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

[Don]

1 hour ago, Summer Sun said:

3.4c to the 11th

2.3c below the 61 to 90 average
2.4c below the 81 to 10 average

A rise for the next few days.

[Rob 79812010]

4.2

[SLEETY]

any idea what mean temp 

for northern scotland this month so far is, must be close to 0c

Edited March 12, 2023 by SLEETY

[Daniel*]

1 hour ago, SLEETY said:

any idea what mean temp 

for northern scotland this month so far is, must be close to 0c

-1.1C exceptionally cold. Anomaly on right 6C below average. Huge!

 

Edited March 12, 2023 by Daniel*

[summer blizzard]

Do we have the 10th, 16th and 20th figures for 13 and 18 to compare to.

[Roger J Smith]

3 hours ago, summer blizzard said:

Do we have the 10th, 16th and 20th figures for 13 and 18 to compare to.

Here you go, bonus extra dates ... 

CET after n days ____ 2013 ___ 2018 ___ 2006 ___ 1962 (all v2.0 data)

11 ____________________ 4.2 _____ 3.8 _____ 3.2 _____ 2.1

12 ____________________ 3.9 _____ 4.1 _____ 3.0 _____ 2.1

13 ____________________ 3.8 _____ 4.3 _____ 2.9 _____ 2.1

14 ____________________ 3.6 _____ 4.5 _____ 3.0 _____ 2.0

15 ____________________ 3.7 _____ 4.8 _____ 3.1 _____ 1.9

16 ____________________ 3.8 _____ 5.0 _____ 3.0 _____ 1.9

17 ____________________ 3.8 _____ 4.8 _____ 3.0 _____ 1.9

18 ____________________ 3.8 _____ 4.5 _____ 3.0 _____ 1.8

19 ____________________ 3.7 _____ 4.3 _____ 3.2 _____ 1.9

20 ____________________ 3.7 _____ 4.3 _____ 3.2 _____ 1.9

 

25 ____________________ 3.2 _____ 4.8 _____ 3.6 _____ 2.1

 

31 ____________________ 2.8 _____ 5.0 _____ 5.0 _____ 2.8

________________________________________

Had a look at 12z GFS and would estimate CET at 4.2 by 28th, trying to project 29th-31st from maps on 28th, could see 4.5 by 31st. Uncertainty factor about 0.5 on my estimates (uncertainty factor on 12z GFS might be more like 1.5). So all forecasts from 4 to 6 are probably in good shape at the moment.

 

 

[damianslaw]

15 minutes ago, Roger J Smith said:

Here you go, bonus extra dates ... 

CET after n days ____ 2013 ___ 2018 ___ 2006 ___ 1962 (all v2.0 data)

11 ____________________ 4.2 _____ 3.8 _____ 3.2 _____ 2.1

12 ____________________ 3.9 _____ 4.1 _____ 3.0 _____ 2.1

13 ____________________ 3.8 _____ 4.3 _____ 2.9 _____ 2.1

14 ____________________ 3.6 _____ 4.5 _____ 3.0 _____ 2.0

15 ____________________ 3.7 _____ 4.8 _____ 3.1 _____ 1.9

16 ____________________ 3.8 _____ 5.0 _____ 3.0 _____ 1.9

17 ____________________ 3.8 _____ 4.8 _____ 3.0 _____ 1.9

18 ____________________ 3.8 _____ 4.5 _____ 3.0 _____ 1.8

19 ____________________ 3.7 _____ 4.3 _____ 3.2 _____ 1.9

20 ____________________ 3.7 _____ 4.3 _____ 3.2 _____ 1.9

 

25 ____________________ 3.2 _____ 4.8 _____ 3.6 _____ 2.1

 

31 ____________________ 2.8 _____ 5.0 _____ 5.0 _____ 2.8

________________________________________

Had a look at 12z GFS and would estimate CET at 4.2 by 28th, trying to project 29th-31st from maps on 28th, could see 4.5 by 31st. Uncertainty factor about 0.5 on my estimates (uncertainty factor on 12z GFS might be more like 1.5). So all forecasts from 4 to 6 are probably in good shape at the moment.

 

 

Thanks for posting these for comparison, we are colder at this juncture than both 2013 and 2018, not too surprised about that especially 2013 which reserved its coldest conditions unusually in the second half.. likewise 2018 yo-yo'd after the extreme cold start it became mild quickly, then cold mid month then mild.

2006 an impressively cold month up to the 25th, its often forgotten that month, but just look at the warm up in the last week, 1.4 degrees, exceptional stuff, must have been some serious mild conditions to produce that.

1987 and 1996 are 2 other good benchmark months, along with 2001.

A rise today and tomorrow, bu Tuesday is looking cold, and Wednesday as well, by the 16th we could be on around 3.5 degrees I think.

[Roger J Smith]

Years with previous DEC below 4.0 and MAR below 5.5 with their JAN-FEB CET (bold are similar to this extended winter season)

Shown in reverse chronological order to make recent cases easier to find ... none in the past century have been as mild in JAN-FEB as this potential case would be. 1969 and 1944 had a mild January though. In fact the most "recent" similar winter with a mild Jan-Feb that qualified was 1882-83 !! and before that only one other qualifying winter had a Feb over 5.8 (1849-50).

. 

The first qualifier going back is 1996 so I also show the nearest miss since then, in 2005-06. Both Dec 2012 and 2017 were 4.7. 

YEAR ___prev DEC __ JAN __ FEB __ MAR _________________________ previous to 1882-83 (same format)

(2006) ___ (4.3) _____ 4.4 ___ 3.9 ____ 5.0 ____________________ 1879 ___ -0.3 ___-0.7 ___ 3.1 ___ 4.7

1996 ____  2.1 ______ 4.3 ___ 2.5 ____ 4.5 ____________________ 1875 ____-0.2 ___ 6.4 ___ 2.3 ___ 5.1

1970 _____3.2 _______3.7 ___ 2.9 ____ 3.7 ____________________ 1870 ____ 2.8 ___ 3.3 ___ 2.8 ___ 4.7

1969 _____3.0 _______5.5 ___ 1.0 ____ 3.3 ____________________ 1865 ____ 3.7 ___ 2.1 ___ 2.3 ___ 2.9

1965 _____3.6 _______3.3 ___ 3.1 ____ 5.2 ____________________ 1862 ____ 3.9 ___ 3.9 ___ 5.1 ___ 5.5

1964 _____2.6 _______3.4 ___ 4.5 ____ 4.3 ____________________ 1860 ____ 1.6 ___ 3.5 ___ 1.7 ___ 4.7 

1962 _____2.2 _______4.3 ___ 4.4 ____ 2.8 ____________________ 1856 ____ 2.4 ___ 3.7 ___ 5.3 ___ 4.4

1951 _____1.2 _______3.9 ___ 3.7 ____ 4.1 ____________________ 1850 ____ 3.4 ___ 0.7 ___ 6.4 ___ 4.7

1947 _____3.1 _______2.2 ___-1.9 ____ 3.6 ____________________ 1845 ____ 0.4 ___ 3.2 ___ 0.9 ___ 2.0

1944 _____3.5 _______5.8 ___ 3.6 ____ 5.2 ____________________ 1840 ____ 3.7 ___ 4.1 ___ 3.6 ___ 3.8

1941 _____3.8 _______0.5 ___ 3.5 ____ 5.1 ____________________ (from here back, Dec <3.8 Mar <5.3 criteria)

1934 _____1.6 _______4.1 ___ 3.8 ____ 4.8 ____________________ 1837 ____ 4.1 ___ 2.7 ___ 3.7 ___ 2.3

1924 _____3.8 _______4.7 ___ 3.3 ____ 4.1 ____________________ 1823 ____ 1.6 ___-0.1 ___ 3.1 ___ 5.0

1917 _____1.9 _______1.6 ___ 0.9 ____ 3.2 ____________________ 1820 ____ 1.4 ___-0.3 ___ 3.2 ___ 4.7

1909 _____3.9 _______3.5 ___ 2.9 ____ 3.7 ____________________ 1818 ____ 2.5 ___ 4.4 ___ 2.7 ___ 4.5

1904 _____3.3 _______4.1 ___ 3.4 ____ 4.3 ____________________ 1816 ____ 2.3 ___ 2.7 ___ 2.1 ___ 3.9

1900 _____2.2 _______4.4 ___ 2.6 ____ 3.7 ____________________ 1814 ____ 2.8 ___-2.9 ___ 1.4 ___ 2.9

1891 ____ -0.8 ______ 1.3 ___ 3.9 ____ 3.8 ____________________ 1812 ____ 3.1 ___ 2.6 ___ 5.3 ___ 3.5

1888 _____2.6 _______3.2 ___ 1.8 ____ 3.1 ____________________ 1808 ____ 1.9 ___ 2.6 ___ 2.8 ___ 3.2

1887 _____1.9 _______2.4 ___ 3.8 ____ 3.3 ____________________ 1806 ____ 3.6 ___ 4.2 ___ 4.3 ___ 5.1

1886 _____3.7 _______2.1 ___ 1.5 ____ 4.2 ____________________ 1800 ____ 1.3 ___ 2.8 ___ 2.2 ___ 4.0

1883 _____3.9 _______4.7 ___ 5.9 ____ 1.9 ____________________ 1799 ____ 1.5 ___ 1.7 ___ 2.8 ___ 3.4

... list continues in column 2 above .... ... ... ... ... ... ... ... ... ....1797 ____-0.3 ___ 3.5 ___ 4.6 ___ 4.3

.... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ... before 1797 frequent qualifiers, see below

Before 1796-97, as with the interval 1797-1823, qualifiers were more and more frequent because Mar mean was low 5 and Dec mid-3.

But only two qualifying winters had Jan-Feb both above 4.0 to provide even a slight resemblance to 2022-23. One other had a 4.0 Feb and a fourth case would have qualified after 1840 before I arbitrarily dropped the entry standards by 0.3. 

1727 _____ 1.8 ______ 4.2 ___ 5.0 ____ 5.1

1720 _____ 3.5 ______ 4.5 ___ 4.0 ____ 4.0

1696 _____ 4.0 ______ 5.5 ___ 4.5 ____ 3.5 ___ qualifies by post-1840 criteria and has the milder Jan-Feb

1668 ______3.0 ______5.0 ___ 5.0 ____ 5.0

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

The frequency of qualifiers was only 10% in the post-war era, about 20% from 1900 to 1945, and closer to 30% in the 19th and 18th centuries. It rose to almost 50% in the colder Maunder but only a few cases had any sort of milder interval mid-winter. 

Now, of course this is only relevant if March 2023 finishes below 5.5 C. If it relaxes and finishes 5.5 to 6.0 I might look for a few similar cases to that combination but as it seems quite possible for March 2023 to end below 5.5 we will leave it at this for now. 

[Roger J Smith]

Mainly for the interest of prolongedSnowLover I modified the EWP scoring summary first estimate (back on page 5) to show what outcomes between 91 and 101 mm would give fourteen forecasters an extra 0.19, whatever number of those happen, equal the potential loss of points for prolongedSnowLover. The table remains valid as originally posted if the outcome is 101.1 mm or more. Anyone who predicted 72 mm or lower would need an outcome below 91 mm to change their scoring. 

[ItNeverSnowsInWindsor]

It’s looking quite wet on the latest GFS 12z run!

[The PIT]

Sunny Sheffield at 3.4C -2.1C below average. Rainfall 59.2mm 97.7% of the monthly average.

[Roger J Smith]

No CET update today, would likely be a rise of 0.5 or so. 

EWP is around 50 mm now (37.6 to 11th, wet yesterday and to 12z), 12z GFS goes to town after day 13 and runs up the score to at least 70 more for 120. All that work I did on the what if adjustments to scoring would be moot. But the scoring table is otherwise still valid at any final total (within about .02, tiny variations ensue from different classes of percentage error size adjustment). The best forecast always scores 10 (minus late penalty as per last month), no matter what its error sizes. (that is, unless everyone in the field was on the wrong side of normal which has never happened). 

CET will be more on the rise than not, but will check for tomorrow and Wednesday at around 4.5. Then milder for about a week, moving up towards 6.0 and levelling off in high 5 to low 6 zone in a cooler interval 22nd-28th according to current GFS output , still rather chilly looking on 29th with more northerly flow developing then, so that could be taken as final estimate too. 

[Summer Sun]

4.3c to the 13th

1.4c below the 61 to 90 average
1.5c below the 81 to 10 average

[Summer Sun]

On 12/03/2023 at 10:27, BLAST FROM THE PAST said:

The CET will imo at least hold or drop, the recent cold isn’t the ‘hit’ I’ve been expecting as it was too short, that’s from next week on….

 

BFTP

No sign of it holding or dropping, the CET is up 0.9c since Saturday

[Roger J Smith]

Yesterday's max of 13.3 was not close to a date record (17.3 1991) nor the mean of 11.0 (12.8 1991) but min of 8.6 was just 0.4 short of record (9.0 1961, mean for that date was 11.3 with a max of 13.6). 

[The PIT]

Sunny Sheffield at 3.7C -1.8C below average. Rainfall 75.1mm 123.9% of the monthly average.

[damianslaw]

6 hours ago, Summer Sun said:

4.3c to the 13th

1.4c below the 61 to 90 average
1.5c below the 81 to 10 average

Hadn't expected such an increase, the last 24-48hrs warmth caught me out, today will bring a drop, a very cold night ahead, probably back in the 3s, then another marked rise. A rollercoaster pattern, something we have not had for a long time. A far more interesting month than many recent ones.

[Roger J Smith]

I thought from your earlier comments you were expecting the bump up, keep in mind it is over two days (13th report was missing because they didn't update until today). The missing value was 3.8 C. (3.4, 3.8, 4.3). Agree the rise will check now and resume on Thursday. 

[Summer Sun]

4.4c to the 14th

1.3c below the 61 to 90 average
1.5c below the 81 to 10 average

[ItNeverSnowsInWindsor]

1 minute ago, Summer Sun said:

4.4c to the 14th

1.3c below the 61 to 90 average
1.5c below the 81 to 10 average

Slight drop tomorrow followed by a rise towards average temperatures.

All to play for in final week as models seem keen on colder to average conditions returning.

[The PIT]

Sunny Sheffield at  3.9C -1.7C below normal. Rainfall 77.7mm 128.2% of the monthly average.

A slight drop tomorrow then a steady rise upwards for the foreseeable future. It will probably slow towards end of next week.

Edited March 15, 2023 by The PIT

[Roger J Smith]

EWP now around 54 mm and GFS to end of month says add 65-70 to that, 120 mm will confirm the updated scoring already posted (and remove the need for the adjustments).

CET from GFS guidance, assuming we are at 4.6 after today, would end up around 6.3, but closer to 6.0 if the very warm days at end of month are bogus. 

[damianslaw]

5 hours ago, Summer Sun said:

4.4c to the 14th

1.3c below the 61 to 90 average
1.5c below the 81 to 10 average

Mmm I expected a drop in today's values, yesterday was cold in the CET zone after a cold night, but perhaps not as cold as I thought. Today very cold mean value north half of UK, widely lows below -5 degrees, followed by highs 5 degrees tops, equates to 0 degrees. Certainly has been a cold first half to March in Scotland and far north of England.

 

[The PIT]

Sunny Sheffield at 3.8C -1.8C below average. Rainfall 83.2mm 137.3% of the monthly average.

[Summer Sun]

4.2c to the 15th

1.4c below the 61 to 90 average
1.8c below the 81 to 10 average