South West/Central Southern England Regional Discussion 16/01/13 22z ----->

[gottolovethisweather]

This courtesy of Gibby, from the technical discussion thread.

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Good evening. Here is tonight's report on the 12z output from the big three namely GFS, UKMO and ECM for tonight Wednesday January 16th 2013.

All models are agreed for the next 48 hours though even at this range the specific detail differs between them. A weak front lies close to West Wales in a cold and slack pool of air over the UK over the next 24 hours. Tomorrow night sees an active frontal system moving into the West of the UK with and area of rain, readily turning to snow inland across Western areas by morning. Through the day the front decelerates as it moves East and the energy gradually slides SE late in the day. Widespread and in places heavy snowfall will occur, heaviest in Central and Western areas away from the far SW. Late in the day as the front slides away and weakens the snow will ease down and die out in most places over Saturday.

GFS then shows a quieter day or so with much of the UK under snow cover with cold conditions prevailing as a weak ridge develops briefly. By Monday further sliding Low pressure over the SW renews the risk of further rain and snowfall before towards midweek the Atlantic breaks through with rain and strong winds developing a rapid thaw of lying snow. The rest of the run shows a changeable pattern with another brief colder incursion through FI while on the whole there would be plenty of wind and rain on a milder wind flow blowing from the West.

The GFS Ensembles show the operational run was one of the milder options tonight though one can't ignore the slow trend to nearer to normal conditions as we move through Week 2. There are plenty of precipitation spikes on offer too indicating that rainfall would be commonplace as the Atlantic Lows push in and over the UK later.

The Jet Flow shows a flow weakly blowing SE over the UK. In a day or two the flow markedly strengthens as it steams across the Atlantic and crosses Europe well to the South of the UK. Eventually the flow ridges over the Atlantic and down over the UK in a week or so time.

UKMO tonight shows Low pressure filling and moving SE over France over the weekend with the legacy of Fridays snow dying out slowly over Saturday. Sunday should be a dry and cold day with a lot of cloud over the snowfields. On Monday a further area of rain and snow moves in from the SW with snow once more disruptive for some although rain is possible in the SW. Through the remaining early days of the week there will be further rain, sleet and snow in places as Low pressure close to the South of Britain fails to make inroads into the cold block over the UK.

ECM tonight shows a very wintry spell indeed with a widespread snow event on Friday subsiding away East and South over the weekend leaving cold and grey conditions for many though in any overnight clear skies some very low temperature values can be expected. By early next week a re-run of Friday seems possible as further Low pressure moves in close to the SW and on down into France by Tuesday. A bitter and strong East wind would develop on this second Low's northern flank with drifting of lying snow a major hazard should this setup verify. Through the middle of the week cold, snowy weather persists especially in the South as Low pressure is slow to move away East to the South of Britain. The end of the run shows the weather finally settling down as High pressure develops over the UK but in very cold air and countrywide snow cover some record breakingly low night time temperatures would be possible.

In Summary tonight the weather looks like staying cold through the reliable part of the output and most likely beyond too. The battleground will continue to be the UK for the next 5-7 days as successive attempts of mild air from the Atlantic try to displace the cold over the UK. The resultant copious snowfall remains a major feature of the weather with some very difficult travelling issues likely over the next week. Longer term various options are shown with GFS taking us on a milder route along with its ensembles while ECM looks like a pattern reload in the closing frame of its operational as the cold block remains to the NE, reaching across to the UK still. With pressure falling to the West the Jet is seen to be travelling South again with more disrupting troughs sliding SE over the UK likely in the days that would follow.

Edited January 16, 2013 by gottolovethisweather

[Bumpkin]

Just copying this over from the last thread!

Check out David Braine preparing for his Channel Islands forecast here. Check the ending out too. Totally unedited.

http://www.bbc.co.uk/weather/2640413

You would have thought somebody would have edited that before putting it up!

Currently -1c with a -2 dp here. I'm prepared ready for Friday whatever happens. Got a sack of potatoes and a sack of dog food today, have booked sainsburys to deliver tomorrow and shall nip out to the butchers in the morning. I saw posters mention tescos earlier, i wouldn't buy their burgers anyway, they may be low in salt but they are high in Shergar Sorry mkangel

[Karl83]

That'll be the snowfields

Absolutely. I wonder if -20 can be felt should the snow hang about. Would love to see that on my Thermometer.

[Bristawl Si]

Ian's forecast just now - only mentioned to thursday pm.

Matt Taylor - national - still using meto stuff from earlier today. Seemed a bit outdated to me, seeing latest model runs this eve.

[SizzlingHeat]

BBC south today 2-5cm LOL think a bit more than that love! .

[Davey80]

Well if the BBC1 forecast is live then the stall point is bang on central southern England

[DanDorsetUK]

BBC south today 2-5cm LOL think a bit more than that love! .

Dont be so sure, looks like most of the good heavy stuff is further north tonight!

Although it does stall more in our area!

Edited January 16, 2013 by Rapodo

[iceman1991]

BBC south today 2-5cm LOL think a bit more than that love! .

thats what thought lol

[SizzlingHeat]

Latest gfs giving acc of 10-15cm over dorset by sat morning and even nae supporting 10mm which is roughly 10cm!

[gottolovethisweather]

Can someone help me out? Upgarde for South Central coast or not? Slight Westerly correction is a good thing, yes? Charts look good to my untrained eye, but sense negativity...........

TBF, things are loking pretty peachy, even for the South Coast as things stand. I haven't seen the GFS 18z so can't comment on that and wouldn't advise reacting to its nuances, unless it becomes a solid trend.

For a good level-headed view of the more reliable 12z suites, have a read of Gibbys link, which I have copied above.

[harta]

Again, doesn't sound great IMBY... Ah well, lets hope for some change! Anyway, I need sleep, night guys!

This is what i meant, the area's i mention will see snow but very very little and nothing after Friday late PM, why? hunch, models, snipits on here and the wildlife

[karlos1983]

BBC eluded to the Amber warning, possibly extending further south, I do hoe so!

I own a business, but I don't care, we don't see this often, I rarely saw snow as a kid, SO BRING IT ON!!!

[GazzzaV6]

TBF, things are loking pretty peachy, even for the South Coast as things stand. I haven't seen the GFS 18z so can't comment on that and wouldn't advise reacting to its nuances, unless it becomes a solid trend.

For a good level-headed view of the more reliable 12z suites, have a read of Gibbys link, which I have copied above.

Thank you! Peachy sounds good

[A.J]

NMM 18z hi-res output out now, snowline devon/somerset border around 5am, moderate snowfalls north & north east counties slowly easing off as energy in frontal occlusion splits, at the end of the run (17-18z friday evening) looks like a little shortwave feature sliding up the English Channel pepping up PPN as the frontal system pivots

[khodds]

Ian Fergusson (@fergieweather)

16 Jan 2013 10:31 PM GMT

W COUNTRY CONT'D: Potential 5-10cm M5 nr Taunton; 5-15 Mendips; 10-20 FoD & parts of Cotswolds; 5-10 uplands Wilts, etc.

Latest from Ian

[karlos1983]

This is what i meant, the area's i mention will see snow but very very little and nothing after Friday late PM, why? hunch, models, snipits on here and the wildlife

Well I'm not sure a hunch qualifies, I'll go with the professionals for now!

[PompeyFC]

Lol why did they upload that without editing it?

thats absolutely hilarious lol - especially when at the end as he walks off he just goes "RIGHT"

[harta]

Ian's forecast just now - only mentioned to thursday pm.

Matt Taylor - national - still using meto stuff from earlier today. Seemed a bit outdated to me, seeing latest model runs this eve.

Because there's a backtrack coming ?

[djpaulbailey]

Because there's a backtrack coming ?

[DanDorsetUK]

Because there's a backtrack coming ?

Yep there will be a backtrack tomorrow am, till we find the middle ground, This to much of a shift west, cant see this being the final event

[Bristawl Si]

Because there's a backtrack coming ?

Re Ian? If so, NO, just no time i guess and he'll firm up tom morning i guess on bbc local radio.

As i said yday this is a dynamic situ - these v type of events always are for our region.

[Nights King]

Backtrack resides in the northwest regional thread I believe, dont think hes coming?

Excellent charts again tonight lets hope the upgrades continue through to the 12z thursday and then I'll be ready to ramp my self into an early breakdown (mentaly)

[khodds]

Because there's a backtrack coming ?

No!

Because they use data from earlier runs on the both the regional and national news, plus Ian doesn't always have time to adjust things as the latest info has just been released to him. The general public don't need to be alarmed unduly...

[kumquat]

Could somebody let me know where the ignore button is? I try to remain tolerant most of the time but some of the inane comments over the last couple of pages are getting on my wick!

[khodds]

Backtrack resides in the northwest regional thread I believe, dont think hes coming?

Excellent charts again tonight lets hope the upgrades continue through to the 12z thursday and then I'll be ready to ramp my self into an early breakdown (mentaly)

I've reached that point already! Ha ha!