18z is quite similar to the 12z. Some slight changes here or there... but the Net result is the same. Areas of snow affecting areas of the UK. Those areas seemingly driven by LP activity than strictly wind direction....

Last time i remember seeing that was 2010. Not saying this is the same... just when stuck under a big trough. Micro features develop. Its where we saw areas get repeated 6" falls.

Interesting times.

Yes I agree with this.

Being stuck under a big slack low can lead to dry weather for some and very cold nights, but also the risk of snow coming at very short notice. Being up in Scotland in December 2009 was notable for this. 

Tuesday & Wednesday are looking interesting. Light winds, low pressure and cold 850’s. Hard to see exactly where at this stage has the highest snow risk. Irish Sea convection looks likely and the showers could be slow moving. 

http://www.wetterzentrale.de/maps/GFSOPEU18_120_1.png

http://www.wetterzentrale.de/maps/GFSOPEU18_144_1.png

Uppers about -7C, dewpoints comfortably below freezing. Not snow for all, but I’d cautiously suggest snow for most at this stage (rather than rain). 

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The odd thing about the recent cold snap was that the convection clouds in the Irish Sea got right across, albeit with the aid of a trough, to Norfolk, with both a dusting Wednesday night and another this morning, both with proper fluffy snow flakes. Ok - nothing massive but some years I'd be mighty grateful for those two garage light events and morning dusting reveals, so if that's the Amuse Bouche, bring on the main course please. 

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The odd thing about the recent cold snap was that the convection clouds in the Irish Sea got right across, albeit with the aid of a trough, to Norfolk, with both a dusting Wednesday night and another this morning, both with proper fluffy snow flakes. Ok - nothing massive but some years I'd be mighty grateful for those two garage light events and morning dusting reveals, so if that's the Amuse Bouche, bring on the main course please. 

The key, as you say, was the disturbance that ran SE - and became a discrete low pressure system in the southern North Sea.  

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Yes Gandalf, agreed. The track seems similar to the prognosis in the model outputs today (GFS and ICON), with slider lows tracking behind - like the parent following behind yesterday's child- running ahead...

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The snow eye candy of the GFS does not hold water - no pun intended, because the 850hpa is too high in our region for too long. But hey, it's a pretty picture for sure - 1979 like but less cold. Odd just how close this is to real time at 150hrs, with 144 being semi-reliable in normal conditions, but now T96 is not even a sure bet. These are strange times indeed. E.g ice in the high Arctic off Norway given 10 years max to disappear! Sad but a call to arms hopefully. I am cutting down on meat to once a week, small beer, but if everyone reduced meat it all helps. Saves money and belly fat too. Lol. 

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.  

 

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The odd thing about the recent cold snap was that the convection clouds in the Irish Sea got right across, albeit with the aid of a trough, to Norfolk, with both a dusting Wednesday night and another this morning, both with proper fluffy snow flakes. Ok - nothing massive but some years I'd be mighty grateful for those two garage light events and morning dusting reveals, so if that's the Amuse Bouche, bring on the main course please. 

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.

 

 

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Not much change on this morning’s output with a generally cold andunsettled outlook after the current blip. Cold enough for some snow at times but mostly on inland high ground.

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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...

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Not much change on this morning’s output with a generally cold andunsettled outlook after the current blip. Cold enough for some snow at times but mostly on inland high ground.

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. 

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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.

 

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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.

 

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

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 "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. 

 

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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.

 

Yes I’d expect a slow continuation of a climb down on met Office extended forecasts over the weekend. The long term signals are fading.

 

Theres 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.

 

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.

 

 

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The ECM 00z op run by day 8 is totally different to its previous run, so in isolation is really not very informative. A shift on its ensembleswill/would be more telling. The pre 4-5 day time period is potentially of more immediate interest for some I think.

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

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.

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Yes I’d expect a slow continuation of a climb down on met Office extended forecasts over the weekend. The long term signals are fading.

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..

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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.  

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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.

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

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