January 2023 C.E.T. and EWP forecast contests

[damianslaw]

Thought we might be a notch lower today, tomorrow may well see us on 5 degrees. Can we end up the same as last Jan 4.7 degrees? When was the last time we had two same months in consecutive years produce same CET?

[SummerShower]

12 minutes ago, damianslaw said:

Thought we might be a notch lower today, tomorrow may well see us on 5 degrees. Can we end up the same as last Jan 4.7 degrees? When was the last time we had two same months in consecutive years produce same CET?

 

In January it's only happened twice in the last century. 1968 and 1969 at 4.5 and 1926/1927 both at 4.6.  

More recently May 2017/18 both had 13.2 but I cannot see any other immediate ones.

The last 2 days of this month do look mild, I'd say 5.0 to 5.1 a likely outcome.

 

Edited January 25, 2023 by SummerShower

[Don]

34 minutes ago, damianslaw said:

Thought we might be a notch lower today, tomorrow may well see us on 5 degrees. Can we end up the same as last Jan 4.7 degrees? When was the last time we had two same months in consecutive years produce same CET?

Not sure as the CET will likely even out from tomorrow until the end of the month?

[damianslaw]

2 hours ago, SummerShower said:

 

In January it's only happened twice in the last century. 1968 and 1969 at 4.5 and 1926/1927 both at 4.6.  

More recently May 2017/18 both had 13.2 but I cannot see any other immediate ones.

The last 2 days of this month do look mild, I'd say 5.0 to 5.1 a likely outcome.

 

Thanks for the info, interesting to note the figures just 0.1 degree out, and not far off what we may expect this year, would be spooky if we had a double 4.5, 4.6 and 4.7!

Alas it does look like milder values may scupper the chance, CET likely to remain static somewhat, but we shall see. We are going to see 2 winter months where the CET value disguises what happened, the very mild spell in Dec cancelling out the very cold spell, and a generally quite cold/chilly latter half Jan in the main cancelled out by an exceptionally mild first half, we have seen little in the way of sustained average conditions so far this winter, flipping from very cold/cold to mild/very mild, this last week of Jan only time more average weather has happened.

[Weather-history]

10 hours ago, SummerShower said:

 

In January it's only happened twice in the last century. 1968 and 1969 at 4.5

 

1967 and 1968

January 1969 was 5.5°C

[Summer Sun]

5.2c to the 25th

1.3c above the 61 to 90 average
0.7c above the 81 to 10 average

[The PIT]

Sunny Sheffield at 5.2C  +0.6C above average. Rainfall 84.2mm 113.2% of the monthly average.

[ItNeverSnowsInWindsor]

Looks like staying in the 5’s now.

[damianslaw]

1 hour ago, prolongedSnowLover said:

Looks like staying in the 5’s now.

Yes touch and go whether we drop into the 4s, outlook looking slightly above average. We shall see.

[Roger J Smith]

This probably belongs in the February thread and I may move it over there after the forecast gathering time has ended, but February was at one time the coldest month of the winter over thirty-year averages. December never became coldest, but came very close in the late 19th century. But it was usually January rather than February as coldest month, looking back through the historical CET records of 30-year averages. As you may know, v2.0 only began to change CET legacy numbers slightly after 1853, so anything before that remains unchanged. This summary was obtained from CET legacy but I have checked it in general terms and cannot see that it would change very much after 1853. 

January was generally the coldest month in the Maunder and early 18th centuries. There was one minor exception, 1670 to 1699 had an equal mean (2.55 C) for January and February. February was never that far off the January mean but began to drift relatively higher as both warmed after the Maunder. December stayed about half a degree warmer than February for the colder portion but began to equal February as second coldest around 1713-42 when it was marginally colder than February for the only time until much later in the records. February began to pull away from December again after that and restored the half degree colder trend by mid-18th century, all the while January stayed about half a degree colder than February and a degree colder than December (rather like recent decades although all three were a bit colder, the relative peak came when January's average was about 3.4 C (around 1721-50), February was around 3.8 and December 4.1. 

January became relatively coldest compared to the other two winter months in the Dalton. But meanwhile before the Sun went quiet, December was slowly but surely becoming colder than February. It first achieved that in 1761-90 and widened its margin to as much as a full degree by the period 1784-1813 when December averaged 3.09 and February 4.04. Within two years of that interval, 1786-1825, January was down to an average of 2.53, although it had been as cold as 2.24 (1763-1792). Around that time, December came within half a degree of January at times but never really threatened its lead. 

So into the late Dalton and intervals ending in the mid-19th century, January had never been anything but once tied as coldest month for any 30-year interval, and December had been second coldest for quite a long stretch, although starting to fade into a nearly equal situation with February by 1812-41 when the two were neck and neck exchanging second place for several consecutive intervals (at around 4.01 to 4.08 C). January meanwhile had a huge advantage of nearly 2 C deg and bottomed out at 2.27 C for the interval 1813-42. December then dropped back for a while and February regained about a half degree edge, while steadily cutting into the large advantage held by January. By 1837-68 the advantage was less than half a degree (3.19 to 3.57) and December had fallen well off the pace at 4.35 degrees.

Even so, it was almost not February that first overtook January, but December. The trend for December began to sink down at a time when January was steady around 3.5 C in the intervals around 1851-80.  For 1870-99, December's average of 3.51 was just above January's 3.38 with February well back at 4.15. However, that was as close as December would come. By 1881-1910, it had fallen back behind February (3.97 to 3.88) with January at 3.49. 

All three months began to warm rather rapidly, but February less so. By 1901-30, February was marginally colder (4.22 to 4.24) with December lagging at around 4.6. Although the lead changed hands several times, January got back into the lead for a while, the largest margin it attained over February coming in 1933-62 (3.41 to 4.01). This slowly narrowed again, and February eventually began to assert a greater margin over January than in the first set of neck and neck lead changes; the largest it achieved was 1965-94 (Feb 3.75, Jan 4.10) although February had a relative minimum of 3.58 for 1962-91 (but Jan was then 3.79). All through these developments, December's average was in the range of 4.6 to 4.8. It was never competitive at 30-year averages after the end of the 19th century. February's last stand was 1970-99 after which it began to fade behind January by a slowly increasing margin which reached 0.1 at times, but faded to near a dead heat around 1981-2010 (4.39 to 4.44 in CET legacy) to 1983-2012 (4.47 to 4.49)... also the quirk of having 1981 and 2010 in the same thirty year interval gave December one last shot, with its average briefly down to 4.63 (it rounded to 4.8 for either side where only one of those cold Decembers counted). Since the mid-1990s, January has begun to widen its lead on both February and December, the last sighting was 4.74, 4.96, and 5.06 in CET legacy and similar values in v2.0. 

March has never been colder than any of the three winter months but came rather close to February in the late 19th century, 1864 to 1893 is the smallest gap (Feb 4.35, Mar 4.95). This was slightly closer than March came to February about a century earlier (1783-1812) with the values 3.96 and 4.63. March was also fairly close to December at times in the Maunder, running about 1 deg warmer.  November has never had a colder 30-year interval than March (at the same time), but the two months were very close at times, the closest being 1851-1880 when March averaged 5.24 and November 5.33. During an era of cold Novembers at the start of the 20th century, the November average crept to within 1.2 deg of December at times, the closest approach was 1896 to 1925 (5.91 to 4.71) which was almost equalled by 1905-34 (5.93 to 4.72). This difference began to increase gradually and reached a maximum of 2.3 C deg around 1936-65. It then again decreased somewhat reaching a differential of 1.6 deg for 1964-93 but has since then returned to around 2.4 deg. 

Reasons for these fluctuations would make an interesting study. One factor could have been the smoky atmosphere of the late Victorian and early 20th century. That would tend to favour a colder November in relative terms (as the month is known for its cloudiness) and also would tend to advantage December over February. But I don't have any solid evidence to offer for that. 

So January has almost always been coldest month, except for a few intervals in the 20th century mostly. You have to wonder if February or December would ever make another run at January. 

[Summer Sun]

5.1c to the 26th

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

[The PIT]

Sunny Sheffield still at 5.2C +0.6C above normal. Rainfall up to 84.5mm 113.6% of the monthly average.

[Roger J Smith]

EWP was 93.8 mm to 25th, likely around 94.5 now. Maps basically dry to 31st so finish still looks close to 95 mm as utilized for preliminary scoring report a few days ago. For those pondering February, the GFS says less than 10 mm by the 12th. 

For CET, not much change indicated now, will likely finish around 5 C. The first few days of February are shown quite mild, then the second week colder although not a deep freeze. Looks like around 6 C by the 12th on GFS output. 

[damianslaw]

12 minutes ago, Roger J Smith said:

EWP was 93.8 mm to 25th, likely around 94.5 now. Maps basically dry to 31st so finish still looks close to 95 mm as utilized for preliminary scoring report a few days ago. For those pondering February, the GFS says less than 10 mm by the 12th. 

For CET, not much change indicated now, will likely finish around 5 C. The first few days of February are shown quite mild, then the second week colder although not a deep freeze. Looks like around 6 C by the 12th on GFS output. 

Turning into a very average winter if you average things out, rainfall and temp wise, but disguises the reality of cold/very dry and very mild/very wet, end figures tell you little about the actual conditions.

[Don]

1 hour ago, damianslaw said:

Turning into a very average winter if you average things out, rainfall and temp wise, but disguises the reality of cold/very dry and very mild/very wet, end figures tell you little about the actual conditions.

Yes, December and January combined will come out very close to the 61-90 average and possibly spot on.  Over to February as to how winter will fair overall.  Current guidance suggesting slightly milder than average?

[The PIT]

Sunny Sheffield still at 5.2C +0.7C above normal. Rainfall unchanged.

[Summer Sun]

5.1c to the 27th

1.3c above the 61 to 90 average
0.7c above the 81 to 10 average

[Summer Sun]

5.0c to the 28th

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

[Roger J Smith]

EWP was 94.4 mm to 27th, likely around 95 now. Maps suggest no more than 0.5 mm to add on during 30th-31st, so holding to the estimate of 95.1 mm as utilized for preliminary scoring report a few days ago.  

For CET, still not much change indicated and it will likely finish around 5.0 C. 

[damianslaw]

Can we nudge into the 4s or hold at 5 degrees, next couple of days looking quite mild, I'd say 50/50 either way. Good to know last time we had a Dec end in the 3s and a Jan in the 4s.. not many a case recently. Indeed good to just see two winter months back to back not produce a silly 6 degree plus figure, lets see if Feb can hold off doing the same.

Edited January 29, 2023 by damianslaw

[Don]

31 minutes ago, damianslaw said:

Can we nudge into the 4s or hold at 5 degrees, next couple of days looking quite mild, I'd say 50/50 either way. Good to know last time we had a Dec end in the 3s and a Jan in the 4s.. not many a case recently. Indeed good to just see two winter months back to back not produce a silly 6 degree plus figure, lets see if Feb can hold off doing the same.

Probably hold at 5C.  Can't think of when we last had December in the 3's and January in the 4's.

[BruenSryan]

15 hours ago, damianslaw said:

Can we nudge into the 4s or hold at 5 degrees, next couple of days looking quite mild, I'd say 50/50 either way. Good to know last time we had a Dec end in the 3s and a Jan in the 4s.. not many a case recently. Indeed good to just see two winter months back to back not produce a silly 6 degree plus figure, lets see if Feb can hold off doing the same.

1923-24.

Dec 3.8C and Jan 4.7C

[feb1991blizzard]

they've updated the ewp after a few days, on the same day as they haven't done a cet update.

[The PIT]

Sunny Sheffield still at 5.2C +0.7C above average. Rainfall 84.9mm 114.1% of the monthly average.

Looks like we will end at 5.3C

Edited January 30, 2023 by The PIT

[Summer Sun]

5.1c to the 30th

1.3c above the 61 to 90 average
0.7c above the 81 to 10 average