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

[jvenge]

42 minutes ago, northwestsnow said:

Well the ecm went downhill at a rate of knots after 168!! 

We had a euro low in place and it looked to be setting up for a north wester, then the northern arm just swept it all away.

Is there anything we can cling to? Its getting pretty desperate now isnt it.

Ps i dont class the EC monthly as any sort of lifeline, its been signposting blocking highs at northerly lats since November, and im pretty sure it did the same last winter, im not sure if people pay for it, if i did i would be wanting a refund,its been dreadful!

Hi,

EPS 46 is showing a colder spell for the UK from Jan 13th to Jan 19th. However, the last run just a few days ago was showing the UK under colder than average conditions for all of January. Those EPS 46 runs have zero consistency and I personally view them as fiction, for the moment anyway.

I think pretty much anything can happen after day 12 at the moment, but I would suspect the confidence for colder than average conditions for January would have slipped with the MetOffice over the past 3-4 days. No idea what their own models show, though.

[knocker]

10 minutes ago, bluearmy said:

You may want to check your calendar knocks. Presume you mean the second half of Jan rather then the first? 

And luke, if you are going to diss macro forecasts of HLB, then please can we see a hemispheric chart to back it up. No doubt that this winter has failed to deliver  for nw Europe coldies but it's definitely been blocked MLB rather than HLB in our part of the NH.  Maybe a halfway bust thus far and the distance between delivering/not delivering really is not as large as you might think. 

Seeing as everyone now has access to the ec46 i shall refrain from future comment on it So yes to be more accurate 850mb temps significantly above average until the 12th then below average until the 21st and then generally above average until the middle of Feb.

Edited January 3, 2017 by knocker

[phil nw.]

There does seem an increasing trend in all the 00z runs to siñk our high by the weekend and bring in the westerlies.

The strength of the northern jet is now showing up again and it is difficult to see anyway back from this now.I think the best coldie's can hope for is some transient polar maritime air as the fronts pass through but as we know from experience  these usually only deliver any snow to the far north and higher elevations.

I am afraid any pretence of even mid latitude blocking is fast disappearing on this mornings charts and although Europe further east continues to get the cold with the Azores high expected to return home there is little prospect of us seeing it come this way.

Edited January 3, 2017 by phil nw.

[Polar Maritime]

Some posts are more suited to the Winter/Meto forecast threads. Please continue with discussion around what the models are showing.

Thanks please continue. 

[Osbourne One-Nil]

This is the Model Discussion Thread. In fairness to those who want to visit the Model Discussion Thread to see discussion about, or discuss, model output, please stick to model discussion. 

I hope that clarifies things?!

[johnholmes]

Understandably the mood is fairly low in here this morning. Some of it is a touch overdone in my view but that is just my view. Some of it is also due to a few folk not understanding meteorology so when forecasts are issued they do not grasp just what is being said. Hard perhaps but it has to be said. Blocking has been a feature of this winter, certainly when compared to this far into last winter. But it has not delivered what most on here wanted, cold but with snow.

 

Anyway my personal rant over how about what weather can we expect in the next 7-14 days? Looking at the anomaly charts with their links below and nothing shouts deep cold nor really mild. The 3 I use show an upper ridge continues to be a major factor. Its position either west of, sometimes SW and sometimes centred SE of the UK. That leaves the UK on the edge of cold but not, other than a day or two at a time, in any depth of cold. Perhaps the probable weather is most easily illustrated by looking at the Met O Fax charts at 24 and 120h. Deep cold into central and eastern Europe with the surface ridge close by the UK preventing any deep penetration of cold air.

 

The upper air predicted continues to show, ‘so near yet so far’ for most of the time. However, in my view, there are still opportunities for deepish cold air to flood south at times, 2-3 days at the most but it is about a 70% probability in the next 2 weeks in my view. That seems to be the best we can expect in that time scale.

 

Met O Fax chart links

http://www.weathercharts.org/ukmomslp.htm#t120

 

Anomaly charts

http://www.cpc.noaa.gov/products/predictions/610day/fxus06.html

 

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

The possibility of a ridge moving out from America that I posted 2 evenings ago looks dead in the water. The ridge is there again on the 00z GFS but it should be showing moving out into the Atlantic at 96h and that is not showing.

So for everyone wanting cold and snow the wait continues. 2-3 days will occur but no deep long lasting cold seems likely at the moment.

I hope my post, the first paragraph is not seen as too unkind to some but an attempt to get folk to be more realistic. Please read some of the Net Wx Guides about model watching and meteorology. It will help some of you to a better understanding of the models I am sure.

[mountsbaysnow]

Im hoping for a last minute turnaround in the models.after all these are just calculations right?so anything can happen....example october storm 87 last minute.com

 

[Singularity]

Very broad-brush this, but it feels as if the models were - perhaps very typically - far too swift with the change of theme when they first picked it up, and have been slowing down the pace at which the jet heads south into Europe ever since, resulting in an increasingly long intermediate period in which we have an unsettled westerly regime affecting the whole country for a change, rather than mostly just the north.

Given the wide timespan of the longer-term diving trough signal for Europe, you'd think we have a fair bit of wiggle room in terms of delaying the onset, but I expect a lot of that rides on an assumption of renewed amplification propagating from upstream thanks to increased tropical/MJO activity in the Pacific. Tamara has said to watch out for this by (as early as?) mid-Jan as a means of kicking off a rise in GLAAM and so helping to facilitate some high(er) latitude blocking, so I remain hopeful, if rather wary.

[Luke Attwood]

I think we are all missing the trick here, as long as pressure stays low over Greenland which it looks like it will do then we will not see anything particularly cold and sustained.So to sum it up the the theme going into next week is for mainly westerly winds occasionally switching northwesterly bring the odd colder shot.. But nothing sustained all very boring really.

Edited January 3, 2017 by Luke Attwood
Mistake

[Scandinavian High.]

Maybe a easterly mid month we could be seeing high pressure building over to the north east and low pressure undercutting going to Europe  .

Edited January 3, 2017 by abbie123

[Luke Attwood]

4 minutes ago, abbie123 said:

Maybe a easterly mid month we could be seeing high pressure building over to the north east and low pressure undercutting going to Europe  .

Very unlikely PV looks to organized

[Guest]

One thing i have to say is i will not believe any form of Easterly until its at t24 across all models and even then i will only be 50/50...lol been burnt many times by phantom easterlies over the past few winters.. i still feel that when cold does come it will be a sudden switch out of the blue, we all remember the 2013 WTF moment from Mr Brown..

[jvenge]

9 minutes ago, abbie123 said:

Maybe a easterly mid month we could be seeing high pressure building over to the north east and low pressure undercutting going to Europe  .

I imagine this is the week or so of colder weather showing on the EPS 46. Surprising that confidence is so low, considering the range and how bullish the mean output was. 

[Scandinavian High.]

10 minutes ago, Luke Attwood said:

Very unlikely PV looks to organized

We all no how things can quickly change with the weather.

Edited January 3, 2017 by abbie123

[Guest]

1 minute ago, abbie123 said:

We all no how things can quickly change with the weather..

Also we have seen in the past that we can get stonking cold spells even with a monster PV somebody put a post in here the other day showing either Jan 87 or Feb 91.. a monster PV and a stonking easterly.. yes its rare but it does happen. the models have shown us some close but no cigar stuff so far this winter we will get more chances im sure of that. we just need that bit of luck for it to go our way..

[booferking]

6 minutes ago, abbie123 said:

We all no how things can quickly change with the weather.

The pv is not the problem this year there are other forces and not even the best lrf models or pros can figure these forces..

[Gael_Force]

13 minutes ago, jvenge said:

I imagine this is the week or so of colder weather showing on the EPS 46. Surprising that confidence is so low, considering the range and how bullish the mean output was. 

Presumably they see whatever has been messing with the model signal as continuing. I wonder if they know what is causing this to happen; would be interesting to find out. Perhaps this is MJO related as I think it is the only one showing amplification out of the COD.

PS. somebody a few pages back asked if it could be ocean temp related. The SST anomaly analog based forecast chart I posted a while back, suggests this is very possible .... and maybe arctic ice related too.

Edited January 3, 2017 by Gael_Force

[booferking]

Just now, booferking said:

The pv is not the problem this year there are other forces and not even the best lrf models or pros can figure these forces..

 

18 minutes ago, Luke Attwood said:

Very unlikely PV looks to organized

The pv is not the problem this year there are other forces and not even the best lrf models or pros can figure these forces out..

[Luke Attwood]

1 minute ago, booferking said:

The pv is not the problem this year there are other forces and not even the best lrf models or pros can figure these forces..

Well it may not be the main problem, but it certainly doesn't help our chances of cold!

[Rocheydub]

46 minutes ago, Luke Attwood said:

I think we are all missing the trick here, as long as pressure stays low over Greenland which it looks like it will do then we will not see anything particularly cold and sustained.

I think you need to rephrase that. Very few of us are missing this at all! It's very rare that we get sustained cold weather with a strong PV over Greenland, but it has and could happen again, 1987 being an example.

[SMU]

Morning-

This mornings evolutions are all about speed & eastward movement- & if people want to improve their inderstanding of why a model is doing X whilst the other model is doing Y at the same time then reviewing the NH plots against the eastward speed of systems as well as their tilt will support that knowledge base -

There was a post last night copying a tweet from the states - below

& this neatly sums up the stark differences between UKMO V GFS/ECM blend today- its all about eastward speed. ( just like last week )

The UKMO is very slow over the states at 120 - 144 it creates a significant snowstorm @132 which hugs the east coast eventually lifting out as it gets Past Nova Scotia -

The UKMO is placing more blocking ahead of that low slowing it up, where as the GFS lifts that low out over the Carolinas & doesnt really develop it

 

The GFS sees less blocking ahead of the low-

solution wise this then manfiests downstream days later with either an Amplified pattern - UKMO or GFS flatter. The other spin off from Amp V flat ( crucially ) is Amp = further west with the pattern in Europe, flat = East

The forecast I went with yesterday was the slower one- infact to get where I wanted to be it would need to be as slow if not slower than the UKMO with significant disruption across the whole atlantic- all the slowest GFS & GEM create enough of a wedge of high pressure to undercut the low SE across the UK like this

NB where this GFS ENs places the east coast storm - just like the UKMO

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=0&code=7&mode=0&carte=1

S

 

 

[SMU]

Note how the GFS 06 v 00z trends to the UKMO in the early stages

first image 06z has more northward component up the east coast

Edited January 3, 2017 by Steve Murr

[Luke Attwood]

5 minutes ago, Rocheydub said:

I think you need to rephrase that. Very few of us are missing this at all! It's very rare that we get sustained cold weather with a strong PV over Greenland, but it has and could happen again, 1987 being an example.

But your giving 1987 as a example,god that is years ago I think you should be a bit more realistic.

[Luke Attwood]

A better looking 6z at 144, a bigger cold pool over the med.therefore lower pressure over southern Europe which is good to see.

[Rocheydub]

8 minutes ago, Luke Attwood said:

But your giving 1987 as a example,god that is years ago I think you should be a bit more realistic.

Just because you weren't alive! You're showing your tender years here.

You're "missing the trick" here my friend, there are many vagaries, too many, when it comes to the movements of weather and pressure systems, and despite it being years ago, it can happen. Our islands lie between a large warm ocean and a large continental land mass, we are just a blip in between! Predicting our weather is fraught with danger. Sometimes inexplicably! Just ask the pros.