November 2021 C.E.T. and EWP contests -- final month of the 2020-21 competitions

[Summer Sun]

9.8c to the 1st

0.7c above the 61 to 90 average
0.3c above the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 9.8c on the 1st

[Roger J Smith]

Autumn gloom rather than summer sun today ...

8.8c to the 2nd ...

0.2c below the 61 to 90 average
0.4c below the 81 to 10 average

(0.6c below the 91 to 20 average)

___________________________

Current high this month 9.8c on the 1st
Current low this month 8.8c on the 2nd

Edited November 4, 2021 by Roger J Smith

[Summer Sun]

8.8c to the 3rd

0.5c below the 61 to 90 average
0.4c below the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 8.8c on the 2nd & 3rd

[Roger J Smith]

EWP running dry, 6 or 7 mm through 4th, only about 5-10 mm indicated for ten days, and not a lot in a wintry northerly flow depicted for days 11-16 (which knowing the GFS could be something we won't actually be seeing, but this is theoretically what will happen). The EWP could be as low as 20 mm well into the month now. 

Mild until that postulated cold turn, running CET likely to remain in the 8 to 10 range until then. FWIW the last five days of the run would average close to 2 C as shown, and that would bring the running CET down from around 9 to 7 C. 

[Roger J Smith]

Also for continuity ...

7.8c to the 4th

0.6c below the 61 to 90 average
1.2c below the 81 to 10 average

1.4c below the 91 to 20 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.8c on the 4th

[Summer Sun]

7.6c to the 5th

0.6c below the 61 to 90 average
1.3c below the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.6c on the 5th

[The PIT]

Sunny Sheffield at 7.7C -2.2C below normal. Rainfall 5.4mm 6.1% of the monthly average.

[The PIT]

Sunny Sheffield at 7.8C -2.0C below normal. Rainfall 5.8mm 6.6% of the monthly average.

[Scorcher]

The only way is up now for the foreseeable future I feel.  Nothing cold on the horizon at all.

[damianslaw]

31 minutes ago, Scorcher said:

The only way is up now for the foreseeable future I feel.  Nothing cold on the horizon at all.

Perhaps for a week only.

[Summer Sun]

7.8c to the 6th

0.2c below the 61 to 90 average
0.9c below the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.6c on the 5th

[The PIT]

Sunny Sheffield up to 8C -1.7C below normal. Rainfall still at 5.8mm 6.6% of the monthlyaverage

Edited November 8, 2021 by The PIT

[Summer Sun]

8.1c to the 7th

0.1c below the 61 to 90 average
0.6c below the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.6c on the 5th

[LetItSnow!]

not getting carried away at the moment (ala february, 2021) but i’m not so confident of a mild month with some of the output appearing at the moment… but i’ve been made a fool out of before so that’s all i’ll say  

[Roger J Smith]

EWP will continue to run very dry and this month seems to have a shot at finishing among the driest Novembers. The current total is 8 mm and that seems to have held from last report to current time. The ten-day GFS estimate is very small, virtually zero over much of southern England and nowhere much more than 10 mm, so would only add 2 mm to the 18th for 10 mm. Then the charts for days 11 to 16 have only small amounts although a band of heavier rain is lurking to the west of Ireland on day 16 (this from the 18z GFS anyway). If this guidance is correct we would not be much higher than 12-15 mm by about the end of the 24th. Of course there could be a deluge from then to the end nullifying the drought but a normal amount of rain for the last six days would be perhaps 15-20 mm which would imply most likely outcome only 40-50 mm. That is quite dry for November -- 40 mm would be the 9th driest since 1766 and the driest since 1956 (33.3 mm, 6th driest -- 17.0 in 1945 was lowest all-time). Since 1956 the driest November was 1988 (50.2 mm, 25th driest). It appears that dry Novembers have become increasingly rare since most of the top ten were in the 19th century, with another from 1909. Since 1988 the driest has been 32nd driest 2004 (52.8 mm).

On the CET side, the mild spell becomes increasingly anticyclonic which raises the possibility of colder nights or inversion situations but thicknesses remain fairly high, overall, until about the 19th after which there is a moderately cold outbreak which is shown to be slowly moderating by the end of the run. So in general, I would expect the CET to continue a slow rise for about a week, reaching perhaps 9 C then stalling or dropping slightly for a few days, and then dropping faster as means around 2-4 C are experienced for several days. Those would drop the running CET by up to 0.3 or 0.4 a day before the situation stabilized, so by the 24th I would estimate we might be around 7.5 C (but could conceivably be quite a bit lower if either there are inversion days or there turns out to be a colder outbreak). I would hesitate to say that any CET forecasts are eliminated yet, much depends on what happens towards the end of the month beyond this model run. A milder turn could bring the mean back towards 8 C and continued rather cold could drop it into the 6 to 7 range, but 5 to 6 not ruled out (I think our lowest forecasts are around 5, and our highest around 9 C). 

[Summer Sun]

8.2c to the 8th

0.2c below the 61 to 90 average
0.5c below the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.6c on the 5th

[Summer Sun]

8.5c to the 9th

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

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.6c on the 5th

[The PIT]

Sunny Sheffield at 8.4C -0.9C below average. Rainfall 5.8mm 6.6% of the monthly average

[Summer Sun]

8.7c to the 10th

0.8c above the 61 to 90 average
0.1c above the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.6c on the 5th

[Summer Sun]

8.9c to the 11th

1.0c above the 61 to 90 average
0.4c above the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.6c on the 5th

[Scorcher]

On 07/11/2021 at 09:35, damianslaw said:

Perhaps for a week only.

It looks like continuing mild now, and probably rather cloudy so not much hope of cold nights either. Perhaps something cooler for the final third of the month, but the CET will be well above average by then.

[The PIT]

Sunny Sheffield at 8.7C -0.7C below normal. Rainfall 6mm 6.8% of the monthly average

[Roger J Smith]

This month seems to be on track to finish among the driest Novembers, unless (a) the guidance is wrong or (b) there is a deluge on the 29th and 30th. The GFS shows basically no further precipitation in most of England and just small amounts in Wales and Cumbria, to add to the estimated total of 15 mm that has fallen so far. The ten-day map is almost dry and the 11-16 day maps are totally dry as blocking high pressure remains in place over the North Sea and nearby land. Some rain looks likely beyond day 16 (which is the 28th) but unless that is quite heavy this guidance suggests 2021 could find its way into the top ten dry November list, which is currently this:

1945__17.0 mm ... 1805_23.1 ... 1788_25.1 ... 1867_30.6 ... 1909_33.0 ... 1956_33.3 ... 1879_37.3 ... 1855_38.4 ... 1871_40.4 ... 1896_40.7

If we do find 2021 in this list, it will probably be the mildest of the dry Novembers, in the same order, the CET values of these were

1945_7.2 ... 1805_4.8 ... 1788_6.1 ... 1867_4.8 ... 1909_4.8 ... 1956_6.0 ... 1879_4.1 ... 1855_5.3 ... 1871_3.4 ... 1896_4.3

Although these appear quite cold, since most of them were before 1920 in an era when November means were often in the low to mid 5's this set is only moderately cold. Some of the winters that followed these were rather cold at times, one or two were generally mild (including 1956-57 which also led to the warmest March). The coldest (1871) was a rare case of November being the coldest month of the winter season (the other months to March were 3.6, 5.0, 6.9, 6.8). Both 1788 and 1879 were immediately followed by very cold Decembers. 

Meanwhile, the CET looks to be heading for a finish near or above 8.0 now, as mild weather will continue all of the coming week and there is only a brief downturn around the weekend of the 20th-21st, with relatively mild conditions to follow. The finish of the contest could be a very close calculation if the outcome is 7.7 to 7.9; at 8.0 or higher I would think Reef has it sown up. Here was a list that I posted in the October thread in case you didn't see it there, and from this I can estimate that perhaps four of the top fifteen have some chance of finishing first ... see the analysis below this list ...

 

Rank __ Forecaster ___ Points behind leader ___ Nov CET prediction

_01 ___ Reef ________________ 0.0 ________________ 8.1

_02 ___ summer18 _________ 3.1 ________________ 6.9

_03 ___ stargazer __________ 10.3 _______________ 7.9

_04 ___ noname_weather _ 14.0 ________________5.5

_05 ___ Quicksilver1989 ___ 18.6 _______________ 7.1

_06 ___ Feb91Blizzard _____ 23.2 _______________ 7.0

_07 ___ Leo97t _____________ 25.8 _______________ 7.5

_08 ___ Roger J Smith ______ 34.1 _______________ 7.8

_09 ___ davehsug __________ 39.8 _______________ -- --

_10 ___ dancerwithwings ___40.3 _______________ 7.6

_11 ___ Summer Sun _______ 49.6 _______________ 7.2

_12 ___ Polar Gael __________ 54.2 _______________ 6.4

_13 ___ weather-history ____ 54.8 _______________ 6.9

_14 ___ Gen Cluster (EdS) ___56.3 _______________ 7.0

_15 ___ Mulzy ______________ 61.6 _______________ 7.3

____________________

The first comment would be that rank after October is not quite as significant as the points differential, with five factors going into the scoring, anyone could easily make up a ten point differential with just a slightly higher November rank (by higher rank I mean lower rank number, this concept is a bit difficult to put into words since "higher rank" means lower rank number, but bear with me ...)

Reef obviously would win with 8.1 or higher and I think that 8.0 would be okay too. Reef has the only 8.1 forecast and entered before Stargazer who has two 7.9 predictions ahead of their entry. There were four 8.0 entries, so Reef would finish sixth as one of the 7.9 entries came earlier; Stargazer would be 8th. So Reef is okay at 8.0 ... however, at 7.9, Stargazer moves up to third and Reef falls to 9th. It is too close to call whether that six-rank differential provides enough points to overcome the ten point differential (Stargazer currently third). The same differential continues to apply if the outcome falls below 7.9 except at some point second place summer18 (6.9 Nov) takes a lead. It would appear that with such a slight points differential, summer18 would only need to finish slightly ahead of Reef, and that begins to happen at outcomes below 7.3 as there are more forecasts in the range 7.0 to 7.3 than 7.4 to 8.0. Meanwhile, a fourth forecast that could win mathematically is the 5.5 from fourth place noname_weather but that one is looking a bit difficult to achieve now. Anyone in that zone between 6.9 and 7.9 is probably too far back in points to catch whichever of the three contenders (or any of them). Quicksilver1989 (7.3) and Leo97t (7.5) might have an outside chance but would probably need to hit their number right on. Quicksilver1989 would finish fifteen ranks ahead of summer18 but has a late penalty so effectively more like ten ranks differential, for the points to be made up it would be very close again. If the CET hits 7.5 then leo97t is about twenty ranks ahead of Stargazer, but he also faces a late penalty. 

Anyway, we shall see when the calculations are made, but it would all be academic if the outcome is 8.0 or higher. 

Various others in the top 10-15 probably have no route to a win because they are too close to at least one higher-ranked forecaster to make up the ground. Almost any of them could finish as high as second or third with a very high finish in November.

Meanwhile in the EWP contest, only Feb91Blizzard or snowray had any chance of winning as soon as Feb91Blizzard picked a number near the middle of the pack which eliminated anyone more than six points back. As Feb91Blizzard predicted 92 mm and snowray 116 mm then it would take a huge collapse in the guidance to give snowray any chance (there are just about enough forecasts between them that I think snowray could overcome their points deficit if the outcome was close to 116 mm or higher although it would be very close as snowray is 2.46 points behind and with 56 forecasts that would require an advantage of about 15 ranks). 

If the month has a very mild outcome then PIT will easily take best combined forecast with 9.0 and 50 mm which was our lowest prediction. About the only other forecast with any chance would seem to be SLEETY at 7.3 and 60 mm. 

[The PIT]

Sunny Sheffield up to 8.8C -0.5C below normal. Rainfall 8mm 9.1% of the monthly rainfall.

[Summer Sun]

9.1c to the 12th

1.2c above the 61 to 90 average
0.6c above the 81 to 10 average

___________________________

Current high this month 9.8c on the 1st
Current low this month 7.6c on the 5th