South West/Central Southern England Regional Discussion 14/01/13, 12z onwards

[khodds]

If this maintains intensity I might even be in the sweet spot...

You'll be more likely than me to get some Mullender.

[Bristawl Si]

If this maintains intensity I might even be in the sweet spot...

Better not drive too far for that cider then!

[theprophecyman]

Yes this area of showers are starting to get a little wider ,but my biggest worry is what will it do when it hits s wales . if it does make it into our kneck of the woods i think we could see wintryness even down to say 120 mtrs in heavier bursts .things still looking good for thurs /friday one to watch .following 24hrs very criticall as i feel we are aprox now 72 hrs from possible action .hoping for a good fax tonight and a good update tomorrow .cheers gang ,looks like system is slowing down a little but we should know come 11pm ish ,[im refering to showers now approaching .

DOH - I need to find a 14mtr ladder

Edited January 14, 2013 by theprophecyman

[Karl83]

UKMO predicting an ice day for many Somerset northwards and eastwards on Thursday;

With the -5c 850hpa line over Cornwall and the -8c 850hpa line nudging Bristol & East Somerset;

The airflow still moving west at this time too.

A quick look to Friday. The GFS version of events has already been covered by posts over the last few pages, so a quick glance at the ECM shows a band of heavy PPN over much of the West Country by 6am Friday Morning;

And 850hpa temperatures below -5c from Devon eastwards and northwards;

Suggestive of some heavy snowfall for many parts of the South West. The ECM shows the Atlantic trying to move eastwards, this shown by the -5c 850 line retreating to Wiltshire/Hampshire by Friday evening;

But unable to break through, and the cold edging west again, shown below by the -5c 850hpa line edging back into Somerset by Saturday morning:

By 18:00 Friday evening however, the PPN would have moved SE, away from the South West;

So the movement of the -5c 850hpa line is irrelevant to snowfall conditions anyway, as the PPN will of cleared through by the time the -5c 850hpa line moves east and back west again. The fact that the PPN heads South East, also suggests the ECM is modelling a slider front, and as such, Fridays band of PPN looks a reasonable bet to stay as snow for all east and north of Devon based purely on this run, with the limited data available to us.

However, without further detailed charts showing clear thickness boundaries, WBFL, Dewpoints etc, I cannot make a realistic forecast for snow potential for Friday from either the UKMO or ECM. All I can say is that they both look like delivering something.

Anyway, I stress that any snowfall will be marginal and is currently to a high degree of uncertainty. Until the NAE and NMM come into range, the high degree of uncertainty will remain, as with it being a knife edge event, a detailed view of each aspect will be needed to sway a forecast in either direction.

Friday has the potential for significant snowfall, but it also has the potential to go Pete Tong. Just keep an eye on the trends for now, and don't bother with detail until much nearer the time. All I can say however is I would rather have the upcoming week of weather and potential weather, than this;

Remember, we are the South West of England, not Siberia!

Short term is looking very cold, although surface temperatures may still be above freezing for some, the bitterly dry easterly air will make it feel bitter out. For midday Wednesday, the NAE has -7c 850hpa temperatures across the spine of the West Country;

Along with Dewpoints of -2/-3c and it will feel bitter outside;

Both the NAE and NMM also show some wintry PPN making it down over Somerset & Dorset tonight;

Which could give some elevated areas such as the Mendips a little surprise.

So to some up my thoughts;

- Tuesday - Thursday remaining cold/very cold across most of the South West, but predominantly dry after tonight's shower activity.

- Friday I think parts of the South West will see snowfall. Where and how much at this stage I don't know. I do believe that away from Cornwall and coastal areas, all PPN on Friday will fall as snow

- The Weekend I think will bring a less cold sector of air off the Atlantic and thus raising thickness' and 850hpa temperatures, turning any PPN to sleet and rain. The timing of this and extent of this at this stage I don't know. I do not believe any snowcover will be kept through the weekend though at this stage.

That's how I see things currently guys, but as ever, changes are likely and I will update on any changes in due course. It's an exciting period of model watching and a potentially exciting period of weather coming up. Things could be far worse for us down here, as we have seen many a year during the last couple of decades. Remember, winters like 2009/2010 are the exception rather than the rule for us.

Enjoy and let's all fight for the blue corner!

Nice job AWD - As always.

[katemart]

DOH - need to get a 14mtr ladder

Loft conversion?

[dancing daisy]

Thanks AWD, your posts are always fabulous and much appreciated.

Looks like my early night has gone for a burton with this prospective snowfall.

[SupaSnowy]

Looking at them NMM and NAE, it does seem it just miss us here. Which looking at it now on the radar looks pretty spot on. Be interesting to see what reports come in as it sweeps down, snow or rain. Looking like mostly snow in Wales.

[BARRY]

Lets hope it don't turn to rain

[fergieweather]

Raw UKMO-GM Friday seems to keep the snow effectively through Cornwall-Devon-Dorset before sliding it away SE (as per EC in terms of latter). Still awaiting modified GM however, which will almost inevitably pick a more considered path based on Exeter's cross-model assessment. Will advise later.

[iowpompeylee]

Raw UKMO-GM Friday seems to keep the snow effectively through Cornwall-Devon-Dorset before sliding it away SE (as per EC in terms of latter). Still awaiting modified GM however, which will almost inevitably pick a more considered path based on Exeter's cross-model assessment. Will advise later.

maybe across to the Isle of Wight ian?

[Bristawl Si]

I knew the HP block was going to strengthen by Friday!

[isleofwightsnowgal]

Raw UKMO-GM Friday seems to keep the snow effectively through Cornwall-Devon-Dorset before sliding it away SE (as per EC in terms of latter). Still awaiting modified GM however, which will almost inevitably pick a more considered path based on Exeter's cross-model assessment. Will advise later.

Hi Ian

Could you say if this may hit the iow Friday?

Many Thanks

(desperado from snowless iow)

[dec10snow]

Raw UKMO-GM Friday seems to keep the snow effectively through Cornwall-Devon-Dorset before sliding it away SE (as per EC in terms of latter). Still awaiting modified GM however, which will almost inevitably pick a more considered path based on Exeter's cross-model assessment. Will advise later.

Is this for Friday? As ever, thanks for the input

Edit: don't worry, I've realised it is indeed for Friday!

Edited January 14, 2013 by dec10snow

[fergieweather]

Oh and PS - re this feature from Wales - Chief has just advised this moment that we're slightly increasing now the risk of localised snowfall in SW England through the next few hours – allowing for loc 2-6cm, mainly over hills, with locally slushy coverings to low levels. Keep radar-watching!

[Nights King]

Be interesting to see how this pans out because if it does maintain intensity there is alot more behind it waiting in the wings right up to the coast of north wales! It might well be that as this enter region those that miss it for a while on its western flank may find it veers more towards them as winds take a more northwards track later in the night.

I'm so excited watching this I have abandoned the pub idea to sit here with you lot and watch radar

[dec10snow]

Oh and PS - re this feature from Wales - Chief has just advised this moment that we're slightly increasing now the risk of localised snowfall in SW England through the next few hours – allowing for loc 2-6cm, mainly over hills, with locally slushy coverings to low levels. Keep radar-watching!

Very interesting, thanks! Looks like I'll miss it though (at the moment)

[SupaSnowy]

Raw UKMO-GM Friday seems to keep the snow effectively through Cornwall-Devon-Dorset before sliding it away SE (as per EC in terms of latter). Still awaiting modified GM however, which will almost inevitably pick a more considered path based on Exeter's cross-model assessment. Will advise later.

Seems like we could just miss this event to, I'm sure nothing is certain yet anyway. Still a while away. How far east it will get is still up there. But the latest few runs do suggest it will stall there and slide SE as you say.

Lots more runs to go, this is what makes me so interested in weather.

[dec10snow]

Be interesting to see how this pans out because if it does maintain intensity there is alot more behind it waiting in the wings right up to the coast of north wales! It might well be that as this enter region those that miss it for a while on its western flank may find it veers more towards them as winds take a more northwards track later in the night.

I'm so excited watching this I have abandoned the pub idea to sit here with you lot and watch radar

Maybe that back end may affect me then, hard to tell at the moment!

[AWD]

Raw UKMO-GM Friday seems to keep the snow effectively through Cornwall-Devon-Dorset before sliding it away SE (as per EC in terms of latter). Still awaiting modified GM however, which will almost inevitably pick a more considered path based on Exeter's cross-model assessment. Will advise later.

Which would therefore keep us cold into the weekend I take it?

Makes you think how stubborn this block could prove to be!

[kumquat]

Be interesting to see how this pans out because if it does maintain intensity there is alot more behind it waiting in the wings right up to the coast of north wales! It might well be that as this enter region those that miss it for a while on its western flank may find it veers more towards them as winds take a more northwards track later in the night.

I'm so excited watching this I have abandoned the pub idea to sit here with you lot and watch radar

Now THAT is dedication

[SupaSnowy]

Hi Ian

Could you say if this may hit the iow Friday?

Many Thanks

(desperado from snowless iow)

The latest runs say we could clip the end of it. But it's anyone's guess at the moment still to far away to pinpoint. All depends how far east it will get. Keep watching the charts :-) If it all stays the same as it is now (which don't happen alot with snow) it be good to watch the NAE and NMM when it creeps into the timeframe.

Edited January 14, 2013 by SupaSnowy

[Bristawl Si]

Which would therefore keep us cold into the weekend I take it?

Makes you think how stubborn this block could prove to be!

Despite the trip to Dartmouth on Friday morning i was hoping we'd be in the firing line in Bristol.

Now looks like we'll be bumping into some interesting weather in Devon - Haldon Hill could be interesting if it is snow!

[fergieweather]

Be interesting to see how this pans out because if it does maintain intensity there is alot more behind it waiting in the wings right up to the coast of north wales! It might well be that as this enter region those that miss it for a while on its western flank may find it veers more towards them as winds take a more northwards track later in the night.

I'm so excited watching this I have abandoned the pub idea to sit here with you lot and watch radar

Chief reckons perhaps 2-6cm tonight parts of Mendips, old chap. Keep eyes peeled!

[BristolBlizzard]

latest from ians twitter

an Fergusson â€@fergieweather

W COUNTRY Forecast amendment: slightly enhanced snow potential tonight, especially Somerset: locally 2-6cm uplands; some slushy at low-leve

Edited January 14, 2013 by bristol blizzard

[AWD]

Despite the trip to Dartmouth on Friday morning i was hoping we'd be in the firing line in Bristol.

Now looks like we'll be bumping into some interesting weather in Devon - Haldon Hill could be interesting if it is snow!

Yeah. I expect pictures if that is to be the case.