Wales/Cymru Regional Weather Discussion

[SnowStorm(Jamie)]

Have to admit the upper air temperature profiles are quite impressive. Euro 4 shows upper temps of -9 to -10c moving across the Irish sea, such cold air going over the Irish sea is likely to assist shower development.

 

 

[Jackfrost]

Oh boy. Midnight Monday. Not great for the South coast and Southwest, admittedly, but those are some very respectable totals from the Valleys up to the North coast. Still, take heart those for whom it doesn't look good; there's still plenty of time for adjustments.

 

Edited December 6, 2017 by Jackfrost

[keithlucky]

1 hour ago, SnowStorm(Jamie) said:

Have to admit the upper air temperature profiles are quite impressive. Euro 4 shows upper temps of -9 to -10c moving across the Irish sea, such cold air going over the Irish sea is likely to assist shower development.

 

 

Totally agree ,west is best lol,this set up suits us pefect wind direction this is perfect

 

Edited December 6, 2017 by keithlucky

[andymusic]

36 hours or less to SNOW DAY

slider still going through us sunday and giving us a dumping

so at least two plus days of heftyish snow showers and a slider dumping on sunday - don't think we can complain about that

Edited December 6, 2017 by andymusic

[andymusic]

43 minutes ago, Jackfrost said:

Oh boy. Midnight Monday. Not great for the South coast and Southwest, admittedly, but those are some very respectable totals from the Valleys up to the North coast. Still, take heart those for whom it doesn't look good; there's still plenty of time for adjustments.

 

a foot of snow on the mountain tops - yeah, looks good to me - and the rest of Wales should see a fair amount too even pembs with the slider on sunday and the south coasts with the artic air digging in with the snowy showers - can't see anyone really missing out this time

[andymusic]

anyone for a 2nd slider next Wednesday too - so we keep what has been dumped with lovely cold frosts over the snow fields and get another top up next Wednesday

[pyrotech]

Andy,

GFS is almost perfect for us, the good news is that GFS has been consistent with position of the low Sunday on both 06z and 12z run today

However lets not discount UKMO who have put the centre of the low much further North, i would be interested in MOGREPS and what that is saying and maybe a clue in the fax charts later

Disruptive snow is very close but fat lady is not singing just yet

Lets keep our feet on the ground as we wait to see which looks more accurate, not what we want to be more accurate

[DeepSnow]

Typical I'm in work all weekend near Barry/Cardiff, right on the coast so even if it snows back home in Tondu ill be in one of the least likely areas in the south to get any snow 

Hopefully being inland 5-6 miles I will get to see some on Friday though! Just see how it all falls into place over the next 48hours. I must admit if we do get it Sunday I will not enjoy driving 20 or so miles in any snow late at night home!   

[Snowyowl9]

12z UKMO takes the snow to Scotland,take your pick.

GFS has seen a huge upgrade overall today,but its a 50/50 bet sunday yet.

[Marcus_surfer]

Is there a front moving down friday night? Looks like northern and eastern areas look best for snow showers whilst the west stays dry?!

[Marcus_surfer]

2 hours ago, SnowStorm(Jamie) said:

Have to admit the upper air temperature profiles are quite impressive. Euro 4 shows upper temps of -9 to -10c moving across the Irish sea, such cold air going over the Irish sea is likely to assist shower development.

 

 

I hope so, how would this very cold air assist shower development? Sort of like lake effect snow?

[andymusic]

1 minute ago, Marcus_surfer said:

I hope so, how would this very cold air assist shower development? Sort of like lake effect snow?

ssts in the irish sea still warmish early in the season - soooooooooo means the temp difference could aid development of hefty snow showers and the showers will also have more longevity in them to travel over the mountains - add to that the wind speeds - gonna be bitter and snow should and will settle widely across wales

[Marcus_surfer]

1 minute ago, andymusic said:

ssts in the irish sea still warmish early in the season - soooooooooo means the temp difference could aid development of hefty snow showers and the showers will also have more longevity in them to travel over the mountains - add to that the wind speeds - gonna be bitter and snow should and will settle widely across wales

looking good...sunday looks a mess. Mid-north wales looks like getting a decent amount

[andymusic]

36 minutes ago, Snowyowl9 said:

12z UKMO takes the snow to Scotland,take your pick.

GFS has seen a huge upgrade overall today,but its a 50/50 bet sunday yet.

I think your in one of the best positions overall - most of the model runs have included mid-wales as a good bet for a sizable chunk of snow from the slider - unless of course it doesn't even make it into the uk for some reason - but that's not looking likely

Edited December 6, 2017 by andymusic

[andymusic]

latest euro4

[Snow Dragon]

4 minutes ago, andymusic said:

latest euro4

Looking good for Barry and Cardiff in this latest one

[georgiedre]

To be honest for some reason BBC weather is not showing any showers on West coast which is weird. Anyone know why this keeps on happening

[SnowStorm(Jamie)]

2 minutes ago, Marcus_surfer said:

I hope so, how would this very cold air assist shower development? Sort of like lake effect snow?

Yes pretty much the same, cold air flowing over warmer sea. Latest Euro 4 doesn't show much precipitation over SW Wales or SW England now looking, streamer possibly setting up over NW Wales pushing south east. Anywhere pretty much could see a snow shower with air that cold (dew points also below 0c).

[A Frayed Knot]

We will be happy with this outcome

[Jayfromcardiff]

3 minutes ago, A Frayed Knot said:

We will be happy with this outcome

Is this from the latest runs? Need it a bit further SW so that south wales and SW england can enjoy it.

[A Frayed Knot]

Brilliant weather report just then on BBC WALES showing plenty of heavy snow showers for Parts of Wales and especially the South East .

[Jayfromcardiff]

7 minutes ago, A Frayed Knot said:

Brilliant weather report just then on BBC WALES showing plenty of heavy snow showers for Parts of Wales and especially the South East .

And the showers are coming the early hours of Friday morning so will settle instantly. Didn't look much in the way of snow during Friday daytime though.

[Pembroke Dangler]

I think Sunday's track of the slider is still open to review South looking at the trends of the last couple nwp runs. I think it will eventually settle on a track that takes it through the Bristol Channel and so 50 miles north of it will be snow. 

[Jayfromcardiff]

Chris Fawkes has just said Sunday could deliver 10-20cm of snow widely! Imagine after Friday too.

[JamesL]

So we are now on the cusp of our first noteable snowfall since Jan 2013. Here in Aberdare we had around 4-5" on the 18th/19th Jan. 

The last noteable snowfall in December was of course the infamous winter of 2010, so it's been a LONG wait. 

As is the case with these set ups; expect the unexpected. Thursday night/Friday I think is our best chance of seeing some snow across the WHOLE region.. Sat sees the showers dying out as pressure rises from the west.

The real uncertainty comes on sat night into Sunday. The shallow low that is forecast to cross the UK is still causing issues for the models. They all have agreement on the feature sliding nw-se but exactly where, will be undecided until 12-24 hours prior and even then radar watching will come into play for the heaviest precipitation and where it will fall. 

Right now as it stands the parts of Wales in the firing line for snow are the North and Mid Wales including the Brecon Beacons and Heads of the Valley regions. The remaining regions MAY see a transient period of snow before it turns to rain and potentially back to snow once it passes through and the colder air filters south. 

What we need is another correction of 50-100 miles south to bring the whole of the country into play (except those coastal districts in the far south and south west where it will be very marginal) 

My current feelings are that the slider will slide south and west of it's current trajectory and bring much of the country into the firing line with the sweet spots being Mid and SE wales incl the valleys and borders. 

Why do I think this? Yesterday I posted my thoughts on the Model Output thread regarding southerly adjustments and sure enough ALL have corrected south today, the GFS currently looking the best for our country. Historically the models seem to underestimate the cold air in situ and the effect thus has on systems approaching the UK from the west. We see it more in a blocked scenario where we have high pressure to the NE and low pressure coming in from the south west approaches. 

Yes it's a very different situation with a trough to our east and a wedge of higher heights to our NW BUT my feelings are the same. 

Call it a hunch, intuition or just the fact I've seen it happen 10's of times over the last 35 years. 

This could IMO potentially be a significant event for many of us especially those above around 100m asl