For clarity, this is for the south, the picture in many northern parts is largely unchanged in the ensemble output.

Having said that there is definitely clear potential for an extension of the colder weather beyond the middle of next week. Potential and a lot of uncertainty. The ECM looks chilly in coming days on the 00z run so far.

Yes. but UKMO is a little disappointing. Race against time to get a pressure rise over Scandi in time

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS

THE CURRENT GENERAL SITUATION A cold and windy WNW flow will continue across the UK over the next 24-48hrs with showery troughs of Low pressure moving SE across the UK at times.

MODELS-2 WEEK HEADLINE Becoming colder with snow showers or snow at times before becoming less cold and changeable again by next weekend.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Forecast shows a week long spell with a deep trough over NW Europe keeping the flow well South of the UK in NW winds. In week 2 the pattern flattens and weakens as the trend towards High pressure to the SW and perhaps NE makes for some sort of link and stalling any would be major attack from the Atlantic away from the NW.

GFS OPERATIONAL The GFS operational today continues to show Northerly winds blowing across the UK through the weekend and much of next week with a slow relaxation of conditions later as High pressure builds NE across the UK from off the Atlantic. In the meantime showers of sleet and snow will affect all Northern, Western and Eastern coasts with the risk of more prolonged sleet or snow in the West for a time early next week. From next weekend on conditions are shown to become more changeable with rain and showers at times, wintry on hills still under Low pressure disrupting from the NW over the UK for a time before Atlantic SW'lies are shown at the very end of the run.

THE GFS CONTROL The GFS control run is much the same in the sequence of events with a cold Northerly for a week before High pressure builds across the UK later with cold and frosty conditions for many with this pattern largely.

THE GFS CLUSTERS The GFS Clusters are are a real mix of options with the majority showing High pressure of some sort near the UK but no real agreement on positioning which of course is fundamental on conditions of air source across the UK. there are still some more unsettled options shown too including some disruption of Low pressure to the SW of the UK by 10% of options.

UKMO UKMO this morning continues to show the UK in a very cold Northerly flow well into the middle of next week and probably longer with unstable air and disturbances running down from the NW next week enhancing the risk of more widespread snowfall for the West for a time early next week before a High pressure ridge attached to a centre over the Atlantic moves slowly SE down across the UK by the end of the week with cold and frosty weather likely then but much less in the way of wintry precipitation.

THE FAX CHARTS The Fax Charts show a concoction of fronts embedded on cold air slipping South across the UK over the next 72-96 hours. Thereafter, Low pressure sliding South to the West of the UK could complicate things in the far West in an otherwise more straightforward and cold Northerly flow next week.

GEM GEM is the pick of the bunch for cold lovers this morning as it takes our cold spell into unchartered territory this Winter. The Northerly is still shown in place for the start of next week but on this run pressure builds to the NW and this then drifts across towards Scandinavia with North winds veering NE and maintaining their strength and continuing to carry snow showers across many Eastern and Northern areas and perhaps the South too with the far West looking brightest and driest later.

NAVGEM NAVGEM today keeps the cold going over the UK well into next week with snow showers in places but the flow is cut off later in the period for late next week as a High pressure ridge collapses SE over the UK.

ECM ECM this morning shows cold and unstable conditions through the next week with mostly Northerly winds and snow showers the likely scenario with the chance of more prolonged wintry precipitation for a time in the SW early next week and again more generally later before the cold finally looks like relaxing its grip at the end of the run at the expense of Atlantic WSW'lies.

ECM 10 DAY MEAN The 10 Day Mean this morning remains in nomansland but indicates a cold pool remaining over Europe while the UK lies on the Western periphery of this. High pressure over NE Europe is hinted at here and a quiet spell of weather for the UK is how I would deduce things likely to be at Day 10.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend remains for much colder and windy weather through the next week. The longevity of the spell has remained about a week as there is still the desire from most output to bring a cessation of the cold Northerly feed and introduce something less cold from the West by next weekend.

MY THOUGHTS The models continue to handle the cold period well with just small scale features harder to pick up within the generally cold and wintry theme. The current cold weather will intensify come the weekend as a more direct flow from the North takes hold and replaces the wintry mix on the showers in the South until then. Northern areas as usual in Northerly set up's will see the biggest share of snowfall, disruptive at times over the hills. For other areas to join in this fun we have to await any small scale disturbances ruinning South or SE in the flow and one such feature looks like possibly affecting Western and SW Britain early next week and providing the air is cold enough could give some sizeable snow amounts over the hills. not all places will see snow and inland Central Britain may miss it entirely with just bright and cold weather with frosts by night. Then we have to look for the end of the spell which still looks likely to come from the West as a ridge of High pressure from our old friend the Azores high creeps across late next week. How significant this ridge is will determine events thereafter with a real mix of options shown with some keeping High pressure and cold and dry weather across the UK while others show milder air filtering in from the west by 10 days, notably ECM while GEM goes the other route in sending High pressure North of the UK and setting up a true Easterly wintry blast. Which is right will not be determined for some while yet with plenty of options likely to crop up in upcoming model runs before an eventual coming together of thoughts will probably arise by the end of the weekend.

Issued at 08:00 Wednesday January 28th 2015

A very rare Icelandic high.Don't see many of them to often.

As has been said, there are so many possibilities on the table. The GEFS has definitely trended colder for most, including for Bergen which highlights a trend away from an Atlantic push. Not good for me as I personally find HP a bit boring but certainly good in extending the UK cold and potential.

I think it is clear as to why the MetO have continued to include the possibility of drier weather with colder temperatures in their forecasts, serving like a disclaimer. Give it another 24 hrs or so with the same trend and I rather suspect they will reverse their wording, the emphasis being on a colder solution, with a return to more unsettled and average temperatures becoming their 2nd and least likely option.

Thanks Martin
I want to focus on Mon/Tues briefly and not in the dedicated thread as it might be lost in the reports of sleetyness in Solihull, etc.

The models have actually handled this quite well IMO, with the highest consistency coming from GFS which as of now takes a developing low SE from SW Eire to The Brest, then turns it ESE along the N France coast. ECM wants to take a shallower feature further east across the SW into N France.
The problems in determining the risk and amount of any snow from this are many fold, but the two main ones are:
1) It needs to track far enough east to effect a sizable chunk of the UK
2) The further in in gets, the larger the area affected by the milder sector

GFS has lifted both dps and 850s into the 'very marginal' zone for areas on the NE edge of the ppn, so it's not as solid for snow this morning as it was yesterday. ECM is also borderline, as it always was, so you can see the problem. Will ppn get in, and if it does will it be cold enough?

My gut feeling based largely on past experience tells me it will slide too far away and we might get a bit of sleet if we're lucky. I would love to be proved wrong.

You can see why whatever falls today for a large part of England will be wet:

http://expert-images.weatheronline.co.uk/daten/proficharts/en/euro4/2015/01/29/basis00/ukuk/taup/15012912_2900.gif

However, a small window later this afternoon early evening:

http://expert-images.weatheronline.co.uk/daten/proficharts/en/euro4/2015/01/29/basis00/ukuk/taup/15012918_2900.gif

GEFS gives the following rough splits of cold/ warm ensembles.

144h 90:10

192h 55.45

240h 70:30

260h 50:50

There area a reasonable number of Scandi hps within the 240h split.

There may be other factors that cause precipitation to be rain/sleet rather than snow, but I wouldn't say these charts show that.... Both show sub-zero dewpoints for the bulk of England away from southern coasts, and as such dewpoints alone should be conducive to snow....  If they were showing anything above zero, even 1c, then I'd agree.

Interesting to see GEM's trough disruption in the western Atlantic appear on the GME 00z for Mon-Tue, given that it's higher resolution is arguably advantageous when handling such developments.

It's a good way to trap the Euro trough close to our shores going forward, providing a quicker route to a long-draw easterly, as GEM is all too happy to show us:

Shield the young one's eyes! 

Of the 'big' models, UKMO comes closest to achieving the trough disruption needed, while ECM and GFS show little interest on their respective op runs.

Seems like it would be winning the lottery, as the ECM/UKMO/GFS combination is rarely out of line at just 4 days range.

Longer term, signs that the Siberian High will become interested in our little island... but at the same time there is a push from the Atlantic.

Two main options are shown  by GFS and ECM;

The former has that push heading entirely NE with the Azores High reaching out to the Siberian High and drawing it toward Scandinavia, with the potential for an Atlantic undercut then illustrated. The Atlantic air hardly gets a look in until right at the end of the run.

The latter aims the Atlantic due east, bringing the Atlantic air back to our shores by day 10, leaving us looking for the Azores High to back west again and allow low heights back into NW Europe. With the Siberian High edging into Scandinavia, the potential for such a slide of low heights SE from the vicinity of Iceland is greatly improved... but there's no relying on the high behaving in this way.

I am given the strong impression that we will finally get to play for the 'Beast from the East' during the second week of February, but there's no telling to what extend we'll win.

I'd rather go down the GEM route though... I think my grin would sever the top of my head if the Atlantic trough did behave so favourably 

Dewpoints are certainly important.

It's an interesting subject generally wrt what actually falls with precipitation intensity, evaporative cooling and upper temperatures in the mix  

I imagine that back at New Year, given the seemingly rather dire model output we were seeing for much of the time, the odds on not one but two cold spells occurring later in the month must have been rather long. Just goes to show how sometimes things can change quite quickly with the models.