January 2023 C.E.T. and EWP forecast contests

[Summer Sun]

6.9c to the 17th

3.1c above the 61 to 90 average
2.5c above the 81 to 10 average

[The PIT]

Sunny Sheffield down to 6.4C +1.8C above normal. Rainfall 84mm 112.9% of the monthly average.

[damianslaw]

Into the 6s at last! Will see further drops in the days ahead, CET zone looks like staying cold until at least Sunday, possibly Monday, expect to be around or even below 6 degrees this time next week - with prospect of high pressure ruling the roost rest of the momth, in a mild position at first but not especially so, in time cold surface air likely and if skies are clear frosty nights, good chance more likely to end in the 5s than 6s by months end, with outside chance of falling into the 4s if heights build sufficently north before month's end. A very contrasting month on the cards, opposite to Dec, with the cold dry first half and very wet very mild second half, on this occasion the cold will not be anywhere near as extreme though. If we finish in the 4s with the cold December - then regardless of what Feb delivers a colder then a near average winter overall on the cards, if Feb is cold, then colder then average.

[ItNeverSnowsInWindsor]

On 17/01/2023 at 21:35, Don said:

You could be pretty close with your CET prediction then!  Little sign of any significant snow fall in the extended, though?

I think it’ll struggle to get to mid 4s let alone the 4s with the weather turning milder next week as the high orients unfavourably for the U.K. dragging milder Atlantic air.

[Relativistic]

On 18/01/2023 at 12:22, Relativistic said:

-1.5°C mean yesterday.

Min was a chilly -5.9°C.

A second subzero mean: -0.2°C yesterday.

Min was cold again at -5.5°C.

 

I noticed that the figures for the 17th have been adjusted to a mean of -1.4°C and a min of -5.7°C, so perhaps yesterday's figures are still subject to change.

Edited January 19, 2023 by Relativistic

[summer blizzard]

How many sub zero days did 2013 and 2018 manage Vs 2022/2023.

[Relativistic]

4 minutes ago, summer blizzard said:

How many sub zero days did 2013 and 2018 manage Vs 2022/2023.

2012/13: 14 (including a '-0.0', which I can only assume was subzero to the second decimal place)

11/12: -0.9
12/12: -2.4
13/12: -0.5
13/1: -0.0
16/1: -2.8
17/1: -1.8
18/1: -1.0
19/1: -0.8
20/1: -0.3
21/1: -0.3
22/1: -1.2
23/1: -0.3
25/1: -0.4
11/3: -0.5



2017/18: 7 (excluding a '0.0' on 10/12/2017, which I can only assume was above zero to the second decimal place)

12/12: -0.4
26/2: -0.1
27/2: -1.0
28/2: -3.5
1/3: -3.7 (date record)
2/3: -2.3
17/3: -1.0



2022/23: 12 (as of today)

8/12: -1.1
9/12: -0.8
10/12: -0.5
11/12: -1.4
12/12: -1.9
13/12: -2.3
14/12: -2.5
15/12: -4.4
16/12: -2.6
17/12: -1.3
17/1: -1.4
18/1: -0.2

 

[Summer Sun]

6.5c to the 18th

2.7c above the 61 to 90 average
2.1c above the 81 to 10 average

[Roger J Smith]

Assuming CET is close to 6.0 after today, a mean of 3.0 for the remaining twelve days would give an outcome of 4.8 C. A mean of 2.5 gives an outcome of 4.6 or 4.7 C. And 2.0 will get us to 4.4 or 4.5 C. The current output looks quite chilly as milder air makes little impact on most of England while streaming up through Ireland into Scotland for a few days, and another high builds up with faint connections to colder highs in Europe. Could see 2.0 to 3.0 being the average for what's left of the month. EWP still looks more or less status quo which is now about 92 mm (89.7 to 17th). Current GFS adds only 1-2 mm, in fact parts of central England are shown dry to at least 4th of February which would be a record long dry spell for this time of year. Nothing carved in stone about any of this, long spells of anticyclonic weather can get pulled off the table after a few days sometimes. 

The projected fall in CET is fairly similar to what happened in 1950 so perhaps an early June heat wave? I don't think the rest of the summer of 1950 was very remarkable after a few warm days in early June. It's interesting because January 1950 was also very mild in eastern North America (like this month is turning out) and their warmth reversed in mid-February suggesting a retrograde pattern as Britain went earlier. 

[Don]

13 hours ago, prolongedSnowLover said:

I think it’ll struggle to get to mid 4s let alone the 4s with the weather turning milder next week as the high orients unfavourably for the U.K. dragging milder Atlantic air.

I'm assuming you mean mid 5's?  Going down into the 4's is probably an outside chance but not out of the question.

[Frigid]

I think it's safe to say a 6C January is out of the equation, well I hope.. I'm thinking a 4C month is becoming more likely by the day, inversion type cold looks possible with the current output. This month is literally the anti Dec 2022, maybe not at the same intensity but still noteworthy. 

[Frigid]

4 hours ago, Relativistic said:

2012/13: 14 (including a '-0.0', which I can only assume was subzero to the second decimal place)

11/12: -0.9
12/12: -2.4
13/12: -0.5
13/1: -0.0
16/1: -2.8
17/1: -1.8
18/1: -1.0
19/1: -0.8
20/1: -0.3
21/1: -0.3
22/1: -1.2
23/1: -0.3
25/1: -0.4
11/3: -0.5



2017/18: 7 (excluding a '0.0' on 10/12/2017, which I can only assume was above zero to the second decimal place)

12/12: -0.4
26/2: -0.1
27/2: -1.0
28/2: -3.5
1/3: -3.7 (date record)
2/3: -2.3
17/3: -1.0



2022/23: 12 (as of today)

8/12: -1.1
9/12: -0.8
10/12: -0.5
11/12: -1.4
12/12: -1.9
13/12: -2.3
14/12: -2.5
15/12: -4.4
16/12: -2.6
17/12: -1.3
17/1: -1.4
18/1: -0.2

 

Quite notable we're already at 12, given we still have ~2 months of winter left. Compared to previous winters:

2021/22 - 0

2020/21 - 11

2019/20 - 0

2011/12 - 10

2010/11 - 20

2009/10 - 16

Wondering if we'll see the most sub-zero CET days since 2012/13.. come on February you can't be another stinker! 

 

[damianslaw]

54 minutes ago, Frigid said:

Quite notable we're already at 12, given we still have ~2 months of winter left. Compared to previous winters:

2021/22 - 0

2020/21 - 11

2019/20 - 0

2011/12 - 10

2010/11 - 20

2009/10 - 16

Wondering if we'll see the most sub-zero CET days since 2012/13.. come on February you can't be another stinker! 

 

Yes it is a notable statistic, the 10 day run in December was very impressive, and considering we have a good 2 months left when sub means can easily be recorded - indeed as 2018 showed mid March not too late.. we could believe it or not be rivalling winter 2012/13.. 

A definate roller coaster winter so far.. with sudden abrupt changes in very short space of time. 

Looking ahead a very dry period on the cards, as also happened first half of December.. did late Jan last year not produced nearly 3 weeks with no rain or very little for some places?

Edited January 19, 2023 by damianslaw

[Roger J Smith]

Yes, last January had a total (EWP) of only 36.3 mm, driest since 2006, and of that, 27 mm had fallen by 9th, so only 9 mm for the last twenty-two days. The average pressure was very high with almost constant anticyclones positioned over or just south of Britain. And although there was no draw on arctic air it was quite cold after such a record warm start. I think that dry interval averaged about 3 C. 

The pattern ahead reminds me a bit of the end of Jan 2006 with an Atlantic high linking up with colder European high pressure right over Britain. It was quite chilly under that setup despite fairly moderate uppers. This is the sort of pattern where the coldest part of the UK would be the inland south and the mildest part would be southwest Scotland. 

[ItNeverSnowsInWindsor]

Looks like finishing close to 5c. There’s some milder Atlantic air circulating around the high which will prevent the CET dropping to mid 4’s.

[Man With Beard]

14 hours ago, Frigid said:

Quite notable we're already at 12, given we still have ~2 months of winter left. Compared to previous winters:

2021/22 - 0

2020/21 - 11

2019/20 - 0

2011/12 - 10

2010/11 - 20

2009/10 - 16

Wondering if we'll see the most sub-zero CET days since 2012/13.. come on February you can't be another stinker! 

 

That's fascinating. Not inconceivable we could challenge 2009/10 for number of very cold days. However the extreme mild around Christmas will cancel it all out on the averages.

[Summer Sun]

6.2c to the 19th

2.4c above the 61 to 90 average
1.8c above the 81 to 10 average

[Frigid]

Looks like they've made another incremental change.. 18th now 0.0C instead of the -0.2C

Is 0.0C still classed as an ice day? 

[Weather-history]

3 hours ago, Frigid said:

Looks like they've made another incremental change.. 18th now 0.0C instead of the -0.2C

Is 0.0C still classed as an ice day? 

An ice day is when the maximum temperature does not get above zero.

[Roger J Smith]

7 minutes ago, Weather-history said:

An ice day is when the maximum temperature does not get above zero.

Correct. But as you have been active in creating lists of subzero CET means, what's your opinion on including or excluding 0.0? My opinion is to include such days. I would have to go into the data and look to see if there was ever a 0.0 within a string of minus values to require a decision before. I can recall there being a 0.2 intruding in a long subzero string so I thought even that case was worth an asterisk so to speak. Other than people on net-weather, who has ever cared to create lists of such days anyway? So it's our decision to make! (he said boldly). 

[Roger J Smith]

So, a partial answer to those questions: in my own compilations of cold spells (in the historical weather sub-forum, as part of the thread on CET records), I have a table with a title "Cold Spells of days 0.0 and lower" so I was inclined to include them. Whether any of the spells listed had a day at 0.0, I am not sure but the data base used was CET legacy and requires an update so in the next few days I may update that post and find out. In the list there were two entries with asterisks due to near-miss intruders in what would otherwise have been longer spells. Those were in 1895 and 1917, in both cases extending the spells to earlier start dates in January. Although the values changed slightly from CET legacy to CET v2.0, the same near miss dates exist. These are the two spells in question with the intruders (and for 1917, also an extender) shown in bold type. My feeling is that for consideration of historic cold spells, one near miss intruder should be allowed and noted because the impact on society (which is why we care at all about these numbers) would be unaltered by the fact that one day managed to creep up to 0.2 C or thereabouts. The same principle applies to heat waves, do we think less of some long hot spell if one day within it has a maximum of 29.8 and fails to reach 30? Probably not. 

1895-01-26 -1.9

1895-01-27 -3.9

1895-01-28 -3.9

1895-01-29 -3.7

1895-01-30 -3.7

1895-01-31 -2.8

1895-02-01 -1.5

1895-02-02 0.3

1895-02-03 -1.3

1895-02-04 0.1

1895-02-05 -3.8

1895-02-06 -7.2

1895-02-07 -7.8

1895-02-08 -8.5

1895-02-09 -7.0

1895-02-10 -6.6

1895-02-11 -3.2

1895-02-12 -4.0

1895-02-13 -5.1

1895-02-14 -5.5

1895-02-15 -3.4

1895-02-16 -0.9

1895-02-17 -2.8

1895-02-18 -1.6

 

1917-01-20 0.2

1917-01-21 -0.3

1917-01-22 -0.5

1917-01-23 -0.5

1917-01-24 -0.8

1917-01-25 -1.6

1917-01-26 -1.7

1917-01-27 -1.4

1917-01-28 -1.5

1917-01-29 -2.0

1917-01-30 -1.5

1917-01-31 0.2

1917-02-01 -1.3

1917-02-02 -2.2

1917-02-03 -0.9

1917-02-04 -1.3

1917-02-05 -4.7

1917-02-06 -5.5

1917-02-07 -6.2

1917-02-08 -3.8

1917-02-09 -2.9

1917-02-10 -2.1

1917-02-11 -0.3

Anyway, there may be other cases with these marginal "intruders" that don't really break a long cold spell. I think we should have a standard like this perhaps: any subzero cold spell remains "valid" if there are intruders in the range 0.0 to 0.4 and at least seven subzero days on either side of the intruder(s). Why 0.4 and not some other value? Because 0.4 rounds off to zero, 0.5 or higher to one. So the principle is that the cold spells have generally speaking means of zero or lower (rounded off). 

[Weather-history]

1 hour ago, Roger J Smith said:

Correct. But as you have been active in creating lists of subzero CET means, what's your opinion on including or excluding 0.0? My opinion is to include such days. I would have to go into the data and look to see if there was ever a 0.0 within a string of minus values to require a decision before. I can recall there being a 0.2 intruding in a long subzero string so I thought even that case was worth an asterisk so to speak. Other than people on net-weather, who has ever cared to create lists of such days anyway? So it's our decision to make! (he said boldly). 

It’s not a case of opinion, Roger. Mathematically, 0.0 is not subzero and that’s why I never included it. I only looked at consecutive runs of minus CET means.

You could include 0.0 but it’s not a consecutive run of subzero, though.

 

Edited January 20, 2023 by Weather-history

[damianslaw]

This cold spell has legs, CET zone set to stay notably cold through the weekend, and now Monday, not until Tuesday see a warm up, and it won't be especially mild with high pressure overhead, What seemed a very outside chance of ending in the 4s is now increasing in probability.. how things can change.

[Relativistic]

I personally would include 0.0°C as 'subzero' because the error is finite and so it could have been.

Akin to giving the striker the benefit of the doubt during a marginal offside decision.. or so it used to be.

Edited January 20, 2023 by Relativistic

[Don]

2 hours ago, damianslaw said:

This cold spell has legs, CET zone set to stay notably cold through the weekend, and now Monday, not until Tuesday see a warm up, and it won't be especially mild with high pressure overhead, What seemed a very outside chance of ending in the 4s is now increasing in probability.. how things can change.

Could this January end up being colder than last year now?