Model output discussion - late November

[SteveB]

7 minutes ago, BLAST FROM THE PAST said:

With 850s at -24 widely one has to ask where this very warm anomaly over vast swathes of Russia comes from?

 

BFTP 

There are some wildly different temp anomalies across the Northern hemisphere,  very dubious why this is. Check out the snow and ice thread. MIA is also experiencing strange readings.  Very suspicious

[SMU]

Another slide under the radar to the ECM from the GFS - more amplification at 168

- Why? 

discussed many times the GFS inability to separate energy streams 

NB 18z V 12z second as the model gets to grip with the pattern & splits the streams

These macro changes across 3-6 runs traversing say 168 down to 144 make a massive difference > Similarly this was discussed with the eastward fast bias from the 06z GFS the other day

 

The net impacts of this run manifests at 192 look at how the UK is colder & deeper cold is closer this run....

 

Edited December 1, 2019 by Steve Murr

[StretfordEnd1996]

GFS a little closer to the ECM by +174, with HP ridge fond enough to bring colder air in but it lasts probably a blink of an eye with the uppers struggling to stay cold for longer than 24 hours

 

[Snowman.]

Here comes the trough disruption

 

Nothing like to throw the models and this forum into choas due to a little trough disruption!

[SMU]

Finally the day 8 snow event I mentioned earlier now appearing in the GFS which wasnt there on the 12z

 

[ALL ABOARD]

1 minute ago, Snowman. said:

Here comes the trough disruption

 

Nothing like to throw the models and this forum into choas due to a little trough disruption!

For all the talk of 'zonal' it's the same old story of the last few months as the time ticks down to t+0 little wedges of heights appearing and bowling ball lows a lot less round than we've become accustomed too? 

How long can it last? 

[Mike Poole]

Wonder what impact the low out west on the GFS T216 will have, wasn't really there on the 12z same time:

[booferking]

Yes stepping more line now with EC good to see.

Sneaking feeling going to see something special in op run after day10 massive chunk of pv moving SE through uk.

[BLAST FROM THE PAST]

Looking yet again, a great run.  Consistency now of disruptive weather come second week to mid Dec.....and its looking more cold than mild to me....

 

BFTP

[Mike Poole]

Pub run also goes for the biblical storm scenario at T264:

...air cold enough for some surprises there too, as we watch the election results come in on the television. 

Edited December 1, 2019 by Mike Poole

[ALL ABOARD]

2 minutes ago, Mike Poole said:

Pub run also goes for the biblical storm scenario at T264:

...air cold enough for some surprises there too, as we watch the election results come in on the television. 

That's the 12z... 

 

 

 

Edited December 1, 2019 by ALL ABOARD

[Mike Poole]

3 minutes ago, ALL ABOARD said:

That's the 12z... 

 

 

 

Yep, thanks, I've just fixed!

Edited December 1, 2019 by Mike Poole

[SMU]

Distinct flavour of Deja Vu here from the GFS - almost exactly the same cycle of bias leading up to this current cold spell.

Its great you can just pick apart all the failings run to run 

So last 4 runs of GFS from 210 > 204 > 198 > 192 shows how gradually the model resolves the jet energy better with each run ( its not always that clear cut over each run with a more staggered transformation but these 4 stills tell the story spanning 00z > 18z )

 

Edited December 1, 2019 by Steve Murr

[Mike Poole]

And then we get to this, which is starting to look very interesting, pub run T300:

If we get anywhere close to this in the 7 day window, this place will be in meltdown...

[booferking]

2 minutes ago, Mike Poole said:

And then we get to this, which is starting to look very interesting, pub run T300:

If we get anywhere close to this in the 7 day window, this place will be in meltdown...

Easterly zonally in full flow 324hr.

[ICE COLD]

8 minutes ago, booferking said:

Easterly zonally in full flow 324hr.

Ha ha Yep zonal cold with -10 850s

Edited December 1, 2019 by ICE COLD

[January Snowstorm]

@Steve Murr

 

While your thoughts on gfs are very clear Steve it's worth keeping in mind the other models also have their flaws. For Example ECM almost always over amplifies beyond 192 hours. How many times has the ECM shown a full blown Greeny high at 240hours only for it to be blown away in closer timeframes. As for the ukmo it's 144 chart was always known to be a bit fickle. Anyways back to the charts this evening and baby steps starting to show up for a colder outlook in a weeks time or so..

Edited December 1, 2019 by January Snowstorm

[SMU]

1 minute ago, January Snowstorm said:

@Steve Murr

 

While your thoughts on gfs are very clear Steve it's worth keeping in mind the other models also have their flaws. For Example ECM almost always over amplifies beyond 192 hours. How many times has the ECM shown a full blown Greeny high at 240hours only for it to be blown away in closer timeframes. As for the ukmo it's 144 chart was always known to be a bit fickle. Anyways back to the charts this evening and baby steps starting to show up for a colder outlook in a weeks time or so..

Yes of course mate however the logical point of view needs to be with the 'most' likely outcome.

Last review ( on the run in to this cold spell ) the swing to the Euro blend was about 80-85% & thus far the ECM hasnt edged back at all today but the GFS has trended every run so we are still at around 100% Swing.....

Lets see where the overnights go.....

What it does mean is the ENS should be dipping away again post day 6

[Catacol]

Just gonna chip in quickly with a look at 15th December again. For me anything pre mid month is unlikely to produce much wintry interest.

12z clusters for mid month, and the trend around those clusters, remains good. We have a definite signal for heights transferring north, and a trough digging in over Europe. Cant see what the UKMet are seeing the week beyond 16 - 23 - the text still says a little above average until perhaps cold at the end of the month....but I'm not seeing a trend to above average in the second half - I'd say average to slightly below to start and then we see whether blocking on the back of the next MJO passage and any vortex downwelling impacts helps dig something a bit deeper...

-NAO signature across the majority. Definite polar maritime. Wet probably....but turning colder too..

[StretfordEnd1996]

Uppers very up and down in the next 5 days or so 

Thereafter the GEFS does look a tad colder than average without question - but I'd have liked a few more members to flirt with the -5 uppers

Still - the mean does look acceptable in the long run with any signs of that horrid euroslug looking quite far south

[Bruegelian]

Shades of December 2012 with the polar maritime potential, let's hope it comes off.

Edited December 2, 2019 by Bruegelian

[CanadaAl]

1 minute ago, Bruegelian said:

Shades of December 2012 with the polar maritime potential.

Yeah i'd semi agree with that too. Difference was December 2012 started off a lot more promising. I was thinking Dec 2014/Dec 2017 as being more similar personally

[Bruegelian]

4 minutes ago, CanadaAl said:

Yeah i'd semi agree with that too. Difference was December 2012 started off a lot more promising. I was thinking Dec 2014/Dec 2017 as being more similar personally

On second thoughts I would say, that is a more accurate assessment.   

[Jordan S]

54 minutes ago, Mike Poole said:

If we get anywhere close to this in the 7 day window, this place will be in meltdown

I think this place was already in meltdown mode just 24hours ago. 

Good agreement between the Gfs, Gem and Ecmwf on low pressure moving back into the north of the UK on Thursday bringing wet and very windy weather to Scotland at first then through Friday and Saturday this spreads slowly south and east with a longer spell of rain for England and Wales.

GFS..

Thursday.. 

Gem..

Ecmwf..

GFS Wind gust chart for Thursday..

The weekend still looking very unsettled with the possibility of a deep low pressure system which was shown yesterday to still push southeast through or close to the UK into the north sea around the 8th or 9th with very windy weather and bands of rain sweeping through.. 

Gfs..

Gem..

It isn't likely to be particularly mild either and indeed the ECM has more in the way of wintriness to the showers come the weekend on a brisk northwesterly flow. Into next week most models keep things unsettled and rather cold upto atleast days 9/10.. 

GFS.. 

Wet and very windy but a mild south-westerly for a time. 

Gem.. 

Unsettled but rather cold with a long fetch northwesterly wind. 

Putting the Ecmwf Gem and Gfs output together it paints an unsettled picture with spells of rain and potentially stormy weather if any lows form in the flow early next week.. 

Another look at the jet stream forecast from the gfs for early and mid next week.. 

A strong jet stream shown with the potential for a few deep lows moving close to or over the UK bringing perhaps a stormier period after the weekend, but still a ways out and will be keeping a close eye on this in the coming days.

[feb1991blizzard]

1 hour ago, Bruegelian said:

Shades of December 2012 with the polar maritime potential, let's hope it comes off.

Dec 2011 was better here - 2012 gave me 1 inch of ice around the time 'That ECM' came out but nothing else - Dec 2011 a few minor snow events totalling about 2-3 inches of snow altogether.