Latest GFS(P) run has the storm deepening rapidly as it moves across the UK during Wednesday afternoon. On this run it would be an afternoon / evening event.

Low gets down to 958mb as it exits into the North sea near the English / Scottish border.

Wind gusts inland across much of England reach up to 120kph (75mph) at 18z on Wednesday with some places perhaps as high as 130kph (80mph). Stronger gusts around the coasts.

The fact this system has been modelled fairly consistently for some days now even though it is 5 days away still is cause for concern. Suggests even at this stage there is a fairly high probability of it verifying as a major system somewhere over the UK.

http://modeles2.meteociel.fr/modeles_gfs/runs/2015010918/114-515PUK.GIF?09-18

http://modeles2.meteociel.fr/modeles_gfs/runs/2015010918/120-515PUK.GIF?09-18

http://modeles2.meteociel.fr/modeles_gfs/runs/2015010918/126-515PUK.GIF?09-18

http://modeles2.meteociel.fr/modeles_gfs/runs/2015010918/114-289PUK.GIF?09-18

http://modeles2.meteociel.fr/modeles_gfs/runs/2015010918/120-289PUK.GIF?09-18

http://modeles2.meteociel.fr/modeles_gfs/runs/2015010918/126-289PUK.GIF?09-18

PS - you may need to change the title of the thread Neil to 14/15 Jan

And there is a thread discussing it

The low next Thursday is still very much there, but you can feel the 'easing' of severity from most models today. It remains a potent Atlantic system, but the way it develops and tracks ENE across Scotland (most tracks) is starting to look typical for a winter storm rather than high-end bomb.

All can and will change though so watch and brief

Oh great 

Both GFS and GFS(P) 12z runs take the midweek low over the north of Scotland at around 945mb. However, this does not mean the south gets away with it as far as winds are concerned. Some very strong gusts are expected to be associated with the cold front as it moves through. The winds look slightly stronger on GFS(P)

GFS

http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/108-515UK.GIF?10-12
http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/114-515UK.GIF?10-12

http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/108-289UK.GIF?10-12
http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/114-289UK.GIF?10-12

GFS(P)

http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/108-515PUK.GIF?10-12
http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/114-515PUK.GIF?10-12

http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/108-289PUK.GIF?10-12
http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/114-289PUK.GIF?10-12

Meanwhile UKMO brings the low further south and would give most areas a spell of very stormy weather

http://www.meteociel.fr/ukmo/run/U120-515UK.GIF?10-17

GME looks similar to the other models

http://modeles.meteociel.fr/modeles/gme/run/gme-0-108.png?10-12

At this point it does look increasingly likely we will see a low with a central pressure somewhere between 945mb and 955mb. The track is still somewhat uncertain though. Either a northerly track with the centre of the low passing over the north of Scotland or a more southerly track with the low centre passing near the England / Scotland border.

Not one, not two, but three interacting systems involved in the behaviour of this storm... with some hints of development along the trailing frontal boundary as well (the big kink in the isobars extending SW from the low we're concerned about).

At the very least, it has the hallmarks of a vicious frontal system leading the charge (70-80mph gusts widely), and then there's the tight circulation around the low itself which currenty looks like bringing similar strength gusts on it's southern flank.

The track will remain highly uncertain until quite late on due to the complex multi-system interaction.

Thanks James - yes the gross situation is consistent, it's just the detail. The solutions have trended to the 'less' severe options but plenty to do yet between now and Weds/Thurs with some complex interactions to model.
I am always fascinated by the fact that this storm is still some five days away from even appearing as a shallow kink somewhere 2000 miles to our West, and the power of weather models to predict these things with even modest accuracy is incredible.

As well as lots of rain and very strong winds we could potentially also see a fair bit of snow with this system as we go into Wednesday evening. The links below are from the GFS(P)

18z Wednesday and most places seeing rain http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/102-779PUK.GIF?10-12

By 0z Thursday most of Scotland has snow together with the Lake District, north Pennines and Snowdonia http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/108-779PUK.GIF?10-12

by 6z Thursday many parts of Wales and the Midlands together with the moors in the SW could see some snow - although I doubt we will see much settling away from the highest ground http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/114-779PUK.GIF?10-12

Dew points certainly look favourable http://modeles2.meteociel.fr/modeles_gfs/runs/2015011012/114-101PUK.GIF?10-12

Something to keep an eye on. This system could cause a lot of trouble.

GEM also shows a 950mb low.

We need to watch out for the possibility of secondary or daughter lows developing. Some of the models - including these charts from GEM show signs that this could happen. Such features will not be properly modelled this far out but if a secondary low were to develop it could bring further heavy rain and strong winds to the south

http://modeles.meteociel.fr/modeles/gem/runs/2015011012/gem-0-108.png?12

http://modeles.meteociel.fr/modeles/gem/runs/2015011012/gem-0-114.png?12

GFS Control run

http://modeles.meteociel.fr/modeles/gens/runs/2015011012/gens-0-1-114.png

GEFS mean

http://modeles.meteociel.fr/modeles/gens/runs/2015011012/gens-21-1-114.png

18 of the 20 perturbations on the GEFS this evening produce monster storms. The mean above looks less bad simply because the track is still ill defined. Three of the most worrying options are linked below. Perturbation 2 is a genuine Armageddon scenario.

http://modeles.meteociel.fr/modeles/gens/runs/2015011012/gens-2-1-108.png

http://modeles.meteociel.fr/modeles/gens/runs/2015011012/gens-9-1-114.png

http://modeles.meteociel.fr/modeles/gens/runs/2015011012/gens-20-1-102.png

Some of the GEFS members look downright scary for the south

This one is bad enough 

http://www.meteociel.fr/modeles/gefs_cartes.php?code=16&ech=108&mode=0&carte=

But this one is not good at all!

http://www.meteociel.fr/modeles/gefs_cartes.php?code=9&ech=114&mode=0&carte=

Before the 18Z runs to end of next week, we have a complication developing in the form of a sharper trough - maybe a closed low - on Tuesday.

This will need to be watched in high-res runs as this adds not only strong winds but potentially wintry ppn in places as it zips through in quite unusually cold maritime air.

Jeeesus - we're in for what looks like a January 1990 Burns day storm here. This is scary as we are now closer to the time these were first progged and they are still showing up - indeed in even more detail.

Fraid so, I think this is going to be pretty bad. 

Not much change on the 18z runs. Still 2 main clusters of options with a more northerly and more southerly track.

For those of a nervous disposition I would strongly suggest you don't look at perturbation 12 of the 18z GEFS suite.

Latest fax charts go for the more northerly option

http://weather.noaa.gov/pub/fax/PPVM89.TIF

http://weather.noaa.gov/pub/fax/PPVO89.TIF

Notice the 528dam line running slightly ahead of the occluded front. Suggests the possibility of back edge snow for some.

Well I had to have a look didn't I? The word 'armageddon' springs to mind. 

Malcolm
Wakefield & Gothenburg, SWE

No Armageddon... Only likelihood of SNOW... Panic...Panic.........

Deep low Weds/Thurs

There are some extreme pertubations but don't get too carried away - the OP runs are the ones to watch especially as we get into near-time.

The UKMO are likely to tweak the system north on fax output as experience dictates these lows tend to steer left on approach, but it's not a set script because of the myriad of variables the model has to handle and the interpretation overlaid by the forecasters.
By Monday it is in range of the E4 which is a high-res hybrid of the UKMO shortscale model and proven to be reliable in the 48hr range so all will become apparent by then - within reason! I would expect early warnings by Mon am purely because this system has been so persistent and is more likely to impact a large area of the UK than not.

I will however refrain from entering into any debates about the level of warnings, etc.

Trough/Wave Tues

There might be some snow in places - someone will probably start a thread about it I'm sure

Ouch ECM says it will be very windy Thursday.  The exact track and pressure gradients are still up for grabs though.

Indeed - the control run from last night's 12z shows it tracking NE'wards across northernmost Scotland, for example.

Both GFS and GFSP this morning show a broad swathe of 55kt winds crossing England, with all areas, including inland areas, seeing those values at some stage. Not nice!

The 10M wind gusts chart corresponding to that ECM chart (from last night, this morning's won't be ready until 11AM) has 45kt gusts widely across southern and central England. The 50kt contour runs around 20 miles inland of the south coast and also runs along a line parallel to the Wash. Strongest gusts are >70kts over NW Wales, with >60kt gusts over Cumbria, SW Scotland, all of Wales, Devon and Cornwall.