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

[cornish snow]

Yeah, not perfect but better than a long fetch of a south westerly. Who knows, will always be very marginal for us but im helped if the MO can predict snow for lands end.

Looks like we might have to drive to helston . meto gives them heavy snow nearly all day

[dancing daisy]

Blimey, I go away to do some work and miss a right old bun fight. Story of my life!

I have also been looking at holidays, Tunisia looks lush and reasonably priced, but still a bit chilly in February.

Anyway back to the weather. Is it time to invest in the radar?

[Bristawl Si]

Not of specific interest to our patch but I have noticed how the front to the East has now formed its own Low centre which has turned winds NE around the Humber area pulling the remains of the snowfall back SW over Eastern England. There are already some potent snow showers further out in the North Sea moving SW towards the NE coast later tonight.

That ties in with latest bbc news24 forecast i saw 30 mins ago as well.

[khodds]

WELLS? Who said Wells?! Are we thinking snow or that horrible stuff called rain Iceberg?

[katemart]

This is the latest nae precip map for 9pm if you have radar you can see that even though nae picked up on the signal for the showers, it has massively underplayed them.

Current stream is over 100 miles long and over 30-40 miles wide in places so is more akind to a trough tbh.

Net weather radar shows it as a mix of sleet and snow, travelling due se, might be a more southern component but not until midnight IMHO.

It looks, to my untrained eye, to be pivoting slightly towards central Southern England (but that might be wishful thinking?)

If the temps are right, somebody will be in the sweet spot for sure! (Doubtful imby - still 2.7C here, dropped 1 degree in past hour, DP -0.6C)

PS - this radar http://www.southamptonweather.co.uk/rainradar.php shows a lightning strike at 20:00. Any body able to confirm this?

[dec10snow]

My snowman disappeared 5 years ago to go shopping at John Lewis`s Havent seen him since.

Haha, very good!

[Nights King]

I'm going to shower and get ready for a drink in my local!

Depending on whether it goes east or west of me is how I will determine which pub to drive to for a pint lets hope it maintains intensity or grows more

[Dean E]

That stuff coming SW out of Wales is interesting.

Ian said above 200m (Mendips)

Again, im harping on now, its just not cold enough at lower levels. Just my opinion, its 2.8 IMBY.

Air temperature is better the lower it is, but 2c is just as likely as -2c with showers (evaporative cooling)

If your Dew Points are below 0c, quite likely

SM

[katemart]

Yes! Here it is:

Not thundersnow but thunderpotentialsnow!

[dec10snow]

By all means show me a single forecast I've ever given that wanders off-message from Chief Forecaster's briefings? Plus: as I am not a snow fan, I'm not prone to enjoy "hype and drama" as you rather insultingly suggest. I suspect few of my regional colleagues are even so obsessive about getting our message correct as to spend days abroad on holiday still getting UKMO briefings while away in Tunisia... as my missus will attest.

Well said Ian

[Gibby]

My radar trajectory path suggests an area between Bristol and Minehead will be the first to see these showers from roughly 21:30. It's a case of having left the Brecons how much they can hold together in the next hour or so.

[Iceberg]

WELLS? Who said Wells?! Are we thinking snow or that horrible stuff called rain Iceberg?

Not sure, tempted to say it might be snow.....currently temp of 1.1 and falling with a dp of -1 so snow where I am in Dorset at 100m and we should get another couple of hrs of cooling.

[quantock girl]

My radar trajectory path suggests an area between Bristol and Minehead will be the first to see these showers from roughly 21:30. It's a case of having left the Brecons how much they can hold together in the next hour or so.

That's a pretty big stretch - I'm in that area (just) so will keep checking, there was no cloud about an hour ago.

[Nights King]

My radar trajectory path suggests an area between Bristol and Minehead will be the first to see these showers from roughly 21:30. It's a case of having left the Brecons how much they can hold together in the next hour or so.

It looks like its going to hold together!?

Looks like it might just hit us gibby! now we just need meto to give us an amber warning... keep checking

Edited January 14, 2013 by mullender83

[dec10snow]

You tell them Ian, us long standing members appreciate all your imput.

As the new members (me) do!

[Bumpkin]

My guess would be through banes, bristol somerset and dorset area curently.

Oh how I hope it hits us. Ive seen these situations before when you watch main ppn band missing you by 5 miles for several hours its so frustrating!

last night i was watching the radar and could see a band coming towards me here and hearing reports of it snowing in Ilminster etc. Then the band would reach the little red dot on the map (indicates my location) and just disappear lol It did that a couple of times so perhaps we have some sort of shield around us.

[khodds]

Not sure, tempted to say it might be snow.....currently temp of 1.1 and falling with a dp of -1 so snow where I am in Dorset at 100m and we should get another couple of hrs of cooling.

Just checked my temps here its certainly dropped since earlier! 1.2c DP 0c.... Weatherstation says snow... Was showing rain an hour ago

[Bristawl Si]

Looks like it's just veering more south/south east now, rather than directly south east.

That would indicate just missing Bristol but heading to North Somerset.

Unless i'm calling it incorrectly.

[katemart]

Snow coming out of that streamer in the Wales thread

Come to mama....!

Edited January 14, 2013 by katemart

[Dean E]

Those showers over wales are most likely going to move into Northern Parts (Somerset/Devon) before the Winds turn NNW, then Northern parts of Devon/Cornwall more prone later

SM

[AWD]

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!

Edited January 14, 2013 by AWD

[khodds]

Snow coming out of that streamer in the Wales thread

Come to mama....!

I LOVE Streamers! When they deliver they can keep going for a while and give a nice surprise! Hope if it happens, itll wipe the smiles off my work mates faces - fed up of being wrong about snow. And they laughed at me at 5pm tonight when I told them AGAIN it might snow. COME ON SNOW! PROVE ME RIGHT THIS TIME!

[Nights King]

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

[legritter]

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 .

[Bumpkin]

reports of heavy snow on A483 in wales. I'm waiting for that band to come across the channel and just evaporate.