South West & Central Southern England Regional Discussion - January 11th 2013>

[Bumpkin]

Morning All,

I'm going to take this as gospel and keep everything crossed that temps are a little lower than forecast for Wednesday - 26mm, mmmmm, yes please

http://www.netweathe...tion=10day;sess

beat you, I'm forecasted 27mm

Got below freezing here at 8.30am and i had to scrape ice off of the car.

[jethro]

beat you, I'm forecasted 27mm

Got below freezing here at 8.30am and i had to scrape ice off of the car.

On the plus side, after yesterday's grim weather, today is absolutely glorious.

[latitude]

beat you, I'm forecasted 27mm

Got below freezing here at 8.30am and i had to scrape ice off of the car.

Wednesday? Looks like rain according to latest output my friend.

[katemart]

The good news in Southampton is we are forecast a light dusting on both Sunday night and Monday night, whilst there will be sunshine during the day and the temps remain below freezing so it should stick around. Unfortunately we are then forecast to have torrential rain on Wednesday morning. Better than nothing but can't deny I'm a little disppointed after some of the forecasts we've seen

[Wilxy]

06z run is very bad for prolonged cold. must say im disapointed again and time for error is running out.

[gottolovethisweather]

Let's hope we get a flip back westwards because yday eve it looked like almost the whole of our region could have a really decent snowfall. Even Ian F put up graphics for Monday.

Feels like a slight trending away from that scenario this morning.

Maybe my 'wintry mix' scenario for next week is more likely, but things could still change for the better.

I think your wintry mix type forecast is all that can be expected at such a range as well.

No doubt some will be disappointed, but we do have some tasty synoptics around and that is where the focus should be for now.

Let's simply enjoy the potential and wait until <t+6 hours to write things off or on.

I personally think away from the immediate coastlines, a whole lot of places could do very well out of this, assuming this precipitation come about as planned.

[gottolovethisweather]

In Summary the weather output for our region this morning suggests that our area will be on a marginal boundary between rain and snow on occasions as we go through the next week or so as the cold spell transpires. In general places such as BANES, South Gloucestershire and Wiltshire will probably see some appreciable snowfall at times, while Dorset, Devon and Cornwall are more likely to see more transient snow events with rain or sleet at times as mild sectors brush close by, especially near the Coast. With regards to tomorrow night's event snow is looking far less likely this morning except on the highest parts of the Cotswolds and Salisbury plain as the rain looks to be more sporadic and lighter as well as being quicker to move away with an ice risk from the wet surfaces a much more likely problem for those travelling late tomorrow night under clearing skies.

Thanks for this Gibby.

In my rather untechnical view, that is pretty much how I currently view things.

In the short-term, it looks like it could disappoint for a few folk, however I simply can't take my eyes off the medium to longer range prospects at this stage.

I suggest the overused phrase of "screams of potential" is going to be heard even more often in the coming days.

[Bumpkin]

Wednesday? Looks like rain according to latest output my friend.

Don't worry I'm not expecting it anyway. Could be dry, rain, sleet or 10 ft of snow nobody knows.

[latitude]

Thanks for this Gibby.

In my rather untechnical view, that is pretty much how I currently view things.

In the short-term, it looks like it could disappoint for a few folk, however I simply can't take my eyes off the medium to longer range prospects at this stage.

I suggest the overused phrase of "screams of potential" is going to be heard even more often in the coming days.

Yes its always 'potential'. Wish those ECM charts were more +24 than 120. The GFS is so messy, a clean movement to cold on the operational would be nice.

[SilverWolf]

Looking forward to the coming week, could be good for my bit of the SW, in the Cotswolds. With regards to snow don't forget the winters of 09 and 10 snow was forecast but the predictions of where/when/how much had no real clarity until just hours before the event really - in fact some of the falls I remember only had that clarity when it started showing on the radar! So yeah an interesting week coming up. Lava java coffee for this one...

[latitude]

Looking forward to the coming week, could be good for my bit of the SW, in the Cotswolds. With regards to snow don't forget the winters of 09 and 10 snow was forecast but the predictions of where/when/how much had no real clarity until just hours before the event really - in fact some of the falls I remember only had that clarity when it started showing on the radar! So yeah an interesting week coming up. Lava java coffee for this one...

True. Difference here is we are much more uncertain of rain or snow due to upper air temperatures. The -5 line was out past Cornwall during most of the 2010 cold spell.

[gottolovethisweather]

Well further to Lats attitude towards the unfolding output, I make the following observations.

As lats suggested, Saturday has slowly trended towards something of a non-event in parts. However, most folk should get to see a few flakes, most probably with nothing accumulating to any depth. However, currently I would suggest inland parts of Devon, Somerset and Bristol & Avon are on target for some of the heaviest preciptation, as reflected in NMM output. I totally agree that radar watching and lamp-post watching will also be the way forward from here on in.

Regarding the rest of the week, Monday was always another date to watch and we will not know more until most proabbly tomorrow evening. What should assist most folk's chances will be a snowcover prior to that particular event, so fingers crossed. So as far as I am concerned, as I suggested before, my ears will be tuned in to reports of settled snow out East slowly spreading Westwards during the day. Get the snow on the ground and all the predictions of Air Temps and Dewpoints will have to be altered downwards in turn. From Monday, eyes should be fixed firmly out West on precipitation attempting to nudge Eastwards over the frozen tundra in Central and Eastern parts of the UK.

I daren't look as far out as Wednesday for now, but one thing is looking increasingly likely, most of us will still be in Battleground UK at that time. I am not dismissing or acknowledging Wednesday's chances based on a basic numerically modelled forecast chart which states a 0% or 110% chance of snow on my roof. No way.

Edited January 11, 2013 by gottolovethisweather

[SilverWolf]

True. Difference here is we are much more uncertain of rain or snow due to upper air temperatures. The -5 line was out past Cornwall during most of the 2010 cold spell.

Thanks for that, didn't look for that back then. Will do this time!

[Bristawl Si]

A couple of people have been comparing past snow events for our neck of the woods.

I'm just wondering if next week will be like the 1st week of Feb in 2009 - some of you will remember we were on the 'right side' of marginal 3 or 4 times in one week and we got a few decent snow events in the space of a week or so back then, whilst other parts of the country (in other NW regional threads) were looking on enviously!

Chins up!!

[gottolovethisweather]

Yes its always 'potential'. Wish those ECM charts were more +24 than 120. The GFS is so messy, a clean movement to cold on the operational would be nice.

Of course and without potential, what have we got.

If as and when the ground gets covered with snow in your locality or anybody elses, for that matter. These forecasted projections dished out by the various model suites, run after run, will be next to useless. They aren't modified to include what falls in the future, so everything after t+0 is purely computer generated guesswork. For now, I would concentrate on the short-term, I would even ignore Monday as even then, the snowfall/rainfall conundrum is just like FANTASY ISLAND.

The model output does indeed scream of potential and had we not had a prolonged cold spell in 2010, these charts would be MIND BLOWING.

Enjoy the rollercoaster but await the ups and downs and tight turns along the way.

Edited January 11, 2013 by gottolovethisweather

[latitude]

Well further to Lats attitude towards the unforlding output, I make the following observations.

As lats suggested, Saturday has slowly trended towards something of a non-event in parts. However, most folk should get to see a few flakes, most probably with nothing accumulating to any depth. However, currently I would suggest inland parts of Devon, Somerset and Bristol & Avon are on target for some of the heaviest preciptation, as reflected in NMM output. I totally agree that radar watching and lamp-post watching will also be the way forward from here on in.

Regarding the rest of the week, Monday was always another date to watch and we will not know more until most proabbly tomorrow evening. What should assist most folk's chances will be a snowcover prior to that particular event, so fingers crossed. So as far as I am concerned, as I suggested before, my ears will be tuned in to reports of settled snow out East slowly spreading Westwards during the day. Get the snow on the ground and all the predictions of Air Temps and Dewpoints will have to be altered downwards in turn. From Monday, eyes should be fixed firmly out West on precipitation attempting to nudge Eastwards over the frozen tundra in Central and Eastern parts of the UK.

I daren't look as far out as Wednesday for now, but one thing is looking increasingly likely, most of us will still be in Battleground UK at that time. I am not dismissing or acknowledging Wednesday's chances based on a basic numerically modelled forecast chart which states a 0% or 110% chance of snow on my roof. No way.

Nice post, ties in with my thinking. Glad you agree with me. My attitude for the latest output from the 06z GFS is an upgrade for snow on Monday with the cold air holding on longer. I wont look past Monday until tomorrows 12z.

And just to make it clear, I only post what model shows, cold, hot, wet, snow, upgrades, downgrades, flips and flops. I have no agender. Take it from me I want a foot of snow and drifts.....but try to just talk about what the models show on face value without any cold or mild emotion.

Edited January 11, 2013 by latitude

[AWD]

GFS 06z for the SW;

Good Short Term;

Bad Long Term;

However, I would advise not to worry about output beyond Wednesday yet, there is far too much model divergence to come up with a forecast of any degree of confidence.

Based on the 0z GEFS suite for Somerset, the 06z Operational looks far too progressive with the pattern. The mean is much slower in rising to nearer average temperature, albeit it is slowly rising towards the end of next week;

The mean surface temperature in the 0z GEFS never gets about 5c for Somerset;

So my opinion is the GFS 06z Operational is too progressive on the pattern, and we will see the cold air hang in longer with potential battleground scenarios before the Atlantic could breakthrough next weekend.

Enough on the long term anyway, there's enough uncertainty on the short term. The GFS has some wintriness tomorrow evening along the M4 Corridor east of Bristol and it also has a significant snow event for a good part of the West Country on Monday. This is the main focus for now, and its this timescale that the GFS 06z Operational has done a slight westward shift on.

Look out for further westward corrections in the 12z data and be very cautious on output beyond T120, whether it shows cold or mild.

[Nights King]

It is almost a guarantee it will breakdown in time for the 19th as I have never once seen it snow on my birthday in what will be 30 years this year.

[AWD]

To add to my previous post, these short ensembles from the 06z suite are for the Bristol/Bath/North Somerset area;

As with my thoughts above, Operational is too progressive and all but a mild outlier by the end of next week. The mean is slowly rising, but much more slowly suggestive of a struggling Atlantic trying to make inroads, but not doing it very fast. This is another way of saying "Battleground". Also, there is a significant cluster of members that keep us around the -5hpa line, as does the Control run, for most of next working week.

Cannot discard the Operational, it is plausible, but I favour a colder evolution with further snowfall than what it showed next week, especially the further north and east you are in the region.

Surface temperatures next week;

Now that is cold!

[gottolovethisweather]

Nice post, ties in with my thinking. Glad you agree with me. My attitude for the latest output from the 06z GFS is an upgrade for snow on Monday with the cold air holding on longer. I wont look past Monday until tomorrows 12z.

And just to make it clear, I only post what model shows, cold, hot, wet, snow, upgrades, downgrades, flips and flops. I have no agender. Take it from me I want a foot of snow and drifts.....but try to just talk about what the models show on face value without any cold or mild emotion.

Thankyou, I'm still learning and I think we all are.

I appreciate everybody's efforts in here and when there aren't too many IMBY type posts in here, this regional is as good as anywhere.

I also appreciate our passions will get the best of us from time to time and come the time the snow starts falling, let the IMBY posts flow.

Everyone is allowed to suggest when a forecast doesn't look particularly enthralling above their house, as long as they make this last point blatently clear, to avoid confusion. Remember, as always though, forecasts are simply projections of what the future climate may resemble. Thereby, from t+0 onwards, everything in the atmosphere is fluid and has already altered from the get-go.

Anyway, enough of my garbage and here's to something wintry in the near future.

[Beast of Plympton]

GFS 06z for the SW;

Good Short Term;

Bad Long Term;

However, I would advise not to worry about output beyond Wednesday yet, there is far too much model divergence to come up with a forecast of any degree of confidence.

Based on the 0z GEFS suite for Somerset, the 06z Operational looks far too progressive with the pattern. The mean is much slower in rising to nearer average temperature, albeit it is slowly rising towards the end of next week;

The mean surface temperature in the 0z GEFS never gets about 5c for Somerset;

So my opinion is the GFS 06z Operational is too progressive on the pattern, and we will see the cold air hang in longer with potential battleground scenarios before the Atlantic could breakthrough next weekend.

Enough on the long term anyway, there's enough uncertainty on the short term. The GFS has some wintriness tomorrow evening along the M4 Corridor east of Bristol and it also has a significant snow event for a good part of the West Country on Monday. This is the main focus for now, and its this timescale that the GFS 06z Operational has done a slight westward shift on.

Look out for further westward corrections in the 12z data and be very cautious on output beyond T120, whether it shows cold or mild.

Afternoon all.

Just a (rookie) question. I am new to this but as far as I understand the chance of snow and cold really depends on where the 528dam line is, where the -5 line is and where the cold air is being brought in from! Perhaps a novice way to look at it but thats all I have!!

My altitude is 369 ASL so where rain may be forecast, can we expect perhaps some snow at this level?

Many thanks for any answers in advance!

Ian

P.S The reason the above is quoted is becaase it shows the precipitation.... Thanks A.W.D!

Edited January 11, 2013 by Beast of Dartmoor

[Frosty_wsm]

To add to my previous post, these short ensembles from the 06z suite are for the Bristol/Bath/North Somerset area;

As with my thoughts above, Operational is too progressive and all but a mild outlier by the end of next week. The mean is slowly rising, but much more slowly suggestive of a struggling Atlantic trying to make inroads, but not doing it very fast. This is another way of saying "Battleground". Also, there is a significant cluster of members that keep us around the -5hpa line, as does the Control run, for most of next working week.

Cannot discard the Operational, it is plausible, but I favour a colder evolution with further snowfall than what it showed next week, especially the further north and east you are in the region.

Surface temperatures next week;

Now that is cold!

All looks very fascinating for next week going by those charts AWD, certainly will be interesting to see how it plays out but I still hate our region being so close to the rain/snow line, I'd rather there's a definite shift west with the pattern, plus that would benefit our snow friends in Devon and Cornwall too.

[Biensie]

I am confused.... the confiedence on this forum (which I have enjoyed) and the Net Weather forecast shows Gillingham where I am, to be getting snow with 90% confidence from Sunday onwards infact most of next week. However BBC Weather and Met Weather are showing nothing for Medway? Who should I go with??

[AWD]

Afternoon all.

Just a (rookie) question. I am new to this but as far as I understand the chance of snow and cold really depends on where the 528dam line is, where the -5 line is and where the cold air is being brought in from! Perhaps a novice way to look at it but thats all I have!!

My altitude is 369 ASL so where rain may be forecast, can we expect perhaps some snow at this level?

Many thanks for any answers in advance!

Ian

As a laymans basic way of looking at snowfall, then yes, you're right.

However, if the cold air is of a "dry feed" or as been engrained over the UK or there is snowcover then its quite possible, and indeed likely for snow to fall under 850hpa temperatures of -2c/-3c/-4c.

The 528 line is the level of thickness at 500mb. Again similiar to above, it can snow when thickness' are slightly higher depending on the above scenario's.

You also have to take into account the Dewpoint, especially for "settling snow". This ideally needs to be below freezing for snow to stick/settle.

Then there is the Wet Bulb Freezing level. This is the indicator of the height above sea level any PPN is likely to fall as snow.

The list goes on.

[gottolovethisweather]

Afternoon all.

Just a (rookie) question. I am new to this but as far as I understand the chance of snow and cold really depends on where the 528dam line is, where the -5 line is and where the cold air is being brought in from! Perhaps a novice way to look at it but thats all I have!!

My altitude is 369 ASL so where rain may be forecast, can we expect perhaps some snow at this level?

Many thanks for any answers in advance!

Ian

P.S The reason the above is quoted is becaase it shows the precipitation.... Thanks A.W.D!

I would say yes if the front is over your location. However as you have suggested, you have probably picked up on two-thirds of the ingredients for snowfall, but even then I think there are other ingredients to add to the snowfall conundrum.

I hope that helps.

Have a gander at the following link.

http://forum.netweather.tv/topic/27989-how-to-try-and-forecast-snow/