The South West Of England Regional Discussion Thread

[lfcdude]

really tho.. is there much hope of anything settling... the ground is a wee bit wet.... understatement there lol

[Frosty_wsm]

really tho.. is there much hope of anything settling... the ground is a wee bit wet.... understatement there lol

Personally I don't care about any settling, to see snow falling would be nice, even if I have to go drive up the mendips late tonight to se it lol, which I did the other night and managed to get up there while a shower was passing which was snow up there.

[Mark Parsons]

Back end of the precipitation is already visible on the nw & met radar, looks to me like it'll of passed by our patch by midnight or not long after! All the forecasts I've seen show rain/snow still falling around here by rush hour tomorrow!

Either there's more precipitation coming in which is out of range of the radar or this system is rattling through alot quicker than predicted.

Don't think there is to much to be bothered about the fact there is more rain further north than forecast, it's the warm front coming into the south you should be looking at and at present I don't think it has got past the south coast yet! The temp here at the mo on the south coast is actually starting to fall interestingly, 7c down from 7.3c in 15 mins!!

Also the rain will rap around and come back over the top of the low.

Edited December 15, 2011 by Bridport snow

[Aceman]

earlier this week the ground was drenched but after 20mins of heavy big flake snow it settled and dusted everything. not saying that it will settle tonight (or even snow!) but persistant snow can settle on wet ground

[Nights King]

Hardly warm rain here at the moment. 2.7c and a dew point of 2c.

Shall keep an eye on the walesregional thread to see when it starts to turn later.

[Schmac]

earlier this week the ground was drenched but after 20mins of heavy big flake snow it settled and dusted everything. not saying that it will settle tonight (or even snow!) but persistant snow can settle on wet ground

Very true... This happened in Bath (up by the racecourse) yesterday... Ground was soaked, but the snow still managed to stick/settle/pitch (take your pick!) regardless.

I also experienced this up in Huntingdon a few years ago... Heavy rain all morning... Turned to snow about midday... By 15:00 in the afternoon there was a good couple of inches on the ground!

However, I think with tomorrows set-up, even if the snow does stick (or settle or pitch...) it probably won't be around for long, which is a shame really, as the weekend is looking quite cold (well, it was the last time I checked but I've not seen the latest model runs!).

[Aceman]

ok, i get up for work at 6 so should i get up a little earlier or stay up later. Like someone else has said, seeing it snow and not settle is better than nothing at all, seeing it twice before crimbo is quite simply GERT lush :smiliz19:

[Paul T]

ok, i get up for work at 6 so should i get up a little earlier or stay up later. Like someone else has said, seeing it snow and not settle is better than nothing at all, seeing it twice before crimbo is quite simply GERT lush :smiliz19:

There will certainly be no snow before midnight, so i would go for the wake up early option....

[Severe Siberian icy blast]

Just a question really guys . . .

As the low heads west but rotates anticlockwise does that mean the ppn also moves in a anticlockwise motion??

So although it may reach its northern flank with lighter ppn over you if its heavy directly south for example as it rotates its spins the ppn over on a similar motion ??

Maybe someone with better knowledge can help many thanks ! ?

[fergieweather]

New NAE run gives key changes to any snow distribution and I've now checked the latest UK4 snow depth prog to 10z Fri.

E Mids now more threat; W Country somewhat less (now mostly Cotswolds E'wards, as per previous forecast emphasis); more for Chilterns etc. Totals are generally less too. Hopefully therefore, this won't prove an issue for rush-hour through a fair part of M5 corridor (Bristol, Glos etc.) - maybe some wet snow not easily settling, prior to 0800hrs - but more of a problem M4/M40 corridors eastwards. Tricky call re amber warning (they're all impact-based nowadays, as you will all know) but will await UKMO conference in a few mins.

Ian.

[Paul T]

To answer the ppn Q's:

I have attached the position at 9pm. it shows the big/heavy band of PPN moving along the coast.

I have also attached the 3am position, its show the channel PPN moves off into France, and then another occluded front developing on the north/west side of the low - this is the one that may produce snow, as its shrouded in the colder T850's.

Still don't see snow for much of the SW under 150m asl though..

[lfcdude]

New NAE run gives key changes to any snow distribution and I've now checked the latest UK4 snow depth prog to 10z Fri.

E Mids now more threat; W Country somewhat less (now mostly Cotswolds E'wards, as per previous forecast emphasis); more for Chilterns etc. Totals are generally less too. Hopefully therefore, this won't prove an issue for rush-hour through a fair part of M5 corridor (Bristol, Glos etc.) - maybe some wet snow not easily settling, prior to 0800hrs - but more of a problem M4/M40 corridors eastwards. Tricky call re amber warning (they're all impact-based nowadays, as you will all know) but will await UKMO conference in a few mins.

Ian.

Thanks for the update.. Nice to see you back in the regional thread

[Nights King]

Just a question really guys . . .

As the low heads west but rotates anticlockwise does that mean the ppn also moves in a anticlockwise motion??

So although it may reach its northern flank with lighter ppn over you if its heavy directly south for example as it rotates its spins the ppn over on a similar motion ??

Maybe someone with better knowledge can help many thanks ! ?

Its quite complex and others may do better but from what I gather this small low is currently building very rapidly and as it moves through channel rotating ainti clockwise it builds which will cause wind speeds to increase later as well as the ppn to expand and double back around towards wales and west as it turns.This then starts to drag colder air down with it as it moves away to the south east. What we need is the ppn to intensify more than forecast if possible as it does so which could give a few surprises later on regarding evaporative cooling.

temperature still steady at 2.7c

[AWD]

Bye Bye snow ( IMBY anyway ) Maybe another day!!

[fergieweather]

UK4 additional snow depth to 10z Fri gives fair steer....prob underplayed in E Midlands.

[Severe Siberian icy blast]

To answer the ppn Q's:

I have attached the position at 9pm. it shows the big/heavy band of PPN moving along the coast.

I have also attached the 3am position, its show the channel PPN moves off into France, and then another occluded front developing on the north/west side of the low - this is the one that may produce snow, as its shrouded in the colder T850's.

Still don't see snow for much of the SW under 150m asl though..

Thats great thanks , so we need to be looking at the ppn already looking quite stron over towards the irish sea and southeast ireland . Thankyou

[Iceberg]

Of your still around Ian I've watch the first few frames of the 18z NAE and it's still massively underplaying the amount of precip we have at 21.00 in the midlands etc.

What's your take on this ?. Have to admit it's difficult for me to have too much faith in the output if it's not getting the rainfall right 3 hrs out.

[Nights King]

Bye Bye snow ( IMBY anyway ) Maybe another day!!

Such a shame really I think its time for me to go to the pub. Thought earlier NAE charts were too good to be true.

Might still be a spanner in works last min though who knows.

[MP-R]

Talk about back and forth whether it will snow or not. I'm hoping for at least an 11th January 2008 affair where it poured with rain so much that the temperature eventually becam conducive to snow and after 2-3 hours of blizzard, between 1-2cm settled at home with less so in Bristol itself.

[snowking]

Of your still around Ian I've watch the first few frames of the 18z NAE and it's still massively underplaying the amount of precip we have at 21.00 in the midlands etc.

What's your take on this ?. Have to admit it's difficult for me to have too much faith in the output if it's not getting the rainfall right 3 hrs out.

Well done that man - completely agree with you and have been posting about this all evening over on the storm thread.

18z NAE looks a little closer to the track, but even this looks maybe 10-20 miles further south than the northern most extent of the precip observed at 2100GMT.

I had said earlier this morning that this exact thing had happened last december with the shortwave track bought further and further south until about 12 hours before, when the 18z, and subsequently the 0z NAE runs moved things a tad further north once more, and I had feared this would happen for those south of the M4 again this time.

IF, and its still an if, this does prove to be correct thats perhaps an NAE bias to be considered in the future, because I must say these past 48 hours have played out almost exactly the same as last decembers shortwave from memory

Another common one we might be seeing playing out too is the underplaying of convection by modelling again, something we've seen quite a few times in the past and is perhaps to be expected given the complex nature of the process.

Kind regards,

SK

Edited December 15, 2011 by snowking

[fergieweather]

Jst off UKMO conference. Still same broad tenor of forecast for W Country: 2-5cm Cotswolds (locally more); N Wilts, M4, etc. Some into S Glos, Bristol / Bath higher ground especially, early - say 5-7am.. M4 could be v difficult across Wilts into Berks rush-hour: wet snow; settling amounts uncertain but certainly perilous on roads for a while. Chance of further wintry PPN Cotswolds later into Fri eve as feature runs SE out of Wales. Gotta dash! Cheers Ian

Edited December 15, 2011 by fergieweather

[Mark Parsons]

Just a question really guys . . .

As the low heads west but rotates anticlockwise does that mean the ppn also moves in a anticlockwise motion??

So although it may reach its northern flank with lighter ppn over you if its heavy directly south for example as it rotates its spins the ppn over on a similar motion ??

Maybe someone with better knowledge can help many thanks ! ?

That is kind of correct but at the same time the ppn moves with the low as it tracks east.

[lfcdude]

tar ian so still all to play for in devizes i guess btw..ian im johnpockos on twitter lol

[Nights King]

Temperature has increased slightly over last half hour so now up to 3.0c

Looks like a proper nowcast event though and like many i'll still be happy to just see it falling even if it doesnt settle.

Still hope models have under played ppn a little...

[Severe Siberian icy blast]

Well i can confirm that its sleet at mine , theres wet flakes in the mix very wet but deffinately there, all up from hear now i feel !