Model output discussion - deep cold inbound?

[ITSY]

6 minutes ago, kold weather said:

Even the GEM OP does have some snow btw, its less than some of the other models but I'm not sure you can describe it as no:

850hpa temps between -4 to -6c, dew points of -1c and temps around 0c.

For sure, not the big totals seen on some of the other models, but its still giving some snow for most of EA/SE.

Apologies, you're right. I've been guilty of IMBY-ism here. GEM is a no to widespread inland snow as I described this morning (for Cambs, Beds, Herts, Lincs, Leicestershire etc). That's at odds with ECM, GFS, GFSP but in line with ARPEGE and similar-ish to ICON which has admittedly edged much closer towards the more widespread group this afternoon, which is welcome news. Only pointing this out as it still needs ironing out. GEFS mean looks v good though and quite different to the GEM Op:

 
 

Edited February 4, 2021 by ITSY

[DAVE_ALLEN]

Very interesting to see that in a typical cold set up. Its usually the fringes in Kent, W Wales , SW and N Ireland that see frequent wintry/snow showers. And now the reverse if being forecast.. Really is quite odd. 

[Griff]

Gem going great... 210  

[That ECM]

Here's the mean as good way to see a trend. 

Edited February 4, 2021 by Paul
no need

[Battleground Snow]

Gem is pretty close to the ECM 00z later on, I'm looking forward to the ECM later.

Re gem snow totals, it's still going to be missing streamers , so there will be accumulations from that for sure.

[chris55]

1 minute ago, DAVE_ALLEN said:

Very interesting to see that in a typical cold set up. Its usually the fringes in Kent, W Wales , SW and N Ireland that see frequent wintry/snow showers. And now the reverse if being forecast.. Really is quite odd. 

Its because its an easterly not a northerly

[Paul]

There are two whacking great orange boxes on here - one right by the post editor - which are asking everyone to stay on topic. So, on the basis that there's not really a way to avoid seeing those, it's probably fair to assume the small handful of people who keep posting whatever they fancy in here, model related or not, just don't care. So, with that in mind, if those people continue they will shortly be stopped from posting in here. 

 

Edited February 4, 2021 by Paul

[NewEra21]

The further into the run, the GFS op definitely becomes much more on the milder/less cold side. So that's a good sign, much more of a colder cluster in there!

Edited February 4, 2021 by NewEra21

[kold weather]

3 minutes ago, ITSY said:

Apologies, you're right. I've been guilty of IMBY-ism here. GEM is a no to widespread inland snow as I described this morning (for Cambs, Beds, Herts, Lincs, Leicestershire etc). That's at odds with ECM, GFS, GFSP but in line with ARPEGE and similar-ish to ICON which has admittedly edged much closer towards the more widespread group this afternoon, which is welcome news. Only pointing this out as it still needs ironing out. GEFS mean looks v good though and quite different to the GEM Op:

 
 

I think it is fair to say though that ICON is less keen on bringing the snow further west, so your not totally wrong, its just not as impressive as other runs.

Beyond Sunday as others have mentioned looks like a 2 day window where there could be some decent enough easterly winds to push any showers well inland. ARPEGE is very keen on developing impressive bands of convection.

And thats obviously ignoring the chances of any streamers that may well develop.

[bumpydogz]

6 minutes ago, MattStoke said:

Good old GFS Always wobbles about like jelly in an earthquake, blows up lows, tries to bring in less cold air etc. Doesn’t concern me whilst all other models are against it.

Indeed, but when the Metoffice latest forecast (prior to the 12z GFS) highlights the risk, and shows rain into Kent and southern Home Counties I think people should take notice. I don't think it should just be dismissed.

[Tim Bland]

1 minute ago, sheikhy said:

Cmon ecm put this crappy gfs in its naughty chair!!!!the perfect run would be the snow coming into the east on sunday and then prolong the cold as well like ukmo!!

Crappy? 23cm not enough for you after just 2 days into the cold spell Think we are being spoilt mate! The only ones saying the GFS runs are poor are just trying to get a reaction. Anyone remember Ian Brown

[sheikhy]

Gfs goes higher end of the scale from the 9th!!phew!!

[Tim M]

Genuine question from a lurker with little knowledge but a strong interest... If, as everyone is saying/implying, the GFS is such a poor model for so many situations  (blowing up lows, too progressive with westerlies breaking through blocks etc), why are we all scrutinising it so much and so often so many times every day?   If the UKMO is really king surely that is all we should be concerned with?

[sheikhy]

Just now, Tim Bland said:

Crappy? 23cm not enough for you after just 2 days into the cold spell Think we are being spoilt mate! The only ones saying the GFS runs are poor are just trying to get a reaction. Anyone remember Ian Brown

Let me correct my self!!fantastic run but in terms of longevity not the best

[Jason M]

Anyone that bets against the meto at such short range is brave imho. All looks good in the hood tonight from where I’m sitting. Given that I’m only about 7 miles north of Kent you guess where my money is going.

GFS is a good model but it’s strength isn’t really short range detail in our backyard. 

[bumpydogz]

1 minute ago, Tim M said:

Genuine question from a lurker with little knowledge but a strong interest... If, as everyone is saying/implying, the GFS is such a poor model for so many situations  (blowing up lows, too progressive with westerlies breaking through blocks etc), why are we all scrutinising it so much and so often so many times every day?   If the UKMO is really king surely that is all we should be concerned with?

Mainly because it comes out more frequently, and before the other models.

[nick sussex]

The GFS over develops a shortwave in the Channel which essentially holds up the cold from being able to push further sw . It’s a very discrete feature , you can only see this if you go to the GFS 0.25 .

This shortwave is reluctant to clear and starts heading back west .

If you compare that to the GEM and go to the France view , that has a minor shortwave which quickly become absorbed and doesn’t effect the cold from heading sw.

[Weathizard]

3 minutes ago, NewEra21 said:

The further into the run, the GFS op definitely becomes more of an outlier. So that's a good sign, much more of a colder cluster!

With respect, I think using the term ‘outlier’ to describe that is really wrong. There’s a colder cluster and then there’s at least 5/6 runs along the same lines as the OP so it’s by definition not an outlier.

[Tim Bland]

GFS is borderline a mild outlier ..

[Snowman.]

5 minutes ago, Tim Bland said:

Crappy? 23cm not enough for you after just 2 days into the cold spell Think we are being spoilt mate! The only ones saying the GFS runs are poor are just trying to get a reaction. Anyone remember Ian Brown

It is poor compared to the other runs and what is available from the overall synoptics.

It's not poor compared to Dec 2015.

GFS 12z ends everything too quickly and I would describe as a one pump champ. GEM has go out with a bang almost every part of the UK getting snow but turns to rain for most in the end and I would imagine the UKMO wants your pipes to freeze and explode.

 

 

Edited February 4, 2021 by Snowman.

[NewEra21]

1 minute ago, Weathizard said:

With respect, I think using the term ‘outlier’ to describe that is really wrong. There’s a colder cluster and then there’s at least 5/6 runs along the same lines as the OP so it’s by definition not an outlier.

Very true, it is definitely on the milder/less cold side though.

[Weathizard]

1 minute ago, Tim Bland said:

GFS is borderline a mild outlier ..

Am I misreading this as I’ve seen the mild outlier mentioned by two people now and by looking at them ensembles it’s clearly not an outlier

[Tim Bland]

Day 10 on the GEM and most of the us is buried, still under cold air and still some snow around. Hope ECM follows suit! 

[Mr_Pessimistic]

43 minutes ago, Captain Shortwave said:

No saggy bottoms here...

 

After the winds beer easterly that low over Europe starts to bend the winds more north easterly so showers will still be piling into the east. Interestingly the UKMO offer little modification of the deep cold over the south that has popped up in other models.

Presumably due to the short sea track, those showers will not be particularly heavy though?...   Met only suggest light snow showers in the east..

[Tim Bland]

2 minutes ago, Weathizard said:

Am I misreading this as I’ve seen the mild outlier mentioned by two people now and by looking at them ensembles it’s clearly not an outlier

I said Borderline ...at the end there are only a couple (out of 34) as mild ...

Edited February 4, 2021 by Tim Bland