October 2023 C.E.T. and EWP contests

[reef]

We're running at 12.6C but it hides an abrupt cooldown. 

We averaged 15.9C for the first 10 days, but 10.1C for the next 14 days.

Summer to mid-Autumn in an instant.

[Roger J Smith]

EWP is now around 117 mm (est 4 added to 113 reported to 22nd), GFS takes that to around 155-160 mm with heaviest amounts near south coast. By the way, if you were looking at 24h rainfalls on meteociel and saw 901 mm for Cork, that was an error, yesterday's total rainfall at Cork was 22.8 mm (close to 0.90" perhaps that is how the error crept in). 

As for CET, still looks like a gradual drop into mid-12 range. Drops will be irregular as rounding of second decimals will determine which days see a drop, the daily means will be in the 8 to 11 range, if overall average was 10.5, then outcome would be 12.4 C. 

[Summer Sun]

12.8c to the 24th

2.3c above the 61 to 90 average
1.9c above the 81 to 10 average

[The PIT]

Sunny Sheffield still at 12.8C +1.4C above normal. Rainfall up to 177.4mm 214.3% of the monthly average.

[Summer Sun]

12.6c to the 25th

2.1c above the 61 to 90 average
1.8c above the 81 to 10 average

[damianslaw]

Will be interesting to see the difference between CET for first half of Oct to second half. Whilst not especially cold, temps in the second half have been much closer if not a little below average in the north at least, probably bang on average in CET zone, and the remainder of month will continue as such. 

A finish in the low 12s most likely.

 

[The PIT]

Sunny Sheffield down to 12.5C +1.3C above average. Rainfall 178.2mm 215.2% of the monthly average.

Looking like we will at up at around 12C for the final figure +1.6C above average.

The October record of 198.1mm of rain could be within reach. It depends on how wet Saturday night is. We already have 2nd place sorted out.

As for the year it's looking like we will get over 1000mm for only the 7th time since 1954

Edited October 26, 2023 by The PIT

[Roger J Smith]

Probably worth tracking two decimal CET values now, last two reports of 12.8 and 12.6 work out to 12.82 and 12.64. Today's max and min look to be around 15 and 5 for a mean of 10. That would work out to 12.53 for tomorrow's report but it could stay on 12.6 (12.55 rounded up) for any mean above 10.6. GFS numerical guidance for each of five remaining days look like being close to 10, possibly closer to 11 near end. Using 10.5 as mean for 27-31 brings CET average to 12,2 C. (edit) ... looks to be outside top ten lists for record falls from Oct 10th or 15th to end of month. Would need to get to 11.0 to enter, so it was fairly close to an average drop from 15th (it was 14.1 then) and top twenty possibly for 10th when it was 15.6 C. (record drops for 10-31 are in the 4 to 5 deg range).

EWP latest total is around 128 to 130 mm and will end up around 160 to 165 mm. Will leave scoring table alone (posted several days ago) until tracker ends, as only minor edits are needed for 160-165 vs 150 as basis. Only two forecasts were above 150; 172 would finish first if total is 161-173.5 and 175 wins for anything above 173.5. Top ten (1766-2023) requires passing 10th place tied 1891 and 1932 at 162.3 mm. 

 

Edited October 26, 2023 by Roger J Smith

[Metwatch]

On 05/10/2023 at 15:36, Metwatch said:

i think the first half of October looks be one of the warmest in modern records, similarly to September (if anyone can dig out the top 5 warmest first halves that would be interesting to see). The warm airmass may stay over us until the end of next week.

So it begs the question if October ends up warmer than May, does that happen often?

Since 1960, i've found at least 20 Octobers which have been warmer than May and 7 in this century (2021, 2015, 2013, 2011, 2006, 2005, 2001, 1996, 1995, 1984, 1979, 1978, 1977, 1972, 1971, 1969, 1968, 1967, 1963, 1962).

However the CET this year for May was at a warmish 12.5C, and only about 10 Octobers have had a CET of 12.5C or above in the series. The only 3 years which had both, a May and October CET of 12.5C or above, is 2022, 2001 and 1959 (correct me if i'm wrong but that seems to be the only ones i found).

2022: May CET 13.1C, October CET 12.8C

2001: May CET 12.5C, October CET 13.2C (only year when October was warmer than May and also both a CET at or above 12.5C. 2023 would be the second instance if October CET comes out at or above 12.5C).

1959 May CET 12.8C, October CET 12.6C

If it does happen again this year, it would be the 4th time of such occurrence and the 2nd time in a row after last year. Just another possible statistic of how strange 2023 has been regarding temperatures.

It's still early on in the month, and the 2nd half of October can be much colder, but one to think about in the coming weeks regardless.

 

Safe to say this quirk won't happen for the 2nd time this year, but many more attempts in the coming years to come for sure.

[Roger J Smith]

October was colder than April in many years but frequency is currently decreasing after peaks in late 18th and 19th centuries, as illustrated by groupings in 50-year portions of data (1659 to 1700 and following half-century groups): 

1676, 1673, 1692

1703, 1708, 1733, 1734, 1740

1755, 1760, 1762, 1763, 1775, 1778, 1783, 1786, 1791, 1792, 1794, 1796, 1798, 1800,

1805, 1814, 1817, 1820, 1840, 1842, 1843, 1850,

1852, 1865, 1868, 1869, 1880, 1885, 1892, 1893, 1894, 1895, 1896,

1905, 1912, 1926, 1939, 1944, 1946,

1952, 1955, 1974, 1987, 1992, 1993,

2003, 2007 and 2020

(and Apr, Oct were equal in 1689, 1694, 1704, 1707, 1711, 1761, 1867, 1881, 1980), and also ...

October was colder than Nov in 1743, 1817, 1852, 1895, 1917 and 1939, and ...

October was colder than Dec (but not Nov) in 1974 (7.6 vs 7.9). Oct and Dec were equal (7.2) in 1842.

October never equalled nor fell below March CET in same year, but was equal to February in 1817! (6.4 C). October 1778 was also colder than following February 1779 (7.4 vs 7.9). 

The closest October has been to a colder value than March of same year was 0.2C in 1992 (7.7 Oct vs 7.5 Mar).

October was 0.5 colder than March in same (extended) winter season in 1778-79, 7.4 vs 7.9, and was 0.1 colder in 1892-93 (7.1 vs 7.2). October 1676 (7.0) was equal to March 1677 (7.0) but 17th century CET values are rather approximate, and also October 1840 was equal to March 1841 (at 7.5).

October 1956 (9.4) was only warmer than following March 1957 (9.2) by same as 1992 differential of 0.2 C.

Record cold Oct 1740 (5.3) still beat Mar 1740 (3.9) and 1741 (4.2) by larger margins, but was colder than Jan of 1736 and 1737, and Mar 1736, 1737 and 1739. 

The closest October has come to being colder than January in same year is 0.8 C warmer in 1796 (8.1 vs 7.3), and closest to being colder than January following was in 1974-75 (7.6 vs 6.8), also a margin of only 0.8 C. 

In 1852 October was only 0.1 above Dec after being 0.1 below Nov, so all three had essentially equal CET values (7.8, 7.9, 7.7). 

Edited October 27, 2023 by Roger J Smith

[Summer Sun]

12.5c to the 26th

2.0c above the 61 to 90 average
1.8c above the 81 to 10 average

[Roger J Smith]

CET in two decimals is now 12.53 C. Yesterday's mean was 10.1 C.

1991-2020 running means are a bit warmer than 1981-2010, we are 1.4 C above the value to 26 Oct . The adjustments of v2.0 left 1981-2010 reduced from CET legacy by 0.1 or 0.2 (rounded) and equal to 1961-90 (10.53 to 10.51) by my method of calculation but I think the met office use a different system based on average of their max and min data sets so I am not sure what official values are, my 1991-2020 average is 10.8. 

Totally off topic but at my location we currently have -2 C and 2 cm of snow on ground. NYC predicted max of 27 C today. 

 

[The PIT]

Sunny Sheffield still at 12.5C +1.4C above normal. Rainfall 182.4mm 220.3% of the monthly average.

[The PIT]

Sunny Sheffield down to 12.2C +1.2C above average. Rainfall 182.6mm 220.5% of the monthly average.

Now looking at 11.9C to 12.1C finishing zone here. Rainfall overnight Saturday doesn't look like it will be enough for a new record rainfall wise so a silver medal for 2nd place.

[Summer Sun]

12.5c to the 27th

1.9c above the 61 to 90 average
1.8c above the 81 to 10 average

[Roger J Smith]

CET in two decimals is now 12.46 C. Yesterday's mean was 10.6 C. It wasn't quite cool enough to change the previous day\s value of 12.5, but any return for today below 12.4 is likely to bring about a shift to 12.4 on next report. Today's reported high and low were around 15 and 7 so next report is likely to be around 12.40 (to 28th). Last three days of October will probably average 10.5 which would give 12.2 as likely final value. 

No change in EWP outlook, 155-160 range is expected final. 

 

[Weather-history]

Last time that a year did not return a single month with an EWP of at least 100.00mm was 1973. 50 years ago.

Other years: 1788, 1793, 1805, 1815, 1820, 1837, 1844, 1850, 1854, 1858, 1864, 1887, 1902, 1908, 1933, 1953, 1964

Quite a gap since the last one.

[Roger J Smith]

Yes, 2023 is within reach of being a top ten wet year and largely due to rainfalls since a dry spell in May and June. I believe it would require about 273 mm from now to end of year. About 428 is required to beat 1872, wettest year on record. November looks quite wet on current guidance so it will depend on whether Dec is also wet, to see how high 2023 can finish. The top ten wet years f.y.i. are as follows: 

01 __ 1872 __ 1284.9 mm

02 __ 1768 __ 1247.3

03 __ 2012 __ 1244.4

04 __ 2000 __ 1232.4

05 __ 1852 __ 1213.0 

06 __ 1960 __ 1195.0

07 __ 1903 __ 1160.3

08 __ 1882 __ 1146.2

09 __ 1877 __ 1144.1

10 __ 1848 __ 1130.1

(11__ 2002 __ 1117.9) 12th is 1792 at 1116.8

(2014 is 16th at 1104.6 and 2019, 2020 rank 18th and 19th with 1097.2 and 1095.0)

========

If and when this month finishes near 160 mm, 2023 will be up to 887 mm  with 397 additional needed to get to first place, which requires near-record values in both NOV and DEC, but tenth place needs only 243 additional so if 170 or so fell in NOV it would be well within reach of even a somewhat dry Dec. 

Edited October 29, 2023 by Roger J Smith

[The PIT]

Sunny Sheffield still at 12.2C +1.4C above average. Rainfall 193.9mm 234.2% of the monthly average.

[LetItSnow!]

3 hours ago, Roger J Smith said:

Yes, 2023 is within reach of being a top ten wet year and largely due to rainfalls since a dry spell in May and June. I believe it would require about 273 mm from now to end of year. About 428 is required to beat 1872, wettest year on record. November looks quite wet on current guidance so it will depend on whether Dec is also wet, to see how high 2023 can finish. The top ten wet years f.y.i. are as follows: 

01 __ 1872 __ 1284.9 mm

02 __ 1768 __ 1247.3

03 __ 2012 __ 1244.4

04 __ 2000 __ 1232.4

05 __ 1852 __ 1213.0 

06 __ 1960 __ 1195.0

07 __ 1903 __ 1160.3

08 __ 1882 __ 1146.2

09 __ 1877 __ 1144.1

10 __ 1848 __ 1130.1

(11__ 2002 __ 1117.9) 12th is 1792 at 1116.8

(2014 is 16th at 1104.6 and 2019, 2020 rank 18th and 19th with 1097.2 and 1095.0)

========

If and when this month finishes near 160 mm, 2023 will be up to 887 mm  with 397 additional needed to get to first place, which requires near-record values in both NOV and DEC, but tenth place needs only 243 additional so if 170 or so fell in NOV it would be well within reach of even a somewhat dry Dec. 

Drought fears during mid-2022 seem such a distant memory. It follows a point I made several years ago, that dry spells are quickly becoming less potent in comparison to wet spells. In times past, we would perhaps see 2-5 years of quite dry conditions and then a flip to wet, maybe with the odd curveball month here and there. Since 2012 it seems to be the odds are so heavily stacked on being wetter than average. We have had dry spells, like summer 2016 through spring 2017, or the spring of 2020, but it always usually seems to be followed by wet weather, usually quite extreme. I think it was you that pointed out how prolific the 2020s is at producing very wet months. 

 

I am aware we’ve also had very dry spells in this time, but they never seem to last that long. I wonder if this is to do with global warming or a natural cycle? Perhaps a mixture of both. 

 

Still, we could swing to dry. After a very dry 2003, 2004 swung to being quite wet at times (but not as wet as now) but then turned dry again in 2005 and 2006. I wonder if 2024 will turn out like that or just be a typical year of high rainfall totals interspersed with short droughts. 

[Summer8906]

3 hours ago, Roger J Smith said:

Yes, 2023 is within reach of being a top ten wet year and largely due to rainfalls since a dry spell in May and June. I believe it would require about 273 mm from now to end of year. About 428 is required to beat 1872, wettest year on record. November looks quite wet on current guidance so it will depend on whether Dec is also wet, to see how high 2023 can finish. The top ten wet years f.y.i. are as follows: 

01 __ 1872 __ 1284.9 mm

02 __ 1768 __ 1247.3

03 __ 2012 __ 1244.4

04 __ 2000 __ 1232.4

05 __ 1852 __ 1213.0 

06 __ 1960 __ 1195.0

07 __ 1903 __ 1160.3

08 __ 1882 __ 1146.2

09 __ 1877 __ 1144.1

10 __ 1848 __ 1130.1

(11__ 2002 __ 1117.9) 12th is 1792 at 1116.8

(2014 is 16th at 1104.6 and 2019, 2020 rank 18th and 19th with 1097.2 and 1095.0)

========

If and when this month finishes near 160 mm, 2023 will be up to 887 mm  with 397 additional needed to get to first place, which requires near-record values in both NOV and DEC, but tenth place needs only 243 additional so if 170 or so fell in NOV it would be well within reach of even a somewhat dry Dec. 

I've said this in the general chat thread but I wonder how close we are to a record wet July-Dec period if we assume Nov will be yet another wet month and especially if Dec is also somewhat wet.

Interesting that none of these were between 1961-99 inclusive, and only one was between 1904-99 inclusive - yet three since 2000 are in the top 11, and this year is likely to be a fourth in the top 12 and a seventh in the top 20 for the 21st century. It does seem that the 21st century has been especially wet so far compared to the late 20th: I haven't been imagining this. The prime cause appears to be increased incidence of a low-latitude jetstream; I wonder if the main effect of climate change for us will be increased rainfall rather than any threat of a Mediterranean-style climate?

Were any years from 1961-99 in the top 20?

Edited October 29, 2023 by Summer8906

[Summer8906]

32 minutes ago, LetItSnow! said:

Drought fears during mid-2022 seem such a distant memory. It follows a point I made several years ago, that dry spells are quickly becoming less potent in comparison to wet spells. In times past, we would perhaps see 2-5 years of quite dry conditions and then a flip to wet, maybe with the odd curveball month here and there. Since 2012 it seems to be the odds are so heavily stacked on being wetter than average. We have had dry spells, like summer 2016 through spring 2017, or the spring of 2020, but it always usually seems to be followed by wet weather, usually quite extreme. I think it was you that pointed out how prolific the 2020s is at producing very wet months. 

 

I am aware we’ve also had very dry spells in this time, but they never seem to last that long. I wonder if this is to do with global warming or a natural cycle? Perhaps a mixture of both. 

 

Still, we could swing to dry. After a very dry 2003, 2004 swung to being quite wet at times (but not as wet as now) but then turned dry again in 2005 and 2006. I wonder if 2024 will turn out like that or just be a typical year of high rainfall totals interspersed with short droughts. 

The wet spells do indeed seem to be more severe than the dry spells. The "drought" of 2022 never really happened much in this part of the country: only Jan, April, and July were especially dry and Sep-Dec were wet to varying degrees, especially Oct-Dec.

As for 2024 I suspect it'll follow the typical pattern of recent years. The tendency seems to be flips between very wet and very dry, and I'd expect the next very dry spell to be centred around March and April, so we'll get a spring dry spell as seems so common nowadays.

[Summer Sun]

12.4c to the 28th

1.9c above the 61 to 90 average
1.7c above the 81 to 10 average

[Roger J Smith]

5 hours ago, Summer8906 said:

Were any years from 1961-99 in the top 20?

No, 1998 ranks 31st, 1966 ranks 32nd and 1994 ranks 37th.

_______________________________________

CET update, two dec value for 1-28 (12.4) is 12.37, yesterday's average was 10.2. Any value below 12 for today will drop the next report to 12.3. 

[Summer8906]

55 minutes ago, Roger J Smith said:

No, 1998 ranks 31st, 1966 ranks 32nd and 1994 ranks 37th.

_______________________________________

CET update, two dec value for 1-28 (12.4) is 12.37, yesterday's average was 10.2. Any value below 12 for today will drop the next report to 12.3. 

 

Just shows how wet the period since 2000 has been for those of us who grew up in the 1961-99 period.

As I said the explanation seems to be an increase in incidence of low jetstream tracks, and consequently lows tracking across southern UK rather than the traditional route close to Iceland. The traditional kind of zonal setup with lows further north and well-defined ridges, common in the late 20th century, doesn't seem to happen as much these days.

 

Edited October 29, 2023 by Summer8906