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

[Dennis]

3 hours ago, fromey said:

i ve seen this posted 

"Models are indicating a stratospheric ridge to build in over Europe during the late 11-15d period."

what does this mean and how would this effect us here on our small little island.

also the zonal winds are indicated to drop, i assume this is taken into account in the models

Be gentle, trying to learn

 

fromey

this is the model you talked about  - zonal winds go down

Edited January 5, 2017 by Dennis

[nick sussex]

Overall today still some issues with shortwave energy in the Atlantic, the GFSs two runs today are a bit more complicated. This is mainly due to the handling of a shortwave crossing the USA, the amplitude of this does effect the high exiting the eastern USA.

You can see the different handling here between the ECM and GFS.

So ECM 00hrs run to T144hrs                                              GFS06hrs run to T138hrs.

Looking across the main models the GFS does have the flattest solution so it would be a surprise if it was correct, but anyway you want the more amplified solution to verify.

There after the trend is to have troughing to the east with high pressure displaced further west. The Russian high helps to lock the troughing and stop this from being pushed too far east. I think the issue at the moment is the sustainability of any colder conditions, shortwaves are likely going to run over the top of the high and head se near the UK with associated milder sectors.

So some wintry weather possible but we're not seeing anything that has deep cold so conditions are likely to be marginal away from higher ground in the north.

I think the big issue going forward is what the PV does, theres no signal to remove this from Greenland and it doesn't really want to clear east. With this type of set up with troughing over Europe the only way to get some deeper cold is for the main PV chunk to pull nw to allow some ridging over the top of the troughing. The GFS has played around with this in some of its ops but we're not seeing anything concrete and the ECM isn't interested.

So overall turning colder at times with some wintry weather but still we're short of anything meaningful in terms of depth of cold and non slushy snow.

 

[feno13]

8 minutes ago, Gael_Force said:

Try having a look at the ensembles for your own location: simple as a click on the map provided.

http://www.meteociel.fr/modeles/gefs.php?carte=1

 

Thanks for that , i did not realise you could click the map i was only seeing London ensembles , you learn something new everyday

[Iceaxecrampon]

12Z

+192

Well everyone - all eyes down for a week tomorrow - this will be a test for anyones patience in terms of model cold delivery.

It's going to be interesting (again) to say the least.

Bookmarked.

Edited January 5, 2017 by Iceaxecrampon

[The PIT]

Just now, Iceaxecrampon said:

12Z

+192

Well everyone - all eyes down for a week tomorrow - this will test anyones patience in terms of model cold delivery.

It's going to be interesting (again) to say the least.

 

Seen plenty of cold shots at T192. Indeed with had a quid for everyone shown we'd all be millionaires and probably bankrupt if we depended on it verifying.

[bluearmy]

Given that we don't look at more than a dozen runs per day absolute max, you would have to live for well over 200 years to be a millionaire (a quid a time) if every single run let you down!

the eps more solid on the low anomoly hanging around in the 10/15 day period than the 12z suite with the London temps responding in kind

no sign of snowmageddon but looks like we may have a raffle ticket for end next week onwards for somewhere between 2 and 5 days (could extend ). As Dave mentioned this morning, disturbances will likely  crop up in the base of the troughing which looks like it will be down the west side of the country.

the gefs a bit bi polar in their clustering so he mean looks a bit uncertain - of course, we no longer have cluster info on the eps to assist.

[swfc]

Id tend to agree with nick earlier in regard to any true cold wintry weather.Atlantic ridge ,blast  from the north west then toppler.Pv to the nnw looks like its not on the move atm and the azores high-ridge seems to be a hinderence .Im not seeing via the nhp any signals for a sustained cold snowy period so i guess the guys to the nw will be best positioned.

[lassie23]

Azores high and the euro high are ruining winter again, will they still be there in the summer? Been very quiet regarding atlantic storms, yet we still find ourselves snowless.

[Luke Attwood]

5 minutes ago, lassie23 said:

Azores high and the euro high are ruining winter again, will they still be there in the summer? Been very quiet regarding atlantic storms, yet we still find ourselves snowless.

Yes i agree that's the problem,but wouldn't it be rare if we didn't have HP down to the Azores,it always seems to be there! Hah

[IDO]

As you can see from the GEFS clusters the period of cold trough is no certainty for a UK event. In fact, although the best case scenario is the biggest cluster, all four clusters remains equally likely IMO:

here

The trend on the 06z with respect to the 0z is positive in that regard, however the 06z suite after D7 is a law to itself so I would await the 12z before I would call it as a move towards the ECM? As it is very fine margins.

As with a NW flow its pretty much a non-event for snow showers down in the SE, in fact Birmingham South. Favoured coasts on the NW and Scotland and hills and mountains, etc. Looking at the mean uppers from D9, still showing below average, 2-3c below till D16, so no done deal for snow at sea-level with those uppers?

It will be nice to see even charts like this, taken at face value, get down to within the D6 more reliable time frame. Still potential but no more just yet based on the GFS.

Edited January 5, 2017 by IDO

[Backtrack]

1 hour ago, Luke Attwood said:

Yes i agree that's the problem,but wouldn't it be rare if we didn't have HP down to the Azores,it always seems to be there! Hah

It's called the Azores high for a reason, so yes, if it's displaced it's uncommon, but not uncommon to get LP's into Spain etc, especially in the winter months 

[radiohead]

Let's hope the 12Z GFS can improve on the 06Z. Rolling out now.

It seems we have more delays on the GFS(P) again today.

[Team Jo]

without wishing to nag,some recent posts would probably be best suited to a PM conversation or the banter thread.......if we could keep on topic for the imminent runs, that would be super!

 

Thanks!

[radiohead]

T180 12Z GFS

[Fozfoster]

Looks like 12z brings the 528 dam line in a bit quicker.

[There's a storm a coming]

So the UKMO follows its morning run with lows passing over the north of Scotland and then diving into Europe and the Azores high still close by to the sw...good for the northwest as this will bring cold air and snow showers.

GFS seems to be following the script also up to 144hrs

Tasac

Edited January 5, 2017 by There's a storm a coming

[MattTarrant]

The high pressure does seem to have retrogressed somewhat more than the 6z run which is good to see(I only got to quickly look at the 6z this morning so sorry if i'm wrong). 

The North Westerly (PM) incursion is already evident as incoming around 156h 

[tight isobar]

A decent 'northern hemispherical' profile. 

The azores sore thumb getting squashed out...and seeping upstream towards eastern seaboard. .something of an evolution we need to see lot's more of throughout raw output. 

[MattTarrant]

4 minutes ago, tight isobar said:

A decent 'northern hemispherical' profile. 

The azores sore thumb getting squashed out...and seeping upstream towards eastern seaboard. .something of an evolution we need to see lot's more of throughout raw output. 

I was thinking the same thing though there is still too much energy coming of the Eastern seaboard for it to have the potential to form a more robust block. 

It's once again quite a potent PM incursion (Excluding the South West of course )

Edited January 5, 2017 by MattTarrant

[Ravelin]

Is that -12 850s I see over Scotland...

[Weathizard]

What a stonker! A very intruiging 12z, much more amplified in the Atlantic.

[MR EXTREMES]

1 minute ago, Ravelin said:

Is that -12 850s I see over Scotland...

More than enough cold uppers across the entire UK into northern France would be pretty Dam cold.

But it's gfs fi let's see what ukmo and ecm say.

One thing that's lacking is hlb it's all getting more and more zonal but lucky it's only one model and gfs 

[Mucka]

16 minutes ago, Ravelin said:

Is that -12 850s I see over Scotland...

I think Nick has alluded to this but I would be wary of any clean polar flow and low uppers for now.

The models often oversimplify a troughs behaviour, which while making little difference to to the longwave pattern, can have a big impact on how cleanly we draw in any polar air.

Often there will be shortwave troughs that develop within the flow cutting off any polar component and introducing warm sectors so generally the 850's are overdone (too cold) at those sort of ranges.

We won't really know until it gets inside 120 and we have more idea of how complex the trough will be and far Southwest it can dig.

That said we should at least see a fairly cold PM flow at some stage which will be the best we have done so far this winter.

Edited January 5, 2017 by Mucka

[radiohead]

6 minutes ago, Ravelin said:

Is that -12 850s I see over Scotland...

No it's -13

[Johnp]

2 minutes ago, MR EXTREMES said:

More than enough cold uppers across the entire UK into northern France would be pretty Dam cold.

But it's gfs fi let's see what ukmo and ecm say.

One thing that's lacking is hlb it's all getting more and more zonal but lucky it's only one model and gfs 

More zonal? I'd use the word meridional for this run so far.