Model Output Discussion - Into 2024

[swfc]

1 minute ago, northwestsnow said:

Only my opinion but I prefer GFS at 168 the High is a bit further North...

It is nws. Id be going anywhere between another 72 hours before lighting any fuse

[Harsh Climate]

2 minutes ago, Icebox said:

Never...  the first and golden rule.

I've been telling people at work since the 23rd!

[northwestsnow]

Day 8 GFS V EC

[Lukesluckybunch]

With those 850's on the ECM would it still be cold and of next week?

[seabreeze86]

1 minute ago, northwestsnow said:

Day 8 GFS V EC

Both fantastic and now at day 8 for the retrogression we are reeling it in now 

[Scott Ingham]

14 minutes ago, BLAST FROM THE PAST said:

Interesting post Scott.  Would love to see the comparison of success going forward over next 10 years to the last 10.  2023 I think has become an important year.

 

BFTP

 

 

I don’t think it will always be like this it’s been a year where the tropics have dominated. If we had a stronger Strat or another driver over riding this I don’t think we could call this pattern with the same confidence but gdsm tools are extremely valuable. That I definitely know this year using them

[Alexis]

Amazing how the ECM and GFS are almost identical at 192h.

For some reason this odd setup is making it easier for the models

Edited January 4 by Alexis

[northwestsnow]

Day 9

[That ECM]

Awesome

 It’s always day 9 

Edited January 4 by That ECM

[Scott Ingham]

17 minutes ago, Mcconnor8 said:

UKV goes with -10 for Monday, bone dry though.

Not enough instability. 500hpa heights are too high we need them light blues at least or convection is too shallow

[Ali1977]

Just now, northwestsnow said:

Day 9

[northwestsnow]

Just now, Ali1977 said:

Owwww yes

[BLAST FROM THE PAST]

4 minutes ago, Scott Ingham said:

I don’t think it will always be like this it’s been a year where the tropics have dominated. If we had a stronger Strat or another driver over riding this I don’t think we could call this pattern with the same confidence but gdsm tools are extremely valuable. That I definitely know this year using them

I think (my inference) is that it will become more stable as a tool.  
 

BFTP

 

[Scott Ingham]

1 minute ago, BLAST FROM THE PAST said:

I think (my inference) is that it will become more stable as a tool.  
 

BFTP

 

Aww got ya! Yes! What’s happened is peoples interpretation of it has improved from experience of using it.

[Howie]

The consistency is really mind blowing I have to say 

[northwestsnow]

[Purga]

D10

[swfc]

Even with great synoptics the 500hpa are way to high even with projected 850s. Looks very dry and there's not much instability in the atmosphere. All that said the bricks are being laid on the rd

[That ECM]

3 minutes ago, northwestsnow said:

Northwestsnow-the fast chart poster in the west.

Edited January 4 by That ECM

[northwestsnow]

GFS V EC 850s day 10

 

[Scott Ingham]

Tomorrow 12z should be the first day where a run shows -10 air and lower associated with the Greenland height rises! Then it gets really fun!

I should add (inside 10 days)

Edited January 4 by Scott Ingham

[WYorksWeather]

Quick update this evening on 850s, surface temperatures, and temperature averages.

850s

I still think we need to inject a slight note of caution around the idea of deep cold. Obviously there are various definitions of this, but if you look at the -10C line for instance (blue line added by me for emphasis), we see that though there are a few runs that get that cold, they're very much in the minority, and even those that do reach -10C at 850hPa reach it only briefly. Further north there are a few more, but still not all that many.

Again this isn't a 'the cold spell is a bust' post, but more of a suggestion that people temper their expectations just a little bit. The model output is showing a notable colder than average spell for at least the next 10 days, but at this stage only a minority of the ensemble is showing it going very cold from the 15th.

Still plenty of scope for this to change of course, but as it stands a December 2010 type scenario is not very well supported. If we do get more ensemble support for it, I'll change my opinion. Of course, 850s of -10C and below are not required for large amounts of snow or for it to stick around for a good while if it does fall.

On a more optimistic note, there's no real support for anything mild in the next 7-10 days, with no sign that the warm outliers are gathering pace.

Surface

Temperatures will be colder further north as a rule, but relative to average, the north will likely be somewhat less cold than the south, due to lower temperature averages.

In terms of changes since yesterday, what I'd note is that there's been a slight tendency towards more of a warm up around the 12th or 13th. 850s have always looked like recovering to average temporarily, but previously there wasn't much sign of a change in surface temperatures. Beyond that point, from around the 15th to the 18th, temperatures look a little colder than they did yesterday, with temperatures in the north possibly flirting with ice days.

As the last third of the month begins to come into view, we then see a lot more scatter in what happens around the 20th. Some very mild runs showing up again for the south, and less colder ones, but still a lot of scatter further north in both directions. Opens the door to a possibility of either the whole of the UK turning milder, or a north-south split. Of course, all that is a long way off at this stage, and not really worth worrying about, but thought it was worth flagging.

Averages

Just a further quick note on averages - sometimes good to have a sense for what 'cold' is in January. Of course there's relative and absolute measures of cold, but using relative terms is often better if we're discussing how 'notable' a cold spell is. Just a quick illustration by comparing Kew Gardens to Topcliffe below.

Station - Max - Min - Mean - Air Frost

Kew Gardens - 8.6C - 2.0C - 5.3C - 10 days

Topcliffe (North Yorkshire) - 7.0C - 0.5C - 3.7C - 13 days

Mean temperatures around one to two degrees lower, a few extra air frost days.

It would be interesting if anyone is aware of a useful source for stats on number of ice days. Probably a conversation best continued on another thread though.

[BLAST FROM THE PAST]

Guys…..forget the ‘detail’ of 10+ days….the pattern is rock solid.  For me it will NOT remain a dry cold

 

BFTP

[badgerhud]

12 minutes ago, Alexis said:

Amazing how the ECM and GFS are almost identical at 192h.

For some reason this odd setup is making it easier for the models

Or both gone astray

[Lukesluckybunch]

Is that slightly west based day 10 ECM I think so...