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

[BornFromTheVoid]

It's been a few months....

(As a reminder, I use the provisional CET values up to this point in the month, a 5 day GFS forecast and then historical values to project the CET to the end of the month. The probabilities don't include the monthly downward corrections)

Latest projection from the 13th

 

The chances of finishing:
Close to average (6.9C to 7.9C) is 43%
Above average (>7.9C) is 43% 
Below average (<6.9C) is 14%

The period of the 13th to the 18th is forecast to average 9.9C, 2.6C above the 91-20 average.

[The PIT]

Sunny Sheffield at 9C bang average. Rainfall 8mm 9.1% of the monthly average.

[Roger J Smith]

For continuity ...

9.3c to the 13th

1.6c above the 61 to 90 average
0.9c above the 81 to 10 average

(0.8c above the 91 to 20 average)

___________________________

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

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

(The warmest running CET to 13th is 12.1 (1938) ... this increased to 12.2 after 14 days then started to decline, eventually 1938 passed the baton to 1994 by the 23rd and the month ended up a bit cooler (9.4 -- 5th) than two others that never held the running mean highest value, 1818 (t4 9.5) and 2011 (2nd 9.6). 1938 does retain the warmest daily mean for any November day which was 15.4 on the fifth. 2015 (t4 9.5) briefly held the lead on 10th and 11th between two spells for 1938 holding the lead.)

(At the other extreme, 1782 and 1919 were tied for the coldest running mean on the 13th (2.7 C) and 14th also (2.5 C), 1919 took the lead for about a week then gave it to 1786 for 20th to 22nd, then it returned to 1782 which finished coldest November at 2.7 C. Those two contenders (1786, 1919) finished at 3.3 tied for 8th coldest November, meanwhile 2nd coldest Nov 1915 and 3rd coldest 1807 never held the lowest running mean, fourth coldest 1684 was before daily data began, 5th to 7th (1851, 1862, 1910) also never held the lowest running mean. Before 1782 started its long run, 1880 was the early leader after just one day for 1934. The cold in 1880 faded out and that month finished on 5.4, but the cold must have been retrograde because there are notably long and deep cold spells in eastern North America in the second half of Nov 1880 making it one of the coldest months there.)

[Roger J Smith]

The EWP guidance continues in the same dry theme as previously reported. We are currently at 15 mm and looking at the ten-day GFS output, the grid average might be 5-10 mm at most to the 24th then the maps for 25th to 30th are relatively dry also. In the list that I posted the other day, 20 mm would be second driest and we still have not passed driest 1945 (17.0 mm) although I think we will.

The CET is going to stay in the 9s and could touch 10 C at some point ahead, before a few colder days indicated around 21st to 23rd. Those are not likely to be severely cold and would probably force the running CET back into the high 8s where it could then stay if the milder turn indicated is mild enough, at any rate a finish in the low to mid 8s is currently the most likely outcome.

A finish near 9 or above is not ruled out by any means, and there have only been eight Novembers that warm. 8.0 would be a tie for 29th warmest so there are twenty Novembers that finished 8.1 to 8.9. 

[The PIT]

Sunny Sheffield at 9.2C +0.3C above normal. Rainfall unchanged at 8mm 9.1% of the monthly total.

Can't see much change this week with any upward movement mainly due to nights.

Edited November 15, 2021 by The PIT

[Summer Sun]

9.3c to the 14th

1.7c above the 61 to 90 average
1.0c above the 81 to 10 average

___________________________

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

[BornFromTheVoid]

Latest projection from the 15th, based on the 06z GFS

 

The chances of finishing:
Close to average (6.9C to 7.9C) is 31% (2 day ago was 43%)
Above average (>7.9C) is 64% (2 day ago was 43%)
Below average (<6.9C) is 5% (2 day ago was 14%)

The period of the 13th to the 18th is forecast to average 10.3C, 3.4C above the 91-20 average. Also, the estimated mean CET for the 19th is 11.9C, 0.8C away from the daily record of 12.7C from 1994.

[ItNeverSnowsInWindsor]

The 12z GFS run is a tad colder and should it verify could bring an interesting drop in CET values!

[The PIT]

Sunny Sheffield 9.1C +0.3C above average, Rainfall 8.2mm 9.3% of the monthly average

So a surprise fall and a bonus 0.2mm overnight. Only two dry days this month so far yet as you can see very little in the way of rainfall.

[Summer Sun]

9.3c to the 15th

1.8c above the 61 to 90 average
1.1c above the 81 to 10 average

___________________________

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

[Roger J Smith]

EWP now about level with driest Nov 1945 at 17 mm (est 2 mm grid average on 15th, plus the 15 mm to 14th). The ten -day GFS from the 12z run holds at a very small additional 2-5 mm, but maps for 27th to 30th look a have a bit more potential now, possibly pulling the month out of the top five driest Novembers towards about tenth place which is around 40 mm. As our lowest forecast is 50 mm, scoring will be almost the same no matter what the actual number is, until it reaches 55 mm which does not seem to be very possible.

The week starting Sunday 21st looks quite cold now, with just a slight return to milder weather for 29th-30th. Would estimate an average CET of about 3 C for the last ten days now, after we probably reach just about 10 C by Saturday 20th. If so the outcome for the month would be 7.7 C. An average of 4 would give 8.0, and 5 would be 8.3, etc. So if this cold spell is not being over-amplified as the GFS is known to do sometimes with distant cold spells, the CET will be tumbling into the scoring zone that I described in an earlier post; however, as to that 5.5 miracle scenario, that would take an average of about -3.5 C which would be below daily records. 

 

[Summer Sun]

9.2c to the 16th

1.8c above the 61 to 90 average
1.1c above the 81 to 10 average

___________________________

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

[Derecho]

Judging from a combination of the EC00Z and GFS 06Z, the CET should rise to 9.5C by the 20th and plummet all the way down to 7.2C by the end of the month.  The 06z GFS has a few sub zero CET days the weekend after next. 

If the milder GFS 00z came off however, the CET would only drop to 8.4C before corrections so a lot of uncertainty.

The CET for the 25th-29th November on the 06z gfs is 0.0C according to my workings.

Edited November 17, 2021 by Quicksilver1989

[Roger J Smith]

I see the 12z GFS continues this colder outcome and would drop the running CET towards the mid or even low 7s by end of month. 

The EWP looks like it would finish up around 30-40 mm. At some point if the guidance locks in on any outcome below 55 mm then the EWP contest scoring would also be locked in since the two lowest forecasts we have for November were 50 and 59 mm. I have worked on the scoring file and for various outcomes 30 to 55 mm, the only differences would be in the rankings for average errors but as far as points totals, those can only change by very small amounts until the EWP totals get above 55 mm. 

Will hold off posting anything detailed yet since that other GFS outcome had a lot of heavy precipitation in the final five days and if that scenario returns then the EWP total points would be affected more. However, unless there was somehow over 110 mm, the most likely order of finish for the top five annually would be Feb91Blizzard (Nov 92 mm), noname_weather (80), snowray (116), bobd29 (82) and Midlands Ice Age (89.9). With somewhat more potential for positions to be scrambled if EWP moves past 55, the rest of the top ten would be Godber1 (110), MrMaunder (89), Don (120), Reef (131) and the PIT (50), with February1978 (113) at 11th but in position to move past the PIT if the EWP moved past 65 mm. Mulzy (with 59 mm predicted) would  make a significant upward move from 26th to 18th. Polar Gael and Frigid also move up a few ranks. 

The numbers in brackets in the above show the November EWP forecasts of all eleven contenders to give some idea of the possible changes that a sudden increase of EWP could bring. 

These indications of strong cooling trends bring almost all the permutations discussed earlier for CET scoring into play. With past GFS cold spell forecasts in mind, anything could happen. 

[The PIT]

Sunny Sheffield still at 9.2C +0.5C above normal. Rainfall 9.1mm 10.3% of the monthly average

Will be interesting how much as dint the cooler spell will deliver if it comes off.

Going back to what average the met office uses and I thought the averages on Beeb forecast represented the later set of averages listening recently suggests they are still using the older set of averages.

[Roger J Smith]

Some contest thread readers may already be familiar with my historical CET thread (in the historical weather section) where the daily record means can be found on the first page of the thread. In recent days I have added the record values for the maximum and minimum values. While the daily means go back to 1772, these max and min data go back only to 1878. A few obvious cases can be spotted where max or min temps in the years from 1772 to 1877 were almost certainly more extreme, such as the end of April 1775, or the very cold weather in Jan 1838 or Apr 1837. 

Having said that, I did a comparison of the dates of the highest max and highest min values, because I was wondering how often both happened at the same time. When you see the record daily mean sometimes you might automatically think that the day had the highest max and min. Actually it is not all that common. Given that the 1878-present data would sometimes not capture the all-time daily means, these comments only apply to the period 1878-2021 ... I found that only 55 out of the 366 days of the year had both the highest max and the highest min. Another 42 cases of the highest max were followed the next day by that day's highest min. A further 15 cases were separated by a bit longer, either the min was a day earlier than the record max, or two days later. That was the largest separation that I searched. In addition to those cases, sometimes the record high minimum would be associated with a "secondary" record high maximum, which I had noted in the tables as being either (a) the highest value since 1981 that was not the all-time record, or (b) the record up to 1980 that had been broken since 1981. But there were high minima that went along with some relatively tame daily maxima on some occasions, and vice versa. 

I found in particular that long spells of record high maxima such as those in summer 1976, and autumn 1895 or 2011, often had only record high minima on a few days towards the end of those spells. Presumably the clear skies in the earlier portions of those warm spells allowed for a bit of radiational cooling so that those nights, while fairly warm, were not record breaking. 

It surprised me a little that the CET minima have never exceeded 20 degrees. The highest minimum on record was on 20 July 2016 (19.4) and even in such heat waves as 1911, 1948, 1975, 1976, 1995 and 2003, as well as the recent ones, 18 to 19 C is a rough average of their highest daily minima. So there's a benchmark value to be picked off at some point, a CET minimum of 20 or higher. By contrast, all the daily record high minima at Toronto from about mid-June to early September are above 20 C and some as high as 25 or 26 C. Even here in the mountains of BC we had a couple of nights in the recent heat dome with minima over 22 C. 

All of this new information (new to me at least) can be seen at this link: 

 

 

 

The record daily means are fairly early on in the thread, the other material forms the most recent additions to the thread. 

For the daily maximum and minimum records, I show the all-data and since-1981 extremes so you can compare events you'll recall with those a bit more distant. For the low maximum and high minimum there are only the all-time records shown. A lot of the high minimum records are fairly recent, they have been breaking the old records at a pace that is probably twice that of record high maxima which are also over-represented for the past three decades. Breaking minimum records is fairly unusual, except for late 2010 and March 2018, there have been very few new ones set. In fact there were no record low maxima in any of the twelve years from 1998 to 2009 inclusive. The cold April of 2021 set three daily low minima but no new low maxima, I guess the absence of snow cover and a lot of sunshine in the daytime hours helped get those cold days above the previous record low maxima which were probably set with snow on the ground and under considerable cloud cover.

Now that I have all these records available, I will bring a new feature into these threads, a daily almanac report of the records. My plan is to post that early in the morning (UK time) so it will be available to all readers that day. In fact here's the first instalment ...

Almanac for 18th of November

The daily mean extremes (1772-2020) are 12.8 (2020) and -1.6 (1887). The 2020 record broke 12.2 (1978) and that had broken 11.2 (1875). Since 1940 the lowest daily mean was +0.8 in 1947 (which came a few days before some record high values that will be in the almanac soon).

The highest maximum (1878-2020) was 15.2 (1978). 2020 had 14.2 but the warmest since 1978 was 14.5 in 2003. The highest minimum was 11.3 in 2020. Before that the record had been 10.4 in 1997. 

The lowest minimum (1878-2020) was -4.6 (1929). Since 1981 the lowest value is -3.7 (2005). It was also -4.0 in 1969 but second coldest was -4.1 in 1915. The lowest maximum value was 0.7 in 1887. The second lowest value is 1.8 (1905). 1947 warmed to only 2.4. The cold start in 1929 was followed by a maximum of 6.8. In years since 1981 the lowest maximum has been 4.7 in 1993. 

The wettest day (EWP, data 1931-2020) for 18th November was 18.94 mm in 1939. A close second was 17.67 mm in 1986 and third was 16.66 mm in 1963.

The highest total for a week ending 18th November was 59.29 mm in 1970, then 57.62 mm in 1935, and 56.76 mm fell in 1963; more recently 2009 had 55.10 mm.

The smallest total EWP for a week ending 18th November was 0.27 mm in 1955. More recently, 0.90 mm in 1983, just ahead of 1989 with 1.26 mm. Also quite dry was 1957 with 1.70 mm. 

===============================================================================================

Edited November 19, 2021 by Roger J Smith

[Summer Sun]

9.2c to the 17th

1.9c above the 61 to 90 average
1.2c above 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 down to 9.1C +0.5C above normal. Rainfall up to 9.3mm 10.5% of the monthly average.

[damianslaw]

A sandwich month.. a cold start top layer.. with a big very mild middle followed by a cold bottom layer...

[Roger J Smith]

These Novembers were similar to the above in that they did all four of these checkpoints: 

(1) There were mild days at the start, then

(2) The running CET was at or below 7.5 at some point in the first twelve days;

(3) The running CET was above 9.0 at some point in the middle third and/or 21st

(4) The final CET was below 8.0 C. 

The first of those will require a downward correction from 7.6, the low point so far, on the 5th. That seems likely to happen given the usual outcomes. We don't know for sure yet if this month will make the final checkpoint but it looks possible. 

The only November to do all four of those are the following, with the details of what 1948 did to (barely) qualify 

YEAR ______Mild, then lower CET 3-12 ___ Highest CET 11-21 __ Final CET

1948 ______ 11,0 (3) ___ 7.5 (11) _____________ 9.0 (20) __________ 7.3

A very close effort gpes to 1897:

1897 _______ 8.3 (1) ___ 7.5 (5-6) _____________ 8.9 (14) _________ 7.6

Also close to the right pattern but just outside the cold 3-12 and mild 11-21 criteria:

1902 ______ 10.2 (1) ___ 7.6 (4) _______________ 8;8 (10) 8.6 (16) __ 6.8

That last one is actually a fairly close overlap anyway and was followed by a fairly mild and at times stormy winter (a notable windstorm occurred on 27 Feb, doing considerable damage in the south and east of Ireland). 

I was able to find these few analogues quite easily because almost all Novembers fail to run any CET values above 9.0 in the middle third and most of those that do so had a milder start. 

Nov 1827 and also 1839 were broadly similar also, both lacking any mild start, but warming from 6.7, 5.6 on 1st to 9.0 (13th 1827) and 8.6 on 17th-18th 1839, then finishing 6.9 and 7.3.  These were perhaps the fifth (1827) and sixth (1839) closest analogues. 1955 also fit that pattern although with such a cold start that I wouldn't rate it that highly, from 2.8 on 1st, to 9.9 on 11th, already 7.8 by 21st and finished 7.0.

Nov 1889 also missed slightly with 8.3 on 1st, 7.4 on 6th, 8.6 on 11th and still 8.4 on 20th, then finishing 6.9. Just not quite as mild at mid-month as 2021 but probably the fourth closest analogue. 

The only recent November to have a somewhat similar pattern was 1995, which started with10.4 on 1st, fell to 6.7 by 6th and 7th, rose back to 8.5 on the 15th, then finished on 7.7. If that met the criteria then there would have been a longer list of about two dozen other analogues. 

There were no other cases of the more simple CET 9.0 or higher after 18th then falling off to below 7.5 by end. Just looking at years since 1970, these Novembers were this close to that territory ... 

1977 fell from 8.6 (18th) to 6.6.

1978 fell from 10.5 (19th) to 8.5.

1982 fell from 9.6 (18th) to 8.0.

1983 fell from 8.8 (18th) to 7.5.

1990 fell from 8.6 (18th-19th) to 6.9.

2004 fell from 8.7 (18th) to 7.7

2008 fell from 8.4 (18th-19th) to 7.0.

2018 fell from 9.8 (18th) to 8.3

The last time that a November at 9.0 or higher on the 18th fell to a final value below 7.3 was in 1898; 

Nov 1898 fell from 9.3 on 18th to a final value of 7.2. 

The winter of 1898-1899 was generally rather mild, CET values for Dec to Mar were 7.3, 4.9, 5.1 and 5.1 ... it was a notably cold February in the eastern and central United States setting many records, with a blizzard on the east coast in mid-February. 

The winter of 1948-49 was also quite mild (5.7, 5.5, 5.7, 5.1 March the coldest month of that extended winter season).

[Roger J Smith]

Almanac for 19th November

The highest daily mean (1772-2020) was 12.7 in 1994. Before that, the record had been 12.4 in 1978 (also 12.3 in 1948).

The lowest daily mean (1772-2020) was -2.1 in 1815. In recent years the lowest daily mean was 0.7 in 1962. 

The highest maximum (1878-2020) was also in 1994 (15.6), previously it had been 14.6 (1948). 

The highest minimum (1878-2020) was 12.0 in 1978. The second mildest was 11.2 in 2011.

The lowest maximum (1878-2020) was 2.0 in 1902. More recently the lowest since 1980 was 2.9 in 1985.

The lowest minimum (1878-2020) was -2.6 in 2005. It was probably below that in 1815 (this data does not go back that far). The odd thing about the 2005 record is that in a five-day cold spell where 2005 was always the most recent coldest minimum, this was the highest value of those six, the other five all failed to break earlier records. This one broke the existing record of -2.3 from 1914. It was also -2.4 in 2019 on this date.

The wettest 19th November (1931-2020) in the EWP data was 18.20 mm (2016) followed closely by 17.67 mm (1946) then 1996 which recorded 14.95 mm. 

The wettest week ending 19th November (13th-19th) was 60.23 mm in 1963, followed by 59.79 mm in 1970, 58.41 mm in 1944, 57.01 mm in 1946, and 56.14 mm in 1935; the heaviest in recent years was 49.99 mm in 1986 then 48.95 mm in 2009. 

The least amount falling in a week ending 19th November was 0.37 mm in 1942, just ahead of 0.44 mm in 1955, followed by 1.02 mm in 1983, then 1.52 mm in 1957, and 1.95 mm in 1989, Since then, the driest was 2.26 mm in 2011. 

 

[Scorcher]

20 hours ago, damianslaw said:

A sandwich month.. a cold start top layer.. with a big very mild middle followed by a cold bottom layer...

Yes although the cold start wasn't anything to write home about- we've only had one day all month so far that hasn't reached double figures.  It really has been remarkably consistent since that early spell.  Also plenty of dry, windless days which is rather unusual given it's been so mild. A couple of days that felt surprisingly warm in the sun for the time of year too (today was one of them).

[The PIT]

Sunny Sheffield back to 9.2C, +0.8C above average. Rainfall unchanged

Today was only the 3rd day of the month where it hasn't rained. So despite raining on 15 days so far this month we are in with a very good shout of getting our driest November on record with little or no rain forecast for next week. It won't be warmest on record but in the top ten. Mainly due to any real cold rather than average temperatures being shoved further and further back with each run.

[Roger J Smith]

Any orange avatar will do for this ... 

 

9.3c to the 18th

2.1c above the 61 to 90 average
1.4c above the 81 to 10 average

1.1c above the 91 to 20 average

___________________________

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

============================================

EWP latest month end projections lower again, from 12z model run only about 30 mm. 

We are currently just about level with driest November 1945. (17 mm)

[Roger J Smith]

Almanac for 20th November

The highest daily mean (1772-2020) was 12.8 in 2009. Before that, the record had been 12.6 in 1994 (also 11.5 in 1890).

The lowest daily mean (1772-2020) was -1.2 in 1829. In recent years the lowest daily mean was -0.3 in 1962. 

The highest maximum (1878-2020) was 15.3 in 1947, which replaced 13.5 from 1890. The warmest since 1947 was 14.4 in 1981. 2009 had 14.0 and 1994 was 13.2, 2012 at 13.4. The minimum going with the high max from 1947 was just 1.9 as a cold spell abruptly ended. This daily range of 13.4 while rather large falls well short of the largest range for date in the period 1878 to present, which was 21.4 on 28 March 1965.  

The highest minimum (1878-2020) was 12.0 in 1994. The second mildest was 11.6 in 2009.

The lowest maximum (1878-2020) was 2.5 in 1962. This replaced a tie at 2.6 (1887, 1905). More recently the lowest since 1980 was 3.9 in 1993, then 4.3 in 2005.

The lowest minimum (1878-2020) was -3.7 in 1971. This held on after 2005 recorded -3.6 C. The minimum in 1993 was -2.5. 

The wettest 20th November (1931-2020) in the EWP data was 22.57 mm (1971) followed by 18.46 mm (1950); more recently the highest values are 13.98 mm in 2012 with 13.80 mm in 1986.  

The wettest week ending 20th November (14th-20th) was 60.90 mm in 1963, followed by 60.57 mm in 1935, 58.93 mm in 1946, 57.37 mm in 1944, 56.35 mm in 1970; the heaviest in recent years was 56.16 mm in 1986 and since then 42.21 mm in 2007. 

The least amount falling in a week ending 20th November was 0.66 mm in 1955, followed by 0.81 mm in 1942, then 0.84 mm in 1961, and 1.05 mm in 1983.