I don't think it was a trough at all, I stil reckon it was an occluded front. There was some convective instability aswell going on, but that feature had all the characturistics of an occluded front. It makes a difference because certain types of occluded fronts (ana warm occlusions in particular) are snowmakers that don't need particularly low upper air temperatures. Although that particular feature I think was a cold occlusion not a warm occlusion.

All change again past 120 hours, with a mild outlier. The average still leaves us in the -5 850hpa for much but not of the run in the south, whilst the north does. The run ends with the whole country in -5 850hpa, so average remains cold. Mild outliers getting to be a more regular occurrence though, perhaps signalling the decline in the SSW influence maybe? Just a thought...

Not much change although the GEFS have done another shift to less cold leaving the virtually decent synoptics where they’ve been for most of the winter - in virtual space. 

Sadly the downgrades continue this morning poor output post 144. ICON really is a good model at picking up pattern changes. Para remains good but thats about it post 144.

There’s very little change up here (see ensemble below) but it is still “not cold enough” away from inland higher ground, a continuing theme. THere are however continuing changes in the specific details beyond day 3 or 4 and the possibility of some very unsettled weather being hinted at for next week on some operational runs.

Horrific ECM worst of the lot this morning with its .west based NAO. Just massive downgrades from just a couple of days ago

 "I think you may be being too pessimistic... If you look at 850s from Dec 17 snow event (which i appreciate didn’t give anything to your area - it did here though not to the extent of some places in midlands and SE) they were a notably higher than what the 18z has as complex low pressure systems swirl around our vicinity for days in end in a week or so’s time."

You might well be correct Chiltern, and your location right over there on the east side, you are sometimes affected by different cold incursions than over here. Having used to be residing in "high Suffolk" it was different again, like in 2006, (I think) you will have had that intense and snow fest cold spell that got no further east than Stowmarket. With 2010, I was just too Far East to have seen the worst, a former residence just south of Bury - at 100m was buried and for 2-3 days longer after my lawn returned to green. My current location, in south Norfolk, sees snow events not experienced before, e.g. Convective showers from a northerly, but nothing so far of note. Maybe the next run will show those messy lows delivering again, which I agree, can mean random snow events almost anywhere. 

Gefs up in Scotland still look ok but everything else has gone to shite . Gefs will be the last to catch on to the pattern change they have been a poor guide really this winter. The 7th best models ensembles get to much publicity.

Models flipped to colder solutions yesterday from the day before... Now they’ve flopped back.  At t+120 and beyond they will doubtless flip and flop some more.... Where the actual weather in a week’s time, nobody really knows.

Yes we've had the bites of the cherry and that can only last for so long, another one of those modern winters where despite the  background signals, the NAO never goes negative and the PV just rolls on regardless. Full conventional zonality on the ECM at the end - now that's one day 10 chart that is likely to verify..

On face value it is a horror show for coldies in most of the UK this morning. However, the changes in the output aren't huge. The European sinkhole remains as does the lack of HLB and it is the latter which has scuppered things so far. In Dec the MetO were "confident" high pressure would move to Scandinavia in January but that simply hasn't happened. It's too early to call February and it could of course deliver a few surprises. However, nature seemingly has known what the machines haven't this year.  

This is very true. For what it’s worth although not definite there is some chance of wintriness in many places in the coming week to ten days on many models. Perhaps the GFS is overdoing it?

The GFS op has this by next Thursday morning (as usual and expected nothing here)

By day 9 the GFSP has this

Yes, pretty much summed by today really. One of the guys on the other side did an ECM ensemble watch for Jan 25 from Day 16 down to the big volte face last Friday, up until then members showed various degrees of cold for London from low single digits to ice days - none showed the actual plus 11C.

Yes a real horror show on the ECM. Wednesday is especially poor but it gets better after that (in FI?) for milder weather fans

https://weather.us/model-charts/euro/united-kingdom/snow-depth/20190130-0900z.html

(Apologies for posting actual model output )

 I'm sure the GEFS would be similar. 

So what you’re saying is that the generally or currently more specifically the milder weather at that range should be discounted at that range and we should focus on the next five days or so?

For the record the GEFS had the milder weather for today/tomorrow clearly on the ensembles from Sunday, before then just hints.

I think those snow depth charts have been widely discredited haven't they ? 

fair summary, the hunt continues 

The wintry theme continues this morning :-)

Mid next week continues to be worth a watch.

http://www.wetterzentrale.de/maps/GFSPARAEU00_108_1.png

http://www.wetterzentrale.de/maps/GFSPARAEU00_147_1.png

http://www.wetterzentrale.de/maps/GFSPARAEU00_147_2.png

Overnight Wednesday in particular with a feature crossing central parts within cold air. 

After 1st Feb there is more scatter - but still way too soon to conclude that it’s the shape of the pear. 

They are indicative of the synoptics and potential not the exact depths to be expected. The outlook is cold until the unreliable stage*.

*This unreliability/“FI” discussed by yourself and Brian above.

ECM is indeed more dissappointing as snow would be more likely to be confined to hills. I prefer the GFS solution. 

http://www.wetterzentrale.de/maps/ECMOPEU00_120_1.png