Wales - Regional Weather Discussion

[TonyH]

Probably

[ourson]

In Jay from Cardiff's absence, I feel the need to contribute on his behalf, so

"Will it snow in Cardiff LOL?"

Please do not reply, as I am well aware that no-one knows the answer. I am also loking forward to Andy's mental weather charts from weather-on-line showing heavy snow over Pontypridd for the next sixth weeks.

(LOL, ROFL etc etc etc)

[PeteB]

Frost remained on areas sheltered from the sun all day here, temperature only reached 2.1.

Pete

[keithlucky]

ECM is turning out some amazing snowy charts with back up from other charts , at last we see some wintry weather lined up from Friday onwards.

[Cymro]

Indeed many members in here openly shot down the ecm and now again come this evening it shows the GFS doing exactly as though coming to the ECM dramatically, and look at this mornings outputs people were saying that the gfs was right. I'm not going to lie I dislike the GFS model and I also dislike the defensiveness of those that support the gfs as gospel all the time.

Thank heavens the GFS has got it's act together, but in terms of talking of snow etc that's all rudimentary atm, yes the potential is there now for the systems to fall into place to allow for favourable conditions meaning snow for Wales. I honestly think come a week today most of Wales will be covered in snow to some extent.

[keithlucky]

Yes the potential is there what was interesting was even though GFS was dire for cold lovers this morning.The met went with snow showers for the weekend make you think that the Met disregarded GFS output.

[Cymro]

Yes the potential is there what was interesting was even though GFS was dire for cold lovers this morning.The met went with snow showers for the weekend make you think that the Met disregarded GFS output.

But if you look at the metoffice's updated forecast for the weekhead however you will see that it seems asif they went with the GFS :/ very confusing :S

[SnowStorm(Jamie)]

Still differences in the main models with regards to the initial thrust of cold polar air from the north west.

This can be seen on the GFS, ECM & UKMO 12z data @ 120hrs:

http://images.meteoc...-0-120_pzt9.png < GFS

http://images.meteoc...120-21_vai2.GIF < UKMO

http://images.meteoc...H1-120_uut3.GIF < ECM

The GFS & ECM are simular actually in the sence they are keeping that high just to our west with troughing further east this results in the coldest air going down the eastern side of the country with a drier outlook for Wales. However the UKMO has the high further NW as do other models such as the NOGAPS & GEM models thus troughing further west with a colder more unstable flow seeming more likely on these models.

The UKMO, GEM & NOGAPS 12z data runs would produce more in the way of showers which could well be of snow. But its not worth looking at that because of the divergence we still have between the models. Heres the GEFS Mean @ 120hrs:

http://images.meteoc...-1-120_cth8.png

Looks more allong the lines with the UKMO, GEM & NOGAPS for the shot of cold air from the NW. Will be interesting later to see if the GFS 18z heads more towards its ensemble mean or not.

Edited January 15, 2012 by SnowStorm(Jamie)

[keithlucky]

But if you look at the metoffice's updated forecast for the weekhead however you will see that it seems asif they went with the GFS :/ very confusing :S

Lets see what happens when Met Office updates at midday tomorrow.

[Cwmbran Eira]

Countryfile forecast showed some potential for snow showers on Friday. In fact the temperatures shown were a few degrees down compared to the country tracks forecast this morning

[J10]

Still differences in the main models with regards to the initial thrust of cold polar air from the north west.

This can be seen on the GFS, ECM & UKMO 12z data @ 120hrs:

http://images.meteoc...-0-120_pzt9.png < GFS

http://images.meteoc...120-21_vai2.GIF < UKMO

http://images.meteoc...H1-120_uut3.GIF < ECM

The GFS & ECM are simular actually in the sence they are keeping that high just to our west with troughing further east this results in the coldest air going down the eastern side of the country with a drier outlook for Wales. However the UKMO has the high further NW as do other models such as the NOGAPS & GEM models thus troughing further west with a colder more unstable flow seeming more likely on these models.

The UKMO, GEM & NOGAPS 12z data runs would produce more in the way of showers which could well be of snow. But its not worth looking at that because of the divergence we still have between the models. Heres the GEFS Mean @ 120hrs:

http://images.meteoc...-1-120_cth8.png

Looks more allong the lines with the UKMO, GEM & NOGAPS for the shot of cold air from the NW. Will be interesting later to see if the GFS 18z heads more towards its ensemble mean or not.

After the ECM downgrading earlier today look at ECM at T+168, which then extends the cold potential

http://www.wetterzen...cs/Recm1681.gif

http://www.wetterzen...cs/Recm1682.gif

More akin to its previous runs.

2009 showed that once you get the cold in place, snow can come from a variety of directions.

---------------------------------

Jamie has shown that while the main synoptic pattern is in place, there are slight differences that would make the difference in terms of showery and wintry potential. A wide range of options are available from cool and sunny to wintry showers to snow showers either on the Friday or later. For once I'll sit on the fence.

Perhaps over the next few days, things may become clearer.

[Snowmadsam]

Well plenty of Dangler opportunity coming up soon me thinks

Please correct me I am wrong.

For newbies :- Pembrokeshire Dangler more detail

Edited January 15, 2012 by Snowmadsam

[J10]

My last post of the evening.

FAX T+120 now out

Sub 528dam air for Wales (just).

[Cymro]

Good gosh at 11pm there was no visible frost and the temp was above 0 with scattered clouds, just went out now and everything is frozen solid white over and a temperature reading of -4 which seems way to high compared to the Wales metoffice observations, a very cold one tonight.

Aboyne getting down low considering theres no snow cover at -8.5

This kind of spell can create cold and favourable conditions for real cold that follows. Great stuff.

[TonyH]

Another beautiful Winters day. Frosty last night, only down to -1.7c, with the frost still there in the shade. Brilliantly sunny, 4c and rising.

Sometimes it's better to relax and take in the weather we have now than go through the stress of the models! :wacko:

[Cymro]

Dechrau rhewi fan hyn yn barod.

Starting to freeze here already.

[TonyH]

Going to be a cold one, -1.5c here, quite convenient as we are getting a new fridge freezer tomorrow, so I put the food in the garden for tonight!

[TonyH]

ECM now trending anti cold, just more cool zonal with mild interludes. Uncannily similar to what GFS was showing end of last week (from memory).

Oh well should be some marginal snow chances from time to time.

[Snowmadsam]

ECM now trending anti cold, just more cool zonal with mild interludes. Uncannily similar to what GFS was showing end of last week (from memory).

Oh well should be some marginal snow chances from time to time.

Or it could be having a wobbly you never know!

[J10]

ECM not as cold tonight, but to be fair the outcome is nothing like that suggested by GFS last week, of course the GFS charts for last week are fully available from the archives.

The actual outcome does seem to be a toned down version of what was suggested by ECM last week, a NW dragging down into Europe.

It seems strange that we have another GFS run which is one of the mildest of the ensembles, an almost consistent trait at the moment.

[Snowmadsam]

ECM not as cold tonight, but to be fair the outcome is nothing like that suggested by GFS last week, of course the GFS charts for last week are fully available from the archives.

The actual outcome does seem to be a toned down version of what was suggested by ECM last week, a NW dragging down into Europe.

It seems strange that we have another GFS run which is one of the mildest of the ensembles, an almost consistent trait at the moment.

So no big snow events for the south west this week then?

[Cymro]

Tonyh loves his GFS

[keithlucky]

Please no mass hysteria reach for the prozac if the run is repeated in 24.I see it now Headlines mass nervous breakdown caused by ECM .

Edited January 16, 2012 by keithlucky

[benb]

Well- middle of Jan and, to my mind, there's nothing the right side of marginal, snow-wise, for anywhere in Wales (apart from the very highest peaks in Snowdonia) for the foreseeable future, by which I mean 5-7 days.

All the huff and puff in the model thread regarding the ECM/GFS battle of the models remind me what an inexact and underdeveloped science weather forecasting is, even for trends, beyond that range.

The lack of a foreseeable significant pattern change also calls into question some of the long-range forecasts based on stratospheric warming and what-not, which were forecasting the northern blocking that may have brought some wintry weather to Wales by now.

Personally, I tend to go with GFS at 5-7 days- to my mind it picked out the cold spells of Feb 2009, Dec 2009 and Nov/Dec 2010 pretty accurately from that range and I've no reason to think that it won't do again.

Let's hope the synoptics for a cold spell slot into place for us soon...

Edited January 16, 2012 by benb

[J10]

Just had another look at models after my initial snap judgement. GFS last week slowly moved towards the ECM position and by Friday, the GFS chart of that day does indeed look similar to today's ECM output for Next Friday. so I retract my earlier comment, as there are similarities between ECM of tonight and GFS of last Friday.

The irony of course, other charts are now more positive than ECM and the low pressure pushing south into Europe may well still occur. So ECM might well have been closer to the mark all along, indeed some GFS ensembles are very promising. This certainly wouldn't be the first time for a model to get the scenario right and backtrack away from it closer to the time.