South West/Central Southern England Regional Discussion 03/02/13 12z ------->

[A.J]

Ok folks, carry on here

old thread here ------------->

[gottolovethisweather]

Having had another look at Tuesday, I'm seeing more of a downgrade now. However, this post is more based from a IMBY point of view and I wasn't exactly in the firing line for anything anyway. The MetO current update doesn't offer much developing until later in the day, so maybe that is the timescale to concentrate on.

Firstly the Fax Chart at 00 UTC Tuesday 5th February

Okay, this won't necessarily pick up any showery activity at such a timeframe but there also isn't much currently showing anyway. The good thing is that should something develop during Monday evening, the 528DAM line is well South, so things will largely be conducive for snowfall.

Moving onto the 12 UTC Tuesday 5th February

Now this second chart is more promising. Should the Occluded Front depicted as lying across Central Ireland at midday, trundle Southwards and arrive in our region during the overnight period, then yes, a much better scenario would develop. So without further a do, let's have a look at the current thinking from the MetO for the 00 UTC Wednesday 6th February Fax Chart.

If taken on face value, that Front moves through too quickly and we need the reload of COLDER UPPERS from the North to over-run it. Perhaps it is for this reason that the MetO will not commit to anything other than wintriness at this stage.

Having said all of the above, to my eyes, two timeframes are vital as these will largely have to coincide with the coldest snow-making air profiles as mentioned by Jackone, Coast and AWD etc. The Fax charts will clearly NOT TELL THE WHOLE STORY.

For the best opportunity of SNOWFALL production, I would be on radar watch for trough activity from areas such as Ireland on the Monday for the timeframe 2100GMT to 0300GMT. Currently, for the second event, the timeframe to radar watch has to be similar to that of the day before, if not into the early hours of Wednesday 6th February.

A whole lot to keep tabs on over the coming few days and last minute DOWNGRADES and UPGRADES are highly probably IMHO.

Edited February 3, 2013 by gottolovethisweather

[snowmadchrisuk]

Having had another look at Tuesday, I'm seeing more of a downgrade now. However, this post is more based from a IMBY point of view and I wasn't exactly in the firing line for anything anyway. The MetO current update doesn't offer much developing until later in the day, so maybe that is the timescale to concentrate on.

Firstly the Fax Chart at 00 UTC Tuesday 5th February

Okay, this won't necessarily pick up any showery activity at such a timeframe but there also isn't much currently showing anyway. The good thing is that should something develop during Monday evening, the 528DAM line is well South, so things will largely be conducive for snowfall.

Moving onto the 12 UTC Tuesday 5th February

Now this second chart is more promising. Should the Occlude Front depicted as lying across Central Ireland at midday, trundle Southwards and arrive in our region during the overnight period, then yes, a much better scenario would develop. So without further a do, let's have a look at the current thinking from the MetO for the 00 UTC Wednesday 6th February Fax Chart.

If taken on face value, that Front moves through too quickly and we need the reload of COLDER UPPERS from the North to over-run it. Perhaps it is for this reason that the MetO will not commit to anything other than wintriness at this stage.

Having said all of the above, to my eyes, two timeframes are vital as these particular timeframes will have to coincide with the coldest snow-making air profiles as mentioned by Jackone, Coast and AWD etc. The Fax charts will clearly NOT TELL THE WHOLE STORY.

For the best opportunity of SNOWFALL production, I would be on radar watch for trough activity from areas such as Ireland on the Monday for the timeframe 2100GMT to 0300GMT. Currently, for the second event, the timeframe to radar watch has to be similar to that of the day before, if not into the early hours of Wednesday 6th February.

A whole lot to keep tabs on over the coming few days and last minute DOWNGRADES and UPGRADES are highly probably IMHO.

Ian has just confirmed on Twitter than Snow Showers are expected Tuesday , So we will see, I hope the Showers that develop travel further East , on the Models at the Moment any heavy precipitation is over North Devon .

Ian Fergusson â€@fergieweather

@purecharmer @MattHugo81 correct re Tues. Snow showers expected.

[gottolovethisweather]

Best copy some posts to which I was referring to above, just in case you missed them from the other thread. This wonderful analysis from Jackone

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i have done an analysis of the situation for Wales and have now changed the detail for SW England.

and while some of the detail for SW England is not quite the same, it gives at least a decent estimate, and it is a good summary of the last NAE.

The first NAE chart covering Tuesday morning is now out.

At this stage, there is a WNW flow, with an unusually cold wedge of air associated with it.

Thickness Levels [850/1000HPa], around 1290m-1300m for most.

http://www.weatheron...=1&PERIOD=&WMO=

Thickness Levels [500/1000HPa], around 518-524HPa ( S Wales)

http://www.weatheron...=1&PERIOD=&WMO=

Dewpoints ranging from around 0c South Coast to -2c North Coast.

http://www.weatheron...=0&WMO=&PERIOD=

850Hpa, Temps -6c to -7c generally

http://expert-images...0506_2_0306.gif

Rain/Snowfall chart, certainly the chance of some snow.

http://expert-images...0506_2_0306.gif

Precipitation amounts are always variable in such situations.

http://expert-images...0506_2_0306.gif

2m Temps ranging from 3c to 6c.

http://expert-images...0506_2_0306.gif

In this situation at least early on Tuesday we are in a very cold wedge of air, and this makes snowfall/wintriness more likely than would normally be in the case in a WNW airflow and with air temps above freezing.

Late on Tuesday, a wedge of less cold air will push in from the north, before a NNW flow sets in early on Wednesday, with cold uppers and thicknesses, however these are not likely to be as cold as suggested for early Tuesday.

It will be interesting to see if there are warnings issued from the Met Office as always that will give an indication as their thoughts with access to more detailed models than we have.

Monday:

Mostly dry with most places seeing some sunshine. Chance of a few showers in the far west at times. Becoming increasingly windy, [/size]

[size=3]especially around western coasts and across the moors. Maximum Temperature 9 °C.[/size]

[size=3]Outlook for Tuesday to Thursday

Strong winds and widespread wintry showers continuing on Tuesday and Wednesday, although Thursday may be a quieter, brighter day. [/size]

[size=3]Feeling bitterly cold, especially as winds turn northwesterly then northerly.[/size]

While the snowfall potential does not appear as great for SW England, certainly the chance wintry/snow showers quite widespread.

Edited February 3, 2013 by gottolovethisweather

[snowmadchrisuk]

Good Job we don't follow 5 day forecasts From www.metoffice.gov.uk .

[gottolovethisweather]

And also some of the NAE outputs are starting to show the latest chances, this courtesy of Coast

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http://forum.netweather.tv/topic/75744-south-west-central-southern-england-regional-discussion-26th-january-2013/page__st__680#entry2582440

And this from AWD

http://forum.netweather.tv/topic/75744-south-west-central-southern-england-regional-discussion-26th-january-2013/page__st__680#entry2582527

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I'll be watching the following 48 to 72 hours with much interest.

[snowmadchrisuk]

Well tomorrow will be a good day to keep a check in here , We can follow what happens in real time, the First rash of showers will come in tonight across the NW and the Wind situation looks quite serious across some areas ... It will feel Bitterly Cold on Tuesday in our area , and Heavy PPN will be Blizzard like across our area ,,

[gottolovethisweather]

Good Job we don't follow 5 day forecasts From www.metoffice.gov.uk .

Indeed, hence my downgrade but then whose to say an upgrade won't come with something developing in the flow. More positively IanF appears upbeat too.

[Nights King]

I wonder if we get a bristol channel streamer setup possible with such a westerly/north westerly wind? I find shower setups so much fun to see as your constantly checking radar and running outside to confirm if it is or not.

The more it veers north the less chance we have as wales sucks ppn dry with its hills.

[snowmadchrisuk]

Indeed, hence my downgrade but then whose to say an upgrade won't come with something developing in the flow. More positively IanF appears upbeat too.

Yeah , The only thing I really don't get is why overnight temps are so high Tuesday / Wednesday ... All I can think it is becuase of Cloud cover , also GFS has it's due point's slightly higher then the NAE . Maybe this will come down to now casting ... I am wondering though if it is possible that a Bristol channel streamer will setup .. If it does location will be everything ..

I wonder if we get a bristol channel streamer setup possible with such a westerly/north westerly wind? I find shower setups so much fun to see as your constantly checking radar and running outside to confirm if it is or not.

The more it veers north the less chance we have as wales sucks ppn dry with its hills.

lol great minds thing alike.

[snowmadchrisuk]

6-15 day forecast is taking forever to be released ... the 16-30 was released ages ago .... A rewrite maybe ???

Spoke to soon ... Just out ... Atlantic breaking through , a total rewrite to yesterday .. Hope there wrong ..

Remaining cold on Friday but less windy than the previous few days. Still some wintry showers near the east coast, and some western parts perhaps cloudier with a little rain or hill snow. Brighter elsewhere after a frosty start. A similar set-up continues through Saturday and Sunday. During the following week some bands of cloud and rain will spread slowly eastwards across the UK, with some snow on hills, and possibly also temporarily to lower levels in the east. Turning less cold in the west. Later next week onwards into the following weekend some bright spells are expected, but also some unsettled weather at times, most likely to the north and west where any showers may turn wintry at times. Temperatures then close to or just below average.

Edited February 3, 2013 by snowmadchrisuk

[snowmadchrisuk]

Heavy, squally showers will spread to many parts of Northern Ireland and the western half of northern England during Monday, turning wintry on high ground through the middle of the day and then increasingly to lower levels during Monday evening. Showers will probably remain largely as sleet and hail along some northern and western coasts, but are likely to turn to snow inland, more certainly on ground above 100 or 200 metres elevation. 10 cm or more of snow may affect higher level routes later in the day, with drifting and temporary blizzard conditions. At lower levels, amounts of snowfall will be generally smaller and quite variable but some areas could see in excess of 5 cm of snowfall, with some drifting. Winds will gust to around 50 mph near the heavier showers but higher over hills.

[Mapantz]

9.1°C and overcast today. A day of chilling is needed after last night's antics.

[Nights King]

Heavy, squally showers will spread to many parts of Northern Ireland and the western half of northern England during Monday, turning wintry on high ground through the middle of the day and then increasingly to lower levels during Monday evening. Showers will probably remain largely as sleet and hail along some northern and western coasts, but are likely to turn to snow inland, more certainly on ground above 100 or 200 metres elevation. 10 cm or more of snow may affect higher level routes later in the day, with drifting and temporary blizzard conditions. At lower levels, amounts of snowfall will be generally smaller and quite variable but some areas could see in excess of 5 cm of snowfall, with some drifting. Winds will gust to around 50 mph near the heavier showers but higher over hills.

I am at work but is this for the west country??

[snowmadchrisuk]

I am at work but is this for the west country??

No , thats the warning for Monday in the W/NW , I just posted it as it might be a sign of what's to come for us on Tuesday , as the air will be even Colder by the time it get's to us . I expect they will issue a warning for us tomorrow ...

[gottolovethisweather]

A fair few folk in here, namely AWD for one, will like this particular analysis, courtesy of TWS from the MOD thread.

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Max temps of 5-7C for the south seem plausible to me for the coming week- we'll be in a fairly cold Arctic air mass, but it won't be anything special, with 850hPa temperatures around -5 to -8C. For Scotland and northern England maxima of 3-5C will be more typical.

We are still looking at a mix of sunshine and squally wintry showers late on Monday and into Tuesday, when there could be some pretty dramatic convection about, particularly over south-western Britain, with widespread hail and scattered thunderstorms. A pool of milder air from a depression core will sweep south-eastwards late on Tuesday and into Wednesday and will turn showers back to rain and sleet, with the possibility of an area of more general, frontal-type rain tied in with it, particularly for eastern areas. Indeed, Wednesday could well end up grey, raw and wet for a time over East Anglia and the SE. Showers are likely to turn back to snow from Wednesday afternoon onwards and it is looking likely that we'll have snow showers running down the eastern side of England until Friday. We are probably looking at overnight accumulations of snow and thaws in the daytime sunshine for the majority of North Sea areas, except in areas which catch a number of heavy snow showers.

For the longer-term, we get a battle between cold continental and milder Atlantic air. The ECMWF continues to persist in showing a slack east to north-easterly flow starting next weekend, which would bring a mix of sunshine and snow showers, the majority of the showers in the east, but GFS continues to bring in Atlantic weather systems, though temperatures never really get higher than average.

My feeling is that the Scandinavian high is unlikely to go away very quickly and that we will probably end up with an easterly spell in the third week. However, there is a high likelihood of the colder air at 600-900hPa air being mixed out from the SE, resulting in stratocumulus trapped underneath a layer of dry stable air and thus predominantly dry cloudy weather, rather than frequent snow showers for eastern and central areas. I think the ECMWF would bring this scenario if it ran out beyond T+240 but we'd have a few days of sunshine and snow showers beforehand, rather than belts of frontal rain and temps of 3-6C as suggested by GFS.

Edited February 3, 2013 by gottolovethisweather

[snowmadchrisuk]

latest NAE ,,

[caz100]

so where does that leave us far west Truro area...will we see anything ?

[gottolovethisweather]

so where does that leave us far west Truro area...will we see anything ?

Far too early to tell even at this range. Have a gander at my post from earlier to which I have copied below.

http://forum.netweat...z/#entry2582642

A lot to play for in the coming week and my analysis from previously still stands as far as I am concerned.

http://forum.netweat...20#entry2581174

It will largely be a case of radar and lamp-post watching this week I reckon.

For now, one of the better analyses comes from TWS in my post above. I will also be awaiting what AWD thoughts are of late too.

Edited February 3, 2013 by gottolovethisweather

[snowmadchrisuk]

so where does that leave us far west Truro area...will we see anything ?

Will have to wait and see , the GFS now has a pronounced warm sector during Tuesday , this changes everything back to rain as the precipitation get's heavier , Charts are currently saying Snow to Rain to Snow , but we will have to see how much precipitation there is left as the Cold air digs back in .

[caz100]

have to wait for the cold to come and then see... thanks

[Nights King]

Well my met office forecast now shows heavy snow from 3am until 12pm before turning to sleet after 3pm.

I'll bank that now

Edited February 3, 2013 by mullender83

[Dorsetbred]

latest NAE ,,

Somebody gone mad with the pink/magenta paintpot by the look of that!

Still not on board with this yet...

Confirmed with the following.....

http://forum.netweat...60#entry2582864

Edited February 3, 2013 by Dorsetbred

[Nights King]

Somebody gone mad with the pink/magenta paintpot by the look of that!

Still not on board with this yet...

Confirmed with the following.....

http://forum.netweat...60#entry2582864

Forecast was fairly vague as the detail is still just that but we could do alright from this.

Little concerned this week could end up being wishbone uk with most missing out although time will tell.

[AWD]

Forecast was fairly vague as the detail is still just that but we could do alright from this.

Little concerned this week could end up being wishbone uk with most missing out although time will tell.

Got to admit, I'm surprised at your Met Office App forecast you've posted above for Tuesday. But hey, who knows, still 48 hours out yet!