The hunt for cold - Model discussion (late November)

[Seasonality]

2 minutes ago, DanBaynes said:

A mistake not at all, but over the last 10 years of model watching I and others have noticed a correction west on the models the nearer we get to t0 is often seen

Dan, I know that, it was a joke. A cheesy one I admit. 

[tight isobar]

1 minute ago, DanBaynes said:

A mistake not at all, but over the last 10 years of model watching I and others have noticed a correction west on the models the nearer we get to t0 is often seen

Correct on those points..

But via GFS-

Its worms away..and under-estimates 'power blocks'..

And notoriously...ones of north-eastern form!!!

[DanBaynes]

Just now, Seasonality said:

Dan, I know that, it was a joke. A cheesy one I admit. 

No worries mate, wasn't a dig, but hopefully people that don't seem to notice that may look for it now

[SMU]

Yes Daniel

Just to assist any newer people more ( not sure if anyone interested )

 

Heres the FV3 156 6z V 12z ( Second )

Note pic 1 shows the atlantic pushing East & the cold air boundry moving back into the continent where as 12z the blocks more upright & the cold is held in situ as the jet is bent away from the UK

[Glacier Point]

1 hour ago, Nick F said:

I see, the VP200 does indeed suggest increasing -ve anomaly depth propagating east, perhaps a good reason not to rely on the RMM plots alone. So do you think this more coherent signal of MJO propagation through eastern hemisphere may lead to a temporary relaxation of the block to the NE and resurgence in the Atlantic zonal flow towards the UK? Or do think we can maintain blocking with energy going underneath?

Actually thinking here that there will be two, possibly discrete episodes of ridging to our NE depending on the extent of Atlantic incursion on the back of this. The first being reasonably modelled but probably too progressive in its break down / eastward displacement and a second phase around the 21st - 23rd December. 

[Stormyking]

I definitely am not worrying about anything as yet, not until what ever is showing within the 5 day timeframe

GFS P looking pretty decent again currently, be interesting to see what the ECM brings after showing some good consistence the last few runs.

GFS normal showing something different like it normally does on most runs.

UKMO didn't look too bad either to me on its latest 12z.

Icon looked much better as well, compared to yesterday and this Morning

I do enjoy these wars between the models, makes everything feel more intense and interesting as a weather perspective in general

[Iceaxecrampon]

8 minutes ago, Daniel Smith said:

But Steve, the 6z showed the Atlantic blasting the block away.. 

Joking aside, I agree! The number of times we've seen the GFS in particular make big Westwards corrections when it comes to the Atlantic over-running blocking you'd think people would know by now, especially since it happens at least twice per winter.

GEFS mean further West, too!

Hmmm.....

The law of averages in this computerised "game" say that  - one day -  it will  take a sizeable chunk out of some backsides.

[Glacier Point]

12z GEFS 10 hPa mean is a heartbeat away from a technical strat warming event.....(closer than 00z)

Edited December 5, 2018 by Glacier Point

[tight isobar]

Slide...and evolve..

With aiding of responce..

Warm-air advection...behind the system!

Edit"

Not mention the formidable eastern-quad...block...

@notable

Edited December 5, 2018 by tight isobar

[Johnp]

1 minute ago, tight isobar said:

Slide...and evolve..

With aiding of resoponce..

Warm-air advection...behind the system!

That's from the 6z

[Tim Bland]

Gfs(p) cool and dry. Not much in the way of snow 

[I remember Atlantic 252]

1 minute ago, Johnp said:

That's from the 6z

yes, 12Z here, for same day/time

[Stuie]

@bluearmy 

Ok pushed my day out to the 10th, quite like it

 

[snowray]

7 minutes ago, Steve Murr said:

Yes Daniel

Just to assist any newer people more ( not sure if anyone interested )

 

Heres the FV3 156 6z V 12z ( Second )

Note pic 1 shows the atlantic pushing East & the cold air boundry moving back into the continent where as 12z the blocks more upright & the cold is held in situ as the jet is bent away from the UK

It seems to me that the models are desperate to push the Atlantic fronts in, this is the form horse after all for mid December, but they are constantly having to reassess things. I think that the Atlantic will be held at bay, initially anyway, battleground and undercut scenarios being the order of the day.

I hope that ECM can say on track, although I'm not expecting it to be quite as good this evening. Fingers crossed though.

[Methuselah]

Colder shot down the eastern side of the country; further west too:

[Tim Bland]

Gfs Vs ECM at 192hrs I know which I’d prefer! Let’s pray ECM sticks to its guns shortly

[Mike Poole]

FV3 may have let the high slip too far NE, to bring significant cold, but the run looks much better than the 6z, here T216 then 6z at same time

So still optimistic for the cold outcome, await the ECM...

 

Edited December 5, 2018 by Mike Poole

[Stuie]

Touch annoying, LP off Cornwall drags up milder air for the South (uppers 0), need that the dive further South.

[booferking]

Have to say i am  liking the para..

Edited December 5, 2018 by booferking

[swfc]

I'd agree to a point that gfs does have a bias with proggresivness with the Atlantic"esp in the low resolution" if the ECM shows a similar evolution where does that leave gFS???imo the block will hold to a degree but I'm not a believer in selective model output. Just my thoughts and opinion

 

Edited December 5, 2018 by swfc

[weirpig]

Gfs para  showing much more in undercutting lows  marginal snow events for some   better than it' older sibling 

[tight isobar]

22 minutes ago, Johnp said:

That's from the 6z

T'was your correct..miss press.

Howeve...r the 12z gfs-p..has the ejected spawned revolver...

And notes the slam..into the block...and as again possible tucking underneath!!

 

 

Edit....ya can choose ya friends...but but ya family..

Gfs -p..

Is sister siding!!.

And far 2 explosive...by a country mile..

Edited December 5, 2018 by tight isobar

[Tim Bland]

Googles ‘cottages in snowdonia” for romantic pre Christmas break....

[BlueHedgehog074]

Just a little look at both the 12Z GFS and 12Z GEM between 168 to 240 hours, and the Atlantic gets a little bit too close for comfort at times. 

GFS 12Z

GEM 12Z

Not intended to be a wet blanket about it. It is just 2 runs from 2 operational models afterall. So would advise not doing anything bad with those toys... yet. A chance of some kind of battle ground rain, sleet and snow event at 192 hours (next Thursday) as both models, more so the GEM, shows some undercutting to the Atlantic Low Pressure as it runs up against colder air to our East. A high risk high reward event could be apparent. But not something that would last long, as the Lows try to break through a bit further East and push away some of the cold. Ideally would need Low Pressure in the Atlantic to be less grumpy, more negatively tilted (asides from that 192 hours GEM), and that Scandinavian High to back far West as possible to the North of the UK to put pressure on its opponent (Atlantic Lows). The separation and merging of the various Lows in the Atlantic to watch for too, as this could have impacts on how they push up against the Scandinavian ridge. Usually it’s better for Lows to our West to be seperated and not be too ball shaped, as they’re more likely to slide better under any blocking to our North-East. 

Not terrible runs with no super angry purple blob over Greenland/Western Greenland (except for what the GFS shows in deep Fantasy Island). But a case again of a possible big battle between both the block and the Atlantic coming back into play next week.

While it seems silly to look for any breakdown to a chillier spell or snap, wouldn’t be surprised if the cold weather fans have to endure another spell of Atlantic weather. At least compared to the Winter 2015/16 and 2016/17, the atmospheric conditions and pressure patterns look setup more favourably for meridional flows and blocked weather at times. 

Beforehand, the next few days will see some ferocious weather for places at times as models show further Lows in the Atlantic racing Eastwards through the U.K, bringing strong Westerly to South-Westerly winds, rain and showers at times. Particularly over Northern and Western areas. But not necessarily so.

A chance towards early next week for the weather to start calming itself down as ridging to the West in the Atlantic migrates towards the UK, providing a break to the wild weather. Maybe some wintry showers for Northern and Eastern areas of the UK for a time before the ridge moves in with the flow turning to a colder North-Westerly and Northerly direction.

Although the promise of possible deep cold and prolonged blocking conditions can always get pushed back (or just not happen at all), do persomally believe one day this Winter the cold and snow fans will be on that train to the North Pole.

Edited December 5, 2018 by DiagonalRedLine
Removing extra attachments at bottom of post

[Stuie]

6 minutes ago, tight isobar said:

T'was your correct..miss press.

Howeve...r the 12z gfs-p..has the ejected spawned revolver...

And notes the slam..into the block...and as again possible tucking underneath!!

Doesn`t really do us many favours regarding the uppers though.

Edit: Pretty wet to me.

Edited December 5, 2018 by Stuie W