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

[MR EXTREMES]

return of pacman nice uppers from latter ecm 

more west the colder air than last nights run 

[Iceberg]

I think the ecm would then go on to show increasingly easterly. Post 240. 

 

[Radiating Dendrite]

ECM brings in the second northerly, though it is fairly brief before the high starts to encroach back over us from the west.

I found it interesting that the GFS once again went for the easterly in deep FI, this has now been shown in some form or another for the last handful of runs. This is probably as big a trend as you would ever get from the model in FI land. GFS FI is usually characterised by big swings in synoptic patter from run to run, so for it to keep landing on the same sort of solution is actually fairly unusual.

Personally, I think we will eventually end up with the high back over us, leading to cold and frosty weather. What I have found with our weather over the last few years is that it has become very "stuck in a rut", a synoptic pattern tends to keep repeating during a season. This has been in evidence the last few winters and this winter seems to very much be mid-lat highs either over us or just to the SW / SE with lots of dry weather with cold and frost in the air when we bring in a slightly colder feed or inversion. Think we may be stuck in this pattern for a while yet, it could be worse I suppose.

[Iceberg]

Massive movement back to cold from the last run 12z

heres the 12z t168 compared to the recent 0z t168. 

I think we cal all agreement that we saw a big movement yesterday evening in the models. We've seen quite a big reversal from that this morning 

[Man With Beard]

A few observations this morning:

1. There is still daylight between the UKMO and ECM/GFS (though the ECM has moved towards it a little in the last 24 hours).

2. The correct modelling of these mini-troughs may not be evident until T72 (just thinking of past events)

3. Perhaps a bigger problem in the long-term solution will be a disconnect between the Atlantic trough and the depression off eastern seaboard at T144/T168 (as shown on Iceberg's chart above) - this would allow too much ridging from the tropics of the Western Atlantic and not allow as much WAA towards Greenland in a negatively tilted direction, meaning a flattening of the pattern and no southern flank of troughing under the high.

4. Big pattern changes often get over-modelled at long range - so it will be hard to get straight from the recent situation (no HLB) straight to a Scandi High situation. It may require a series of steps - or of course it may never make it at all.

GEFS continue to sing the easterly (the majority have some form of this by T216) but of course the caveats above apply.

Edited December 31, 2016 by Man With Beard

[knocker]

Without attempting any detailed analysis the ecm is pretty much along the same lines as the GFS and pretty much as expected. You will get the inter run changes, with the energy distribution being quite finely balanced, within the overall pattern.

All in all Sidney is quite relaxed about the outlook

 

[ArHu3]

In the meantime Arpege gives most of the Netherlands quite a decent snowcover, except where I live 

 

[knocker]

40 minutes ago, Iceberg said:

I think the ecm would then go on to show increasingly easterly. Post 240. 

 

May I ask in what particular time frame are you thinking and on what do you base the statement? I only ask, leaving other factors aside for the moment, because it's not obvious to me taking the evolution up to T240 and the chart at that point which shows the trough moving away E/SE and the HP cell to the west and and NW streamlines.

Edited December 31, 2016 by knocker

[tinybill]

well  going  by  the  gfs  things  are  good  for snow for the  uk   in  f1

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

 

[IDO]

The mean Pacific Ridge is gone by D11 so that is our window to get something out of this upcoming two wave push. The music will stop and if the trend for a UK high continues we may be back where we started with a high slap bang over us and waiting for the next episode of forcing in the Pacific. Where as if we can get a HLB that would prolong the cold spell, maybe into the next wave attack?

As it stands just looking at the ops up to D10; as with the upcoming northerly we will be on the wrong side of the trough next weekend and we get a glancing blow. It has shifted westwards in the last 24 hours but still needs a huge shift to make it interesting. However the driver for the shift is within the next 3-4 days synoptic wise so doubtful another u-turn from the models as they are now closing in on some sort of agreement.

The GEFS at D7 support the op for next weeks non-northerly. However there is an opportunity between D8-9 when the op shows a two wave energy flow from the south which delays heights building north as it just blows up the UK HP in situ  (ditto ECM):

op  member

Where as there is a strong cluster with a one wave attack that sharpens the ridge and these lead to heights building further north. That looks like a quicker route as otherwise we are waiting till well into FI, and based on recent shenanigans those charts are pretty useless as too much can scupper them in the interim.

The sensible call would be HP in charge for the foreseeable, as the mean suggests, and the ops agree with (GEM, ECM and GFS).

 

[Scandinavian High.]

 Blizzards for most south east looks snowed in.

[NO LONGER POSTING]

Morning Gang, 

Bit of de juvu? All about placing the high pressure in the right place AND more importantly sustaining it where ever it sets up (if of course it favours cold) 

The models are toying around with different solutions currently and while it's nice to see Stella charts, 9/10 its the extreme end solution and we build down from it or wipe it out completely. 

Even if we use January to build cold in albeit dry  away from any immediate coasts,  then it's good building blocks into February for something more snowy. If we can set up the required flow of course.. 

As ever its a complex situation and instead of viewing each run 1 by 1 I think it's best taking each days run and collaborate them and find the "average"  out, otherwise we find ourselves on an emotional roller coaster. 

Interesting model watching ahead over the next week with plenty of ups and downs I'm sure,  but all the models are trying to pick up on something the vast majority of you UK haven't seen in 2-3 years,  something more seasonable

[Iceberg]

15 minutes ago, knocker said:

May I ask in what particular time frame are you thinking and on what do you base the statement. I only ask, leaving other factors aside for the moment, because it's not obvious to me taking the evolution up to T240 and the chart at that point which shows the trough moving away E/SE and the HP cell to the west and and NW streamlines.

For me their are two key Aspects to the later stages of the ecm run.  The first is the lp coming in at t240 off the lower states. It pulls the mid Atlantic high west with the ridge that is thrown up. Pressure falls for us as the high retrogresses. The low introduces some serious waa and the worse case scenario from there would be a repeat of the pattern. 

However at the 500mb level the ecm also pushes the bulk of the northern arm energy up and over Svalbard with associated lower waa. with the mid Atlantic high retrogression and lower heights appearing over Europe the natural conclusion would be a ridge thrown into Scandinavia. There are limited signs of it in the form of  small col. I think as we move into the t250-300 timeframe we would have a stunningly set of charts with a blocked Atlantic heights to our north and slack lp to the south and se delivery an easterly. 

Just my opinion and largely irrelevant considering the movement in the models at the short time range. But as the model goes it's pretty darn good imho. 

Cheers 

[SLEETY]

17 minutes ago, abbie123 said:

 Blizzards for most south east looks snowed in.

Yes and those charts tie in with Joe B's thoughts of brutal cold in to Europe with much snow starting in the 11- 15 day period,hopefully he is on the money this time,he can be quite accurate sometimes ,others not so,let's see what's transpires

[Dennis]

1 minute ago, SLEETY said:

21 minutes ago, abbie123 said:

 Blizzards for most south east looks snowed in.

Yes and those charts tie in with Joe B's thoughts of brutal cold in to Europe with much snow starting in the 11- 15 day period,hopefully he is on the money this time,he can be quite accurate sometimes ,others not so,let's see what's transpires

Yes good sign to watch - outlook is an  Scandinavian High to be build

[radiohead]

The GEM is not a gem this morning.

[knocker]

11 minutes ago, Iceberg said:

For me their are two key Aspects to the later stages of the ecm run.  The first is the lp coming in at t240 off the lower states. It pulls the mid Atlantic high west with the ridge that is thrown up. Pressure falls for us as the high retrogresses. The low introduces some serious waa and the worse case scenario from there would be a repeat of the pattern. 

However at the 500mb level the ecm also pushes the bulk of the northern arm energy up and over Svalbard with associated lower waa. with the mid Atlantic high retrogression and lower heights appearing over Europe the natural conclusion would be a ridge thrown into Scandinavia. There are limited signs of it in the form of  small col. I think as we move into the t250-300 timeframe we would have a stunningly set of charts with a blocked Atlantic heights to our north and slack lp to the south and se delivery an easterly. 

Just my opinion and largely irrelevant considering the movement in the models at the short time range. But as the model goes it's pretty darn good imho. 

Cheers 

Thanks-we will agree to differ.

[Dennis]

 

[Scandinavian High.]

43 minutes ago, abbie123 said:

 Blizzards for most south east looks snowed in.

Over on two weather outlook brain gaze is saying there is a moderate risk of some extremely colder weather from the east second week of January.

Some members go down to -15 have not seen this for a long time.

Edited December 31, 2016 by abbie123

[AmershamMike]

It's like reading a chuckle brothers autobiography on this thread sometimes!!!! I know it's not model related moderators but honestly how anyone is supposed to learn from this sometimes is beyond me. So many different opinions and interpretations makes it really hard to know what is going on!!!

[Radiating Dendrite]

1 minute ago, AmershamMike said:

It's like reading a chuckle brothers autobiography on this thread sometimes!!!! I know it's not model related moderators but honestly how anyone is supposed to learn from this sometimes is beyond me. So many different opinions and interpretations makes it really hard to know what is going on!!!

It is a forum where people are free to voice their views, not a meteorology learning course.

Perhaps you should look at the weather guides section for help or just pick certain posters and read only their views.

 

[snowbunting]

Looking at it overnight its the GFS that has moved the second Nly to the east. With the ECM giving for a chilly Nly.

GFS

The ECM

Examining the ensembles for next sat it is pretty clear.... they are in a mess! That low to the south changes in direction and intensity. Can an area of low pressure so far south away from the mix of polar and tropical air masses have such a powerful effect  on the area of high pressure? The trend is however, there with settling down of weather in January. Its going to get cold. Where that high goes after that is anyones guess. 

Heart: the 2nd Nly.

Head: the High bringing settled cold weather.

Gut feeling: told hubby to buy in some salt for our track/road out.  It is going to snow. Forget the weather models, my wrist is aching!!!

 

 

[winterof79]

15 minutes ago, abbie123 said:

Over on two weather outlook brain gaze is saying there is a moderate risk of some extremely colder weather from the east second week of January.

Some members go down to -15 have not seen this for a long time.

GP alluded to that a couple of days ago.For those confused with the thread this morning I would say this.There remains a signal for cold to move westward in the 10-15 day period and has done for some time.The conditions are open for high pressure cells to form near or to the E/W or North of the UK.The exact positioning of this cell is the models dilemma which then becomes the members on here's issue of which scenario is correct.

[Iceberg]

Iceland is today's area of special scientific interest...owww bless them.

its the area of the most uncertainty, given the lack of strong lows in that region it likely means a couple of groupings, one high pressure  al la easterly developing one lower pressure which would include potential northerlies (one would like to think if one was being optimistic)

[bluearmy]

just noting that the ukmo is not exactly steadfast with the Azores low couplet - have a check back through the past few days runs and you will see that. However, it did pick up that they would engage slightly  differently with the northern arm that the other models. and it's day 6 output is again not overly consistent, run to run.  Run the ECM archives out to T168 and you will see better modelling. Easily argued that it handled the current route of travel just as well. 

The 8/10 day op output from ECM 26/27th turned out to be pretty good btw.