Model output discussion - Winter approaches

[DavidS]

1 hour ago, NewEra21 said:

GFS 06z OP was a pretty clear mild outlier towards the latter part of the run.

Plenty more cooler/colder runs in there.

Yes, the Control was much colder and closer to the Mean at day 9/10

[feb1991blizzard]

2 hours ago, bluearmy said:

given the overall tone of the 00z eps suite, there will be a fair bit of attention on the ec46 when it appears this evening 

I will only really be paying attention to it if the 12z eps follows suite.

[kold weather]

56 minutes ago, Daniel* said:

Yes, EPS 2M high/low temps for London goes out to day 15, very unusual to have prolonged strong clustering on cool weather they’re not interested in double figures. 

Taking a look through the actual maps throughout the ensemble and there is alot of different variations out there for those cooler set-ups, from having HP over the south of England keeping it cooler, through to northerly topplers, through to weak easterly flows. Good to have choice but given this is a La Nina winter and everything happening in the stratosphere with the strengthening upper PV, we can only fight so long against the inevitable and most of those set-ups aren't going to be bringing much snow away from maybe the mountains.

Quite a few of the evolutions tend to be under-forecasted max temp wise by the models for somewhere like London, so may not be quite as cool as the ensembles would suggest if those were to come off.

Edit - there are some ensemble members from all suites that do have marginal snow events, BUT at this time of year and given we've had basically no cold at all thus far especially further south, I'd not want to assume they would have much of a chance of being on the right side of marginal if they were to come off however.

Edited November 23, 2020 by kold weather

[SMU]

Finally finally after 3 days of undercooking it the GFS has a high pressure over Scandi at day 4

[Tim Bland]

1 hour ago, kold weather said:

 

Edit - there are some ensemble members from all suites that do have marginal snow events, BUT at this time of year and given we've had basically no cold at all thus far especially further south, I'd not want to assume they would have much of a chance of being on the right side of marginal if they were to come off however.

I must have imagined the thick layer of ice on my car this morning then lots more frost to come later in the week as well so the surface is cooling quickly now. Also worth remembering we are only weeks away from the shortest day so less solar input. Here’s to an awesome set of 12z runs ️

[Snow lover 2020]

Wow these charts look like we could end up in a winter wind land with lots of snow later in December? Am I right? Oh my! I’ve got the sledge ready 

[swfc]

5 minutes ago, Steve Murr said:

Finally finally after 3 days of undercooking it the GFS has a high pressure over Scandi at day 4

Looks a bit lightweight tho Steve and sinking??? 

[northwestsnow]

What to make of UKMO this evening !!

Dry,after that, not sure....

Edited November 23, 2020 by northwestsnow

[Ali1977]

14 minutes ago, Snow lover 2020 said:

Wow these charts look like we could end up in a winter wind land with lots of snow later in December? Am I right? Oh my! I’ve got the sledge ready 

Not the GFS 06z, the earlier ECM could bring something beyond day 10. Let’s see what the 12z GFS shows by day 10 , I’ll be happy if it looks similar to the earlier ECM.

 

[Ali1977]

The earlier ECM and the 12z at 192. That big LP to the NE of Canada will scupper this beyond day 10 as the ECM didn’t make much of it.
I think this GFS is a step towards it compared to the 06z however, so hopefully the evening ECM follows this mornings run.

[SMU]

UKMO still out on its own-

Lovely festive GFS to start December with the UK well below ave CET layered in continental air like a weather vienetta...

[TSNWK]

19 minutes ago, northwestsnow said:

What to make of UKMO this evening !!

Dry,after that, not sure....

Tricky I agree, bland, chilly & dank - on a broader theme is it just me who places little faith in UKMO 144 - get it to 120 and below and solid, there just seem to be a big  drop in performance between 120 and 144 for UKMO, which I dont have in my mind for ECM and GFS.

 

[sheikhy]

3 minutes ago, Steve Murr said:

UKMO still out on its own-

Lovely festive GFS to start December with the UK well below ave CET layered in continental air like a weather vienetta...

Whats with the ukmo steve!been flip flopping between runs in the last 48 hours!!!gfs is a big improvement!!!lets hope the ecm does not follow the ukmo!!not sure where the ukmo is going lol!!

[cheshire snow]

4 minutes ago, Steve Murr said:

UKMO still out on its own-

Lovely festive GFS to start December with the UK well below ave CET layered in continental air like a weather vienetta...

Obviously cannot discount any model but to have the UKMO on board is a huge tick,how many times have we seen the GFS and to some extent the ECM go of on winter wonderland tantrums only for the UKMO to say no.

C.S

[TSNWK]

9 minutes ago, Ali1977 said:

The earlier ECM and the 12z at 192. That big LP to the NE of Canada will scupper this beyond day 10 as the ECM didn’t make much of it.
I think this GFS is a step towards it compared to the 06z however, so hopefully the evening ECM follows this mornings run.

Have we any WAA from that North East CAnada Low to help pump the Mid atlantic heights and shift the vortex over towards the pole further.

Edited November 23, 2020 by TSNWK

[Jeremy Shockey]

UKMO 12z @ t120

GFS 12 z @ t120

ICON 12 z @ t120

GEM 12z @ 120t

 

GFS 12z , GEM 12z and ICON 12z all have decent High Pressure 1030 hPa situated over Scandi at t120 ( quite similar to the ECM 0z in fact )

UKMO 12 z has the HP much further South !

We await the ECM 12z with excitement as usual.  At the moment the UKMO is the odd one out 

[Tim Bland]

GEM is looking good so far. WAA up to Greenland and a building high. / block 

Edited November 23, 2020 by Tim Bland

[northwestsnow]

GEM looks a gem...

Gfs struggling to see any amplification in the Atlantic ..

[swfc]

7 minutes ago, northwestsnow said:

GEM looks a gem...

Gfs struggling to see any amplification in the Atlantic ..

Yes gem looks OK but I'd be wary of ignoring gfs it's runs today have looked concistent imo even tho there is an early door pressure rise towards Scandinavia. Easy to be selective on what model suits your preference ie outlook. Gem sounds like it's being promoted as the new ukmo/ecmabye the 500mb charts are in honesty the way forward

Edited November 23, 2020 by swfc

[sheikhy]

If the ecm looks like gfs between 96 and 192 hours i will be satisfied!!dont want the ukmo!!!!

[booferking]

Boom GEM Atlantic shutdown in December 10 years on can history repeat itself.

Edited November 23, 2020 by booferking

[SMU]

So then here woukd be my forecast for the day 5-9 area based on the model variation at the moment.

This is based on what 'normally' happens when we get a fairly robust high over Scandi & a fairly decently alligned upper air cold pool on its southern flank.

I have earmarked the GFS 12z Control run to be the closest as possible, this is unusually over & above the favoured UKMO since its presentations have been very flat compared with the following runs & all ENS suites.

- You will see on the GFS control we have a higher lattitude high 

- Also a stronger flow if isolines across Europe compared with the 12z Operational, this is based on the assumption that the models generally underestimate the energy returning SE through Scandi.

* At some point the high pressures try to merge > maybe day 7 however due to the scandi high & westward forcing we often see the jet amplify quickly again. 

NB the GEM tries this on the 12z

I expect there to be amplification west of what the GEM has -but not east, this then paves the way for a Northerly or a reinforced continental flow depending on where the troughing drops > modelling usually gets corrected west...

Even though the zonal wind is very strong st the moment it appears a quick return to zonality doesnt look on the cards..

[Zak M]

GEM at 240 lines up a northerly:

Think there’s a reasonable chance of some cold weather at the start of Dec.

[dragan]

gfs12z more of the same. after brief high pressure, we see weather coming in the from west/southwest , quite windy at time too. temps around average 

[BLAST FROM THE PAST]

13 minutes ago, northwestsnow said:

GEM looks a gem...

Gfs struggling to see any amplification in the Atlantic ..

Forget the GEM...it’s rarely anywhere near.  Not liking the 12z GFS

BFTP