[Misc] The Award-winning official "More Snow Tomorrow?" Thread [2023-24 Season]

[jakarta]

Been taking down exterior lights (always the most depressing thing about New Year) and its absolutely bloody freezing here in RH20.

Given everything else going on think Hibernation until April would be a good idea!

 

[Papa Lazarou]

There are some early signs of a colder spell mid month. This is the GFS chart for Worthing.

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=47436&model=gfs&var=5&run=6&lid=ENS&bw=1

There are some very cold runs in there, but still a bit early to 'call' it

 

[portslade seagull]

There are some early signs of a colder spell mid month. This is the GFS chart for Worthing.

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=47436&model=gfs&var=5&run=6&lid=ENS&bw=1

There are some very cold runs in there, but still a bit early to 'call' it

Loads of nice coloured lines there Papa

 

[Papa Lazarou]

Loads of nice coloured lines there Papa

As I like it. If this becomes a 'thing' I'll post more info, as will the other Met heads on here.

 

[TheBigUnit]

Up to 50cm in places forecast in the longer 10 day forecast.

https://www.windy.com/-New-snow-snowAccu?snowAccu,53.206,-2.395,6

 

[Braggfan]

There are some early signs of a colder spell mid month. This is the GFS chart for Worthing.

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=47436&model=gfs&var=5&run=6&lid=ENS&bw=1

There are some very cold runs in there, but still a bit early to 'call' it

I love your posts, they're very informative. But I have to say WTF?

That looks like a mess.

 

[Flex Your Head]

There are some early signs of a colder spell mid month. This is the GFS chart for Worthing.

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=47436&model=gfs&var=5&run=6&lid=ENS&bw=1

There are some very cold runs in there, but still a bit early to 'call' it

Has it all gone tits up? Just had a quick look, and it all looks rather... meh! Very few dipping below zero.

 

[Weststander]

There are some early signs of a colder spell mid month. This is the GFS chart for Worthing.

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=47436&model=gfs&var=5&run=6&lid=ENS&bw=1

There are some very cold runs in there, but still a bit early to 'call' it

On another German weather website, their modelling shows very cold weather hitting here around Thursday 21st, with significant snow (10cm plus) from Wiltshire northwards. Its shows low temperatures for Sussex, so it’d be just a case of whether we’ll get precipitation.

If this pans out, of course.

 

[LamieRobertson]

Tad wet out today sigh..guess I should get out there

 

[AmexRuislip]

Tad wet out today sigh..guess I should get out there

https://www.ventusky.com/?p=51.5;-0.1;5&l=rain-3h

This is more like it Lamie

 

[Papa Lazarou]

I love your posts, they're very informative. But I have to say WTF?

That looks like a mess.

To try and explain, that plot represents the outcome of 23 different computer forecast runs, each with slightly different parameters, resolution etc. It allows forecasters to understand the chances of any specific synoptic outcome being 'true'.

This may help. This diagram is today's (latest) GFS ensemble, but in a better format. This one shows surface temp (at 2m), rainfall and snow percentage chance for somewhere Worthingish.



The Operational Run, which is the one published and used by most automated phone apps is the thick black line. This run and the thick blue (the control) are both run at a higher resolution to the others, so should be more reliable (resolution refers to the number of data points modelled globally per the forecast). both of these runs go for the possible N / NE / E blast from about the 21st, with sub zero daytime / night-time temperatures and undoubtedly snow. They are in the cold cluster I've marked.

Alternatively, there are milder options available.

It's a hard one to call.

There are of course many other models to look at. the ECMWF is the best of the rest (probably the most reliable of them all), but they only provide ALL their data if you pay for it. What we can see is their Op run, which goes coldish (but it pushes the coldest air to our West into the Atlantic) and their ensemble 'clusters'. These show the grouped options available in their ensemble.



This might seem hard to interpret, but it shows the clusters top to bottom over 3 days (left to right). Each shows the relative pressure over NW Europe.

Cluster 1, with 19 members shows high pressure over Greenland and the pole, with low pressure to the south. This would be cold for Scotland and Northern England, but would probably be milder and wet for us. This group keeps that setup throughout.

Cluster 2 & 3 with 13 & 9 members both start with a Greenland high with a mid Atlantic ridge. These would all be cold for the UK, with snow. They both keep the cold for the 3 days.

Cluster 4, with 6 members for the UK is much the same as cluster 1.

Cluster 5 from our perspective is like 2 & 3.

So, from this run, for the period 21-23 Jan. We have:

Cold & Snow chance for Sussex (cluster:2, 3, 5) = 26
Milder for Sussex, but colder periods (1 & 4) = 25

On a knife edge.

 

[Papa Lazarou]

FYI - the incomplete GFS 6Z ensemble looks a lot colder / snowier for here. I look forward to the plot.

 

[Papa Lazarou]

That's quite a change - MUCH colder, with precipitation. Those are the 2M temperatures for Worthing.

 

[Change at Barnham]

What is a 2M temperature?
Is it the temperature at two metres above the ground?
If so, is this the default point that temperatures are measured from?

 

[schmunk]

What is a 2M temperature?
Is it the temperature at two metres above the ground?
If so, is this the default point that temperatures are measured from?

Yes, for Brighton weather we've asked Dan Burn to wear a sensor on his chest.

 

[Muhammed - I’m hard - Bruce Lee]

Looks like a lot of the models are now starting to agree on a cold / very cold snap from around the 20th onwards

 

[schmunk]

Looks like a lot of the models are now starting to agree on a cold / very cold snap from around the 20th onwards

They're ready for it:

 

[Peteinblack]

Possible Beast from the East scenario developing for middle/late next week
https://www.theguardian.com/uk-news...eather-might-return-next-week-says-met-office

 

[Peteinblack]

They're ready for it:

Saturday night in Newcastle?
Actually, no; a tad overdressed

 

[Papa Lazarou]

What is a 2M temperature?

Temp at 2m above ground

Is it the temperature at two metres above the ground?

Yes

If so, is this the default point that temperatures are measured from?

Yes, it's high enough to avoid ground cooling / heating. It's the standard used globally I believe