Model output discussion - 5th December 2016 - Into Winter we go

[stewfox]

9 minutes ago, blizzard81 said:

Looks like the gfs 18z is going the same way as the 26 ecm cluster members which went mobile westerly. Not the trend I was wanting to witness tonight. The 18z is normally poor with regards to verification. Just watch it be correct this time though, ugh!

From 29 Nov

""12z ECMWF ENS set against model climatology lean pretty firmly in median 2m temps towards below avg (at times quite markedly) out to at least 9 Dec""

I like that new trend, wont verify .

Probably end up as a raging south westerly  

Edited December 6, 2016 by stewfox

[nick sussex]

1 minute ago, feb1991blizzard said:

This is still a better run long term IMO, higher heights and sharper ridging driving wave breaking nearer to the pole and further upwards in the stratosphere from both sectors.

One trend that's happening is the troughing in the Atlantic is digging further south to the west of the UK. Without that earlier shortwave calamity this run would have been a bigger upgrade on the GFS 12hrs run.

Anytime you get that dig south of the jet to the west theres always a chance something might pop up to the east/ne.

[Frosty.]

The Gfs 18z shows an increasingly angry north Atlantic but the lows are largely held at bay by pulses of high pressure pushing north which deflects most of the Atlantic energy NE to the west of the uk and gradually high pressure becomes more dominant with the Azores high looking stronger as it builds NE.

Edited December 6, 2016 by Frosty.

[karlos1983]

GFS 18z in 64 hours we go from this 

to this

I'm not convinced 

 

[Ali1977]

Where did that FI jump from, nothing to this in 3 days 

[bluearmy]

The 18z finds a stellar end to a very meh run

EDIT:. Replace stellar with cold.!

Edited December 6, 2016 by bluearmy

[blizzard81]

3 hours ago, mountain shadow said:

Retrogression to where? All i see is the bulk of the PV at Day 10 in the worst place possible, namely the Greenland local.

Take a look at the gfs 18z from day 11. At day 10 it is very similar to the 12z ecm. If you look very carefully, you can see the ridge start to edge north. Carry on through the rest of the 18z run and hey presto This is what I believe the 12z ecm would have looked like if it went further than 10 days.

[karlos1983]

2 minutes ago, bluearmy said:

The 18z finds a stellar end to a very meh run

NH still laughs out loud at our corner of it though 

[nick sussex]

Overall this evening we're looking at  a damage limitation exercise in the next ten days. Effectively trying to make the best of a bad situation. The ECM and GFS are on the same page re overall pattern. The uncertainties are more in relation to how far north the high will get and this does make a big difference to the UK in terms of surface temps.

I see the GFS is pulling out something a bit more interesting in its very late stages. We have to be wary here of this type  of quick change as it comes as the GFS goes from the higher to lower resolution of its output.

I think the absolute best scenario and this is low probability is something like the ECM but with the ridge a bit further north and a possible Scandi high, although its unlikely to last as energy spills east from the PV over Greenland.

The more likelier even allowing for the GFS's shortwave trauma is a high far enough north to bring some surface colder conditions especially more towards the se.

Where we go after day ten is I think more up in the air because that needs a change upstream and a break up of the PV to the north. We've seen quite a few false dawns over the last few weeks so we'll see if the GFS later output can survive into the closer range.

[bobbydog]

GFS even pulls some snow out of the bag near the end-

 

[Frosty.]

At last, winter wakes up! Cracking charts late in the Gfs 18z! with some snow which is what most of us want

Edited December 6, 2016 by Frosty.

[karlos1983]

The 18z was just laughable I'm sorry, but that's got to go straight in the bin. Pretty certain the ensembles will concur. Onto tomorrow 

[Frosty.]

4 minutes ago, karlos1983 said:

The 18z was just laughable I'm sorry, but that's got to go straight in the bin. Pretty certain the ensembles will concur. Onto tomorrow 

At least we have some wintry eye candy for a change

No matter how painful the journey was, it was worth it just to see an Arctic blast before bed time!

Edited December 6, 2016 by Frosty.

[bluearmy]

The updated London eps graph shows the very mild spell to be around 4 days in duration. Thereafter, either on the mild side or potentially cold. 

[BARRY]

funny in it when the models show a cold spell it's disowned straight away but when it's mild it's gospel

 

[bobbydog]

Do ya wanna build a snowmaaaan?

Of course I'm just having 'Olaf'

[BLAST FROM THE PAST]

Well I'm not convinced about this high developing as robustly as it has been showing.  I'm still wondering if we see a collapse as dramatic as GFS shows deep in FI within nearer timeframe say about 7-10 days.  

BFTP

[Glacier Point]

9 minutes ago, karlos1983 said:

The 18z was just laughable I'm sorry, but that's got to go straight in the bin. Pretty certain the ensembles will concur. Onto tomorrow 

Was it? The idea of an initial flirtation with an easterly / continental flow followed by height rises to north and north-west has got legs from my perspective. Look at the unsual displacement of the main lobe of the pv over the Canadian interior. That's fitting with the substantive wave break going on from bottom all the way up to 20hPa, and the 10hPa layer becomes highly stressed.

Edited December 6, 2016 by Glacier Point

[Frosty.]

3 minutes ago, BLAST FROM THE PAST said:

Well I'm not convinced about this high developing as robustly as it has been showing.  I'm still wondering if we see a collapse as dramatic as GFS shows deep in FI within nearer timeframe say about 7-10 days.  

BFTP

It's such a tonic to see any wintry charts on an op run

[karlos1983]

6 minutes ago, Glacier Point said:

Was it? The idea of an initial flirtation with an easterly / continental flow followed by height rises to north and north-west has got legs from my perspective. Look at the unsual displacement of the main lobe of the pv over the Canadian interior. That's fitting with the substantive wave break going on from bottom all the way up to 20hPa, and the 10hPa layer becomes highly stressed.

I'll take your superior word for it, Just seemed Very odd to me how the PV blew up and then blew into pieces 66 hours later. 

I'm sure it's feasible, I'm just not clever enough(yet, I won't give up) to understand how. 

Edited December 6, 2016 by karlos1983

[Geordiesnow]

3 hours ago, nick sussex said:

Where did I write the rest of December off? Sorry but I was just reporting what the ECM showed I didn't say its later output would verify. Its pattern at day ten over the USA is too flat. Do you really think I like reporting underwhelming output. And I did say within T144hrs it had a chance to improve. The problem isn't that we don't get a ridge to the ne its the upstream pattern which means currently we can't take advantage of it.

You need a much sharper elongated low to the west at the crucial timeframe and not the football shaped one. Can I be blunt the GFS and ECM at T240hrs are not upto much. The GFS is dire at that point going forward.  Looking for signs of life in the GEFS at T300+ hours is going to lead to disappointment instead look for those earlier changes to build on. The ECM has some scope earlier  but we need to find more amplification.

I probably should of made it clearer in my post but I was not on about you when I wrote about the writing off December after 6 days but there has been posts in here which seem to suggest some members are when in actual fact we should take it a week by week basic especially when there now seems to be a little bit more uncertainty in the output.

Got to admit, at the moment any cold weather does look far away but any short term changes could lead to a quick switch around in the output and we have seen that before which even favours cold weather hence why I think the ECM in the short term at least is not a bad run. UKMO on the other hand is awful and way to flat so in tomorrow morning's runs we got to hope there is more trend towards the ECM.

I'm certainly not saying there is going to be snowy weather on the way but if we do get a little bit of amplification to link up with those fairly weak height rises which is projected to come out from the Arctic then its something to build on. I suppose I'm a bit more encouraged because its the ECM run and not the GFS which is saying this but whilst there is a glimmer of light then theres always hope.

 

[Glacier Point]

6 minutes ago, karlos1983 said:

I'll take your superior word for it Just seemed. Very odd to me. 

Well you're very kind - but run the op gfs 70hPa sequnce and you'll understand what might be going here. This is classic stuff when the troop vortex rapidly intensifies without the mid and lower strat cooperating.

the block forming in our locale next 5 days is showing signs of being a true block. No model run has been able to break it down, except from over the top via the northerly, or through discontinuous retrogression.

Edited December 6, 2016 by Glacier Point

[northwestsnow]

Im with stewart here  the ecm at day 10 is hinting at what GFS18Z shows in FI, ie Atlantic retrogression.Could be some interesting developments tomorrow IMO...

[Frosty.]

Thank you Gfs 18z

Hopefully its a new trend!!!!!!

[karlos1983]

3 minutes ago, Glacier Point said:

Well you're very kind - but run the op gfs 70hPa sequnce and you'll understand what might be going here.

Thanks GP

rest assured I wasn't being facetious, I will genuinely take your word for it.

Where can I find the 70hPa charts?

Edited December 6, 2016 by karlos1983