Model output discussion - Winter has arrived and the hunt for cold is on

[ICE COLD]

3 minutes ago, feb1991blizzard said:

Model charts for Europe (Temperature) | ECMWF/Global Euro HD (10 days)

METEOLOGIX.COM

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ECMWF/Global Euro HD (10 days) - Current forecast valid for 12/26/2019, 12:00am of parameter "Temperature", model chart for map "Europe"

 

Cheers feb . 

[SMU]

Notice the ICON 120 moving along to the UKMO with more amplification

18z First ( Note the angle of the southern arm on the 18z tilted more SE & the bigger loop over greenland )

Net the eastward progression is less--

 

 

[shaky]

Latest icon 18z disrupts that low a bit more near the states at 120 hours compared to 12z run!!think its moved toawards ecm and ukmo in that regard!!together with a few snowy surprises this week its not a bad outlook at all!!

[Ryan3991]

2 hours ago, snowray said:

The mild continent is the problem, end up with the dreaded mild easterly. 

Evening.

to my eye the winds haven’t started there progression downwards yet (easterly) so we are yet to see the effects but it looks quite cold to me over Eastern Europe would only need a few days an could be on our shores. that’s of course if things went in coldies favour  

 

 

Edited December 11, 2019 by Ryan3991

[booferking]

Just now, Steve Murr said:

Notice the ICON 120 moving along to the UKMO with more amplification

18z First ( Note the angle of the southern arm on the 18z tilted more SE & the bigger loop over greenland )

Net the eastward progression is less--

 

 

You can see the tilt well with the low also next week could hold a surprise.

[Mucka]

1 hour ago, Sceptical said:

The Met office have plumped for a milder outlook towards the end of next week. What is it they see, that this thread doesn't.....

This little caveat wasn't there a couple of days ago when they were talking about weeks of zonal, "There remains a small chance of some longer colder, dry spells at times, with an increased risk of both frost and fog."

And you have to remember that a ridge anywhere but West of the UK in that time will result in milder air from the S/SW yet that could be the prelude to blocking and colder air shortly thereafter.

Some of the best easterlies are not only not precluded by mild air in the days before, they are in fact often announced by very mild air as that can be a signal that high pressure is building toward Scandinavia.

When the jet goes over the top the ridge quickly topples and flattens and we continue the mild regime, however if it undercuts then we can get cut off mid lat/high lat blocking which can draw in cold polar air form the N/NE/E

The thing is you can't get the undercut without the ridge first.

 

The other thing I have read is that even if we get NE/E flow there is no cold air to tap into.

Two things.

first if we get a strong ridge the cold air will be further W

Second it will take all but 24/48 hours to draw in cold enough uppers for snow even if the low 850's are not on our doorstep.

 

EDIT

Better add an Easterly is not currently the form horse. (you need more caveats than a snake oil salesman in this place)

 

Edited December 11, 2019 by Mucka

[northwestsnow]

Well, i certainly do not want to put a dampner on proceedings so will revert to the more immediate timeframe, saturday i suspect is a day were the could be some snowfall, high res models will offer good insight..

[bluearmy]

53 minutes ago, ArHu3 said:

No just the graphs, you need a very subscription,  @knocker or @bluearmy might have access ...

As steve has mentioned the control is fun .....basically it undercuts as the op looked as though it might 

the eps again lacking continuity in the extended, showing a tendency for euro heights/mslp  to drop some somewhat 

[damianslaw]

50 minutes ago, Mike Poole said:

There have been some contradictory posts tonight, particularly re the ECM, so here is a summary of where I think we stand tonight. 

• There is a period of mild wild and rainy weather to get through regardless of who wins the general election!
• Model consensus seems to be firming up on a very strong southerly jet, UKMO and ECM seem to send the the whole purple lot south at T144:

• Continuing with the ECM this suggests some big lows undercutting fairly weak ridges, T240:

• JMA jet stream illustrates the strong jet and, importantly, the direction, here T192:

• Sea surface temperatures (SSTs) have changed a bit over the last month, anomalies now first, this time November second:

• 3 points of note, first the Indian Ocean Dipole looks to be falling on its face, good news!  Second the northern eastern Pacific is getting cooler, this should help with the upstream pattern.  Finally, any pattern in the Atlantic is disappearing as it all now looks warm, this is a potential detriment to UK cold.  So, a mixed picture there, but probably on balance slightly positive for UK cold. 
• Finally, the strat.  Forget it for the moment, most models showing vortex intensification, upside: seems to be disconnected to the trop, GEFS T300 showing miriad mangled vortexes:

Have a good Election Day everyone!!

Regards

Mike

A word on SST's - I think a warm atlantic favours cold, it creates less of a temp gradient creating cyclogenises, so this is a positive for longer term cold prospects I would think.

Back to the hear and now, its a cold unsettled theme for the northern half of the UK, sub 528 dam air most of the time for the next 6 days at least, further  south, something a bit milder but not especially so with further rain. Wintry precipitation down to quite low levels for the north for much of the time.

As we head into next week, contrasts between ECM and GFS, the ECM wanting low pressure to break through, GFS pulling in a mild southerly feed thanks to euro high. It does look likely there will be a stand off between the atlantic trough and euro high, but the eventual pattern remains very uncertain for the run up to christmas. No coherent signal at present, other than perhaps the atlantic looks like it will run out of steam somewhat next week, and perhaps something drier and more settled may develop. Quite interesting developments.

This will be last post on models until Monday, when attention will turn towards likely prospects for the run in to christmas.

Edited December 11, 2019 by damianslaw

[Dennis]

looks that a big snowfront is coming late saturday 

[northwestsnow]

18Z looks good for saturday / saturday night

Edited December 11, 2019 by northwestsnow

[Mike Poole]

GFS 18z, T114 left v 12z T120 right:

More amplified on 18z just, baby steps...

[Mike Poole]

GFS climbing on board, look at the 18z T180 v 12z T186:

Look SW, continuous flow with a less pronounced main low on the 18z, compared to separation of a bigger low and no connection to the downstream low on the 12z.  You might think that misses a chance for a ridge to pop up as per 12z but in reality, it sets us up for the undercut, and a weak ridge from Scandi... Edit: Well it didn't quite make it, this time, but a move to the UKMO ECM solution and that is what we kind of expect from the GFS.

Edited December 11, 2019 by Mike Poole

[Mapantz]

Here's a NetWx-MR snapshot for Saturday and Sunday:

   

  

Probably overdoing it, so it's best not to get suckered in.

Edited December 11, 2019 by Mapantz

[I remember Atlantic 252]

Sat night GFS

[northwestsnow]

1 minute ago, I remember Atlantic 252 said:

Sat night GFS

Its an excellent run for the N midlands.

[I remember Atlantic 252]

1 minute ago, northwestsnow said:

Its an excellent run for the N midlands.

Aye but these fronts always end up further South, wouldn't surprise me if it ended up S of M4 event

[snowray]

23 minutes ago, I remember Atlantic 252 said:

Aye but these fronts always end up further South, wouldn't surprise me if it ended up S of M4 event

Hope not, be rain/sleet down this way away from the Downs. Let you guys have your fun up in the NW.

Edited December 11, 2019 by snowray

[Jordan S]

18z Gfs does keep the theme of a feature moving somewhere through central England during Saturday evening/night its done this several times now so something to note as the probability of this happening has increased as you'd expect.  It shows some heavy snow particularly over high ground but down to quite low levels on the northern side of this but mostly rain shown for the south on this gfs update with windy conditions there. 

Placement of any sleet and snow and the Details are alot different to its previous run it's marginal and some models don't make much of this at all so still pretty uncertain.

Edited December 11, 2019 by jordan smith

[Cheshire Freeze]

4 minutes ago, jordan smith said:

18z Gfs does keep the theme of a feature running somewhere through central parts during Saturday evening/night its done this several times now so something to note. 

Details are a lot different to its previous run so still pretty uncertain. 

I've seen these little features zip through before. Historically they have produced 2-4 inches of snow. So somewhere may get lucky...high ground favoured.

[snowray]

27 minutes ago, CreweCold said:

I've seen these little features zip through before. Historically they have produced 2-4 inches of snow. So somewhere may get lucky...high ground favoured.

That's a fair bit of snow, mmm, I might jump on a train up to Buxton the weekend to get my snow fix, if it looks like verifying that is.

[Allseasons-Si]

Hi everyone

late to the party again and took me best part of an hour reading some fab posts,great stuff guys

i am going to kick off with the control run which is siding with the ecm at day ten on a similar evolution with heights to our NE

some gefs ens show this also at day ten

the de-built temps/dew points and wind direction,as i said last night,the control is in control 

and what happened to the gfs in fl,the pv looked shocked lol

 are we finally seeing a pattern change to something more favorable for Christmas?

the pendulum is swinging. 

 

[Allseasons-Si]

The control further into fl,cross polar flow,what a chart

ens,that's better than the 12z.

 

 

[Allseasons-Si]

There is a def trend to colder temps in the festive period according to the ecm ens.

the latest from cfs grabbed by gavinsweathervids.com

GavsWeatherVids - UK Weather Forecasts And Latest News

WWW.GAVSWEATHERVIDS.COM

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Daily weather forecasts and news for the United Kingdom, Europe and North America. Video and written forecasts covering 1 to 90 day timescales. Updated Daily.

worth a view.

[Mucka]

GEM looking excellent this morning. A shame it is one of the lesser models.It is probably closer than GFS though. 

 

What we really need is ECM to follow up and keep the trend going.