South West/Central Southern England Regional Discussion 20/01/13 10z------------->

[SunnySouthCoast]

Had a nice bonus dusting of snow this morning, shame it didn't last as the sun came out & melted it, but looks like we may have another couple of shots of more snow before the cold snap ends The sun raised the temperature to 2C today after a low of 0C & it is 1C still here as there is cloud cover at the moment.

[Wilxy]

Not really sure how low temps will get tonight, temp very stable at -0.8c, metoffice going for low of -3c was -4c seems to have been higher than forecast even last night it ended up higher, i guess thats due to cloudcover, either way cold and calm but cloudy, fingers crossed that cornwall gets some snow not far away now, hope to hear snow reports.

[karlos1983]

has anyone dipped into the Mod thread recently? Interested to hear GP's views on early Feb, as I am aware we are nearing the end of the current cold snap. I've not been in there for over a week now, this thread has been so addictive, and very pleasant may i add, apart from the odd rogue which is to be expected.

May have a little look myself as things are quiet on the S Western front this evening. I will advise if I find anything of interest.

[Stoxs]

has anyone dipped into the Mod thread recently? Interested to hear GP's views on early Feb, as I am aware we are nearing the end of the current cold snap. I've not been in there for over a week now, this thread has been so addictive, and very pleasant may i add, apart from the odd rogue which is to be expected.

May have a little look myself as things are quiet on the S Western front this evening. I will advise if I find anything of interest.

you will be safe tonight the south east have had snow today!!!

By all accounts 14ft has fallen in cnetral London, topping that though Bexleyheath with 14ft 1 inch !! lol

[AWD]

So who wants more snow?

No doubt some of you do so let's see what we can conjure up.

Tonight is looking like a widespread cold, below freezing night. Although skies won't be totally clear, holes in the cloud cover will be there for some. Where these are, along with snowcover, I wouldn't be surprised to see a -7/8c somewhere. Otherwise, -3c to -6c looks likely for many, perhaps a tad less near coastal areas;

Tomorrow will be another cold day for us all. Inland areas of the south could see another Ice Day. The far SW and coastal strips a degree or two above freezing;

A weak front pushes up into Cornwall tomorrow morning and starts to fall as snow as it hits the cold air;

This then runs along the channel, brushing channel coastal strips, including the IOW;

Accumulations however, look to be minimal as the snowfall should be mainly light. Perhaps a centimetre or two in some areas but nothing more than that.

Tomorrow night should be another cold one, although not as cold as tonight due to a but of a breeze picking up;

Much of the south and West Country should still go sub zero however, with perhaps Cornwall & Devon staying above freezing;

Tuesday looks both interesting and very complicated to forecast currently. I must stress there is a large degree of uncertainty on events on Tuesday currently, so stay tuned for further updates. As things stand, a small but potent band of PPN spreads up on an occlusion from the SW heading NE. This has a westerly element to the wind associated with it over Cornwall, Devon and South Somerset so this raises both Dewpoints and the WBFL;

Therefore over Devon, Cornwall and most of lowland Somerset this is expected to fall as rain. The Mendips perhaps being the exception. As it continues its journey NE however, the colder air starts to win out and the winds start to retreat to east of south;

So the WBFL and Dewpoints start to decline and the PPN turns to snow;

As you can see by the darker shades of pink, that although the occlusion is small, PPN rates are rather intense, so some heavy and quick accumulative snowfall is possible. Currently favoured for this are the southern Cotswolds, Forest of Dean and north Wiltshire. However, as I said, this can easily change on future output. Amounts are too uncertain to even speculate about at the moment.

How long this occlusion stays around for is also subject to a lot of uncertainty. The ECM for example shows the PPN to retreat quickly south, so any snowfall would only be brief for northern counties;

Where-as the UKMO sort of "grows" the PPN and this would provide some heavy snowfall and noticeable accumulations for the areas mentioned above;

Both the UKMO and ECM keep the cold air over much of the south away from coastal areas;

And as I said above, with the winds turning more east of south, the continental feed of air should help keep the PPN as snow for many inland areas of the south;

So, with the limited detail available to me, I would punt for a period of snow for anywhere in the south, away from Devon, Cornwall and southern coastal areas where there will be a less cold mix of air present. The northern extent of this PPN is much uncertain, as is its intensity. Below, the NMM shows the PPN barely making Somerset, so that's another option;

So lots of uncertainty for Tuesday and Wesnesday but definetly one to watch.

Beyond Wednesday, without going into much detail as we have enough to examine over the next 72 hours, there looks to be a transition to less cold, more Atlantic influential weather taking hold. Whilst all models agree on this scenario, they differ slightly on how it happens. The GFS would offer the possibility of a snowy breakdown;

(Although not showing snow for the SW here, these charts are for 6/7 days away, so don't take too literally in any detail).

The ECM and the UKMO take energy over the top of the block and sink it, leading to a rather uneventful breakdown;

This would introduce some milder air and rain back to all parts of the region. This is shown clearly by the GEFS suite for Somerset;

And Hampshire;

On both of these the mean (red line) rises to more average levels expected at this time of year.

Long range, who knows. There is a lot of talk in the MOD thread about disastrous output etc for cold. Now whilst taking some of the FI charts at face value such as this;

you could understand sort of what they mean. But looking at the wider picture;

you can see that the PV (the big blob of purple over the Greenland area) is moving eastward towards the UK and Scandinavia. Now, in speculation mode, if this continues to move eastwards into Northern Europe, the UK will be on the western side of the vortex, in receipt of north easterly winds from Scandinavia and subject to height rises over Greenland, favourable for further cold weather.

This is taking FI charts at face value and speculating on long range sypnotics however, both fraught with danger. A period of milder, Atlantic weather does look likely to see January out though.

Plenty to keep us interested short term anyway, with the potential for further snow for some. Lets see if we can turn potential into reality..............

Edited January 20, 2013 by AWD

[gottolovethisweather]

Had a nice bonus dusting of snow this morning, shame it didn't last as the sun came out & melted it, but looks like we may have another couple of shots of more snow before the cold snap ends The sun raised the temperature to 2C today after a low of 0C & it is 1C still here as there is cloud cover at the moment.

The Costa del Southsea snowshield burst again I hear, wowzer.

Never say never is what I say, now for Cornwall's chance.

[gottolovethisweather]

So who wants more snow?

No doubt some of you do so let's see what we can conjure up.

Tonight is looking like a widespread cold, below freezing night. Although skies won't be totally clear, holes in the cloud cover will be there for some. Where these are, along Witt snowcover, I wouldn't be surprised to see a -7/8c somewhere. Otherwise, -3c to -6c looks likely for many, perhaps a tad less near coastal areas;

Tomorrow will be another cold day for us all. Inland areas of the south could see another Ice Day. The far SW and coastal strips a degree or two above freezing;

A weak front pushes up into Cornwall tomorrow morning and starts to fall as snow as it hits the cold air;

This then runs along the channel, brushing channel coastal strips, including the IOW;

Accumulations however, look to be minimal as the snowfall should be mainly light. Perhaps a centimetre or two in some areas but nothing more than that.

Tomorrow night should be another cold one, although not as cold as tonight due to a but of a breeze picking up;

Much of the south and West Country should still go sub zero however, with perhaps Cornwall & Devon staying above freezing;

Tuesday looks both interesting and very complicated to forecast currently. I must stress there is a large degree of uncertainty on events on Tuesday currently, so stay tuned for further updates. As things stand, a small but potent band of PPN spreads up on an occlusion from the SW heading NE. This has a westerly element to the wind associated with it over Cornwall, Devon and South Somerset so this raises both Dewpoints and the WBFL;

Therefore over Devon, Cornwall and most of lowland Somerset this is expected to fall as rain. The Mendips perhaps being the exception. As it continues its journey NE however, the colder air starts to win out and the winds start to retreat to east of south;

So the WBFL and Dewpoints start to decline and the PPN turns to snow;

As you can see by the darker shades of pink, that although the occlusion is small, PPN rates are rather intense, so some heavy and quick accumulative snowfall is possible. Currently favoured for this are the southern Cotswolds, Forest of Dean and north Wiltshire. However, as I said, this can easily change on future output. Amounts are too uncertain to even speculate about at the moment.

How long this occlusion stays around for is also subject to a lot of uncertainty. The ECM for example shows the PPN to retreat quickly south, so any snowfall would only be brief for northern counties;

Where-as the UKMO sort of "grows" the PPN and this would provide some heavy snowfall and noticeable accumulations for the areas mentioned above;

Both the UKMO and ECM keep the cold air over much of the south away from coastal areas;

And as I said above, with the winds turning more east of south, the continental feed of air should help keep the PPN as snow for many inland areas of the south;

So, with the limited detail available to me, I would punt for a period of snow for anywhere in the south, away from Devon, Cornwall and southern coastal areas where there will be a less cold mix of air present. The northern extent of this PPN is much uncertain, as is its intensity. Below, the NMM shows the PPN barely making Somerset, so that's another option;

So lots of uncertainty for Tuesday and Wesnesday but definetly one to watch.

Beyond Wednesday, without going into much detail as we have enough to examine over the next 72 hours, there looks to be a transition to less cold, more Atlantic influential weather taking hold. Whilst all models agree on this scenario, they differ slightly on how it happens. The GFS would offer the possibility of a snowy breakdown;

(Although not showing snow for the SW here, these charts are for 6/7 days away, so don't take too literally in any detail).

The ECM and the UKMO take energy over the top of the block and sink it, leading to a rather uneventful breakdown;

This would introduce some milder air and rain back to all parts of the region. This is shown clearly by the GEFS suite for Somerset;

And Hampshire;

On both of these the mean (red line) rises to more average levels expected at this time of year.

Long range, who knows. There is a lot of talk in the MOD thread about disastrous output etc for cold. Now whilst taking some of the FI charts at face value such as this;

you could understand sort of what they mean. But looking at the wider picture;

you can see that the PV (the big blob of purple over the Greenland area) is moving eastward towards the UK and Scandinavia. Now, in speculation mode, if this continues to move eastwards into Northern Europe, the UK will be on the western side of the vortex, in receipt of north easterly winds from Scandinavia and subject to height rises over Greenland, favourable for further cold weather.

This is taking FI charts at face value and speculating on long range sypnotics however, both fraught with danger. A period of milder, Atlantic weather does look likely to see January out though.

Plenty to keep us interested short term anyway, with the potential for further snow for some. Lets see if we can turn potential into reality..............

You're a star AWD, Many Thanks yet again.

[lettice]

You're a star AWD, Many Thanks yet again.

Yes, second that, superb!

[Costa Del Fal]

Just been out in the back garden to empty some rubbish and for the 1st time this cold spell I have some ice. Looks as though the cold weather has finally arrived in West Cornwall. I was beginning to believe everyone up country was just making things up !!.

Its Bitterly cold out there tonight in Penryn. Think it may have gone below freezing last night bit it well and truly is now at -1 or -2c and the DP at -2c. First time in ages its below 0! With the precip just over the Scilly Isles now, will we finally get some snow?

[Ade]

-1.5 in truro with humidity dropping and low dew point - feeling like snow on way. Coldest day of this cold spell - in fact only day we have gone below freezing.

Now -1.6!

[coldfingers]

Its Bitterly cold out there tonight in Penryn. Think it may have gone below freezing last night bit it well and truly is now at -1 or -2c and the DP at -2c. First time in ages its below 0! With the precip just over the Scilly Isles now, will we finally get some snow?

If the temps stay that low as this precipitation comes in it looks good for snow for you and others in Cornwall and I really am keeping my fingers crossed for you. Mind you, I have experienced freezing rain here before now so below freezing temperatures don't on their own mean snow.

You should know soon anyway as it is steadily moving in for you. Here's hoping.

Edited January 20, 2013 by coldfingers

[Costa Del Fal]

-1.5 in truro with humidity dropping and low dew point - feeling like snow on way. Coldest day of this cold spell - in fact only day we have gone below freezing.

Now -1.6!

Excellent. Meto have upgraded symbols a bit with sleet for most of us around Midnight then some rain then possible sleet again around 9am. I have a feeling its either going to be all rain or mostly snow. My only nervousness is that the Isles of Scilly has an above 0 dewpoint right now but probably down to a much more significant influence from the sea.

[cerneman]

Its Bitterly cold out there tonight in Penryn. Think it may have gone below freezing last night bit it well and truly is now at -1 or -2c and the DP at -2c. First time in ages its below 0! With the precip just over the Scilly Isles now, will we finally get some snow?

Fingers crossed, Got family Redruth and they hoping to see some snow

[Costa Del Fal]

I love how strong the wish for snow is from others for Cornwall. This is my first Cornish winter only going back home to the Midlands in the holidays. I dont think ill ever complain about snow chances there anymore when I compare to here! I can tell tonight and this week will probably deliver the only chance of the winter!

Edited January 20, 2013 by Blizzards

[offerman]

There is a heavy band of precipiation off cornwall at present and at the moment this doesnt look like just skirting with southern most cities on south coast as forecast for monday. Any chance that this could continue on its,current path and affect the whole of the southwest tomorrow?

[dec10snow]

Yes, second that, superb!

Third that! Thanks for the time you put into your posts AWD!

[Argyle1980]

Excellent. Meto have upgraded symbols a bit with sleet for most of us around Midnight then some rain then possible sleet again around 9am. I have a feeling its either going to be all rain or mostly snow. My only nervousness is that the Isles of Scilly has an above 0 dewpoint right now but probably down to a much more significant influence from the sea.

never easy for the isles to have snow bit as for us we do have that better chance and to be honest I think we could have a good evening :-)

[dec10snow]

Still about 0C here according to wunderground, but that is plenty cold enough with no heating! :/

never easy for the isles to have snow bit as for us we do have that better chance and to be honest I think we could have a good evening :-)

It could indeed be a good evening for you:

http://www.metoffice.gov.uk/weather/uk/sw/plymouth_forecast_weather.html

Edited January 20, 2013 by dec10snow

[karlos1983]

Well, that was rather an uninspiring visit to the main mod thread discussion.....Suicide watch should be invoked immediately!!

The way I see it is, look at AWD Post above, fantastic Analysis, many snow opportunities in the days ahead, still uncertainties on the forecast beyond +24, never mind +240.

One thing I have learnt from the time I used to spend in the Mod Discussion thread, is that looking past +96 in any great detail is a waste of time, it can be very frustrating, especially if you are a new model looker, you will find yourself taking every run as gospel, especially when they say what you want to see and when people you believe to be knowledgeable are also seeing this, only for the next run to fall flat on it's face.

Big thanks to AWD, Ian Fergusson, Iceberg, Gibby etc for your input over the last few days, it has been invaluable, and to all you members, you are all legends in my eyes, this event would not have been the same if it wasn't for this forum and all that participate, if it wasn't for this place, I'd have been staring out the window on my sod until 3:55am last Friday morning.

I SALUTE YOU ALL

now onto the next!!

[Brad lough]

-1.6 in Hayle fingers toes crossed

[festivalking]

Flipping Nora its -3.5C coldest so far this winter by a country mile. Should think my altitude and that fields back on to the garden help to make it much lower than centre of plymouth (6 miles south of here). Princetown must be baltic!

[Ade]

That PPN must just be reaching Lands End now ... anyone noticed any flakes in the lamp posts?

We don't have lamp posts in cornwall.

[cerneman]

-1.6 in Hayle fingers toes crossed

Will it rain radar showing light snow Redruth Midnight,,,,,,Let us know folks

[Beast of Plympton]

Flipping Nora its -3.5C coldest so far this winter by a country mile. Should think my altitude and that fields back on to the garden help to make it much lower than centre of plymouth (6 miles south of here). Princetown must be baltic!

Yes indeed sir... currently going slightly above and below -6c.... pretty cold!!

For the people in cornwall, have you looked at the radar lately?? That front is touching lands end or just about, and looks like its gathering strength... its time.

[TheHumph]

We don't have lamp posts in cornwall.

Or snow flakes! (sorry couldn't resist). Good luck tonight and tomorrow for some snow both in Cornwall and Devon. Temps do seem to be dropping so every chance.