December 2022 C.E.T. and EWP contests _ start of a new contest year

[reef]

The minimum is correct. It is in the period between 0900 on the 18th and 0900 on the 19th and most areas were still cold at the beginning of that period.

For the same reason the mean maximum on the 18th is 13.0C as it captures 0900 on the 18th to 0900 on the 19th. This despite most of the 18th being very cold as it captured the rise overnight and into the morning of the 19th.

Edited December 20, 2022 by reef

[Roger J Smith]

Seems like they need to conform more to normal weather practice of a calendar day for max and min, nobody else has a climat day that extends back to 0900h the previous day. The 18th gets two chances to set a minimum. But it's their show and we are just the free audience I suppose. I'm 100% sure that nobody else does this and I wonder if even the Met Office other than this Hadley CET group do anything similar in calculating monthly mean temperatures? If so they don't conform to WMO procedures. 

Do you people with amateur weather stations also do this 0900 previous day thing as well? Has it never been challenged? 

Edited December 20, 2022 by Roger J Smith

[reef]

24 minutes ago, Roger J Smith said:

Seems like they need to conform more to normal weather practice of a calendar day for max and min, nobody else has a climat day that extends back to 0900h the previous day. The 18th gets two chances to set a minimum. But it's their show and we are just the free audience I suppose. I'm 100% sure that nobody else does this and I wonder if even the Met Office other than this Hadley CET group do anything similar in calculating monthly mean temperatures? If so they don't conform to WMO procedures. 

Do you people with amateur weather stations also do this 0900 previous day thing as well? Has it never been challenged? 

It has always been standard procedure in the UK. Before digital and automatic weather stations it was always standard procedure to read the Min and max thermometers at 0900 GMT (or 1000 BST). The minimum temperature is allocated to the current day and the maximum the day before. The rainfall total at 0900 is allocated to the previous day like the maximum.

It's done this way so records continue to be filled as historical readings were. Personally I keep both 0000-0000 and 0900-0900 records for my station. In reality there is little difference overall by the end of the month.

Edited December 20, 2022 by reef

[The PIT]

Sunny Sheffield up to 1.7C -3.8C  below average. rainfall up to 34.3mm 39.2% of the monthly average.

[SummerShower]

I did wonder about the min and maximum readings, those figures from yesterday make total sense now that I know the min readings are done as 24h from 9am the day before and maximums are 24h from 9am on the day.

The overall effect is probably the same I.e warmer the day before and colder the day after I.e. having negligible impact on the monthly cet.

[snowray]

Well I thought that it was 21.00 to 21.00, so the 24 hrs from 9pm to 9pm, you live and learn.

[Summer8906]

Based on GFS 00z I am seriously wondering whether this month will end up very close to the 81-10 average down here in the south, at least - despite earlier comments on the unlikeliness of this happening. On that run, only one day seems to be even average, let alone below: namely the 26th. The rest, varying degrees of mild to silly-mild, with persistent southwesterlies sometimes apparently from a long way south: so wondering in southern and SE England whether we'll get a mean temp of around 9C in the south for the final two weeks (made up of say 11C max, 7C min).

Edited December 21, 2022 by Summer8906

[Summer Sun]

1.4c to the 20th

3.1c below the 61 to 90 average
3.3c below the 81 to 10 average

[Don]

17 minutes ago, Summer Sun said:

1.4c to the 20th

3.1c below the 61 to 90 average
3.3c below the 81 to 10 average

CET in the 3's come the end of month?

[ItNeverSnowsInWindsor]

50 minutes ago, Don said:

CET in the 3's come the end of month?

And rainfall above 100mm ?

[kold weather]

2 hours ago, Summer8906 said:

Based on GFS 00z I am seriously wondering whether this month will end up very close to the 81-10 average down here in the south, at least - despite earlier comments on the unlikeliness of this happening. On that run, only one day seems to be even average, let alone below: namely the 26th. The rest, varying degrees of mild to silly-mild, with persistent southwesterlies sometimes apparently from a long way south: so wondering in southern and SE England whether we'll get a mean temp of around 9C in the south for the final two weeks (made up of say 11C max, 7C min).

I'd imagine given the depth of cold and the number of days close to 0c the south's anomaly so far might be even more severe than the CET, so the requirements to reach average will be again even more stringent than the CET, which is still going to require a heck of a mild spell to even get beyond 3.5c.

 

[Don]

5 minutes ago, prolongedSnowLover said:

And rainfall above 100mm ?

Nope rainfall around 90mm 

[Frigid]

Quite hard to predict the CET at months end, harder than normal I'd say. Consensus looks to be mild to average in most places, though with the models confused as ever, that can change at short notice.

Here are some guesses as to where the CET could be taken from recent cool to cold latter thirds of December (21-31st)

If we had a similar 10 days to Dec 2020, the CET would be ~ 2.1C

If we had a similar 10 days to Dec 2017, the CET would be ~ 3.2C

If we had a similar 10 days to Dec 2014, the CET would be ~ 2.7C

JJF.. If we had a similar 10 days to Dec 2010, the CET would be ~ 0.7C

If we had a similar 10 days to Dec 2009, the CET would be ~ 1.3C

Dec 2020 would be the safest option with 2014 not far off, to keep that CET less than 3C. 

[summer blizzard]

CET here was forecast to be around 5.5C for the 21st-28th so mild but not out of the ordinary and not likely to bring it above 3C for the month.

[kold weather]

57 minutes ago, Frigid said:

Quite hard to predict the CET at months end, harder than normal I'd say. Consensus looks to be mild to average in most places, though with the models confused as ever, that can change at short notice.

Here are some guesses as to where the CET could be taken from recent cool to cold latter thirds of December (21-31st)

If we had a similar 10 days to Dec 2020, the CET would be ~ 2.1C

If we had a similar 10 days to Dec 2017, the CET would be ~ 3.2C

If we had a similar 10 days to Dec 2014, the CET would be ~ 2.7C

JJF.. If we had a similar 10 days to Dec 2010, the CET would be ~ 0.7C

If we had a similar 10 days to Dec 2009, the CET would be ~ 1.3C

Dec 2020 would be the safest option with 2014 not far off, to keep that CET less than 3C. 

2020 had a pretty cool ending to the month (1.8c for the last 8 days), there isn't much in the models that would be suggestive of that level of coolness. 2014 maybe a better match, though it too maybe too cool in the last week vs what the models are showing. Conversely though it also is probably milder than we are likely to get beforehand, so it may well balance out close to that mark.

2017 looks a little too mild overall based on the models, given the northern station is probably going to be cooler than the other two in the next week on at least a few days which will take the top off the temps.

I think somewhere between 2.5-3c looks a most likely landing zone, perhaps edging more towards the lower end of the range. Crucially, the first below 61-90 month since I think May 2021.

 

[The PIT]

Sunny Sheffield up 2C -3.5C, rainfall up to 34.8mm 39.8% of the monthly average.

[ItNeverSnowsInWindsor]

With the lack of cold weather showing in the models I think the 3s should be nailed now.

[damianslaw]

Yes increasingly likely now we will see a predominantly mild remainder to December, helping to keep the CET rising, very much a month of two halves on the way, a very cold first half followed a mild second half or should I say 13 days, both cancelling each other out to an extent, but the depth of cold more potent than depth of mild, so a month below average in the 3s most likely breaking the long run of mild months.

 

[LetItSnow!]

Rough estimated values from now to the 31st using the ECM (I've rounded them out as exact decimals are impossible to forecast).

 

22nd - 6.5 (1.9)

23rd -  6.5 (2.1)

24th - 6.5 (2.3)

25th - 8.0 (2.5)

26th - 3.5 (2.5)

27th - 5.5 (2.6)

28th - 9.5 (2.9)

29th - 8.5 (3.1)

30th - 4.5 (3.1)

31st - 4.5 (3.2)

 

Give or take a couple tenths, it should finish between 2.9 and 3.5 I'd say.

Edited December 22, 2022 by LetItSnow!

[Summer Sun]

1.7c to the 21st

2.9c below the 61 to 90 average
3.0c below the 81 to 10 average

[Frigid]

21 minutes ago, LetItSnow! said:

Rough estimated values from now to the 31st using the ECM (I've rounded them out as exact decimals are impossible to forecast).

 

22nd - 6.5 (1.9)

23rd -  6.5 (2.1)

24th - 6.5 (2.3)

25th - 8.0 (2.5)

26th - 3.5 (2.5)

27th - 5.5 (2.6)

28th - 9.5 (2.9)

29th - 8.5 (3.1)

30th - 4.5 (3.1)

31st - 4.5 (3.2)

 

Give or take a couple tenths, it should finish between 2.9 and 3.5 I'd say.

Disappointing really, we could've had a really cold CET to finish.. but the backtracks scuppered our chances.

Similar to Feb 2021 in a way, though I don't think the CET ever went down to the 0s back then.  

[Don]

11 hours ago, prolongedSnowLover said:

With the lack of cold weather showing in the models I think the 3s should be nailed now.

Well, at least that gives my 3.8C guess a chance!! 

 

[The PIT]

Sunny Sheffield up to 2.2C. -3.2C below average. Rainfall unchanged

A steady rise to continue right to the end of the month by the looks of it.

[LetItSnow!]

23 hours ago, LetItSnow! said:

Rough estimated values from now to the 31st using the ECM (I've rounded them out as exact decimals are impossible to forecast).

 

22nd - 6.5 (1.9)

23rd -  6.5 (2.1)

24th - 6.5 (2.3)

25th - 8.0 (2.5)

26th - 3.5 (2.5)

27th - 5.5 (2.6)

28th - 9.5 (2.9)

29th - 8.5 (3.1)

30th - 4.5 (3.1)

31st - 4.5 (3.2)

 

Give or take a couple tenths, it should finish between 2.9 and 3.5 I'd say.

Turns out the 22nd actually did average 6.5! That means we are at 1.9 now.

[Don]

On 22/12/2022 at 16:22, Frigid said:

Disappointing really, we could've had a really cold CET to finish.. but the backtracks scuppered our chances.

Similar to Feb 2021 in a way, though I don't think the CET ever went down to the 0s back then.  

This month will be considerably colder than February 2021, but yes definitely some similarities!  Other Februaries comparable to this month are 2009 and 2012!