Wales Cymru Cold Spell Discussion

[bennytes]

this is starting to look more and more like what happened 30 years back. we may just have an extraordinary event on our hands here.

now i've gone and done it. 3 days of rain guaranteed now!

[Snowyowl9]

It`s gone colder again today and windy from the west 3.3c with a couple of light rain showers.

Still got some snow lying and ice,sharper frosts returns tonight.

Last mild day was December 10th.

[J10]

Jack one what tempretures like tues wednesday?france doesent look particulary cold at the momement.

Temps around 2-4c on the coast, 0-1c inland. Heavy Precipitation always lowers temps in situations like this.

This is why Evaporational cooling, with the amount of energy requires to thaw upper level snow, lowers the temp, which then means upper level snow falls to the ground as snow.

My guess at the moment is (I have been wrong before, some say I've never right )

Heavy Snow for Mid Wales, Moderate Snow for the Valleys of South Wales, a wintry mix for coastal areas in the south, with some snow for coastal areas with altitude.

Further thoughts from Ian Fergusson

[RainyNWales]

Temps around 2-4c on the coast, 0-1c inland. Heavy Precipitation always lowers temps in situations like this.

This is why Evaporational cooling, with the amount of energy requires to thaw upper level snow, lowers the temp, which then means upper level snow falls to the ground as snow.

My guess at the moment is (I have been wrong before, some say I've never right )

Heavy Snow for Mid Wales, Moderate Snow for the Valleys of South Wales, a wintry mix for coastal areas in the south, with some snow for coastal areas with altitude.

Further thoughts from Ian Fergusson

http://forum.netweat...ost__p__1674916

Does North Wales not count in your guesses

[Marcus_surfer]

If we don't get any snow here on the coast i will definitely be taking a trip up to Pen-Y-Fan to do some snowboarding!

[J10]

Does North Wales not count in your guesses

Depends on how far north the front gets, North Wales could do very well if it does track a little further north than some of the models (excluding) GFS currently project.

So on that basis, I will say Moderate Snow for North Wales.

[keithlucky]

Do you think the set up very simular in swales as 79 jack one really to close to call this one, interesting to see if the temps fall quickley just before rain snow arrives.

[Barb]

We had a heavy wet snow shower earlier with a temporary dusting up on the mountain. A sign of things to come I hope.

the clear focus of PPN discrimination (rain v snow) effectively starts M4 northwards and through M5 corridor up into the Midlands, with Wales looking potentially very nasty indeed for blizzards (in the genuine sense, rather than media hyperbole definition)

I'd take that thank you very much.

[CLH the red dragon]

Whilst today is technically warmer than yesterday it feels a whole lot cooler in the wind. And the direction appears to have shifted. It feels genuinely cold again. Yet it's about 6 degrees.

[marclt]

The wind is bitter out there today. Felt quite mild on the beach yesterday. Very sharp showers of hail and lightning last night tho...

[Wales123098]

GFS isnt good for us at the moment in Wales.

[CLH the red dragon]

GFS isnt good for us at the moment in Wales.

It's been on the sherry, vodka AND Jack. Let's give it some solpadeine and stick with the others for now.

[Wales123098]

Temperture 2.3c here and falling after a max of 4.7c. Hopefully temperture wont rise too much tommorow. Expecting a low of -3/-4c here.

[djwayne]

GFS isnt good for us at the moment in Wales.

Having read a lot of the model output discussion thread it seems GFS is on its own at the moment asd none of the other models agree with it. Think we wont really know until it gets a little bit closer to tues

[keithlucky]

Ian furgerson latest update notice s wales upgrade, attached are the very latest modified NAE frames giving a hint of rain/snow discrimination (the Cotswolds signal in initial frame is as expected); BUT note - as I have already stressed - the Midlands / Wales focus for this initial event (more southerly snowfall risk later in the week) so I do urge caution with expecting any widespread snowfall in the Westcountry from this Tues/Wed feature. Also as per my original posting, the transition to snow on the northerly low-level bounds into the likes of Glos will be extrely hard to call until the day, frankly.

Latest NAE run wants to paint up to 20cm now for southern-central Wales and winds making it all the more problematic too. I'm still concerned that the Cotswolds and other parts of northern Glos could see very troublesome conditions. This new NAE also supports the idea of a faster progression overnight Mon/Tues for arrival of the frontal PPN into the extreme SW.

Attached thumbnail(s)

[worldairgroup]

GFS isnt good for us at the moment in Wales.

wales sorry for being so dumb, can you epxlain what you mean by this? Are the GFS models on Meteogroup the same ones you referring to?

[Wales123098]

Ian furgerson latest update notice s wales upgrade, attached are the very latest modified NAE frames giving a hint of rain/snow discrimination (the Cotswolds signal in initial frame is as expected); BUT note - as I have already stressed - the Midlands / Wales focus for this initial event (more southerly snowfall risk later in the week) so I do urge caution with expecting any widespread snowfall in the Westcountry from this Tues/Wed feature. Also as per my original posting, the transition to snow on the northerly low-level bounds into the likes of Glos will be extrely hard to call until the day, frankly.

Latest NAE run wants to paint up to 20cm now for southern-central Wales and winds making it all the more problematic too. I'm still concerned that the Cotswolds and other parts of northern Glos could see very troublesome conditions. This new NAE also supports the idea of a faster progression overnight Mon/Tues for arrival of the frontal PPN into the extreme SW.

Attached thumbnail(s)

What about for us in the lower SE Valleys?

wales sorry for being so dumb, can you epxlain what you mean by this? Are the GFS models on Meteogroup the same ones you referring to?

No the Netweather ones running out at the moment are disatrous for Wales tuesday/weds. Well south Wales.

[keithlucky]

Need i say more?20cms possible swales even turning to snow in devon tues wed.

[Wales123098]

Need i say more?20cms possible swales even turning to snow in devon tues wed.

Realy, where you getting this info from?

[keithlucky]

Ian furgursson read s west posts.

[djwayne]

I know its easy to see one run of models and think its all over but it seems the GFS is on a limb and I fully expect it to change and come a lot more in line with the other models in the next few runs.

I am quite positive that we will see something very interesting on tuesday but I think we need a bit more optimism in this thread. If it happens great if it doesnt then start looking for the next possibility

[worldairgroup]

GFS on Meteogroup is showing snow at least from 3am until 3pm Tuesday (from Tuesday)

Correct me if I am wrong why is this bad news!?

http://www.meteogroup.co.uk/uk/home/weather/latest_model_forecasts/gfs_popup/archiv/NSea/ww/2009122712/nothumb/on/45/ch/e7b6fabcfb.html

http://www.meteogroup.co.uk/uk/home/weather/latest_model_forecasts/gfs_popup/archiv/NSea/ww/2009122712/nothumb/on/48/ch/c37421ada4.html

[J10]

GFS would be the worst case scenario, and very little chance of any snow in Wales, apart from mountains in North Wales. As it brings in much milder air compared to all other models.

UKMO latest run not only has very good long prospects, but also is an upgrade in that the upper air temps are lower for South Wales, not by much but this is good news.

[Cymro]

Looks to me atm that northwards of Brecon will recieve snow and further south more wintery, Regardless what some say about altitude, this is for tuesday by the way. I hope I'm wrong however, But i can see the warnings changing tomorrow to include, Powys, Ceredigion, Gwynedd, Conwy, Dinbych and Wrecsam only with the rest of us unlikely ?

[J10]

Ian furgerson latest update notice s wales upgrade, attached are the very latest modified NAE frames giving a hint of rain/snow discrimination (the Cotswolds signal in initial frame is as expected); BUT note - as I have already stressed - the Midlands / Wales focus for this initial event (more southerly snowfall risk later in the week) so I do urge caution with expecting any widespread snowfall in the Westcountry from this Tues/Wed feature. Also as per my original posting, the transition to snow on the northerly low-level bounds into the likes of Glos will be extrely hard to call until the day, frankly.

Latest NAE run wants to paint up to 20cm now for southern-central Wales and winds making it all the more problematic too. I'm still concerned that the Cotswolds and other parts of northern Glos could see very troublesome conditions. This new NAE also supports the idea of a faster progression overnight Mon/Tues for arrival of the frontal PPN into the extreme SW.

Attached thumbnail(s)

The charts posted by Ian Fergusson from earlier runs, do indicate a rain event for coastal Wales, snow for much of the Valleys, pretty much down to the M4 in the south, and then most of inland Wales away from the west coast further north.

Lick Rain= Green, Snow =Blue

These charts are very high resolution.