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

[Frigid]

Just now, kold weather said:

Hard to say where we are going beyond Wednesday, especially since the difference between the cold air and the very mild air zones is probably only a few hundred miles which at that sort of range is still uncertain.

I think one thing we can say is Monday and possibly Tuesday will be very mild indeed and will see the CET absolutely race up on those days.

I think odds are we WILL have the warmest year ever now, even if the mildest solutions don't happen.

Quite disappointing, but alas cold spells don't last forever.. 10 days is very good imo. Hoping we do get another cold spell at months end so we end up somewhere close to the 2s. This has been the coldest spell in December since 2010, pretty good for early winter.  Still got 2-3 months of cold potential left. 

[kold weather]

10 minutes ago, Frigid said:

Quite disappointing, but alas cold spells don't last forever.. 10 days is very good imo. Hoping we do get another cold spell at months end so we end up somewhere close to the 2s. This has been the coldest spell in December since 2010, pretty good for early winter.  Still got 2-3 months of cold potential left. 

I'd say this has been a very noteworthy cold spell, especially given the general lack of snowfall for a large chunk of the country. To get multiple ice days in the CET zone without snow cover is something quite unusual, especially these days.

I'd argue that if you placed this cold spell into the 60s or 80 it probably wouldn't be that notable, but in the context of winters since the brief colder spell between 09-13 it IS a pretty impressive cold spell, and this is easily the coldest such sustained spell since Jan 2013 (the beast 18 was at its peak colder, esp relative to average, but this spell has been way longer and therefore nothing 2018 can do over a 7-10 day period can compete).

 

[Midlands Ice Age]

Anyone more up to date than me on 'adjustments', at end of month.

5 -10 years ago when I was very interested, at end of month, it was very common to see end of month adjustments of between 0.0 and 0.5C.

These were applied at the  end of the month retrospectively and were supposed to be because (particularly at this time of year) the time of reading of the minimum every hour (say 08:00), did not always coincide with  the lowest minimum.

Recently, this month,  most of us have seen that the temperature continues dropping until around 08:30.

Do the more modern methods of data collection mean that these are still applied or necessary  (every minute/second/up to date), or, is it unnecessary and not used now?

Various other rumours around adjustments for Urban Heat Island effect of 0,2C,  or thereabouts, I think have now subsided!!!

MIA

 

[Frigid]

Wow.. min CET yesterday was -9.3C

[Summer Sun]

0.8c to the 15th

3.8c below the 61 to 90 average
4.1c below the 81 to 10 average

[Midlands Ice Age]

1 hour ago, Frigid said:

Wow.. min CET yesterday was -9.3C

Well this sneaked up on us....

Yesterday (the 15th) was a new record since 1871 (and the new CET records), the -9.3C beat the previous best legacy and V2 CET records of -8.4C and -8.3C respectively from 1878........ A NEW RECORD .......

I was surprised that we beat the minimum record, and thought it possible that we would beat the low maximum record for the    date of +0.4C, but it came in at +0.5C.

The other thing of interest was that yesterday' s CET mean was -4.4C not far away from the all time record for the date of -5.5C. set back 300 years ago.

So that extends to 8 days  the number of consecutive sub zero mean CET's achieved in this cold spell.

MIA

[summer blizzard]

23 minutes ago, Midlands Ice Age said:

Well this sneaked up on us....

Yesterday (the 15th) was a new record since 1871 (and the new CET records), the -9.3C beat the previous best legacy and V2 CET records of -8.4C and -8.3C respectively from 1878........ A NEW RECORD .......

I was surprised that we beat the minimum record, and thought it possible that we would beat the low maximum record for the    date of +0.4C, but it came in at +0.5C.

The other thing of interest was that yesterday' s CET mean was -4.4C not far away from the all time record for the date of -5.5C. set back 300 years ago.

So that extends to 8 days  the number of consecutive sub zero mean CET's achieved in this cold spell.

MIA

Did Jan 13 get eight consecutive or is this a record back to Dec 10.

[Midlands Ice Age]

16 minutes ago, summer blizzard said:

Did Jan 13 get eight consecutive or is this a record back to Dec 10.

According to the other thread (HIstory of 5 or more ice days),    2013 finished with 8 days.    We should get a 9th tomorrow (for today), but not certain about a 10th as milder air is seeping in on Saturday.

So yes it now goes back to Dec 10.

MIA

Edited December 16, 2022 by Midlands Ice Age

[LetItSnow!]

18th and 19th look very mild, I imagine a very big jump up! After then it looks like temperatures returning closer to average, perhaps slightly milder in the south and slightly colder in the north. By the time we get to Christmas it looks like there are themes being sniffed out at a route back to cold. Still not a done deal we will come out above 3 and I am of course rooting for the lowest number possible, but I think anything severely cold can probably be ruled out. 

I did a rather crude estimation of the C.E.T. for the coming week using the GEM (it’s been performing very well recently) and I came up with:

 

16th : -3.5

17th : -0.8

18th : 3.8

19th : 10.8

20th : 9.2

21st : 5.8

22nd : 7.1

23rd : 3.9

That would leave us at 2.0C by the 23rd. If we are in the low 2s by then then it leaves the month very open to a number of endings. A sustained mild push could lead us comfortably in the 2s and very mild weather could send us into the 3s. However, another cold spell could take us back down into the 1s. Cold zonality wouldn’t probably move it much at all. I think we can rule out anything extreme under 1C though. 

[damianslaw]

1 hour ago, Midlands Ice Age said:

Well this sneaked up on us....

Yesterday (the 15th) was a new record since 1871 (and the new CET records), the -9.3C beat the previous best legacy and V2 CET records of -8.4C and -8.3C respectively from 1878........ A NEW RECORD .......

I was surprised that we beat the minimum record, and thought it possible that we would beat the low maximum record for the    date of +0.4C, but it came in at +0.5C.

The other thing of interest was that yesterday' s CET mean was -4.4C not far away from the all time record for the date of -5.5C. set back 300 years ago.

So that extends to 8 days  the number of consecutive sub zero mean CET's achieved in this cold spell.

MIA

In a year dominated by record breaking heat, its refreshing to see a record breaking cold statistic. What has been notable as others have said is the very low mins have not been attributed to deep snow cover. Had we seen deep snow, then much colder mins would have been recorded, akin to 2010. That's the only difference between this spell and that month.

Its been an unusual situation the abundant clear skies, sunshine, no snow, frost looking like snow, and no wind. We have grown our own cold pole. I suspect mean temps in Cumbria over the last week will have been close to those of the 16-26 Dec 2010, perhaps not as severe, but lakes have started to freeze.

Looking forward to some decent snow for the fells, annoying the snow forecast this weekend will probably be stripped clean of the fells early next week, but hope some will come back before christmas so will at least have some snow to look at, ideally on low ground as well!

Back to the CET I still think good chance will finish in the 2s with a signal for colder settled conditions just after christmas.

[The PIT]

Sunny Sheffield down to 1.3C -4.5C below average. Rainfall unchanged.

Low point tomorrow then a slow climb. Guessing finishing point between 2C to 3C.  Very good chance of it making the top coldest Decembers we have recorded. Right now in third place and you can guess which two are ahead of it. So at the moment in very good company.  Pity it won't stay so far up.

[Roger J Smith]

8 hours ago, Midlands Ice Age said:

Anyone more up to date than me on 'adjustments', at end of month.

5 -10 years ago when I was very interested, at end of month, it was very common to see end of month adjustments of between 0.0 and 0.5C.

These were applied at the  end of the month retrospectively and were supposed to be because (particularly at this time of year) the time of reading of the minimum every hour (say 08:00), did not always coincide with  the lowest minimum.

Recently, this month,  most of us have seen that the temperature continues dropping until around 08:30.

Do the more modern methods of data collection mean that these are still applied or necessary  (every minute/second/up to date), or, is it unnecessary and not used now?

Various other rumours around adjustments for Urban Heat Island effect of 0,2C,  or thereabouts, I think have now subsided!!!

MIA

 

So far the new v2.0 regime has been almost free from later adjustments, I've been watching for them and the only examples of later changes made occurred a couple of days ago as I mentioned in this thread. Otherwise I think there has been an unbroken regime of posting then holding on to values without end of month adjustments. I would never say never, sent the Met Office a message recently asking them to clarify some potential transcription errors in a portion of the "CEP" portion of EWP (any day that was 19th of any month in CEP had any second digit values stripped out, mostly 1s but one 2 and one 3, meaning there were about thirty errors of 10 mm, one of 20 mm and one of 30 mm (19 June 1973). I verified this from comparing their numbers to (a) my downloaded data base from an earlier table and (b) their own tables now have that number of discrepancies between additions of daily data and monthly data which remained as before. I speculated that maybe this happened because some technology of scanning the old data (in rows) missed the far left end of row 2 (row 1 had a month designator) and missing zero in 0x.xx makes no difference but missing 1x.xx (over thirty times) does matter. At the same time I had one question about CET data to add to that, 23 Dec 1884 has a higher min (0.5) than max (-2.6) as it also did in the legacy set. I suspect that has to be an error, a min can't be higher than a max unless you have non-overlapping time frames and then you would have more than one in that many data points. 

Will let you know what they tell me about these queries. But the basic answer to your question is, don't expect many changes after first posting of v2.0 CET, but now we've seen that it can happen. 

I updated the table back in the thread with the record comparisons and will bring it to current date around Sunday when the cold spell appears to be over. 

[Roger J Smith]

Will probably see another record low minimum for today, Pershore shows -10.3 as their min, the other two locations appear to be well below -7 also. The record low was -5.6 in 1899. But the daily records do not include 1859 which was probably closer to -10 based on the record low mean. The max for today was around 1.5 to 2.0, so the daily mean could be around -3 or -3.5. That will bring tomorrow's update in around 0.5. 

Edited December 16, 2022 by Roger J Smith

[Midlands Ice Age]

So Roger...

I think you are looking specifically at data errors. And yes they must be picked up.

I am talking about possible systematic errors, which you may not pick up in your clearly excellent data checking algorithm's.

Is it true to say that we can assume that they must now be getting online temperatures from their 3 main  stations and that they can collect the data automatically to find their maximums / minimums?

It would be very simple to automate and I am amazed that it apparently hasn't been done before. 

If so.....      Has this 'change' been reported/announced anywhere.?

I am aware that certain (many?) stations were sending online data when we hit the max back in July, but everyone was watching for that. Minimums are a lot less visible, and can occur at weird and unexpected times (as per yesterday).

 It would be nice to understand any changes made.

MIA.

 

[Roger J Smith]

Well as you may know, the CET is generated from three locations, two of which (Pershore, Rothamsted) are shown on meteociel maps so I can see their max and min, but Stonyhurst (Lancs) is not on the map so I have to estimate that one from the regional grid. I would imagine what they now do is collect those three in real time and add 0.2 as their urban heat island correction (which I think in reality is zero at two locations and 0.6 at Rothamsted which is near Luton and probably somewhat urban-heated, but the other two locations remain essentially rural). If they collect them in real time and adjust them, then there's no need to do the old end of month corrections, I am not sure why those were ever needed as the three stations must have been reporting in real time for most of the recent decades at least. But whatever the reason, v2.0 operates differently than the CET legacy era and we are now apparently going to have more or less instant "set" values which is how climate stats generally operate in other countries (albeit with quality control in the background which theoretically can change a posted value eventually). Odd things happen at climate stations. I have 182 years of Toronto data as you may know, in 2020 the downtown Toronto location started picking up small amounts of rain almost every day when the surrounding grid was mostly dry with a few wet days. I speculated that perhaps some lawn watering sprinkler system turned on and off each day and variable winds resulted in variable amounts of that moisture finding the rain gauge which the observer was clearly reading each morning for the previous "day." Have made an effort to chase this down but so far it's the usual "Roger can't be right about anything, he's not one of us" that has been my lot in life ever since I left the objective testing environment which was regularly proving that paradigm to be incorrect. You can't fix stubborn (or anything else starting with stu). 

Edited December 16, 2022 by Roger J Smith

[ItNeverSnowsInWindsor]

Looking good for low 3’s with such mild weather on route next week and possibly the following week not looking wintry!

[ItNeverSnowsInWindsor]

13 hours ago, Roger J Smith said:

Will probably see another record low minimum for today, Pershore shows -10.3 as their min, the other two locations appear to be well below -7 also. The record low was -5.6 in 1899. But the daily records do not include 1859 which was probably closer to -10 based on the record low mean. The max for today was around 1.5 to 2.0, so the daily mean could be around -3 or -3.5. That will bring tomorrow's update in around 0.5. 

Most places were sub zero with only some towns and cities above freezing.

Edited December 17, 2022 by prolongedSnowLover

[Summer Sun]

0.5c to the 16th

4.0c below the 61 to 90 average
4.4c below the 81 to 10 average

[Frigid]

Maybe a further reduction today - CET zone was quite cold last night, but after that the rise commences. 

[LetItSnow!]

4 hours ago, prolongedSnowLover said:

Looking good for low 3’s with such mild weather on route next week and possibly the following week not looking wintry!

Hmm… not entirely sure about that. Still cold solutions being played around with for Christmas and beyond. The mean for the 25th is quite juicy. I’m feeling 2s. Could be 3s if that fails. Watch this space. 

[Snowyowl9]

Nearly as cold as 1981 who d thought that..

Mild go away to spain..

[Midlands Ice Age]

18 hours ago, Roger J Smith said:

Will probably see another record low minimum for today, Pershore shows -10.3 as their min, the other two locations appear to be well below -7 also. The record low was -5.6 in 1899. But the daily records do not include 1859 which was probably closer to -10 based on the record low mean. The max for today was around 1.5 to 2.0, so the daily mean could be around -3 or -3.5. That will bring tomorrow's update in around 0.5. 

Correct Roger...

 The new record minimum  low for yesterday turned out be -8.0C, bettering the previous best by 2.4C. 1899.

This allowed the  mean to be another negative at -3.0C, as the high was +2.1C for yesterday.. 

Well - we have managed a run of 9 consecutive below zero days now, during which time we have a mean (average) low of -.2.2C, placing it in the top half in the table of as one of the top cold spells of the last 100 years. (based upon length of the spell and mean temperature). It also ranks in the top 10 for December.

 

MIA

[The PIT]

Sunny Sheffield still at 1.3C -4.5C below average. Rainfall at 19.9mm 22.7% of the monthly average.

The main reason why there's a huge difference between the national CET and here is lack of very cold nights. The lowest -5C.

Unless it gets warmer overnight should manage a slight fall for today.

[Roger J Smith]

So here's how 2022 finished up relative to the coldest years in the first half of December (will update this table) ... this just repeats an earlier post with 2022 added to date. (note on 18th, some minor changes have been made to the 2022 data, not sure if that will continue and any of the posted values may change eventually).

 

Coldest running means (v2.0 CET) for 15th to 18th ... in order of the values for 1st-16th since that's officially the first half of a 31-day month ...

The table includes all years 1772 to 2021 that had a running mean of 1.0 or lower on any of those four days. Also shown, the coldest running mean after 18th (if it continued to warm, then from before or during this interval in brackets), and the end result by 31st. I will add 2022 actuals to this table and repost it after 18th (if the cold spell goes on longer then will extend it, current guidance shows big warming trend 18-19). (ties such as 1879, 1844 on 16th broken by second decimals)

YEAR ____ CET 1-15 __ CET 1-16 __ CET 1-17 __ CET 1-18 ____ coldest ______ end DEC

1879 _____-1.3 _____ -1.0 _____ -1.0 _____ -0.9 ______(-3.7) (7th) _______ 0.7

1844 _____-1.2 _____ -1.0 _____ -0.7 _____ -0.4 ______(-1.4) (14th) ______ 0.4

1878 _____-0.7 _____ -0.8 _____ -1.0 _____ -0.9 ______ -1.5 (25th) ______ -0.3

1796 _____-0.8 _____ -0.7 _____ -0.6 _____ -0.6 ______ -1.0 (27th) ______ -0.3

1788 _____ 0.2 _____ -0.2 _____ -0.3 _____ -0.4 ______ -0.4 (20th,23rd) __ -0.3

1846 _____ 0.1 _____ -0.0 ______ 0.0 _____ -0.1 ______(-0.1) (18th) ______ 0.5

1819 _____ 0.2 ______ 0.2 ______ 0.5 ______1.0 ______(0.2) (14th,15th) ___ 1.4

2010 _____ 0.0 ______ 0.3 ______ 0.1 _____ -0.1 ____ (-2.2) (8th), -1.5 (27th) _ -0.7

1890 _____ 0.4 ______ 0.3 ______ 0.2 ______ 0.2 ______ -0.8 (30th,31st) __ -0.8

1784 _____ 0.3 ______ 0.3 ______ 0.4 ______ 0.4 __ (0.1) (13th)  0.2 (26th-29th) _ 0.3

1981 _____ 0.6 ______ 0.4 ______ 0.2 ______ 0.0 ______-0.5 (26th) _______ 0.1

2022 _____ 0.8 ______ 0.5 ______ 0.4 _______ ??? ______0.4 (17th) _______ ???

1791 _____ 0.8 ______ 0.7 ______ 0.5 ______ 0.4 ______ 0.3 (22nd) _______1.1

1782 _____ 0.9 ______ 0.9 ______ 1.0 ______ 1.4 ______ 0.1 (3rd) ________ 2.8

1882 _____ 0.8 ______ 1.0 ______ 1.3 ______ 1.6 ______ 0.3 (2nd) _______ 3.9

1916 _____ 1.2 ______ 1.0 ______ 0.8 ______ 0.7 ______ 0.7 (18th,19th,20th) _ 1.9  

1859 _____ 1.6 ______ 1.1 ______ 0.6 ______ 0.1 ______-0.2 (19th) _______ 1.6

1933 _____ 1.1 ______ 1.1 ______ 1.2 ______ 1.2 ______(1.0) (13th,14th) ___ 1.6

1807 _____ 1.4 ______ 1.3 ______ 1.2 ______ 1.1 ______ 0.7 (23rd) _______ 1.9

1801 _____ 1.7 ______ 1.5 ______ 1.2 ______ 1.0 ______ 0.5 (20th) _______ 1.5

_______________________________

for comparison, some more recent cold and the odd non-qualifying before and after cold of Dec 1870 and the later cold of Dec 1874

(any years that were colder than 1.0 before 14th and failed to qualify otherwise are not shown, for example Dec 1803, 1952)

 

1950 ______ 1.7 ______ 1.6 ______ 1.6 ______ 1.6 ____(1.2) (6th,30th,31st) _ 1.2

1962 ______ 3.1 ______ 3.2 ______ 3.4 ______ 3.5 ____ (-0.3) (6th) _______ 1.8

1976 ______ 1.7 ______ 1.6 ______ 1.6 ______ 1.6 _____(0.5) (5th) _______ 1.8

2012 ______ 2.3 ______ 2.6 ______ 2.8 ______ 2.9 _____ (1.9) (13th) ______4.7

1870 ______ 2.8 ______ 2.8 ______ 2.8 ______ 3.0 ___ 0.9 9th-10th, 0.6 (31st) _ 0.6

1874 ______ 1.9 ______ 1.7 ______ 1.5 ______ 1.4 _____ (-1.0) (2nd) ______-0.2

______________________________________________________

 

(so, 2022 was 12th coldest first half of DEC in 251 years with daily data, just around the zone where end of month outcomes start to become more variable (see the group immediately below 2022, compared to those just above it). 

Edited December 18, 2022 by Roger J Smith

[The PIT]

Sunny Sheffield down  to 1.2C -4.5C below average.  Rainfall 22.4mm 25.6% of the monthly average.

Low point of the month then probably end up between 2C to 3C  for us and 1.5C to 2.5C in the CET zone. Hard to call really.