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

[SMU]

I like the UKMO 144 tonight

downstream sees lows being sheared apart over scandi & Moving south, with the atlantic trying to amplify & squeeze ridging ( towards 168 ) 

could be a very interesting ECM this eve

[Interitus]

13 minutes ago, ArHu3 said:

that will surely influence us next week post 192h, I think this is what he is refering too

 

There is a possibility of a nor'easter, that's what they are looking out for, though looks like the low will be too far offshore.

[johnholmes]

re my post last evening about the surface ridge over NE N America and it extending into the Atlantic, similar time frames for the 12z today show a deepish low is developed on the 12z today where the ridge was yesterday so the 168 chart near the UK looks nothing like that of yesterday. I will persevere and see how the 24 hour off the 168h-192h looks tomorrow. You never know it might re-appear!

 

[radiohead]

Look out Scotland...

Dragging cold air across the Atlantic.

Edited January 2, 2017 by radiohead

[MattTarrant]

GFS 12z does begin to push increasing heights out of NE America around 198h which by 210h push up towards the Arctic. Hopefully this continues in the next runs.  

[radiohead]

A snow cover for almost everywhere by T240 on the 12Z GFS, with 46cm showing over high ground in Scotland.

[Daniel*]

A very perturbed polar vortex.

 

[EML Network]

High pressure linking from Italy in the East right across the Atlantic and joining up to form another High system covering the entire eastern seaboard of the United States.

+192

PPN running along the Jet stream and that's about as flat as it gets :-(

As with pretty much every single GFS run in the past 2 weeks it shows colder weather (this time in the form of cold zonality) spilling into the UK.

If it's not going to be cold then I would rather it stay dry and that's about all one can say about the weather for the foreseeable future.

 

 

 

 

Edited January 2, 2017 by EML Network

[ArHu3]

1 hour ago, karyo said:

I don't know why there is this interest in the east US weather! There is not enough relevance to what happens here.

There is a far stronger link with southeast Europe, 9/10 we have the opposite weather of what the southeast Europe gets.

The best cold spells in the past were almost always preceded 5-7 days before by a spell of very negative EPO

[tinybill]

3 minutes ago, EML Network said:

High pressure linking from Italy in the West right across the Atlantic and joining up to form another High system covering the entire eastern seaboard of the United States.

+192

PPN running along the Jet stream and that's about as flat as it gets :-(

As with pretty much every single GFS run in the past 2 weeks it shows colder weather (this time in the form of cold zonality) spilling into the UK.

If it's not going to be cold then I would rather it stay dry and that's about all one can say about the weather for the foreseeable future.

 

 

 

 

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

if  f1  right  the  fun  starts  jan  11  onwards  here  in the  uk

 

[bluearmy]

They say madness can be defined as doing the same thing over and over again and expecting a different result .

The retrogression on the GFS looks simple enough but note the gem doesn't go the same way as a weak trough develops mid Atlantic to prevent it. Signs on the ECM op that the same thing could happen. 

Just saying ..........

[Catacol]

2 hours ago, Law of averages!! said:

Isn't this what big Joe bastardi said in last few days or so...cold West side of the states, cold western Europe towards 10th onwards??... let's hope 

It is the classic temperature profile of a -PNA, forecast now to be sustained negative until mid month at least. It's one of a number of teleconnections still pointing to decent chances of cold. The trouble is that readers of this forum mix up chance/probability with definitive forecast. It makes for wringing of hands and curses directed at these forcings when the goods aren't delivered. We even have some posters who then rubbish the teleconnectiive indicators and plump for "intuition" instead. 

Forecasting is all about macro trends leading to micro variations. We are a very long way away in forecasting terms from being able to get the micro developments right in the short term - and when it comes to precipitation mistakes are still made at ranges less than 72 hours fairly frequently. However we ARE getting better at predicting the macro drivers and thereby giving probability forecasts with greater confidence. Macro indicators for January are still pretty good. It isn't a perfect teleconnective scenario, but there is enough in the vortex profile, MJO pattern, suggested GWO composites, low solar activity and the fundamentally obvious observational reality of a long dead zonal Atlantic to remain positive. Come the end of winter it is entirely possible that we will look back at a setup that was a "so near and yet so far" scenario, and if this comes to pass then in my opinion we can lay blame at the unique failure of the QBO to reverse to an easterly this year. Who knows what the ramifications of this will be in 2017/18...

...but it is also entirely possible that we will get the block to set up in the right place to give us a day, a few days or maybe even a week or more of proper wintry weather. In my book deepest winter still has 6 weeks to go and that is a hell of a long time in weather following. 

So place a little faith in the teleconnections and hope that the macro drivers can align sufficiently to allow us a roll of the dice at micro developments bringing snow. The bottom line is that it is very difficult to get both micro and macro alignment for the UK. I remember half a dozen snow phases in my 46 years that have stuck in my memory and still make me smile. Best by far was Feb 96 - and by law of averages that means a memorable snow phase roughly every 6 years (given I don't have many memories from early childhood...) That is the real world in which we live.

So keep coming back to this excellent forum; do so with a desire to learn. But also do so with a tinge of realism and keep the toys firmly in the pram. You'll be disappointed 5 winters out of 6 based on my own experience... but let's try and remain optimistic and look forward to the next memorable snow event. It WILL come - and drivers still say that could be this current season. Best chances I reckon for several years.

[Backtrack]

20 minutes ago, radiohead said:

Look out Scotland...

Dragging cold air across the Atlantic.

I think that would bring in the coldest westerly I've even seen!

[Catacol]

2 hours ago, karyo said:

I don't know why there is this interest in the east US weather! There is not enough relevance to what happens here.

Not according to data gathered by the University of California. They see a link and have published a hemispheric composite to show what the data suggests.

[chris55]

32 minutes ago, radiohead said:

A snow cover for almost everywhere by T240 on the 12Z GFS, with 46cm showing over high ground in Scotland.

There looks to be a growing trend for the Euro trough to descend in our vicinity bringing cold (but not exceptionally cold, though just about cold enough for snow) unstable air, with the potential for some kind of easterly flow thereafter.

As Bluearmy has pointed out many times the Euro trough showing in the anomalies is gathering pace and something that could well deliver into the middle of Jan.

Its salient to take note regarding the anomalies, as all the semi pros/pros on here do. It's kind of clicked with me recently that the anomalies are the starting point and the Ops/Dets are are just that, deterministic within the wider pattern, determining the finer details within the bigger picture.

So a decent anomaly will increase the chances of a favourable synoptic pattern developing within that wider sphere.

But then there is also the "wildcard" as many of us look for, and as Steve M has highlighted for today.

But overall I'm pretty upbeat regarding the middle/latter part of Jan.

Lets see what ECM brings next....

Edited January 2, 2017 by chris55

[knocker]

14 minutes ago, Catacol said:

Not according to data gathered by the University of California. They see a link and have published a hemispheric composite to show what the data suggests.

A link to that research would be appreciated.

[law of averages]

3 hours ago, Law of averages!! said:

Isn't this what big Joe bastardi said in last few days or so...cold West side of the states, cold western Europe towards 10th onwards??... let's hope 

I won't drag this out but from I remember of the tweet by Joe b...he was referring to the WEST COAST STATES being cold and WESTERN EUROPE being either cold or very cold at the same time, as if the western side of the states cold was being pushed into siberia and the cold there being pushed into eastern europe, into mainland Europe!!

Not tother way round... eastern seaboard into the Atlantic...that's how I read it but could be wrong??

[Polar Maritime]

Model Discussion please, Thanks.

[There's a storm a coming]

GFS op following the GFS det. In FI with deepening low pressures driving across Scotland and then into Europe bringing a cyclonic cold spell to us. I think this looks like the way forward next week what happens next  is still " up in the air"

lets see what the ECM brings later

tasac

Edited January 2, 2017 by There's a storm a coming

[SMU]

Evening so is this a forecast - Hum perhaps not- however I though id throw it out there to 'POSSIBLY' expect a big change over the next 48 hours to a Jan 13 type Scenario with a split jet energy dropping south of the UK-

The follow on from my observation of the UKMO is that we have enough wedge of high pressure 'in the gap' to allow for a slowing of the eastward propagation & significant acceleration SE of low pressure around the 180 Mark- So ignore the 'fun' runs of the GFS FI as they will all disappear hopefully to be replaced by an UKMO style swing to cold- can the slayer become the Giant?

Who remembers Jan 13-

This was the actual chart that Verified

Note the low stalled over the UK -  14 Jan 2013

Just 5 days before the GFS had it here

7 days before

So we Know GFS will be East especially in the ENSEMBLES-

So my 'PUNT' for a better way of putting it would be day 8 & 9 & 10 sees significantly more trough disruption due to a wedge of high pressure over Scandi diverting Low pressure SE-

Lets hope if we roll the dice things turn out like this just 4 days later

This was the run UKMO went to the top of the charts,.....

http://www.meteociel.fr/modeles/ukmo2.php?jour=16&mois=1&annee=2013&heure=12&archive=1&mode=&ech=72&map=&nh=0&carte=1021

The same poor GFS run from the 12z that day

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=16&mois=1&annee=2013&heure=12&archive=1&mode=0&ech=6&runpara=0&carte=0

Something similar - just a bit further EAST?

Best

S

 

 

 

Edited January 2, 2017 by Steve Murr

[booferking]

Over 40mins since the last post on the model thread says a lot really looking at the ens you can see why trending the wrong way again.

[AWD]

3 minutes ago, booferking said:

Over 40mins since the last post on the model thread says a lot really looking at the ens you can see why trending the wrong way again.

The 12z GEFS;

Look, aside from small scale variability expected within an ens suite, very similar to the last few GEFS;

 

Not much change & not much to talk about from a cold perspective, apart from some frosty nights, until mid month where the last few GEFS have shown a fall away of 850hpa temps recently.

Certainly not trending any different to the last few GEFS IMO.  We continue to chase the FI carrot.

[nick sussex]

The ECM at T120hrs is much closer to the UKMO than the GFS both to the east/ne and over the USA.

[snowwman]

10 minutes ago, booferking said:

Over 40mins since the last post on the model thread says a lot really looking at the ens you can see why trending the wrong way again.

Perhaps the latest GFS run at D16 has found a solution the the difficulty of the Northerly considering the strong vortex over Canada, now gone in this chart:

 

.

[booferking]

12 minutes ago, AWD said:

The 12z GEFS;

Look, aside from small scale variability expected within an ens suite, very similar to the last few GEFS;

 

Not much change & not much to talk about from a cold perspective, apart from some frosty nights, until mid month where the last few GEFS have shown a fall away of 850hpa temps recently.

Certainly not trending any different to the last few GEFS IMO.  We continue to chase the FI carrot.

That is not the 12z ens which i was commenting on that is 00z & 06z...

I see editing 12z ens in now and they are worse going the wrong way.

Edited January 2, 2017 by booferking