Model Output Discussion 1200 hrs 15/11/14

[SMU]

http://www.meteociel.fr/modeles/geme_cartes.php?ech=6&code=0&carte=1&mode=0&archive=0

 

GEM is out to 102-

 

Looks like the best run of the 12s so far.... let see but at 102 its the most amplified.....

 

the key to this is if the GEM is MORE amplified at 102 the atlantic energy will also separate & split North south holding the block to the east in Situ....

 

That's the plan..........

[snowy weather]

Retrogression hints at a East to West reverse zonal flow, which thereby encourages colder air to infiltrate our little island from the cold continent.

 

Baby steps at first though, so time will tell.

thanks mate

[Mucka]

http://www.meteociel.fr/modeles/geme_cartes.php?ech=6&code=0&carte=1&mode=0&archive=0

 

GEM is out to 102-

 

Looks like the best run of the 12s so far.... let see but at 102 its the most amplified.....

 

the key to this is if the GEM is MORE amplified at 102 the atlantic energy will also separate & split North south holding the block to the east in Situ....

 

That's the plan..........

 

Here it is out to 120h with comparisons for folk to see what you mean as you can only currently post links. GFS(p) is about the closest match.

 

 

 

It does go on to form an Easterly but the jet is over the top so not really a sustainable cold spell

Edited November 25, 2014 by Mucka

[SMU]

So as a result of that MINOR change at 120 with a slight redistribution of energy the GEM 192 looks like this

 

http://modeles.meteociel.fr/modeles/gem/runs/2014112512/gemnh-0-180.png?12

http://modeles.meteociel.fr/modeles/gem/runs/2014112512/gemnh-0-192.png?12

 

http://modeles.meteociel.fr/modeles/gem/runs/2014112512/gem-1-192.png?12 850s ...

 

A lot better profile of cold to the EAST & strong Easterly flow over the UK..... - not quite on this run but you get the gist.

Edited November 25, 2014 by Steve Murr

[phil nw.]

Some interesting 12z runs.Almost a step change in the European set up showing next week.

Sufficient ridging deep into the pole to finally release some of the pent up Siberian air south and west into mainland Europe.

GFS(p)and GEM especially good on this,the UKMO model not quite so.This all around T120/144hrs so i dare say more tweeks to come on this evolution.

Promising signs though of a much cooler spell for the UK especially if we pick up the flow off the continent.

[knocker]

Yes Phil it was a close call but I came within a whisker of posting a cold chart. And I'm glad my seafaring days are over looking at this chart. Not nice.

Charts courtesy weatherbell.com

 

[carinthian]

Just had our latest up -date ( Central European forecast ) Info for central Europe to turn colder on Tues/ Wed next week. A trough development from Denmark to Switzerland with some snowfall, mostly light accumulations, possible to lower levels.

The UK is on the outer perimeters of our updates, but some lower temperatures seem likely. Possible development later next week for some more prolonged precipitation in the SE. The behaviour of the upper trough into SW Europe is causing a lot of uncertainty as the block still holds firm to the east, but the case for more widespread colder conditions seem to be firming up more generally from the start of next week.

 C

Following on from the above post, The UKMO also has the Genoa Low in place by 144hours. That ties in with our numericals for Central Europe with a potential trough development towards the Low countries. Beyond that there is some thought of this action pushing into SE England post 144hours with potential for some cold unsettled weather in this location.

 C

[phil nw.]

A look back at the 00z 2 Mtr temp graphs showed a decline.

Here are the ones for Warsaw,Berlin and then London.

 

 

so if this trend is followed C.and E Europe go into the freezer next week with the UK colder too-maybe low single figures for many areas.

Let's see if the 12z ens follow this,certainly indications of the cold pool spreading this way on the outputs so far. 

[Mucka]

A look back at the 00z 2 Mtr temp graphs showed a decline.

Here are the ones for Warsaw,Berlin and then London.

 

ensemble-tt6-warsaw (1).gifensemble-tt6-berlin (2).gifensemble-tt6-london (2).gif

 

so if this trend is followed C.and E Europe go into the freezer next week with the UK colder too-maybe low single figures for many areas.

Let's see if the 12z ens follow this,certainly indications of the cold pool spreading this way on the outputs so far. 

 

I will be very encouraged by this evenings runs if the ECM plays ball, generally all the output has headed in the right direction for me. If we get the same rate of improvement through tomorrow I think we will start to see some good cold runs appearing among the ensembles 10-12 day output.

[stratty]

A look back at the 00z 2 Mtr temp graphs showed a decline.

Here are the ones for Warsaw,Berlin and then London.

 

ensemble-tt6-warsaw (1).gifensemble-tt6-berlin (2).gifensemble-tt6-london (2).gif

 

so if this trend is followed C.and E Europe go into the freezer next week with the UK colder too-maybe low single figures for many areas.

Let's see if the 12z ens follow this,certainly indications of the cold pool spreading this way on the outputs so far. 

...........certainly feel the GFS Ensembles will be trending colder too

[Summer Sun]

GFS following on from previous runs with a chilly start to December with temperatures for many places only just making mid single figures from Tuesday

 

 

Frost and fog could become more widespread next week with the latter in some places lasting all day if it did temperatures could struggle to reach 2 or 3c.

 

 

Snow tease from GFS P at the end of its run

 

 

Edited November 25, 2014 by Summer Sun

[LomondSnowstorm]

...........certainly feel the GFS Ensembles will be trending colder too

They are - far more amplified than the 6Z with a good number of blocked solutions and a mean Italian low and easterly flow for most of Europe showing up even out to D8.

Edited November 25, 2014 by LomondSnowstorm

[mushymanrob]

.... all i see on the gfs 12z are minor tweeks as to the timing and exact position of the pressure systems both high and low. the story is the same, a declining european block, a growing displaced azores high which looks like it could replace the current european block. nothing to get excited about, they are pretty much what youd expect within differing runs. looking pretty average/normal to me.

of course this is only the current prediction and isnt set in stone.

[Barry12]

.... all i see on the gfs 12z are minor tweeks as to the timing and exact position of the pressure systems both high and low. the story is the same, a declining european block, a growing displaced azores high which looks like it could replace the current european block. nothing to get excited about, they are pretty much what youd expect within differing runs. looking pretty average/normal to me.

of course this is only the current prediction and isnt set in stone.

 

Compare day 6 today from yesterday across the models and you will see that the block is getting stronger:

 

GFS P:

 

 

ECM:

 

 

GFS:

 

 

Surely a trend in the reliable time frame, is more important than a trend in FI.

 

Also, while the block does deteriorate in FI today, it's not as much as it did in FI yesterday...

 

P.S whats wrong with the Azores High ridging in if it gives us an Easterly?

Edited November 25, 2014 by Barry95

[Polar Maritime]

A nice cold N/Wly showing in the later stages of the GFSP, With -4/5 uppers and snow over the much of the UK.  

 

[Captain Shortwave]

A nice cold N/Wly showing in the later stages of the GFSP, With -4/5 uppers and snow over the much of the UK.  

 

Needs more north PM, only sunny and cold for us down here  

Well that Arctic ridge trend is certainly a good one, even if it fails to bring cold weather this time.

Day 6 GFS mean

We need that ridge to hold on for as long as physically possible to allow cold air from Siberia to drift into Europe and support low heights there. If the ridge severs then the most likely result will be a UK high as the Arctic high hopes to the Pacific side of the pole and the remaining ridge over Europe sinks ushering in the alternative pattern change. At this moment it seems to require a lot of luck to get cold into the UK through this route. But hey, miracles do occur.

Edited November 25, 2014 by Captain shortwave

[Snowy L]

Compare day 6 today from yesterday across the models and you will see that the block is getting stronger:

 

GFS P:

 

 

ECM:

 

 

GFS:

 

 

Surely a trend in the reliable time frame, is more important than a trend in FI.

 

Also, while the block does deteriorate in FI today, it's not as much as it did in FI yesterday...

 

P.S whats wrong with the Azores High ridging in if it gives us an Easterly?

 

Azores high ridging in is what has constantly denied the jet diving south these last 2 winters.

[Mucka]

GFS 12z ensembles have things cool/chilly for Central England 2nd week of Dec.

 

 

Let's hope to see those snow probability percentages continue to increase over the coming week.

Edited November 25, 2014 by Mucka

[SMU]

.... all i see on the gfs 12z are minor tweeks as to the timing and exact position of the pressure systems both high and low. the story is the same, a declining european block, a growing displaced azores high which looks like it could replace the current european block. nothing to get excited about, they are pretty much what youd expect within differing runs. looking pretty average/normal to me.

of course this is only the current prediction and isnt set in stone.

 

Hi Mushy the final destination of the azores high is crucial to the possibility of the cold.

 

In the day 6/7 timeframe the GFS is indeed making minor tweaks, however there is a tipping point where the WHOLE patter changes- this tipping point if where the angle if the azores high is so amplified that it sends the atlantic system up to the left of the arctic high as opposed to under its base.

 

Yesterday the 12p has the angle HERE

http://modeles.meteociel.fr/modeles/gfsp/archives/gfs-2014112412-0-144.png?12 note its about 45 degress from the North

 

Then the 00z at 132 had it HERE

http://modeles.meteociel.fr/modeles/gfsp/archives/gfs-2014112400-0-132.png?0 Note the correction to about 35 Degrees - so now theres less energy propergating EAST & more North east.

 

once we get to this scenario around 20 degrees

http://modeles.meteociel.fr/modeles/gens/run/gens-3-1-120.png?12 your past the tipping point

 

so we go from this at 168 yesterday 12z

http://modeles.meteociel.fr/modeles/gfsp/archives/gfsnh-2014112312-0-168.png?12 EASTWARD energy

to

144 today

http://modeles.meteociel.fr/modeles/gfsp/archives/gfsnh-2014112412-0-144.png?12 Energy more spread North east & South east-

 

Another tick in amplification & we get here

http://modeles.meteociel.fr/modeles/gens/run/gensnh-3-1-138.png?12

 

 

we are very close to the margins -  it could go either way....

Edited November 25, 2014 by Steve Murr

[Barry12]

Looking good at 96, with more pressure up North than on 00z

 

 

Got a feeling this is going to be a good run...

[ITSY]

Have a look at the GEFS ens for the other side of the channel in Belgium or holland and they look encouraging with a steady 6/7 runs below the -4 upper line. Taken with GEM cautious optimism should be in order. A few bonkers runs recently will get people looking for the -15c's but that's is so unlikely it's not worth taking into your outlook until we have a better idea of coming pattern change. Changes over the arctic and how any HP cell interacts over either Northern Europe or Northern Atlantic will also be crucial. So much going on - great to watch the analysis develop

[Weather Boy]

Hi Steve

Sorry, unable to post charts on this device, but from a uk perspective GEM seems a cracking run. Easterly from reliable (developing this weekend) to well into FI.

Downsides, I suppose are

1. It's GEM, limited reliability even by General model standards

2. Persistent LP over Greenland preventing retrogression and thus threatening sustainabilty of the system

3. Not overly cold continent given recent conditions and early stage of season making snowfall questionable.

Are these the reasons that you are not getting too excited?

Nice to see these runs, though, especially when they are not flatly contradicted by other models.

The

[SMU]

Hi WB-

 

because it needs the big models on board -

 

ECM out to 144 still trying to deepen the low & force it through-

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014112512/ECH1-144.GIF?25-0

 

the JMA is reasonable out to 132

http://www.meteociel.fr/modeles/jma.php?ech=24&mode=1&nh=1&archive=0

 

S

[Mark Neal.]

Hi Steve

Sorry, unable to post charts on this device, but from a uk perspective GEM seems a cracking run. Easterly from reliable (developing this weekend) to well into FI.

Downsides, I suppose are

1. It's GEM, limited reliability even by General model standards

2. Persistent LP over Greenland preventing retrogression and thus threatening sustainabilty of the system

3. Not overly cold continent given recent conditions and early stage of season making snowfall questionable.

Are these the reasons that you are not getting too excited?

Nice to see these runs, though, especially when they are not flatly contradicted by other models.

The

Interestingly the. GEM does keep an easterly for much of its run however pressure generally high over Uk. -8c uppers get close by mid next week as they are over the continent. Cariathian alluding to a disturbance coming close to the SE corner of. UK with unsettled conditions, GEM shows this( Attached).. Something to keep an eye on and another take on the outlook. Looks like chilly regardless next week with Fog/Frost and some bright conditions with high pressure generally in control.

[Captain Shortwave]

ECM closes the door and we end up with a mid-latitude high

Still chilly enough with wintry showers possible for a time in northern areas before most areas become dry and settled. 

This route to cold via the east is very low odds given the ECM/UKMO/GFS all cut off the Arctic high from our side. But I guess still possible. In the end the outcome either way doesn't look too bad and it will probably feel seasonal after the brief milder spell at the end of this week.

Can't complain with this for 8 days away

850s still below 0C so some sharp frosts and freezing fog likely.

Edited November 25, 2014 by Captain shortwave