Model Output Discussion - A cold start to Spring?

[Lukesluckybunch]

GEM going down the route of ECM this morning

[ICE COLD]

Loving the Gem

[seabreeze86]

1 minute ago, Lukesluckybunch said:

GEM going down the route of ECM this morning

Keep the blocking over Greenland also which keeps the cold coming. Probably best case scenario the GEM 

[Guest]

UKMO 168hrs, messier than some would like:

[Ali1977]

1 minute ago, Tidal Wave said:

UKMO 168hrs, messier than some would like:

Snowier

[Bricriu]

Just now, Ali1977 said:

Snowier

Pity that low won't go under. It might mean the cold is prolonged and more areas get snow. 

[Guest]

1 minute ago, Ali1977 said:

Snowier

Wouldn't be so sure:

Need colder uppers than those for many.

[Lukesluckybunch]

2 minutes ago, Ali1977 said:

Snowier

is that a snowy chart?

[Ali1977]

3 minutes ago, Tidal Wave said:

Wouldn't be so sure:

Need colder uppers than those for many.

Not necessarily, the dew points and DAM would be low in that airmass in dropping temps 

Edited February 27, 2023 by Ali1977

[winterof79]

5 minutes ago, Tidal Wave said:

UKMO 168hrs, messier than some would like:

Yes ,disgusting really

 

[LRD]

GEM getting a lot of love and attention - it was like it didn't exist this morning! 

[EML Network]

Talk about swings and roundabouts Hard to really make much sense out of it all at the moment really.

None of the models are really in any agreement even at 144. GEM and UKMO are the closest matches

ECM

GFS

GEM

UKMO

 

 

[LRD]

2 minutes ago, bluearmy said:

 

Clearly not - sorry 

It’s a shame that their website forecast doesn’t match it ……

shouldn’t be difficult really ! 

Must admit, the vid was a great presentation and explanation but I also thought it didn't match the written update. Which, funnily enough, everyone thought was an upgrade (for cold) for next week but I thought it was a backward step (for cold). Better long term but for next week I thought it was 'meh'. The joys of the English language

[Bricriu]

Just now, Ali1977 said:

Doesn’t mean that at all, it will depend on many factors - ideally sliders as they can keep the cold in place 

I certainly hope that is the case, but I would not be confident at this stage 

[ICE COLD]

The control looks better than the op at T144 

[Tim Bland]

Worth stating that GEM doesn’t give lying snow for 80% of the population 

[BlueHedgehog074]

26 minutes ago, Mucka said:

Fingers at the ready for the UKMO 168

First poster wins the Golden Finger 

Looks like the award goes to :

23 minutes ago, Tidal Wave said:

UKMO 168hrs, messier than some would like:

[bluearmy]

the gem solution (similar to the ec 00z) would appear to be where Exeter think we’re most likely headed. Of course beyond day 7 that’s likely to be less and less accurate. Looking at the hemispheric view on both gem and Ukmo, it wouldn’t surprise me if we don’t see the models playing with even lower heights dropping down on a second wave around day 12/13.   That will depend on the upstream ridge and the amount of retrogression. 

[bluearmy]

1 minute ago, Tim Bland said:

Worth stating that GEM doesn’t give lying snow for 80% of the population 

I’d say that the period where we could see precipitation from that set up is outside of the ‘reliable’ at day 7. (Assuming it has the broad pattern correct).  And I’d also say that uppers are looking increasingly marginal in the colder scenario runs as we see warm sectors running south - this is even more likely to require some correction by the models over the next few days. but whether we have a slack mixing of air masses or a more vigorous one also plays a big part. 

[Matt Jones]

19 minutes ago, Ali1977 said:

Big upgrade from METO longer term 

Sounds great but it's a forecast, maybe a cold/snow ramper on duty today. Judging by the forecast models though they will be as clueless as we are.

[Mucka]

12z Model output analysis

So looking at the UKMO 168 we are in a halfway house.

Compare output to see what we need to change.

UKMO 00z V UKMO 12z 120h, note how the UKMO 00z has the core of the high further NW and tilted toward Greenland.

144 00z V 12z And so we get the undercut at 144 on 00z but much less so on the 12z resulting in more energy being forced N thereafter and less E/SE on the 12z and so the high is much further S on the 12z cutting off the cold NE flow

This comes about because the 12 puts more energy and forcing into the Atlantic sector early in the run, see the differences on the W flank of the high at 96h and GFS has the Atlantic even stronger at this point so no coincidence the output degrades for cold accordingly later in the runs

UKMO 00z V UKMO 12z V GFS 12z 96h

For a starker and more obvious contrast GEM 12 with GFS 12z at just 96h and yet again we see GEM went on to deliver.

I think it is pretty clear that how much forcing we get from the Atlantic trough earlier in the runs is going to have a clear impact on later outcomes. 

Which model has this right? 

We can't say because they are all adjusting back and forth and those are large differences at just 96h, likely caused with the models struggling with the impacts of the SSW.

As if that were not enough uncertainly the Operational output of GFS is somewhat at odds with its ensembles at this stage in the amount of energy it puts into the upstream.

In this case that is positive news because the mean has less Atlantic forcing which equates to more ensemble members having the Atlantic low making less inroads at this pint (96h)

GFS 12z Op V GFS 12z ensemble mean

Another positive spin on the output, although based in reality, is that the GFS 12z mean is a little better then the 06z mean

GFS 12z mean V GFS 06z mean 168h

 

All this means is that  FI is basically 96h+ when it comes to whether we get a cold spell and Greenland high post 144.

 

Edited February 27, 2023 by Mucka

[ICE COLD]

The control backing the other model outputs and not it’s own op run . 

Edited February 27, 2023 by ICE COLD

[seabreeze86]

GFS op looks very isolated doesn’t mean it’s wrong but odds against it now . The control run very good 

[Bricriu]

6 minutes ago, bluearmy said:

the gem solution (similar to the ec 00z) would appear to be where Exeter think we’re most likely headed. Of course beyond day 7 that’s likely to be less and less accurate. Looking at the hemispheric view on both gem and Ukmo, it wouldn’t surprise me if we don’t see the models playing with even lower heights dropping down on a second wave around day 12/13.   That will depend on the upstream ridge and the amount of retrogression. 

What seems clear from their update is we are unlikely to get a robust Greenland high and a direct hit for very cold uppers to make their way here. Which likely means cold rain for many rather than snow due to uppers being too marginal for the time of year. Some areas may get lucky, however, but I feel many will have at best slushy stuff or just  cold rain

[Stuie]

Nice spot today regarding the NAO. Note the mean drops from 7/10/14 days.

Trying really hard to go negative.