Wales - Regional Weather Discussion

[TonyH]

A good frost last night down to -4.4c, the second coldest night of the season.

Rather cold today but bright, max just 4.3c.

Sennybridge is misty and could manage an 'ice day' as it was only on -1.6c at 1300.

My preliminary thoughts on next week tend to favour the milder GFS, unless we see significant changes in the models this weekend, I am delaying my weather guide to tomorrow!

Edited January 14, 2012 by TonyH

[Cymro]

A good frost last night down to -4.4c, the second coldest night of the season.

Rather cold today but bright, max just 4.3c.

Sennybridge is misty and could manage an 'ice day' as it was only on -1.6c at 1300.

My preliminary thoughts on next week tend to favour the milder GFS, unless we see significant changes in the models this weekend, I am delaying my weather guide to tomorrow!

Based on what?

Considering most models tend to show agreement signs with the ECM?

Yes had a hard frost here to got down to -4 and didn't lift untill about 12pm lovely day atm just a max of 2 degrees today and it's now 1.6 so had we have had some mist year who knows, wouldnt be surprised at all. We are all preoccupied with next week we're forgetting how nice it is to have cold now.

[J10]

The GFS is completely on its own re the latter part of next week, if it is right, then it will deserve all of the merits going.

If I had to guess, I would guess some sort of hybrid between ECM, UKMO and GEM, with some ridging up to Greenland and a cool/cold Polar Maritime NW flow.

http://forum.netweat...ost__p__2212408 has the charts for today for future reference.

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

Heavy frost here, temp was 1c at 10pm last night, not sure of minimum, finally starting to brighten up after early cloud.

[Cymro]

One thing I think we have a great thread here, we talk about the models and have a good discussion, it's like a mini Welsh model threat as of late, great stuff and we all learn off each other, had you see some of the other threads where they constantly bicker and rarely go into depths regarding patterns and what not, we ought to all take a step back and pat ourselves on the back methinks

When was the last time a moderator had to put someone in their place here ?

Da iawn pawb

[TonyH]

Based on what?

Considering most models tend to show agreement signs with the ECM?

Based on the sheer consistency of the GFS that cannot be discounted, and to my eyes that UKMO lies somewhere between GFS and ECM at 144 hours, and not more akin to ECM as some are suggesting, I feel that it's more timing discrepancies out in what is still FI at the end of next week.

GFS may well trend colder from next weekend, but a cold spell is still not assured even for the following week.

However I am deferring until tomorrow as even the end of next week is not yet set in stone!

Edited January 14, 2012 by TonyH

[Cymro]

Based on the sheer consistency of the GFS that cannot be discounted, and to my eyes that UKMO lies somewhere between GFS and ECM at 144 hours, and not more akin to ECM as some are suggesting, I feel that it's more timing discrepancies out in what is still FI at the end of next week.

GFS may well trend colder from next weekend, but a cold spell is still not assured even for the following week.

That's fair enough, I don't think it's going to turn out exactly as the ECM is suggesting either, but I tend more towards that based on the sheer agreement and even consistency, in a way you could argue that the GFS is trying to come on board, it's a much colder run today thatn it was yesterday, it's deepend the cold of the NWstly outbreak. It all depends on next weekend and where that leads us. I also feel that the GFS is way overdoing the temperatures for mid week, yes it will get milder but I feel it's way overcooking temps.

GFS always tends to bring in westerly quicker than most models I feel, it's more conducive to picking a westerly rather than an eastelry pattern, and as such never fares well amid easterly outbreaks, just look at December 2010. However ECM also tends to overdo the cold.

As for UKMO i wouldnt say so, I'de say it's been gradually edging more towards the ECM in the last few runs, time will tell, time will tell.

[TonyH]

Cloud and breeze this afternoon has risen the temperature further towards 5c now, also Sennybridge is above zero.

Edited January 14, 2012 by TonyH

[soupsurfer7]

Superb day here and went for a walk this morning in the frost with dazzling winter sunshine. Wish we could have a few more days of this to cure the January blues

[J10]

So based on this evening's charts

GFS 12Hz Op run keeping a more westerly flow and generally mild. (although even this is going for a cold shot at T+192.)

GFS 12Hz is also very much on the mild side on the ensembles around the 21st. Although you could say that GFS is being consistent with this.

UKMO 12HZ a great run IMO and very much trending if not moreso towards ECM.

GEM similar to previous runs (quite promising).

Onto the smaller models, NOGAPS remaining very similar, and very promising.

Will do a full update later and give my latest thoughts after ECM comes in.

[keithlucky]

UKMO has joined ECM quite a wintry outlook nearly in the reliable time same charts tomorrow GFS comes on board bingo.(even if its a couple of days event).

Edited January 14, 2012 by keithlucky

[Cymro]

This has been going on for a few days now with most models jumping on board with that of the ECM yet there are still some people who'd rather stick to the GFS not based on current performance but past tendencies and personal modelism (like patriotism but over the models instead) People tend to get very protective over a model in which they personally favour hence such heated personalities in the model thread, I tend to keep a level head and don't get on the back of either.

Would I be right in suggesting or saying that Tonyh and Andy are both fond of the GFS model? based on past comments etc? There's nothing wrong with this however but perhaps it's masking over what is currently about to happen to an extent for such members?

LIKEWISE Simon from weatherweb.net tends to overly favour the GFS. Only time will tell of course, but met-office updates today seem to be veering towards ECM also and now with the UKMO 12z on board their update tomorrow will look far more wintry IMO.

[J10]

So based on this evening's charts

GFS 12Hz Op run keeping a more westerly flow and generally mild. (although even this is going for a cold shot at T+192.)

GFS 12Hz is also very much on the mild side on the ensembles around the 21st. Although you could say that GFS is being consistent with this.

UKMO 12HZ a great run IMO and very much trending if not moreso towards ECM.

GEM similar to previous runs (quite promising).

Onto the smaller models, NOGAPS remaining very similar, and very promising.

Will do a full update later and give my latest thoughts after ECM comes in.

ECM looks good at T+144 to about T+192, thereafter while the cold is there, the synoptic patterns get very messy indeed and the models are struggling at this stage to deal with parts of the Polar Vortex breaking up.

It seems likely now that we will get some sort of Polar Maritime outbreak from the North West from around late next Thursday. Possibly it might be a toppler (or not) in that the high pressure ridge gets pushed aside from the west. Detail is very hard to pin down at this stage, and how long the "cold" air lasts is another matter and perhaps not as longlasting as hoped for.

[keithlucky]

Yes very interesting weather coming up should see some snow even if its only transient .

[SnowStorm(Jamie)]

Another frosty night tonight across Wales perphaps slightly less so in the South West as some cloud moves in from the South keeping temperatures slightly up - shown on NAE charts below:

http://expert-images...011506_1406.gif < Temps

http://expert-images...011506_1406.gif < Total Cloud Cover

The longer range....

GFS, ECM & UKMO 12data @ 144hrs:

http://images.meteoc...-0-144_csq7.png < GFS

http://images.meteoc...144-21_cmf4.GIF < UKMO

http://images.meteoc...H1-144_qhu0.GIF < ECM

As you can see when in comparison against these 2 other models the GFS is very much the model wanting to keep a flatter pattern with high pressure over the UK, while we have the UKMO offering more or less the same situation as the ECM a colder N/NW flow. We then see the ECM position a ridge of high pressure over the west of the UK @168hrs:

http://images.meteoc...H1-168_hjg5.GIF

Notice the troughing (low pressure) in europe as opposed to being further West with a full on easterly. Still cold under that chart with some of the colder air from the NE gradually working its way towards the UK especially eastern parts.

So is this where the middle ground will set up, an initial shot from the N/NW heralding snow showers for prone locations in Wales then high pressure becoming close to/or over the west of the UK keeping fairly settled, dry & frosty conditions under clear skies.

Great time to be watching the models & trying to figure out which solution is the most likely.

Edited January 14, 2012 by SnowStorm(Jamie)

[TonyH]

No model bias from me no. In fact ecm is better than gfs overall. Fact is even ecm is not showing the prolonged cold and possibly snowy spell that some of the big names have been touting lately.

Edited January 14, 2012 by TonyH

[J10]

Another frosty night tonight across Wales perphaps slightly less so in the South West as some cloud moves in from the South keeping temperatures slightly up - shown on NAE charts below:

http://expert-images...011506_1406.gif < Temps

http://expert-images...011506_1406.gif < Total Cloud Cover

The longer range....

GFS, ECM & UKMO 12data @ 144hrs:

http://images.meteoc...-0-144_csq7.png < GFS

http://images.meteoc...144-21_cmf4.GIF < UKMO

http://images.meteoc...H1-144_qhu0.GIF < ECM

As you can see when in comparison against these 2 other models the GFS is very much the model wanting to keep a flatter pattern with high pressure over the UK, while we have the UKMO offering more or less the same situation as the ECM a colder N/NW flow. We then see the ECM position a ridge of high pressure over the west of the UK @168hrs:

http://images.meteoc...H1-168_hjg5.GIF

Notice the troughing (low pressure) in europe as opposed to being further West with a full on easterly. Still cold under that chart with some of the colder air from the NE gradually working its way towards the UK especially eastern parts.

So is this where the middle ground will set up, an initial shot from the N/NW heralding snow showers for prone locations in Wales then high pressure becoming close to/or over the west of the UK keeping fairly settled, dry & frosty conditions under clear skies.

Great time to be watching the models & trying to figure out which solution is the most likely.

As you say, GFS is on its own (although doesn't mean it's wrong)

Good agreement for the initial NW at T+144, between UKMO, ECM, NOGAPS, JMA and to an extent GEM. Some sort of mix between these are likely, with cold for a few days and wintry potential. Beyond this who knows.

I have seen enough charts today now.

[Cymro]

Mae'r tymheredd yn cael ei dala fan hyn gyda'r cymylau uchod, damo oni'n edrych ymlaen i gael noson arall o rew.

The temperature is holding up above freezing here with over head scattered cloud cover, and there was me hoping for another night of frost

[welshwizard]

no frost here this morn either but its cold outside in my shorts ha ha,a lot better weather than we been having for sure dry and cold.and no rain and wind yippy.

just went into the mad model thread for a laugh,i had a good read and some say gfs has come in line with ecm and others saying compleat opposite how? and this cold weather is 120 hrs away then its 240. by the way its going,we be having the bitter cold in june lol. im happy with dry and cold right now anything better than rain every day.

[J10]

Finally some agreement in the models, the GFS has moved to the consensus of a cool NW flow for next Friday more in line with the other models.

However the ridging that was present on other models to Greenland has been dissipated over time, which in turn reduces the cold potential, however the UKMO today still looks pretty good at T+144. So ECM has moved away from its cold spell output.

So a good call to those who said that GFS and ECM might blend together.

Wintry potential remains towards next weekend, despite the main agreement of the models, exact detail does vary and this will impact on the wintry potential particular as we go into the weekend when different options remain open. then but the snow potential has been reduced somewhat/considerably,

[TonyH]

Weather guide Monday 16th to Sunday 22nd January (west Wales and central Midlands centric!)

Headline: Dry and bright start, then unsettled with variable temperatures

In spite of high pressure last week, nuisance weak troughs plagued west Wales, so that our dry interlude was delayed and spells of drizzle up to Thursday put another 8mm in the Llanwnnen rain gauge. However, this amount is far below a typical weekly deposit for January. The Midlands did though manage a mainly dry week, with less than half a millimetre falling on Coventry in the past 7 days. Dry weather proper has now arrived in Ceredigion for the first time since mid November.

The models have been very interesting to follow over the past week, with the GFS continuing to keep the worst of Winter at bay, while ECM has been consistently threatening a cold northerly blast come the end of the coming week. However, I am inclined to go with the equally consistent but more moderate, milder outlook that the GFS has been delivering, plus that ECM seems just this morning to have moved well away from the very cold, potentially snowy prognosis of a few days ago. Therefore, I foresee no real change to significant cold later this week.

High pressure is still close to England during Monday and Tuesday, so that the pleasant dry, bright spell continues for a few more days. Further frosts by night, down to as low as -3c. A chilly south east breeze on Monday, maxima 4-6c, but less cold on Tuesday.

A deep low pressure then passes close to Iceland bringing with it cloud, wind and rain at times for Wednesday and Thursday. Also it turns mild, maxima on Wednesday above 10c once more. The cold front clears through some time on Thursday, so cooling off, with perhaps some late sunshine and showers . After an early ground frost, Friday sees a chilly blustery north west wind, with sunny spells and some showers, these perhaps wintry over high ground.

A mixed weekend then follows with mild and colder interludes, with a west to north west flow prevailing, and there will be some rain at times but also with drier spells between.

Edited January 15, 2012 by TonyH

[J10]

ECM looking promising tonight, and starting to show a little consistency.

However as good as the charts are they are at T+192, if this can get down to T+96, then we can get excited.

Which it didn't manage to do, and there lies a lesson.

[keithlucky]

Very good country file forecast for Wales front pushes through Thursday night colder air pushes south SNOW SHOWERS moves down from the N West possible covering of snow further snow showers Saturday with possible streamers forming .

[DeepSnow]

Not the best first half of winter here, December managed a low of -1.2C with one frost, Jan so far has managed a low of 0.7C with 1 frost, no snow in either months as of yet. I hope the second half of winter manages to do a lot better, though currently I don't have high hopes. Next weekend is looking like it could be interesting however, though being a week away a lot can still change.

[keithlucky]

Well at last model agreement some snow possible Thursday night Friday Saturday .we could even get A JACKONE streamer,

[Marcus_surfer]

It would be nice to see a quick NW blast with a few snow showers and a streamer, is this too much to ask for?