November 2023 C.E.T. and EWP contests -- final month of the 2022-23 competitions

[Roger J Smith]

add to previous daily CET update,

0.3 above 1991-2020 average of 8.9 C for 1-6 Nov. 

[The PIT]

Sunny Sheffield still at 8.7C -1.2C below average. Rainfall 43.4mm 49.2% of the monthly average.

[ItNeverSnowsInWindsor]

20 hours ago, TillyS said:

The ECMWF would be a LOT colder though with the high pressure, no? It is very different from the GFS. There’s some intense cold knocking on our door here:

 

It’s not looking promising this morning on any models! Back to mild mush.

[Summer Sun]

9.1c to the 7th

2.6c above the 61 to 90 average
0.5c above the 81 to 10 average

[WYorksWeather]

ECMWF meteograms

Luton:

Pershore:

Clitheroe:

Above average except for the next three or four days, and therefore well above average with respect to 1961-1990 as these are analogous to 2004-2023 averages.

[The PIT]

Sunny Sheffield still at 8.7C -1.0C below average. Rainfall up to 46.3mm 52.4% of the monthly average.

[reef]

19 hours ago, The PIT said:

Sunny Sheffield still at 8.7C -1.0C below average. Rainfall up to 46.3mm 52.4% of the monthly average.

I didn't realise the start of November was so warm further inland. The rolling 1991-2020 mean here to 8th November is 8.8C, almost a degree lower.

[Summer Sun]

9.0c to the 8th

2.6c above the 61 to 90 average
0.4c above the 81 to 10 average

[Roger J Smith]

EWP now at around 50 mm, will add a similar amount in next two weeks according to GFS, to sit near 100 mm by last few days of November. 

A colder look to today's model run, in fact quite cold for about a week after a near average week, if it verifies, CET will drift down slowly at first to 8.5 and will later fall faster towards 7 C and possibly into 6.0 to 6.5 range. Would like to see trend repeating a few times before buying into it completely. 

Warmest autumn was going to need 8.9 in Nov and it's not looking very likely, in fact top four or five are being taken off table by current outlook (see my table posted a few days ago for prospects). 

[The PIT]

Sunny Sheffield down to 8.6C -1.0C below average. Rainfall 47.7mm 54% of the monthly average.

[Summer Sun]

8.9c to the 9th

2.4c above the 61 to 90 average
0.4c above the 81 to 10 average

[Froze were the Days]

A bit off kilter here...but looking at the 61-90 and then onto the 81-10 mean, that's one hell of a jump in 20 years - 2c warmer!!

Edited November 10, 2023 by Froze were the Days

[WYorksWeather]

21 hours ago, Roger J Smith said:

EWP now at around 50 mm, will add a similar amount in next two weeks according to GFS, to sit near 100 mm by last few days of November. 

A colder look to today's model run, in fact quite cold for about a week after a near average week, if it verifies, CET will drift down slowly at first to 8.5 and will later fall faster towards 7 C and possibly into 6.0 to 6.5 range. Would like to see trend repeating a few times before buying into it completely. 

Warmest autumn was going to need 8.9 in Nov and it's not looking very likely, in fact top four or five are being taken off table by current outlook (see my table posted a few days ago for prospects). 

To be fair (presuming this was yesterday's GFS 12z) it was very much a cold outlier - I looked at it on the model thread. The GFS mean is nowhere near that cold, and is in fact above average. The colder option is still there, but it's a minority option, around four or five model runs out of 30.

I'll do my ECM meteograms again which are somewhat better I feel for showing the range of outcomes with the box plots.

Luton, Pershore, Clitheroe (in order):

Luton looks to have some extremely mild nights later on with current guidance, as does Pershore. Clitheroe a little less so, but still it's hard to see the next 15 days or so netting out to anything below average. A couple of colder days over the weekend won't counteract a week of mild weather. Of course, subject to whether it verifies.

 

[Roger J Smith]

7 hours ago, Froze were the Days said:

A bit off kilter here...but looking at the 61-90 and then onto the 81-10 mean, that's one hell of a jump in 20 years - 2c warmer!!

Not so fast, as I explained to another reader a few days ago, 61-90 is taking running mean and comparing to end of November (61-90 average) and metoffice changed to that way of reporting when CET legacy ended and v2.0 started. 81-10 is being compared to a running mean so yesterday's value was for 1st to 9th. That explains almost all of the differential. 

I don't know why the reporting changed after April 2022, but I wish it hadn't because this discussion keeps arising. I could work out the 61-90 running means but a rough estimate would be 0.3 colder compared to 81-10, and 0.5 colder relative to 91-20 running means which are available in the thread (see a table I posted on 2nd of Nov, it is where Summer Sun gets the 81-10 data for comparison). In the invitational post at start of thread as you may know there are various 30-year averages including 1961-90 and 1971-2000 which we never talk about, and also 1993-2022. Also century averages and various other historical info are posted. 

-------------------

On a different topic, I note yesterday's colder run of GFS is only partially sustained today and would estimate a less substantial fall into low to mid 7's as a result. A weak push of cold air happens a couple of different times but it does not look as potent, probably a few daily means around 4 or 5 as a result. 

[Summer Sun]

8.6c to the 10th

2.2c above the 61 to 90 average
0.2c above the 81 to 10 average

[The PIT]

Sunny Sheffield down to 8.3C -1.1C below average. Rainfall 47.7mm 54% of the monthly average.

[WYorksWeather]

Took a few minutes this afternoon to tweak the chart I posted earlier. Here's the averages for the first third of November. The point for 2023 is tough to see, but to one decimal is 8.6C, exactly the same as the long-term average 1994-2023.

 

[Midlands Ice Age]

21 hours ago, Roger J Smith said:

Not so fast, as I explained to another reader a few days ago, 61-90 is taking running mean and comparing to end of November (61-90 average) and metoffice changed to that way of reporting when CET legacy ended and v2.0 started. 81-10 is being compared to a running mean so yesterday's value was for 1st to 9th. That explains almost all of the differential. 

I don't know why the reporting changed after April 2022, but I wish it hadn't because this discussion keeps arising. I could work out the 61-90 running means but a rough estimate would be 0.3 colder compared to 81-10, and 0.5 colder relative to 91-20 running means which are available in the thread (see a table I posted on 2nd of Nov, it is where Summer Sun gets the 81-10 data for comparison). In the invitational post at start of thread as you may know there are various 30-year averages including 1961-90 and 1971-2000 which we never talk about, and also 1993-2022. Also century averages and various other historical info are posted. 

-------------------

On a different topic, I note yesterday's colder run of GFS is only partially sustained today and would estimate a less substantial fall into low to mid 7's as a result. A weak push of cold air happens a couple of different times but it does not look as potent, probably a few daily means around 4 or 5 as a result. 

Roger...

 To save more people from this misunderstanding could we not ask Summer Sun to add the word  monthly to his 61 - to 90 'monthly' average

.....and 'current' to his 81 to 10 'current' average figures?. 

I think most people would understand this then.

MIA

[Roger J Smith]

EWP is around 61-62 mm and GFS grid average is around 40 mm (mostly around 30 with larger amounts in west) so by 27 Nov if it verifies, around 100 mm near end of November. CET outlook is a blend of quite mild spells mid-week and near end of run, and cooler days now, and in between two mild spells. Would say mid 7 to possibly 8.0 look well positioned but a lot depends on later second mild spell not yet into reliable forecast range. FWIW maps for 27 Nov at end of run would suggest storm potential around 29 Nov.  

[Roger J Smith]

2 hours ago, Midlands Ice Age said:

Roger...

 To save more people from this misunderstanding could we not ask Summer Sun to add the word  monthly to his 61 - to 90 'monthly' average

.....and 'current' to his 81 to 10 'current' average figures?. 

I think most people would understand this then.

MIA

Agreed but I will leave it to S Sun how he wants to organize his posts. I could work out 61-90 running averages too, and we would have a better basis for reporting. I prefer to have running averages because obviously Nov is going to be a lot higher for CET at start than finish, usually. 

[Roger J Smith]

This is a really deep dive, but just so people know, the differential quoted for 61-90 is not done for one dec, but for two, and so you can see 0.1 changes day to day in the 61-90 end value if you're using one dec, for instance, if today was 8.64 and 61-90 average was 6.48 (not saying these are actual values) then they would say 2.2 above average even though in one dec it would be 2.1 (8.6 vs 6.5) so, since the website only shows one dec, you think the 61-90 average is 6.4 but actually it is 6.5 ... this happens on a few days and can go either way, so you can't always calculate the 61-90 average directly. 

I wasn't told this but figured it out back in 2022 when I was trying to figure out what was happening to the reporting when it changed on their site. At first I could see they had switched to end of June (when I was looking into it) but day to day the back-calculation to 61-90 kept changing up and down in a narrow range. So I worked out second dec and found out the cause. 

This end value results in chaos in spring and fall, less obvious in January and July when values are fairly flat. In spring it appears 61-90 CET is a lot higher than 81-10, at least for first half, the fact that 61-90 is about 0.5 colder than 81-10 at end starts to decrease the strange look before end (of April especially). In fall you get this large positive differential that persists to end because 61-90 is now about 0.5 lower than current averages. 

I can't believe they continue to use 61-90 and I wonder if 71-00 will ever get a period of usage or they would just go straight to 81-10 or 91-20? Perhaps in 2052 people will be wondering when the old 81-10 averages will get the hook. Let\s hope they can say "but it doesn't really bother us because 81-10 is 0.1 higher than 21-50" but I won't put any cash on that proposition. 

[The PIT]

Sunny sheffield down to 8.1C -1.2C belwo average. Rainfall unchanged.

[Summer Sun]

8.4c to the 11th

2.0c above the 61 to 90 average
Bang on the 81 to 10 average

[Summer Sun]

8.2c to the 12th

1.7c above the 61 to 90 average
0.2c below the 81 to 10 average

[The PIT]

Sunny Sheffield down to 7.9C -1.2C below average. Rainfall 55.4mm 62.7% of the monthly average.