Model output discussion 24/01/21

[Kentspur]

34 minutes ago, Tim Bland said:

Re ensembles...wouldn’t usually look at them for close range but this caught my eye for snow tomorrow at midday in the south...

I don't trust these at all I watched them last weeknd with the failed snow pretty similar and we ended up with mostly rain and a bit of sleet though I guess they could be useful for more inland/elevated areas

[Sky Full]

What a great day it’s been on here.....20 pages of top posts and quite frankly some jaw-dropping charts for coldies.   And it’s not over yet !   Whether or not the current very promising charts verify, I reckon this has been the best day so far this year and I’ll remember the excitement of watching today’s developments on this forum for a long time.  We may be locked down and unable to get out to enjoy ourselves but at least we can have some fun on here while there’s the chance of some historic winter weather around the corner!  

[Tim Bland]

1 minute ago, Kentspur said:

I don't trust these at all I watched them last weeknd with the failed snow pretty similar and we ended up with mostly rain and a bit of sleet though I guess they could be useful for more inland/elevated areas

I agree it’s probably game over for Kent for tomorrow I’m afraid. These ensembles are for  London which is just about in striking distance of the colder air. For settling snow it’s probably Chilterns across to Cotsworlds but according to the 06z ECM somewhere with modest height EG Luton could see moderate snow for a while. Will see what the 12z says shortly ..

[Kentspur]

28 minutes ago, Griff said:

Parallel satisfactory at 204

+1c uppers over Hastings and Dover sourced from Libya no thanks  

[sebastiaan1973]

1 minute ago, bluearmy said:

Genuinely amazed that posters can have any moans about the current output (apart from someone with a squirrel in the sw)

Even if it goes awry, it’s still brilliant model watching and half the reason the vast majority of you are here ! 
 

just enjoy it and ou never know, you may get to enjoy a few walks in the snow at some point in feb ....

Blue, what's your idea about UKMO120h and 144h. Seems to me that after 144h anticyclone, east of the Azores will be dominant, and the pattern will be more west -> east. Just like GEM showed.

[I remember Atlantic 252]

Just now, Kentspur said:

+1c uppers over Hastings and Dover sourced from Libya no thanks  

Not a Mediterranean wet fart! long way in FI though

[AFCBSNOW]

1 hour ago, Drifter said:

Day nine and the south still doesn’t have uppers below -4c. 

To be fair, nothing below -4c has been in any of the models before 6th Feb,  I wouldn't sweat the small stuff, plenty of time to change.  Pattern first, uppers after.

[tight isobar]

6 minutes ago, bluearmy said:

Genuinely amazed that posters can have any moans about the current output (apart from someone with a squirrel in the sw)

Even if it goes awry, it’s still brilliant model watching and half the reason the vast majority of you are here ! 
 

just enjoy it and ou never know, you may get to enjoy a few walks in the snow at some point in feb ....

✌ Some in here think winter ends on June 15   and that between now and then its Ice-days and blizzards!!! Quite AMAZING!!

[Allseasons-Si]

24 minutes ago, Allseasons-si said:

Watch for that chunk of pv to break away to the NE as that separation splits the flow 

a good run this.

Getting there,...JFF though at that range.

 

 

[Sweatyman]

1 hour ago, nick sussex said:

I think to be blunt this is quite a downgrade from the 06 hrs run and this all stems from the day 6 and 7 output.

The disruption of energy is too south and not se . You need low pressure in northern Italy as this funnels a wider pool of colder air sw wards , it also impacts the longer term in sustaining the block in a favourable position for any Atlantic attack .

After a weekend at the Ritz we’re now back to the Premier Inn. The UKMO is equally uninspiring .

Hopefully the ECM can repair some of the damage . 

YUKMO now is it?  Earlier it was great. Dont know what to think FGS.

[Griff]

1 minute ago, Allseasons-si said:

Getting there,...JFF though at that range.

 

 

Had time to eat my super, come back and pleasant surprise.

Am I the only person looking at bigger picture and chances for nation wide possibilities in FI, I don't understand comments from others regarding specific locations, temperature and precipitation in +5 days (bonkers to try and judge +10 days surely). These charts are about synoptics not weather forecasting at range? Or have I missed some veiled attempts at humour?

Genuinely confused. Synoptics point to opportunities. Even high res models at short range struggle with actual forecasting.  

[bluearmy]

4 minutes ago, sebastiaan1973 said:

Blue, what's your idea about UKMO120h and 144h. Seems to me that after 144h anticyclone, east of the Azores will be dominant, and the pattern will be more west -> east. Just like GEM showed.

Sebastian - quite honestly the way that the Atlantic has been overplayed at day 5/6 on what are supposed to be high res models at that timeframe means I’m paying less attention to the op runs than I probably should. we have a broad direction of trave.l but no definitive route to arrive there .... so pretty much anything could fill the gap and we may end up with frigid easterlies, ‘tepidish’ sou’easters, or under a cold high.  hopefully it settles down soon and we get cross model agreement on the mid range. 

 

 

[Rollo]

Before the hoped for start of the fireworks so to speak there are another 21 to 25 new charts to be issued from GFS, surely there will be several upgrades and downgrades, we cannot expect each successive chart change to be an upgrade, it may go all tits up but enjoy the ride, if it’s too much for you give  it a rest for a couple of days

[nick sussex]

2 minutes ago, Sweatyman said:

YUKMO now is it?  Earlier it was great. Dont know what to think FGS.

I’d like to see more energy heading se by day 6 . 

So that stands for all the outputs so far . The quicker we see pressure drop in northern Italy the better the chances for sustained cold.

 

[Man With Beard]

I mentioned I wanted to see a minus 20C uppers run in the UK, just for fun - I think the GFS P is going to get close in the final few frames...

[chris55]

25 minutes ago, Singularity said:

 

Honestly, there's no reason to complain about the UKMO 12z. It has the stronger low to our east rather than west which means the very cold air would be funnelled in more during the following days.

GFS also places that strongest low further north than GFS(P) for example, which doesn't help.

That said - the single strongest model bias I know of is creating overly large, rounded troughs beneath highs in the Greenland-Iceland area.

Just look at this weekend with only weak high pressure there. We've gone from a balmy southwesterly flow most of the way up the UK to a genuinely cold weekend for all but the southwest corner, as the low has corrected to a flatter shape with secondary features splitting away east and as a result, no Iberian high sustenance.

So really, don't worry about models building broad troughs with Iberian ridges in the longer range. Only if that happens within the 5, maybe 6 day range is there legit reason to be concerned.

Good post.

One reason why UKMO is a good model to follow in a realistic sense is that it only goes to 144.

Thats pretty much the limit of reasonable reliability, and in the current situation with all the nuances, day 6 is pushing it. Im talking about the details here not the broader pattern.

We can look at trends beyond day 6, ensemble means and the like, and with consistency and inter model agreement we can get a decent idea of the direction of the output. But taking each op run in isolation (including the ensemble set to go with it) isn't a realistic way to predict the weather in 8 days. 

Stick to day 6 and take each run beyond as just a guide.

With that in mind, we are being guided towards a very cold pattern, the question is, will this verify......

 

[Battleground Snow]

ECM still bullish for settling snow tomorrow.

Will come down to nowcast for sure.

 

[Drifter]

1 minute ago, Man Without Beard said:

I mentioned I wanted to see a minus 20C uppers run in the UK, just for fun - I think the GFS P is going to get close in the final few frames...

Yikes - good spot. 
Is it me or do the op and para take turns in delivering the goods?  I can’t remember the last time they *both* delivered an epic run.  

[Tim Bland]

Just now, Battleground Snow said:

ECM still bullish for settling snow tomorrow.

Will come down to nowcast for sure.

 

*cough* have I been Furloughed

looks good for many areas to at least see falling snow !

[Tim Bland]

Wales and south mids see some light snow Sunday afternoon...

[tight isobar]

5 minutes ago, Tim Bland said:

Wales and south mids see some light snow Sunday afternoon...

Luton to Birmingham..look like decent accumulation spots...and around a 100 mile radius...give or take.

[supernova]

31 minutes ago, I remember Atlantic 252 said:

Not a Mediterranean wet fart! long way in FI though

 

32 minutes ago, Kentspur said:

+1c uppers over Hastings and Dover sourced from Libya no thanks  

Tbf guys your +1 uppers at 204hrs have got a much better chance of verifying than what the Para goes on to deliver at 342hrs+ but a worthy frame if only JFF. Hard for us not to get enthusiastic about a potential Easterly up here in Lincolnshire, not least this winter where we've had bugger all thus far, so fascinating model watching currently and the broad direction of travel remains encouraging, even if the details are too far out to debate with any confidence.

Edited January 29, 2021 by supernova

[Gowon]

33 minutes ago, Kentspur said:

+1c uppers over Hastings and Dover sourced from Libya no thanks  

It doesn't really matter at that timeframe but it's still produces a lot of snow for the south.

[tight isobar]

The angle of attack on the ec 12 should see some eye candy 144+...that alignment in the AT..is steadfast.

[chris55]

EC 120, looking good.

 

EDIT

UKMO for comparison.

Edited January 29, 2021 by chris55