South West England Cold Spell Discussion

[Bristawl Si]

Cheers Ian, thanks for the update.

Well, the model discussion thread has gone into overdrive in the last couple of hours. The period T96 - T144 looks particularly interesting, possible snowy period. Any thoughts, Ian?

[SteveB]

I looks like our potential cold spell next week (because this is not a cold spell at the moment) hinges on the low next week staying south, to far north & the real cold air and potential for loads of snow will be snuffed out.

I bet it goes to far north.

Edited December 30, 2009 by SteveB

[Thundersquall]

I looks like our potential cold spell next week (because this is not a cold spell at the moment) hinges on the low next week staying south. to far north & the real cold air and potential for loads of snow will be snuffed out.

I bet it goes to far north.

I would say the Low pressure system will end up, as usual, tracking too far south and we'll get very cold, but mainly dry conditions.

[SteveB]

I would say the Low pressure system will end up, as usual, tracking too far south and we'll get very cold, but mainly dry conditions.

Most likely outcome as it currently stands. What ever way it goes I bet snow will not be on the menu. Cold & dry or cold & wet.

I mean in this so called cold spell, it is currently 3.5c & rain showers

Edited December 30, 2009 by SteveB

[Evening thunder]

Hi Ian, thanks for that

was just wondering if the MetO charts were still showing this possible snow event for the SW later this weekend, or am quite curious as to why the MetO have this as rain on their website forecasts, especially if you look at Saturday night which shows temps widely well below freezing across the south west but snows rain symbols in Devon and Cornwall.. Hmm -4C with light rain in Exeter Saturday night?

I'm not trying to be picky or criticize their forecasting or anything I just don't really understand myself why it would be rain as I cant see there not being at least some snow with this, if it does reach the south of course!

Just wondering if you knew anything about this but don't worry if you don't and I expect its a bit to far off for them to really talk about it yet

I don't think the low pressure will get too far north, probably more likely that it ends up to far south I think. I think that the low will either be far enough north to give a bit of snow to some places or maybe just as likely miss us to the south.. Even so the outlook looks good and we just need a bit of precipitation to manage to crop up on us at some point! although it would be sods law if it did go to far north!

Edited December 30, 2009 by StormMad26

[BristolBlizzard]

Most likely outcome as it currently stands. What ever way it goes I bet snow will not be on the menu. Cold & dry or cold & wet.

westcountry snow shield working again lol.

[Ian Fergusson]

Cheers Ian, thanks for the update.

Well, the model discussion thread has gone into overdrive in the last couple of hours. The period T96 - T144 looks particularly interesting, possible snowy period. Any thoughts, Ian?

No worries.

Re the latter - no special thoughts, for now. General view from our medium range forecast gurus is for snow risk to be largely N/NE/E/England + Scotland and with low SW risk, but they stress a caveat of organised snow PPN bands proving more widespread and persistent. We'll keep powder dry until further runs.

Speculation / ramping on a website is, of course, not subject to scientific peer review (neither are Ghost, Loch Ness Monster or UFO 'factual' authors) and so forgive me while I'll await the scientific consensual modelling......!

But bear in mind: The expert model analysis on some threads needs to be discriminated from the fluff, and it's very evident that those threads are blessed with some very real, talented and diligent folk who know what they are talking about.... so yes, certainly one to watch. An interesting spell awaits.

There's sufficient short-term forecast problems to not bother (from my perspective, at least) fretting about the T+84/96/144 frames and indeed beyond that, into the realms of GFSpeculativeSpuriousAndDefinitelyNotCertainScience hyperventilation zone. That's meandering into the realms of speculative blah, but clearly it's all worthy of proper, qualified discussion and learned speculation. (NB: I'm not isolating GFS for critique - just those who follow it slavishly, like some Weather Modelling Bible).

Edited December 30, 2009 by Ian Fergusson

[SteveB]

No worries.

Re the latter - no special thoughts, for now. General view from our medium range forecast gurus is for snow risk to be largely N/NE/E/England + Scotland and with low SW risk, but they stress a caveat of organised snow PPN bands proving more widespread and persistent. We'll keep powder dry until further runs.

Speculation / ramping on a website is, of course, not subject to scientific peer review (neither are Ghost, Loch Ness Monster or UFO 'factual' authors) and so forgive me while I'll await the scientific consensual modelling......!

But bear in mind: The expert model analysis on some threads needs to be discriminated from the fluff, and it's very evident that those threads are blessed with some very real, talented and diligent folk who know what they are talking about.... so yes, certainly one to watch. An interesting spell awaits.

There's sufficient short-term forecast problems to not bother (from my perspective, at least) fretting about the T+84/96/144 frames and indeed beyond that, into the realms of GFSpeculativeSpuriousAndDefinitelyNotCertainScience hyperventilation zone. That's meandering into the realms of speculative blah, but clearly it's all worthy of proper, qualified discussion and learned speculation. (NB: I'm not isolating GFS for critique - just those who follow it slavishly, like some Weather Modelling Bible).

Thanks Ian, pretty much sums up the weather for our neck of the woods over the next week or so in you first pargraph. Snow in the north & east, dry & cold every where else. Any precip that does turn up down her like to be of rain? The snow that was forecast a couple days ago for this area tomorrow has fizzled out into nothing. Much the same could be said about any chance next week I guess.

Edited December 30, 2009 by SteveB

[David-kig]

Thanks Ian, pretty much sums up the weather for our neck of the woods over the next week or so in you first pargraph. Snow in the north & east, dry & cold every where else. Anyy precip that does turn up down her like to be of rain?

lol i think ian just ment dry no rain lol

[Ian Fergusson]

Hi Ian, thanks for that

was just wondering if the MetO charts were still showing this possible snow event for the SW later this weekend, or am quite curious as to why the MetO have this as rain on their website forecasts, especially if you look at Saturday night which shows temps widely well below freezing across the south west but snows rain symbols in Devon and Cornwall.. Hmm -4C with light rain in Exeter Saturday night?

I'm not trying to be picky or criticize their forecasting or anything I just don't really understand myself why it would be rain as I cant see there not being at least some snow with this, if it does reach the south of course!

The reason why is exemplified by the attached. This is modelling the WBFL and PPN discrimination. Note how the far SW hangs onto the milder regime while the remainder of the UK starts to turn decidely frigid. Hence the likelihood of still seeing any PPN (and it will be little if any, I think) for the first half of the weekend as rain.

This MetO's NAE and Global Models directly and automatically drive/update our BBC Website weather data summary graphics/temps (we / colleagues at Weather Centre can locally tweak it and I routinely do so, based on realtime obs). It's not plucked from thin air.

Your risk of something more wintry is at the end of the weekend, not Sat night.

Best

Ian

[Evening thunder]

Thanks again Ian That last bit made me laugh and I agree there about the GFS etc!

Edit: just seen last post, thanks for that that explains it, I just wondered what the reasons were and now I know!

Edited December 30, 2009 by StormMad26

[SteveB]

I can already see the danger of not even tapping into this cold spell. If the mild air is to hang around in the south west up to Saturday night, then that gives us potentially 1 day of cold on Sunday before the low moves in on late Sunday early Monday, and if it move to far north ( which it could do) then we could well be looking at no cold spell down here.

Edited December 30, 2009 by SteveB

[Lynxus]

I can already see the danger of not even tapping into this cold spell. If the mild air is to hang around in the south west up to Saturday night, then that gives us potentially 1 day of cold on Sunday before the low moves in on late Sunday early Monday, and if it move to far north ( which it could do) then we could well be looking at no cold spell down here.

I wouldnt worry.

The cold over the next few days doesnt show is for much snow risk anyway.

Remember, the winter has really only just started with some of my coldest days being in feb / march.

Maybe this is a good sign of things to come later on.

Who knows.

[Nights King]

Thanks Ian that makes it clearer.

so i shall hold on to hope that medip hills might just spark of some extra snowy ppn friday although chances are slim.

[fromey]

Thanks Ian that makes it clearer.

so i shall hold on to hope that medip hills might just spark of some extra snowy ppn friday although chances are slim.

1 quick question, does your weather station record wind speed as i have noticed it says 0 and yet here in frome its breezy.

cheers

fromey

[Nights King]

1 quick question, does your weather station record wind speed as i have noticed it says 0 and yet here in frome its breezy.

cheers

fromey

Yes it does and i have just checked it since that question but it is all working fine it is just in a bit of a sheltered spot regarding wind although maybe it could do with a clean or new solar pack.

My rain guage however is a different story! I really need a new one as it broke in febuary with that snow and cold, looks ok but is kaput.

Hmm you have we concerned now!! looked at data and no wind speeds been recorded all day!? This is going to get expensive.

Edited December 30, 2009 by mullender83

[yipikiaye]

Why do weather people talk in termonology that the average guy can not understand unless he is interested in wether ology or what ever it is called dont stand a chance of understanding . pls is it going to snow over the next week ?

[rbw]

Why do weather people talk in termonology that the average guy can not understand unless he is interested in wether ology or what ever it is called dont stand a chance of understanding . pls is it going to snow over the next week ?

Possible chance of a spell of snow early next week - but far too early to tell. Also possible risk of some snow showers

R

[dogs32]

ITV Had snow for some this Sunday...Until Then mainly glos for wintry shower's

[Paul T]

I can already see the danger of not even tapping into this cold spell. If the mild air is to hang around in the south west up to Saturday night, then that gives us potentially 1 day of cold on Sunday before the low moves in on late Sunday early Monday, and if it move to far north ( which it could do) then we could well be looking at no cold spell down here.

Oh my.

watch the charts, this is going to be a fantastic little spell of cold weather!

I used to study weather (Earth science to be exact) until i realised accountancy paid better, but I still understand what the SW requires for a proper snow event:

The most important 3 requirements are:

-A cold spell lasting at least 48hours 'cold spell' being a period of more than 48hours where the max temp reaches +2

-Uppers within the 528 thickness (Re; MO) and/or 850hpa's of lower than -4oC.

-Moisture; and not the type that's heats up just before it arrives!

When you study/focus on your specific location, forecasting weather shouldn't be too difficult.

When it comes to snow I know Plymouth and the SW of England off to a T now, and I hate to say it but I just look at the upper temps, moisture content and the current pressure situation....thats it!

People make things very intricate on this site at times, but just research current and PAST events and understand what generates snow in the area you live….

I.e: My father (Whom used to be a weather forcaster with the MO and I'm not saying who!) said to me earlier (With regard to Plymouth/SW):

'The situation of Dec 30^TH1962 was very similar to the prediction you are talking about for sun/Monday ….a low tracking to the SW of us, encroaching onto a cold landmass temp and yielding significant snowfall (on that occasion, 14-18inchs onto Plymouth and torpoint, unreal….yet true!)

So I looked up the graphs….

DEC 30th 1962

Not too disimilar to the expected 'event':

Jan 4th 2010

...Not quite there, and almost certainly wont be, but still go back to what i focused on earlier and i think you shall agree....it will be a very interesting period of weather for the SW.

Paul

Edited December 31, 2009 by Paul T

[Paul T]

And i would also like to ackowledge Ian F - every post i have read from him has been accurate. Nice one.

Ian. although your avatar does remind me of Brick Tamland, i salute you.

[BristolBlizzard]

Below is what I filmed on me phone the sunday before last. Sorry for the crappy size and quality but the program wouldn't let me have it any different.

Anyways you still get an idea of how hard it was coming down in North Bristol

[Paul T]

Below is what I filmed on me phone the sunday before last. Sorry for the crappy size and quality but the program wouldn't let me have it any different.

Anyways you still get an idea of how hard it was coming down in North Bristol

Nice moderate snow there.

[Iceberg]

Still some support from all the models for a possible snow Sun/mon/tues

I'd probably only estimate 60% chance for precip in Cornwall (rain on coasts, snow on hills)

For a wider event maybe a 30% chance to include devon, somerset, Dorset.

But these haven't really changed in the last few runs, so still very undecided. IMO

Beyond this there are oppotunities but no real consistance to get excited about them yet.

[chapmanslade]

Why do weather people talk in termonology that the average guy can not understand unless he is interested in wether ology or what ever it is called dont stand a chance of understanding . pls is it going to snow over the next week ?

Because it is a weather forum populated on the whole by people who do understand the terminology. It comes down to the 'why don't you tell me in simple terms ?' when the answer is that it cannot be explained in simple terms. The answer to your question is maybe, depending on a lot of factors that if I were you I would have a go at finding out about - this is after all an ideal location. I'm afraid everything in life isn't simple - thank goodness !