast of mild on Monday will survive the day.

 

Steve,

We get ice days from good Northerlies and North Easterlies up North which is why blocking to W and NW tend to be better for us than blocking to the E and NE and we get more chance of snow.

Euro4 not very good for SE snow chances.but keeps changing.

Cheshire gap showers showing up nicely.

Fridays band of rain/sleet/snow pushing down from the North

 

ECM 96h very close to yesterday mornings run. Fantastic consistency.

Edited January 12, 2017 by Mucka

[That ECM]

Having gone through all 20 perbs at t144 they are all singing a similar tune and there is not one a coldie wouldn't take as a starting point. Some are better than others obviously. Ukmo at t144 has moved to a similar place. Very exciting ecm to come and imo this has led the way over the past week or so.

Edited January 12, 2017 by That ECM

[Chris K]

21 minutes ago, metaltron said:

The GFS control run is more amplified than the OP this morning. I read here a few days ago that the control has the same starting data as the op but with lower resolution. So is the control meant to point out possible errors in low resolution? For example today the low resolution version of the same starting data is more amplified, so should we expect the ensembles to be biased towards amplification this morning?

Not neccesarily. Same initial conditions run at a lower res, yes. But I thought that where the control is different to the operational, it is used as comparison to help to identify if a spread in the ensembles is more likely being caused by variation in the initial starting conditions, or resolution issues. It doesnt mean, for example, that one cluster should immediately be assumed to be more likely than another.

This is because an ensemble set for one point (e.g T850 for one location) can be a 'magnified' view within a synoptic evolution, so reviewing the sets of overall synoptic patterns is required.

Hopefully that's explained correctly!

Edited January 12, 2017 by Chris K

[metaltron]

3 minutes ago, Chris K said:

Not neccesarily. Same initial conditions run at a lower res, yes. But I thought that where the control is different to the operational, it is used as comparison to help to identify if a spread in the ensembles is more likely being caused by variation in the initial starting conditions, or resolution issues. It doesnt mean, for example, that one cluster should immediately be assumed to be more likely than another.

This is because an ensemble set for one point (e.g T850 for one location) can be a 'magnified' view within an synoptic evolution, so reviewing the sets of overall synoptic patterns is required.

Hopefully that's explained correctly!

Ah ok so if the control and op are different then ensemble spread is most likely to be caused by resolution, whereas if they are similar the ensemble spread is most likely to be caused by starting data. Think I've got it. Thanks!

[Cheshire Freeze]

20 minutes ago, Mucka said:

Best set of GFS ensembles for a while. Any "warm up" very brief indeed. 

Not sure MetO's forecast of mild on Monday will survive the day.

 

Steve,

We get ice days from good Northerlies and North Easterlies up North which is why blocking to W and NW tend to be better for us than blocking to the E and NE and we get more chance of snow.

Euro4 not very good for SE snow chances.but keeps changing.

Cheshire gap showers showing up nicely.

Fridays band of rain/sleet/snow pushing down from the North

 

ECM 96h very close to yesterday mornings run. Fantastic consistency.

Not overly impressed at 120 hrs but I suppose still fairly chilly

[SMU]

All 3 models identical @ 144 with a deep pool of surface cold heading west out of the continent...

Expect snow to feature.....

Edited January 12, 2017 by Steve Murr

[shaky]

2 minutes ago, Steve Murr said:

All 3 models identical @ 144 with a deep pool of surface cold heading west out of the continent...

Expect snow to feature.....

Steve do you think there will be more snow than currently forecast on sunday!!!hopefully the front drops down the centre of the uk bringing in colder air futher west than what is shown at present!!

[SMU]

11 minutes ago, shaky said:

Steve do you think there will be more snow than currently forecast on sunday!!!hopefully the front drops down the centre of the uk bringing in colder air futher west than what is shown at present!!

At the moment the models have edged a tad east for sunday so not at this stage however the margin is only 100 miles so within the realms of reality - I think you maybe just to far west... also depends on timing...

[That ECM]

7 minutes ago, Steve Murr said:

All 3 models identical @ 144 with a deep pool of surface cold heading west out of the continent...

Expect snow to feature.....

What about this on ecm. Less so on ukmo and not on gfs Steve? Could be useful looking at its track?

Edited January 12, 2017 by That ECM

[SMU]

14 minutes ago, That ECM said:

What about this on ecm. Less so on ukmo and not on gfs Steve? Could be useful looking at its track?

Yes 100% day 9&10 as at 168 its got blocking ahead of it meaning energy will sweep east underneath & should also help reinforce the easterly at 192

S

[joggs]

6 minutes ago, Steve Murr said:

Yes 100% day 9&10 as at 168 its got blocking ahead of it meaning energy will sweep east underneath & should also help reinforce the easterly at 192

S

Or could it just spin due north into low heights?

[SMU]

16 minutes ago, joggs said:

Or could it just spin due north into low heights?

Yes - depends on the other low @ 168 trying to dig a little over norway stopping the full on blocking-

still bitter either way...

[That ECM]

Pv on the move! This is a trend we have seen for awhile. Not a lot NW to come and flatten the pattern.