January 2024 CET and E.W.P. forecast contests

[Don]

1 hour ago, Earthshine said:

Potential for exceptionally mild end to the month.  Long way off of course but quite a few of these are very February 2019-esque

I'm starting to get 2018/19 winter vibes this season which concerns me ref to a potentially colder February!

[cheese]

33 minutes ago, Don said:

I'm starting to get 2018/19 winter vibes this season which concerns me ref to a potentially colder February!

I'll take a repeat of Feb 2019 please and thank you 

[Don]

30 minutes ago, cheese said:

I'll take a repeat of Feb 2019 please and thank you 

I'll take the opening days, but the last few days of the month can do one!  However, I wouldn't be too upset if I were in your shoes now!

[cheese]

17 minutes ago, Don said:

I'll take the opening days, but the last few days of the month can do one!  However, I wouldn't be too upset if I were in your shoes now!

I'd be fine with a cold, snowy February - but that's unlikely, and I'd rather have a very warm and sunny February than a boring average February. 

[The PIT]

Sunny Sheffield down to 3.9C -1.0C below average. Rainfall at 48mm 64.5% of the monthly average.

Looking like we will end up with an average January now at least.

[damianslaw]

6 hours ago, kold weather said:

Whatever happens we roll onto yet another month above the 61-90 average, makes it 24 out of the last 25. Starting to become statistically quite striking.

Yes, hence feel we should measure against 91-20 average or at least 81-10 averages. A few months have fallen below these means. 

[Roger J Smith]

I believe we will see a min of 3.5 reported on Saturday for 1-19 Jan, it will edge up to 3.6 after Sat 20 Jan, and afterwards, mean dailies 21st to 31st look like on today's 12z GFS run: 

21 _ 8.5

22 _ 7.0

23 _10.5

24 _ 7.5

25 _ 9.0

26 _11.0

27 _ 6.0

28 _ 5.0

29 _ 4.0

30 _ 3.0

31 _ 2.0

... and outcome would be 4.6 C

It does turn very mild but colder end to January now depicted cancels out some of warming, running CET peaks at 4.8 after 27 Jan in my estimate. Could go up or down depending on model accuracy after seven days (warm spike could be overdone, or warm interval could be prolonged).

 

[Dancerwithwings]

4 minutes ago, Roger J Smith said:

I believe we will see a min of 3.5 reported on Saturday for 1-19 Jan, it will edge up to 3.6 after Sat 20 Jan, and afterwards, mean dailies 21st to 31st look like on today's 12z GFS run: 

21 _ 8.5

22 _ 7.0

23 _10.5

24 _ 7.5

25 _ 9.0

26 _11.0

27 _ 6.0

28 _ 5.0

29 _ 4.0

30 _ 3.0

31 _ 2.0

... and outcome would be 4.6 C

It does turn very mild but colder end to January now depicted cancels out some of warming, running CET peaks at 4.8 after 27 Jan in my estimate. Could go up or down depending on model accuracy after seven days (warm spike could be overdone, or warm interval could be prolonged).

 

That 4.6C out come would suit me just fine

[LetItSnow!]

39 minutes ago, Roger J Smith said:

I believe we will see a min of 3.5 reported on Saturday for 1-19 Jan, it will edge up to 3.6 after Sat 20 Jan, and afterwards, mean dailies 21st to 31st look like on today's 12z GFS run: 

21 _ 8.5

22 _ 7.0

23 _10.5

24 _ 7.5

25 _ 9.0

26 _11.0

27 _ 6.0

28 _ 5.0

29 _ 4.0

30 _ 3.0

31 _ 2.0

... and outcome would be 4.6 C

It does turn very mild but colder end to January now depicted cancels out some of warming, running CET peaks at 4.8 after 27 Jan in my estimate. Could go up or down depending on model accuracy after seven days (warm spike could be overdone, or warm interval could be prolonged).

 

4.6... A bog standard January for the christmas pudding and just under a degree above normal. A very mixed January with a bit of something for everyone. Would imagine the same synoptics 50-100 years ago would have produced a far colder mid period and probably some more substantial snow and even ice days. Alas with added warmth in the atmosphere the mild has more of a kick and we have a C.E.T likely to be in the 4s instead of the 3s. Apart from the added mildness it's probably a very typical January of the early 20th century. Can't say this month hasn't been variable! I imagine with unsettled weather on the horizon it'll be wet overall too.

Presuming January is around the 4.6 mark, February needs to come in approximately the low 6s higher to score a top 15th warm winter.

Edited January 16 by LetItSnow!
Baffling autocorrect / attempt two because it didn't work?

[SollyOlly]

7 hours ago, kold weather said:

Whatever happens we roll onto yet another month above the 61-90 average, makes it 24 out of the last 25. Starting to become statistically quite striking.

Yes, the CET and the WMO recommended 1961-1990 reference period is my hobby horse...and I completely agree, it is very striking. Remarkable, in fact. SO warm these days...!!

[damianslaw]

28 minutes ago, LetItSnow! said:

4.6... A bog standard January for the christmas pudding and just under a degree above normal. A very mixed January with a bit of something for everyone. Would imagine the same synoptics 50-100 years ago would have produced a far colder mid period and probably some more substantial snow and even ice days. Alas with added warmth in the atmosphere the mild has more of a kick and we have a C.E.T likely to be in the 4s instead of the 3s. Apart from the added mildness it's probably a very typical January of the early 20th century. Can't say this month hasn't been variable! I imagine with unsettled weather on the horizon it'll be wet overall too.

Presuming January is around the 4.6 mark, February needs to come in approximately the low 6s higher to score a top 15th warm winter.

Could end up somewhere between the last two middling Januaries.. 5.2 and 4.7 respectively. 4.7 incidentally is the 91-20 mean average. 

Edited January 16 by damianslaw

[LetItSnow!]

1 minute ago, damianslaw said:

Could end up somewhere between the last two middling Januaries.. 5.2 and 4.7 respectively. 

Yet another January to fall inbetween the range of unexceptionally below average and unexceptionally above average since 2009. In all these records we've seen we haven't even come close to a record warm January since 2007 and all the warmest Januarys are back in the 20th century and prior. Wonder when we'll challenge that... Never hopefully! Unlikely in the modern world though. 

[WYorksWeather]

I still doubt a finish below 5C will actually happen - today's GFS 12z was an extreme cold outlier in FI, actually the coldest in the entire ensemble from the 27th on.

 

[damianslaw]

34 minutes ago, WYorksWeather said:

I still doubt a finish below 5C will actually happen - today's GFS 12z was an extreme cold outlier in FI, actually the coldest in the entire ensemble from the 27th on.

 

We shall see, who knows the longevity of the upcoming very mild spell may implode in duration and extreme just the same as the earlier projections for this current cold spell.

Ridging by late Jan could allow for colder nights, and temps struggling by day if a dry continental feed sets in.

[WYorksWeather]

3 minutes ago, damianslaw said:

We shall see, who knows the longevity of the upcoming very mild spell may implode in duration and extreme just the same as the earlier projections for this current cold spell.

Ridging by late Jan could allow for colder nights, and temps struggling by day if a dry continental feed sets in.

My usual rule of thumb is that a mid-month estimate, even if you use the ensemble mean, nearly always under-reads. Over 90% of the ensemble of the ECM is mild literally every single day until month's end. A stronger signal than that you'll rarely see. And the most extreme period of mild weather, from the 22nd-24th, is now in the semi-reliable. The last few days could possibly see a change, but I think early February is more likely.

The minority options for a change in the last few days turn the wind into more of a southerly, which as you say would probably be somewhat less mild, temperatures near average. But not as extreme as the GFS 12z scenario. That is a major outlier, and is sensibly taken to be suspect I think until it starts to gather ensemble and cross-model support.

The key reason for the extreme mildness being favoured is a key background signal - the temperature of the sea over the Azores, which is 2-3C above normal. This of course intensifies any mild spell, and is why I actually think there's more upside to my central estimate of 5.5C than downside. A finish above 6C would surprise me less than a finish below 5C. I mean it'd be extraordinary given we've had a significant cold spell (albeit not that snowy), but I actually wouldn't find it that surprising.

I'd love to be wrong on this. I think timing of any change of pattern will start to become clearer in the next few days. If we don't see colder options gathering ensemble support by Friday or Saturday in model FI I think January can be written off, and we look to February.

 

 

 

[Don]

1 hour ago, damianslaw said:

We shall see, who knows the longevity of the upcoming very mild spell may implode in duration and extreme just the same as the earlier projections for this current cold spell.

Ridging by late Jan could allow for colder nights, and temps struggling by day if a dry continental feed sets in.

Nah, that doesn't happen with mild spells these days, only cold! 

If this month finishes around 4.6C, we will have done well, given the model output!

 EDIT:  Or maybe not going by the tentative signs in this evening's model output! 

Edited January 16 by Don

[LetItSnow!]

1 hour ago, WYorksWeather said:

My usual rule of thumb is that a mid-month estimate, even if you use the ensemble mean, nearly always under-reads. Over 90% of the ensemble of the ECM is mild literally every single day until month's end. A stronger signal than that you'll rarely see. And the most extreme period of mild weather, from the 22nd-24th, is now in the semi-reliable. The last few days could possibly see a change, but I think early February is more likely.

The minority options for a change in the last few days turn the wind into more of a southerly, which as you say would probably be somewhat less mild, temperatures near average. But not as extreme as the GFS 12z scenario. That is a major outlier, and is sensibly taken to be suspect I think until it starts to gather ensemble and cross-model support.

The key reason for the extreme mildness being favoured is a key background signal - the temperature of the sea over the Azores, which is 2-3C above normal. This of course intensifies any mild spell, and is why I actually think there's more upside to my central estimate of 5.5C than downside. A finish above 6C would surprise me less than a finish below 5C. I mean it'd be extraordinary given we've had a significant cold spell (albeit not that snowy), but I actually wouldn't find it that surprising.

I'd love to be wrong on this. I think timing of any change of pattern will start to become clearer in the next few days. If we don't see colder options gathering ensemble support by Friday or Saturday in model FI I think January can be written off, and we look to February.

 

 

 

I'm not sold of an above 6 finish at all, that would require something ridiculous. 4.6 to 5.2 could be a good landing zone but it remains to be seen. Hope the colder end being sniffed out is correct!

[WYorksWeather]

1 minute ago, LetItSnow! said:

I'm not sold of an above 6 finish at all, that would require something ridiculous. 4.6 to 5.2 could be a good landing zone but it remains to be seen. Hope the colder end being sniffed out is correct!

Sorry if it wasn't clear, I'm saying that I think a finish above 6C would be less surprising to me than a finish below 5C, not that it's all that likely. My view is that it's less than a 10% chance of finishing outside the 5C to 6C range, with the probability of an above 6C finish being higher than the probability of a below 5C finish.

[TillyS]

12 hours ago, LetItSnow! said:

4.6... A bog standard January for the christmas pudding and just under a degree above normal […] Presuming January is around the 4.6 mark […]

That's brave. Most mid-month estimates seem to under-estimate mild spells by quite a significant margin.

The CET will take a hit this week, although tempered by slightly less intense cold in the north-west area the past 36 hours. Then from Sunday onwards it will be mild for quite a while.

4.6C looks far too low to me. 

Another month in the official ‘well above average’ category looks probable to me. 

[LetItSnow!]

14 minutes ago, TillyS said:

That's brave. Most mid-month estimates seem to under-estimate mild spells by quite a significant margin.

The CET will take a hit this week, although tempered by slightly less intense cold in the north-west area the past 36 hours. Then from Sunday onwards it will be mild for quite a while.

4.6C looks far too low to me. 

Another month in the official ‘well above average’ category looks probable to me. 

Upper 4s, low 5s a safe bet at this time. 

[TillyS]

1 hour ago, LetItSnow! said:

Upper 4s, low 5s a safe bet at this time. 

Nothing is ever a safe bet with UK weather, which is characterised by mobility and temperate climes with occasional cold blocks. And especially no safety in betting when we are talking about a fortnight still to go.

I frequently punt, successfully as it happens, but almost never on UK weather. It’s not ‘safe’.

I’m guessing around 5.5C from here, but it’s only a guess and could still be out by at least 1C either way.

[Summer Sun]

3.9c to the 15th

0.1c above the 61 to 90 average
0.5c below the 81 to 10 average

[LetItSnow!]

6 hours ago, TillyS said:

Nothing is ever a safe bet with UK weather, which is characterised by mobility and temperate climes with occasional cold blocks. And especially no safety in betting when we are talking about a fortnight still to go.

I frequently punt, successfully as it happens, but almost never on UK weather. It’s not ‘safe’.

I’m guessing around 5.5C from here, but it’s only a guess and could still be out by at least 1C either way.

The guess was not actually mine and was Roger’s who is a respected poster and quite good with his predictions. I anticipate low 5s but upper 4s into the 5s a safe bet because it would take something remarkable to get into the 6s, which I suppose could happen if the build of pressure fails and we remained under blow torch south-westerlies for the rest of the month. I’m sure someone can make a calculation of what would be required to reach 6.0C. Conversely, if heights do build and we manage a colder / more average end it could stall, hence why I think upper 4s to low 5s could be a good bet, but also a fair chance of higher. I am very aware of the nature of forecasting being tricky. A lot of us thought February 2021 could have been sub zero around the 8th of that month but then things flipped, not unlike now with record cold over America shunting the pattern into unfavourable conditions for cold, squeezing the heights down into Europe and up come the south-westerlies. Nonetheless, Interesting times! I wonder what February will bring. Could still be in the game for a pattern reset come end of the month.  

[damianslaw]

Suspect today's and possibly more so tomorrow's CET returns will be close if not below 0 degrees and coldest of season so far, will dent the CET somewhat.

[TillyS]

It will indeed. I was rather surprised that today’s update didn’t dent it by as much as I’d expected. Weds-Thurs-Fri will all take it down. Then it’s upwards for a good while by the looks of things.

Low 5’s, which I take to mean 5.0C to 5.3C  may well be the landfall but it’s not a 'safe bet’. 6’s may or may not be out of reach but I’d rule out nothing upward of 4.5C from here.