Whether it is down to a distorted view of the past or actually sound observation, but I find that March tends to be more of a 'winter month' in terms of cold and frost/snow potential than January. To observe snow in January seems an almost impossible task! 

Good point. Every January in the past 50 years has been 3.9C above CET after the first 14 days.

https://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

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The persistent theme of the MO extended outlook - unsettled returning and never too cold - is all you need to know. The polar snap(s) are not a given despite the odd OP or control run in the last 24hrs. Let’s get the UK high in first and see where things go.

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Good point. Every January in the past 50 years has been 3.9C above CET after the first 14 days.

https://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

The past 50 years? Are you sure about that, Brian?

I'd be amazed if the likes of the Januarys of 1979, 1985, 1987 and 2010 too were as much above CET in the first half of the month.

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Whether it is down to a distorted view of the past or actually sound observation, but I find that March tends to be more of a 'winter month' in terms of cold and frost/snow potential than January. To observe snow in January seems an almost impossible task! 

Makes sense. Our climate is determined by sea-surface temperatures. These are at their coldest in March. Therefore any weather coming from the north or east has a wider range of tracks on which it is still cold enough to deliver frost or snow by the time it reaches here. 

Synoptics which are marginal in December or January can deliver in February or March. That's why I've never agreed when snow in March has been accompanied by comments along the lines of "if only we'd had these synoptics in December or January". If we had, it would probably have been cold rain.

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The past 50 years? Are you sure about that, Brian?

I'd be amazed if the likes of the Januarys of 1979, 1985, 1987 and 2010 too were as much above CET in the first half of the month.

I was being sarcastic. This Jan is most definitely not par for the course so far!

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I was being sarcastic. This Jan is most definitely not par for the course so far!

OK, thanks. I did wonder at first it was perhaps a typo or something like that!

I'm fairly sure that the last below average January for temps was probably 2010 (although 2013 turned colder as the month went on but not as cold as 2010 IIRC). Someone please correct me if I'm wrong though!

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In Copenhagen at the moment - yesterday, Denmark recorded its warmest January temperature on record - 11.2 degrees.i

Surprised its a low as that! I would have thought it could easily get to 13 or 14 in the right conditions. Wonder what comparable temps were like in 1989. 

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Surprised its a low as that! I would have thought it could easily get to 13 or 14 in the right conditions. Wonder what comparable temps were like in 1989. 

Don't forget that Denmark is maritime with sea temperatures moderating the temperature in either direction. Also, it has no hills (let alone mountains) capable of delivering any Foehn effect - that is why in these conditions, there is little diurnal temperature range and it remains unremittingly grey - nothing to disrupt the westerly grunge.

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Don't forget that Denmark is maritime with sea temperatures moderating the temperature in either direction. Also, it has no hills (let alone mountains) capable of delivering any Foehn effect - that is why in these conditions, there is little diurnal temperature range and it remains unremittingly grey - nothing to disrupt the westerly grunge.

I see, but looks like you will get something like normal winter later next week

Would prefer the block to sit over us, but as long as it stays dry I don't mind the chill

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Whether it is down to a distorted view of the past or actually sound observation, but I find that March tends to be more of a 'winter month' in terms of cold and frost/snow potential than January. To observe snow in January seems an almost impossible task! 

 

For me, Feb has been the worst of the 4 months for snow (at least since the turn of the century).

In terms of frequency, it's January - but most have been up to only a couple cms and only a small minority have lasted 3 or more days. December best for good falls (either 5cm+ or the snow remains on the ground for 3 days or more)

MBY seems to have missed any decent Feb falls.

 

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P00 the thick blue - is this P00 the coldest ens? I can't get to this - it shows -12c@ 850hpa

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=gfs&var=2&run=0&lid=ENS&bw=1

 

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OK, thanks. I did wonder at first it was perhaps a typo or something like that!

I'm fairly sure that the last below average January for temps was probably 2010 (although 2013 turned colder as the month went on but not as cold as 2010 IIRC). Someone please correct me if I'm wrong though!

Recent cold, or at least chilly, Januaries:

Jan 2009: 3.0

Jan 2010: 1.4

Jan 2011: 3.7

Jan 2013: 3.5

Jan 2017: 4.0 (which is probably just about below average, depending on which reference period you are using)

 

 

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06z builds a strong block, but too far south. Dry and frosty though. 

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P00 the thick blue - is this P00 the coldest ens? I can't get to this - it shows -12c@ 850hpa 

Control run Tally, need to select it on the left rather than click on the 850 graph for some reason. FWIW, control run similarly chilly on the 6z.

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P00 the thick blue - is this P00 the coldest ens? I can't get to this - it shows -12c@ 850hpa

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=gfs&var=2&run=0&lid=ENS&bw=1

 

The pert. 00 is the control run (thick dark blue). It’s run with no tweaks to initial input data (as per the OP) but at about half the resolution as the OP.

When there is a big difference between OP and control you know resolution is having an effect on outcome.

The suite (1-20) are also lower resolution but with small tweaks to input data - these illustrate how minor changes early on might cause big differences down the line. When control and OP are close together confidence increases.

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That cold plunge out east later in the 06z run isnt a millions miles from us, plenty of time for other options to be presented.

The control was hinting at this this morning from overnight too

I would say this has an element of optimism for end of january at the moment

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The pert. 00 is the control run (thick dark blue). It’s run with no tweaks to initial input data (as per the OP) but at about half the resolution as the OP.

When there is a big difference between OP and control you know resolution is having an effect on outcome.

The suite (1-20) are also lower resolution but with small tweaks to input data - these illustrate how minor changes early on might cause big differences down the line. When control and OP are close together confidence increases.

I think the op and control currently have different physics too. 

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If you're after colder weather the trends in the model output are tenuous but encouraging at present. For example the mean t850hPa by day ten for this location is down to -8°C on the 06z GFS suite.

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Control run Tally, need to select it on the left rather than click on the 850 graph for some reason. FWIW, control run similarly chilly on the 6z.

Thought it was control but couldn't get the the chart when clicking on graph thanks anyway!

Meanwhile a lot of interest post 24th Jan - a flip to colder ENS in medium term when a day or so back they were milder and operational was colder outlier.

26th or 27th seem cold. Timing of cold and positioning of HP is crucial. But plenty of interest here AND GOOD SUPPORT FOR A NORTHERLY. - this has cropped up at short notice.

P04:

P08

P17:

P12:

P19:

control: - P00

 

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Control run Tally, need to select it on the left rather than click on the 850 graph for some reason. FWIW, control run similarly chilly on the 6z.

Yes Operational is in the milder END of the runs at +2c when when it's ensembles are widely down to -4 or -5c @ 850hpa from 24th Jan.

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