C.E.T. forecasts for December 2015 (start of 2015-16 competition year)

[The PIT]

Quick bung with possible max temps for the day and 99.999999% sure Sheffield will finish on 8.6C a record mild month by 1.1C. Only -0.1C below November value. The average temp +4.1C above normal 4.3C for the Max temp and 3.8C for the min.  The only thing that won't break any records is the rainfall unless we get 130mm today.

Edited December 31, 2015 by The PIT

[reef]

Its looking like the final figure is 9.2C here this month, a mere 1.9C above the previous record of 1988. That's just 0.1C below November and the same as May 1987.

Edited December 31, 2015 by reef

[BornFromTheVoid]

A very slight chance of finishing at 9.8C before corrections if maxima today are above 9.8C, but it will probably be 9.7C. Probably 50/50 as to whether we can finish above 9.5C or not, and I doubt we'll be any less than 9.3C after corrections.

[Weather-history]

23 hours ago, BornFromTheVoid said:

 

If we take the minimum for this month (7.2C before corrections) and rank in in among the December mean values, it would be the 13th mildest December on record.

It's warmer than any April CET minimum in the records!

[Timmytour]

If December's CET ends up being 9.6C or greater, the past three months will have been warmer than April May and June 1977

[Relativistic]

What?! I don't believe it. December confirmed at an astonishing 9.7C, a full 1.6C above 1934 and 1974. May 1833 has lost its crown as the most ridiculously anomalous month in the CET series. This month was warmer than November 2015, the third warmest on record, and would rank as the second warmest November ever, let alone December. Mind-blowing.

 

http://www.metoffice.gov.uk/hadobs/hadcet/mly_cet_mean_sort.txt

Edited January 1, 2016 by Relativistic Sting Jet

[Methuselah]

A full 4.2C above my guess - for a mild month. Incredible!

Edited January 1, 2016 by Ed Stone
Whoops!

[Relativistic]

Unfortunately, I don't have the know-how (yet) to determine what the next mildest 31 day Winter period is, but I would imagine that it is some way below 9.7C. Surely nothing has come close to that?

[Summer Sun]

With December now confirmed at 9.7c does anyone know when the last time both November and December finished warmer than April?

[reef]

There's really no words to describe how dire December has been. I supposed its fitting it blasted the old record into orbit as it was about the only interesting thing that come out of such a month.

However, with December giving a confirmed 9.7C (ridiculous!) then a mean of 5.3C is required for the remaining 60 days of winter to give the mildest winter on record.

Not a difficult figure to hit really.

 

[Weather-history]

9.7

Warmer than any March, warmer than any November bar 1994, warmer than the previous November and that was the joint 3rd warmest November, the mean minimum warmer than any April mean minimum. 

It is so off the scale, it's unreal, I feel like when the announcement was made this piece of music should be played with the timpanis banging after each record it has broken is made.

 

[J10]

Now that 9.7c has been confirmed by the Met Office.I can put the scores up, with the revised scoring system. (which is explained in more detail in the Rules thread.)

However the changes are made to :-
1. Reflect total scores more than average scores.
2. Better reward those who have some very good punts and some bad ones, rather than those who are say always say 0.7c out, but never get any spot on.
3. Change the accuracy system to give extra to those who are closer in a month like this, as opposed to a "normal month" when everyone is within 1.0c
4. Finally to give a standardised top score of 500, to try to make the scores mean something a bit more concrete.
I will continue to do the old scoring method behind the scenes, to see if there is much difference in the methods.

Excel (2007) format -> Dec 2015 cet New.xlsx
PDF  Format -> Dec 2015 cet New.pdf

Scores the Top 3 in all categories are.
1. IHaveNoTrueFriendsNow! (formerly Craig Evans) who was 0.7c under
2. Roger J Smith who was 2.3c under
3. March Blizzard who was 2.5c under

Stats Zone
In terms of statistical analysis, late entrants did better, as they were able to see that December was looking a mild month.
This can be seen with a correlation of - 0.29 and that the later quartiles all did far better than the first quartile entries.

Edited January 1, 2016 by J10

[Summer of 95]

1 hour ago, Summer Sun said:

With December now confirmed at 9.7c does anyone know when the last time both November and December finished warmer than April?

1934 (Dec 8.1, Nov 6.1, Apr 8.0). April and especially November were a lot colder than this year though. This time it beat one of the warmest Novembers and sunniest Aprils on record.

 

[Froze were the Days]

Who started the thread 'when will we have our next above average CET month' a couple of months back?- whoever it was I blame him/her! for whats happened the last 2 months

Just about to do my calculations for December for my area (Essex coast) - actually expecting it to be even warmer than November, December has been a ridiculously mild month.

Edited January 1, 2016 by Froze were the Days

[Weather-history]

The gap between September and December was less than 3.0C, that must be a record. 

The gap minimum wise between September and December was just 1.1C! It was warmer than May's minimum!

 

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Craig evans' guess was 0.7 under the actual outcome, that says it all. 

[The underwriter]

The CET series goes back over 300 years and if the monthly values were set out on a graph it would be bell-shaped with the most frequent values clustered around the mean. December 2015 at 9.7c would sit at the far right of the distribution. I would be interested to know, if anyone can calculate it, what the return period would be for such a value.

Bearing in mind that no December has come remotely close in over 300 years it is reasonable to assume that the return period is more than 300 years but at such an extreme value could it be a 1 in 1000 year return period?

[AderynCoch]

So there we have it - surely the worst winter month ever recorded. This after a terrible November too.

Mother Nature owes us big time after the fail year of 2015.

[Roger J Smith]

I am looking into several of these questions and hope to have answers shortly.

Meanwhile, worth noting that the unprecedented warmth shows up on both sides of the Atlantic. New York City's Central Park station had an anomaly of +7.4 C deg and this appears to be a similar amount above their previous record. Washington DC was 6.4 above their normal value and Chicago (O'Hare) was 6.3 above, Boston was 5.9 above and Atlanta managed 7.3 above normal.

Worth noting that in the 1982-83 El Nino, Toronto broke its previous December record at that time (1982) by several degrees and had four days warmer than the previous record high (which was 16, the warmest of those days was 21) and at that time the records were 142 years. I recall there being a similar degree of astonishment about those records, also some values reached in March 1990 that were 10-15 degrees above previous record highs for mid-March. I imagine the 1936 heat wave in North America caused quite a stir among weather watchers of that era when previous record highs fell by many degrees day after day. These things happen, climate is not quite as random-chance or bell-curve distribution oriented as it appears, the idea of quantum leaps applies in our science whether you believe it is due to human or natural causes, that much can be agreed upon.

So I'm looking now at a file where I can isolate the comparisons from your recent posts. Here are some of the results:

The only other Decembers that were warmer than the previous Aprils or equal were as follows (with the Novembers added in)

YEAR ______ APR __ NOV __ DEC ___ comparison to 2015

2015 _______ 9.0 ___ 9.5 ___ 9.7 ____ this previous April was still above normal!

1710 _______ 6.5 ___ 8.0 ___ 7.5 ____ probably a late Maunder equivalent to 2015

1771 _______ 5.5 ___ 6.3 ___ 5.6 ____ this was the 2nd of 5 times Nov and Dec were warmer

1837 _______ 3.7 ___ 5.2 ___ 5.3 ____ this was the 3rd of 5 times Nov and Dec were warmer

1922 _______ 5.5 ___ 5.9 ___ 5.8 ____ this was the 4th time Nov and Dec were warmer

1986 _______ 5.8 ___ 7.8 ___ 6.2 ____ this was the 5th time Nov and Dec were warmer

1918 _______ 6.7 ___ 5.5 ___ 6.9 ____ this case failed because of Nov

1934 _______ 8.0 ___ 6.1 ___ 8.1 ____ this case also failed because of Nov

1806 _______ 6.8 ___ 7.8 ___ 6.8 ____ this case had an equal Dec-Apr (Nov warmer)

 

so the answer appears to be 5 or 6 times depending on whether you can accept the equal value in 1806.

December has been warmer than the previous April (or equal) nine times out of 357.

December has never before come closer than 2.9 degrees of beating the previous May, that coming in 1852 (7.7 vs 10.6), but this year it came within 1.1 degrees.

December has once beaten the previous October, that coming in 1974 (8.1 vs 7.8) and once it has tied the previous October in 1842 (both were 7.2). So there's one thing this December was not able to match.

As to previous warm 31-day periods that were in calendar winter so to speak, these would appear to be the previous highest values:

As you might expect the only hope for a period milder than the 8.1 C means of Dec 1934 and 1974 lies in those winters using much of December. Other cases have nothing much to offer in terms of useful days in the following January. So for 1934, the best improvement is 3 Dec to 2 Jan 1935 which bumps it up to 8.2 C ... and there is no improvement to Dec 1974 from the first few days of Jan 1975. You can improve Jan 2007 by starting on 23 Dec 2006 and that gives 7.3 for the 31-day mean.

The mild Jan of 1916 (7.5) improves to 7.7 taking the period 30 Dec 1915 to 29 Jan 1916. There wasn't much improvement possible to Jan 1796. Slight increases to 7.5 can be made in Jan 1921 by taking the last five or six days of December 1920 instead of the same days in January.  In general, it does not appear that there's any 31-day period above 8 C that is mostly in January-February.

In the warm Feb of 1779, one needs to add three days from January (or more) to stay in calendar winter, that drops the 7.9 of that month to 7.7 or lower. If you allow the first of March in, then you have 7.8 C.

I will run a more comprehensive program but I don't think I'm going to find a period much milder than the 8.2 of 3 Dec 1934 to 2 Jan 1935.

 

 

 

 

Edited January 1, 2016 by Roger J Smith

[Roger J Smith]

Back on page 13 of this thread you will find two posts edited with the confirmed information showing:

-- Dec 2015 had 18 days at or above 10.0 C which shattered the previous record of 9 days in 1974.

-- The spell of six consecutive days 15th-20th broke a record from 1856 (five days) which was itself tied by the spell of five days 26th-30th 2015.

-- There was also a spell of four days 5th-8th.

-- Five new daily records were set, 16th to 19th, and 27th. These broke records from 1842, 1904, 1987, 1993 and 2014 (the 18th). The record high of 13.1 on 19th also broke the all-time December mark previously 12.9 from 12th, 1994.

-- Meanwhile, Dec 2015 does the business at both ends, the former record for highest minimum daily CET was 4.2 set in 2013, now it's 5.6 from the 13th. And in anomaly terms, that was over one degree higher relative to its daily average either long-term or 1981-2010. The former futility record in that category was +0.2 also from 2013. (see the post for the exact details)

While most of us prefer cold records to warm records, at least we got records. One that barely escaped was the streak of four consecutive days with record highs, from 28-31 July 1948. That is now tied with 16-19 Dec of 2015. As explained earlier, a previous record of seven days (28 June to 4 July 1976) had been obliterated by another record warm day in 2015, namely 1st of July, which broke that old mark into two three-day streaks. So there's co-operation between records in 2015 (a total of nine have been set, one in July, three in November and five in December).

Edited January 2, 2016 by Roger J Smith

[BornFromTheVoid]

I'll post up a bit more tomorrow, but a few other records for this month include:

• The mildest December day on record is now 13.1C from the 19^th. This is also the latest date to achieve a CET of 13.0C or more, beating the previous record from November 23^rd.
• The previous record for the most days of 10.0C or more was 9 back in 1974. This year saw 18 such days.
• We set 5 daily records, the 16^th through to the 19^th and the 27^th.
• On average, the coldest day of December is -1.4C and the mildest coldest December day being 4.2C in 2013. The coldest day this December was 5.6C.
• The anomaly of +8.8C on the 19^th is the joint 3^rd largest daily anomaly in the entire CET series

[Man With Beard]

Congratulations Roger on a ( reasonably) good punt in December!

Goodness knows what the CET was down here on the south coast. ALL days exceeded 11C, and often up to 15C! Only SIX nights in the whole month got below 10C! So I'd have thought my CET would have been between 11C and 12C.

Edited January 1, 2016 by Man With Beard

[Nick L]

Let's lock that December away and never speak of it again...

[J10]

1 hour ago, BornFromTheVoid said:

I'll post up a bit more tomorrow, but a few other records for this month include:

• The mildest December day on record is now 13.1C from the 19^th. This is also the latest date to achieve a CET of 13.0C or more, beating the previous record from November 23^rd.
• The previous record for the most days of 10.0C or more was 9 back in 1974. This year saw 18 such days.
• We set 5 daily records, the 16^th through to the 19^th and the 27^th.
• On average, the coldest day of December is -1.4C and the mildest coldest December day being 4.2C in 2013. The coldest day this December was 5.6C.
• The anomaly of +8.8C on the 19^th is the joint 3^rd largest daily anomaly in the entire CET series

Hopefully the mildest month on record will be broken again this June.

 

1 hour ago, Man With Beard said:

Congratulations Roger on a ( reasonably) good punt in December!

Goodness knows what the CET was down here on the south coast. ALL days exceeded 11C, and often up to 15C! Only SIX nights in the whole month got below 10C! So I'd have thought my CET would have been between 11C and 12C.

http://www.met.reading.ac.uk/~brugge/PREV.html

The above link gives monthly stats at a number of locations.

[Roger J Smith]

That won't happen again (until at least February).