It does look like the best we can hope for is a snowy breakdown. Let's hope we get one, I could do with that snow about 50 miles further east though.

Whilst I hope as much of the UK gets snow, I so don't want that to be at the expense of us further west.

Looking through the GEFS, I would say that there will be a S-N divide as we move through next week, driest in the SE and wettest in the NW.

Beyond that, if I was a betting man, I would say the next cold spell will come from the N rather than the E.

Some consistent signs appearing that heights may eventually begin to retrogress westwards. IMHO.

I don't think there will be a great deal on those fronts as they track East, the best set-up is fronts from the SW coming up against a block to the NE.

I agree with this Mike, I think after a fairly short spell under the hairdryer, we will see High Pressure in the Atlantic again, hopefully far enough North to form a proper block.

Yep, that is my take on things too (at this time).

Based on the MetO update I'm assuming MOGREPS is showing a very cold outlook persisting. Perhaps TomC can update us if he is around?

And therein lies the impossibility of the models predicting 4 days out how far East the front will travel before fizzling out.  It is unlikely that Monday morning's forecast will be any more accurate - a Nowcast event.......or non-event.

Indeed. See https://www.wmo.int/pages/prog/amp/pwsp/documents/ken_Mylne.pdf for info about MOGREPS

Check out page 4 that describes how "Tiny errors in how we analyse the current state of the atmosphere lead to large errors in the forecast" and look at the resulting 4 day forecasts

Very well then 

We have signs of a somewhat unusual displacement-ish event in the stratosphere. I add the 'ish' because the event itself is sort of like a displacement in terms of how the warm area initiates, but then the way it develops is more a like a split in terms of where the main vortex ends up. Yet there isn't actually a divided up vortex...

This may be another manifestation of the uncharted territory that we are in this year with respect to the combination of forcing mechanisms in place.

What makes it very interesting is when you look at how tropical forcing wants to move the lower atmosphere around - it actually favours a Euro trough with blocking to the NW by end of Jan/early Feb, and this aligns well with how the strat. is trying to move. This suggests to me that there is the potential for such a pattern to lock-in for an extended period as it has support through a large amount of the atmosphere.

Now then, what about this disrupting low debacle... I've been watching in the background and as of yesterday evening the signs were so strongly in favour of a sliding low on Monday with the cold/mild boundary barely making it to the SW and cold conditions being able to hold on until at least mid-week that it was hard to imagine the models suddenly going off the idea the following morning.

Yet that's exactly what we've seen. Upon seeing this I sought to learn what the Met Office make of it all and thanks to good old Fergie it has become apparent that they don't find the faster removal of the cold to be a reliable signal. I find this reassuring, especially when remembering yesterday evening's snippet of info from him, which was that their parallel UKM, being trialed as an upgrade to the current operational UKMO, was keen on introducing west-east mobility at latitudes south of the UK, implying a cut-off high scenario that goes beyond what even the op UKMO was showing yesterday. Hopefully that's the case again this morning!

The trouble we have is that this particular disruption of a trough happens very soon after it interacts with an ex-subtropical storm moving up from near the Azores having developed near Bermuda. It's not at all certain how long this feature will hang on to its tropical characteristics prior to interacting with the trough and this will affect how things pan out. Another factor is the precise track, with small changes having a significant impact on the distribution of instability as the systems interact.

Just how it all comes together I'm not sure to be honest - the scenario features a frontal boundary that extends southeast from the trough and under our high, and it looks like it will start to move NE ahead of the incoming Atlantic trough in a few days time, meaning we need the disrupting low to form and break away SE prior to that NE motion of the boundary kicking in. The 00z runs of today carry it too far north before the disruption begins and by that time the door is closing on an exit SE. You just get that frontal boundary acquiring a big of a negative tilt (SE to NW) which allows for a snow event in a distinct band across the UK.

Figuring out how exactly the behaviour of the subtropical low will influence that might well be enough study for a dissertation!

The 12z runs really will be getting to the range at which such large uncertainty feels ridiculous. It seems like anything could happen, from an uneventful arrival of milder air early next week as the front fizzles out (today's ECM 00z op), to a heavy snow event as the cold air puts up a bit of a fight (today's GFS 00z & 06z op runs), to a variant in which the slider low develops and turns the flow more to the east on the cold side of the front, causing further negative tilt (the optimum outcome for a snow event that affects a wide area, maybe UKMO was close yesterday), to a weak slider SW of the UK with the cold air holding firm and little precipitation anywhere (12z ECM-GFS-UKMO consensus of yesterday unless UKMO was further across with the precip than I interpret).

Imagine having issued a 4-14 day outlook to customers last night... because that's what I had to do. Obviously it was only a guide by day 7 but even so, it was tough going and this morning I nearly tore my hair out!

GFS vs NAVGEM with fronts annotated on.

Really quite complicated low, I'd be surprised if the models handle it well. 

The NAVGEM is perhaps the simpler solution, although it would be quite difficult to get that ridge that far north. I suspect subtropical storm alex and his warm air advection may make such a solution more likely however.

How often does that happen in January?

Is there a historical precedent for what the effect on the UK winter might be? Are there decent analogues for this.

One thing is for sure - it will change the model output one way or another

[edit] just read the following on another site:

"Alex is the first Atlantic hurricane to form in the month of January since 1938, and is the first Atlantic hurricane to exist during January since Alice of 1955."

 Projected track takes it towards Greenland:

http://www.nhc.noaa.gov/refresh/graphics_at1+shtml/143540.shtml?tswind120#contents

The temperature contrast as it moves north will be enormous, although it will quickly lose its sub-tropical features, the amount of warm air advected due north will have a major impact on our weather.

Lol, took me like long to post that and then you'd edited it with the same date.😁

Let's see what the 12zs throw up, I think we will see a really progressive GFS.

Tell me something that will surprise me 

I think it will backtrack yet again to the meto model. 

RE the past few post's with an Atlantic Hurricane in the mix's it very interesting model viewing how ever it turns out in the end.

You be careful in the morning - you know what happens when you're exposed to direct sunlight 😉

NAVGEM 144 6z:

Lets pray its the GFS!!!