Model output discussion - Winter has arrived

[Scott Ingham]

3 minutes ago, Mike Poole said:

Can’t find the info now Scott, sorry, link was on my work computer, which i have not been able to access since lockdown in march, perhaps someone has it handy, it is the NOAA presentation on the FV3 upgrade to GFS?  

Ill have a look for it ik sure I'll be able to find it. Should be an interesting read. Thanks anyway Mike

[Allseasons-Si]

Thanks @DiagonalRedLine

i don't get all the sniping in here sometimes and it deflects newbies from posting in here that are trying to understand/learn what the weather will be doing

anyway the control follows the op in some way in trying to get that ridge going in the Atlantic

at day ten.

[phil nw.]

We can see that any concerns about a lack of cold air over Europe can quickly disappear if that GFS pattern verified. 

Atlantic amplification is a classic way to kick off a switch to a cold setup. 

[Mike Poole]

GEFS 18z ensembles, here’s the mean, compared with ECM T240:

I dont like GFS, bigger vortex fragment in its home territory, less of arctic high, weaker heights to north of UK, but a lot of that could be down to the GFS errors at earlier times (the op was off the rails by T144).  

Meanwhile, up top T336, on the pub run:

We are so in the business this winter.  Now just need some snow...

 

[Bricriu]

A fair chunk of the vortex looks to be taking up residence in its usual home on that GFS chart, that to me makes a significant cold outbreak unlikely. The warming in the strat does look encouraging though for the longer outlook.

[SMU]

Morn 

Reasonable UKMO today - with the energy continually being moved further south -

Also a fair change in GFS as it starts to get a grip on the pattern

note the full on retraction & change in 12 hours from this at 156 to now 144 energy cutting underneath

gg

 

Of course fast foward the 00z run to 168 & the GFS tries again to pile up the lows > & so starts the next cycle of understanding where the energy is going to go.

Classic poor resolution morphing into clearer resolution over a day or so.

 

 

[Ali1977]

Here we go again, heights flooding into the Arctic. Could be another good run beyond day 10. Trends are friends etc.....

[Mucka]

Good morning.

Yes good agreement between UKMO and GFS this morning out to 144.

Arctic high, check

Scandi ridge, check

Stalling L West of Ireland, check.

Quite a bit of uncertainty thereafter with the behaviour of the stalling low, how much WAA can it push toward Greenland and will it push through E/SE and prevent pressure rising to our S or will it disrupt mostly NE and residual energy plump up heights to our SE as with this GFS run.

If as seems probable we can keep pressure lower in Europe than GFS has here we will be in a very good position for N lat blocking opening the Arctic flood gates even by day 10 (block in place I mean, the arctic air will take a couple of days to arrive thereafter.)

GFS deep FI, somewhat tortuous and convoluted but there in time for Xmas.

Let's see where ECM goes.

If things go as they usually do then ECM will show blocked with cold pending day 10 and from there all the models will be in complete agreement until we are under -12 uppers and inches of snow - that is how it always goes right?

Edited December 7, 2020 by Mucka

[Cheshire Freeze]

Arctic HP (our side) and bitter air flooding SW through Scandi once again in GFS FI

[Cheshire Freeze]

Snow maker fully operational by the end of FI

Edited December 7, 2020 by CreweCold

[swfc]

7 minutes ago, CreweCold said:

Snow maker fully operational by the end of FI

Yes crewe, dream end also with low to North. Dream and bank

[Cheshire Freeze]

3 minutes ago, swfc said:

Yes crewe, dream end also with low to North. Dream and bank

The end of the run is as good a chart as you'll ever see...Atlantic locked out, cold locked in for 10 days at least. The dream.

[Cheshire Freeze]

It has to be said, the GFS may be picking out the correct final solution but maybe just a tad too soon? 

Either way, that FI is ridiculous eye candy

[feb1991blizzard]

7 minutes ago, CreweCold said:

It has to be said, the GFS may be picking out the correct final solution but maybe just a tad too soon? 

Either way, that FI is ridiculous eye candy

0z GFS - a touch of the 18's.

[snowlessayr]

 

Looks a tad marginal to me 

On a more serious note, although unlikely to verify we do continue to see heights rising up towards Scandi or Greenland at FI on the GFS. if your wanting deep cold it is pattern you continue to want to see, if there is one decent thing about the GFS is that it can spot trends so at least it is something to keep an eye on for the next few runs.  I know some people tend to be pessimistic when models show cold but just remember how awful last winter was and enjoy the ride.

Although I am fairly young, I have been reading this thread for many years and it is massively helped improve my understanding of model watching. I decided to start posting now, finally. Some extremely knowledgable posters on here, thank you for all your insights. I know this place gets very heated at times but I think for most of us watching the models hoping for some cold and snow is a massive escape  from the world that we live in at the moment. 

Thanks 

[KTtom]

40 minutes ago, CreweCold said:

It has to be said, the GFS may be picking out the correct final solution but maybe just a tad too soon? 

Either way, that FI is ridiculous eye candy

It is as good as you can get really, and the ingredient needed to kick it all off is the Russian high finally shifting allowing trough to dig south into Scandinavia.  Forget the Russian high moving west and constant reviews as to if the lows are backing west, we need them east first to displace the high if anything even remotely like this mornings gfs to to come to fruition

[IDO]

GFS still maintaining the overall synoptic it has been highlighting the last few days, and we can see that this it takes us out of the stalemate of the nuisance Russian high that is unlikely to become an easterly. Pushed aside it allows more scope from the Atlantic ridge and on this occasion meets with the Arctic high for a great profile:

 

I always feel that the Russian high is more a winter killer than a snow maker so good riddance. 0z gfs: Unlikely to happen but at least we are moving forward.

The gem is similar again to the gfs with the initial Iberian heights post d7 but flattens the pattern and the Arctic high does not really help:

gem> ecm> 

Sadly a possibility as well, but all models now easing the Russian high away and we can cross-off that unlikely possibility of the heights moving in to our NE from it and see where we go with a reset? ECM also similar to gfs, variations on a theme of a few days of the UK trough bound (d5-d8) before the Atlantic ridge topples. gefs are still all over the place post-d8 so although some headway, still some firming up for mid-Dec onwards?

Edited December 7, 2020 by IDO

[mountain shadow]

I'm liking the trend of both the ECM and GFS of moving bitter Arctic  to our North East in the extended.

The ECM then has a disrupting low South of Greenland which could encourage that air towards us.

All FI of course.

[bluearmy]

I hope any evolution to bitter cold isn’t solely dependent on the behaviour of the arctic high ....... v tricky to model well 

[mountain shadow]

12 minutes ago, bluearmy said:

I hope any evolution to bitter cold isn’t solely dependent on the behaviour of the arctic high ....... v tricky to model well 

I think that's why there's a lack of posts this morning.

Impossible to make a forecast in the medium term.

Anything could happen.

[TSNWK]

4 minutes ago, mountain shadow said:

I think that's why there's a lack of posts this morning.

Impossible to make a forecast in the medium term.

Anything could happen.

Or hungover after last night's fun.. hope they are up for hair of the dog! This morning  

[northwestsnow]

EC mean continues to deteriate this morning.

[Nick F]

IMO a reshuffle needed in the northern hemisphere pattern if we stand any chance of tapping into deep cold and proper snowy potential. The stalemate of high pressure block over NW Russia with low pressure stalling over or west of UK with upper flow energy feeding low heights over Europe is not going to deliver anything more sustained than what we've experienced. The trouble is, the high to the east is rooted quite far south, so there's no route for deep cold to get round then west to NW Europe, while its extension far enough west prevents arctic air reaching us from the north too. We need the NW Russian high to sink, models indicate this in the longer term.

It's looking increasingly like we will have to sustain the hardship of brief less cold Atlantic maritime flow for a few days, as low pressure moves in to the NW, strong support for this from the models. But this burst of upper flow energy over the Atlantic bringing this looks not to be sustained. With any surge from the west likely to weaken after 5 days.

Some interesting evolution by both 00z EC and GFS to our north days 9-10. GFS raises heights over Greenland driven, this time, by WAA from the Atlantic. While EC shows emergence of an arctic high into to Svalbard area, which is backed up the EPS mean. Both show deep cold over northern Siberia edging west towards NW Russia. The northern hemisphere generally looks very interesting, with the TPV not really consolidating this side of the northern hemisphere with wave breaking from the south this side and over Alaska preventing this.

00z EPS mean looking good at T+300, with +VE heights over Svalbard cross polar link up. TPV over NW Canada/Alaska.

00z GEFS indicates +ve height anomaly over Greenland quite far out, which is encouraging too.

One thing is clear from ensemble guidance recently is no strong signal for a strong TPV to return over Greenland.

Edited December 7, 2020 by Nick F

[Zak M]

That 00z GFS is a peach of a run, shame it's in FI!

   

And if it was to come off, it looks like it would be a proper snow-maker...

Merry Christmas! 

Edited December 7, 2020 by Zak M

[Sky Full]

Had to look twice at the GFS in FI this morning because it’s showing EXACTLY what I want for Christmas!   Got my gifs ready all excited to post on here and then realised that everyone’s already been there and done it!  Must get up earlier.....

Anyway, since it looks so lovely and not likely to be repeated, here is the evolution shown by the GFS between +240 and +384 (23rd December):

                          850s                                                        500s

  
 

That would be a very nice Christmas present indeed!  ️️

Well, at least it’s possible.....