Model Output Discussion - The Run In To Christmas

[Rocheydub]

I'm off to pin a tail on a donkey.

 You're spot on, the spread of options across all models and ensembles is huge. To hang your hat on any particular outcome, would be a brave option. We'll know a lot more tomorrow by 7pm… Or maybe 10.45pm… Or maybe the next morning at 4.45… You can see where this is going!

Edited December 20, 2014 by Polar Maritime
To bring it back on topic.

[sundog]

Be careful not to make an ass of yourself!!! Eeeeawwwlways says that!

 

Anyway, back on topic, you're spot on, the spread of options across all models and ensembles is huge. To hang your hat on any particular outcome, would be a brave option. We'll know a lot more tomorrow by 7pm… Or maybe 10.45pm… Or maybe the next morning at 4.45… You can see where this is going!

The models havent a glue atm as there is so many options. Its like pullin a xmas cracker this xmas as regards the models , you just dont know what you will get inside it. But hopefully a nice surprise.

Edited December 20, 2014 by sundog

[Midlands Ice Age]

the 18z not far off giving us an easterly in FI - doesn't make it this run but another option on the table longer term if the high to our north-west dos not sink as fast as the GFS shows

 

http://www.wetterzentrale.de/topkarten/fsgfseur.html

 

Yep GFS P is toying with the idea of the uK High linking up with the big bad siberian monster?

Could ithis be the trend that is confusing the models? Maybe GFS has spotted a trend again in deepest FI. We will have to wait and see. I know a lot of people on here thought it to be the likely outcome.

 

MIA

Edited December 20, 2014 by Midlands Ice Age

[Frosty.]

Anyone for Round 2 ??

 

 

LOL I hope it's better than round 1, having said that, next week is turning colder from the north and it's not going to be a mild Christmas..frosty early and late which suits me.

[phil nw.]

A decent London ens graph for cold seekers.

 

 

like the 00z set earlier today the GFS op at the top end of members in week 2.

As expected the ECM the much colder model and apart from the mild blip around day 8/9 close to the mean, which is low single daytime max's later.

Note a good clutch of below zero members towards month end,probably the onset of the Northerly.

Edited December 20, 2014 by phil nw.

[SE Blizzards]

ECM Day 8 mean...

 

 

GFS Day 8 mean...

 

 

It's been quite a while since i've seen such a difference at Day 8.

 

I am totally and utterly confused  

[Man With Beard]

The Christmas day fax chart is a teaser for eastern coastal counties with a small trough running down the North sea bringing the chance of wintry showers.

PPVO89.gif

I'm so glad you posted that, and I'm so glad IF posted about the white Christmas possibility on yesterday's ECM - with everyone's eyes on the 27th onwards, I think we're missing the here and now - sub 528 line clearing the south coast by 12z on the 25th, sure, pressure possibly too high but low pressure not far off, northerly streams are notorious for late developing features - maybe just maybe!

edit: just to add, a staggering ECM ensembles chart posted by Phil just above. There must be a very good chance of a prolonged cold spell based on that, regardless of what GFS says.

Edited December 20, 2014 by rjbw

[bryan629]

well thats pretty interesting in deepest FI

 

heights running right across the N hemispere 

 

just about at the same time as a split is forecast in the strat   

 

i wonder if we could end up with a classic `H` from that, if it verified of course :smiliz19:

 

 

[Mark Neal.]

ECM Day 8 mean...

 

 

GFS Day 8 mean...

 

 

It's been quite a while since i've seen such a difference at Day 8.

 

I am totally and utterly confused  

Yes very differing output at the day 7-10 range once again, pressure over Greenland there is a 25mb difference there. Hopefuly the 00z runs and through tomorrow the mist clears, albeit slightly.

[ukpaul]

 

It's been quite a while since i've seen such a difference at Day 8.

 

I am totally and utterly confused  

 

It's down to the way the GFS sees the Canadian lobe of  the polar vortex. At 186h or so, the ECM keeps it intact but shunts it northwards, other models split it, GFS keeps it where it is and subsequently strengthens it even more. 

[Frosty.]

with all due respect, I think you need to stop Ramping. Your post have gone from severe blizzards to some wet snow, to cold and frost. No wonder members are confused.

Please don't misquote me, I never said anything about severe blizzards. There is a zero tolerance against your type of stupid comments so be warned!

[Bolton67]

Please don't misquote me, I never said anything about severe blizzards. There is a zero tolerance against your type of stupid comments so be warned!

Please look back at some of your posts.

Edited December 21, 2014 by lancs_northants

[Polar Maritime]

Let's be polite and respectful. The Models at the time of posting have changed, As always in these set-ups with such unpredictable swings .. So don't shoot the messenger!  

Edited December 21, 2014 by Polar Maritime

[TEITS]

Brief summary from me and the key points I shall highlight below.

 

1. Christmas day is unlikely to be white for most so I would forget about the models changing towards a white xmas. The day appears mostly settled with slightly below average temps.

 

2. Boxing day could start very chilly but turning milder from the W but still below average in the E.

 

3. A return to cold or very cold is likely and the uncertainty for me isn't will it turn colder but how long will the spell of milder SW,lys last. As you can see from the 18Z GFSP it turns cold much sooner than the ECM.

 

4. The combination of the GFSP & ECM ensembles suggest to me it will turn even colder in the New year but from the E rather than the N.

 

Finally the comments about the ECM backtracking are rubbish as the Ops have been largely consistent. This is why my outlook hasn't really changed!

Edited December 21, 2014 by TEITS

[Duane S.]

All getting a bit tetchy in here this evening! Not really sure why, I think all in all we have taken a big step in the right direction from 24 hours ago.

 

As to the long-since-becoming-tiresome question of whether or not the ECM has 'backtracked', or not, probably comes down to wording and people's interpretation of that wording. The general theme from the ECM is in indeed pretty much as it was, it's the outcome on the 12z that is quite different than the previous few OPs and IMO closer to the eventual mark.

 

Bottom line, if we get the same degree of shift towards cold in the next 24 hours as today (quite plausible too taking into account the background signals) this forum is going to be buzzing by tomorrow night.

[grca]

When the various models still show various solutions and there is no agreement is it correct to think that what is shown on each individual op run is going to be correct? It is obvious that currently in the accurate range of the models up to up 120hrs they agree, after this time we have a variation of solutions. Each person on this forum has his / hers own preferred outcomes be it mild or cold be it what they prefer or what we personally would wish.

What we have tonight is a move towards a colder solution which tomorrow could be gone, however in the last 3 days I personally prefer tonight's runs than the last 3 days as potentially we could get some colder and more seasonable weather.

Whilst watching every run of the models and checking every frame of what happens I still cannot pin point the the actual outcome during Christmas week apart from stating potentially it could be mild at times or pretty cold with some snow even in the south which is what various models show depending on which run is viewed.

So as said many times best wait a couple of days before we make a confirmed statement either way.

[johnholmes]

my contacts at Meto Intelligence 5 tell me that the top secret S.P.E.C.T. R.E model has confirmed 50cm of snow for the whole of the UK on christmas day. but don't tell anyone ok.......

 

silly comment in my view-will post in more detail tomorrow

Edited December 21, 2014 by johnholmes

[Fred Sykes]

silly comment in my view-will post in more detail tomorrow

Don't take lift too seriously! He was clearly having a laugh

[JP1972]

The models havent a glue atm .

 

I agree, they just don't seem to be able to stick to a consistent forecast.

 

No adhesion whatsoever at all.

[East_England_Stormchaser91]

As I've mentioned in the past, a low pressure in place of the Azores high is always what you want to see if you're looking for cold. All the notorious winters I can think of had deep lows over the azores. 

What we're seeing at the minute are very good prospects and all of the parameters are certainly in place for a real cold shot, not only just after Xmas, but further on into the new year aswell. 

[Formula_1_Fan]

I've been following this thread for a number of years and at the moment I'm getting a sense of deja vu. To me everything has a feel of 2012/13, I'm not trying to pattern match or make predictions with this post (there are many more experienced and knoweledable people to do that), I'm just trying to highlight how the models seem to behave in my eyes when there is a sniff of cold spell.

So using 2012/13 as an example we started getting charts like this in deep fi

Indeed by the 20th Dec pressure looked like it would rise towards Greenland, even had a low pressure in that North Sea, going off the achieve threads none of this actually happened when the day came.

Moving into Jan 2013 and we still got hints at pressure rises towards Greenland but when the cold did eventually make it into the reliable it came more from the east rather than the North.

Now just again push the point that I don't really know what I'm talking about here so I'm not trying to pattern match or make predictions. I'm just saying people shouldn't go crazy if this all goes wrong for a cold push over the Christmas period. It seems to me sometimes the models sniff something and then can take a painful couple of weeks of teasing us and dissapointing us before the actual weather we want comes to fruition.

Here is a link to the archive threads from back then should anyone be interested https://forum.netweather.tv/topic/75363-winter-model-discussion-cold-hunting-231212/

Edited December 21, 2014 by Formula_1_Fan

[summer blizzard]

Both the GFS and Parallel back a minimum 4 day cold spell (the high is still cool at the surface) before the Euro would have us back in the money.

 

[Iceni]

Both the GFS and Parallel back a minimum 4 day cold spell (the high is still cool at the surface) before the Euro would have us back in the money.

 

That is a thing of beauty and a joy for.... A few weeks? Omega high. Mmmm.

[alexisj9]

The storm on the 27th is now modeled on both GFS models and on the UKMO, and still looks very dangerous to my untrained eye. 

 

GFS http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=150&mode=0

 

GFS P http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=150&mode=0&runpara=1

 

UKMO http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=144&carte=1021

I would expect the UKMO to deepen further in the next frame like the others.

Edited December 21, 2014 by alexisj9

[Mucka]

Yes pretty good agreement across the output this morning so far with any cold being very transient behind a deep low.

Is it time to call any cold spell for December dead?

I will wait for ECM and then GFS this evening and UKMO and JMA and the ensembles and maybe tomorrow...

 

Seriously though, it doesn't look likely now.

Edited December 21, 2014 by Mucka