September 2016 C.E.T. Forecasts

[Summer Sun]

17.1 to the 18th

3.1c above the 61 to 90 average

2.5c above the 81 to 10 average

[Relativistic]

5 hours ago, crucible72 said:

For the period 1981-2010, the CET for the first 21 days of December is 4.8 and the CET for the same period in March is 6.2, so significantly closer in value than their respective monthly averages of 4.6 and 6.6. These values get even closer if you go back through earlier years, as historically March tended towards cold starts.

30 years averages for 1st-21st March/ December:

1781-1810: 4.2/ 3.4

1791-1820: 4.6/ 3.5

1801-1830: 5.1/ 4.0

1811-1840: 5.2/ 4.6

1821-1850: 5.3/ 4.9

1831-1860: 5.0/ 4.6

1841-1870: 4.8/ 4.8

1851-1880: 5.0/ 4.3

1861-1890: 4.8/ 4.0

1871-1900: 4.9/ 3.9

1881-1910: 4.7/ 4.4

1891-1920: 5.0/ 4.9

1901-1930: 5.3/ 4.7

1911-1940: 5.3/ 4.6

1921-1950: 5.3/ 4.6

1931-1960: 5.3/ 4.8

1941-1970: 5.2/ 4.7

1951-1980: 5.2/ 4.9

1961-1990: 5.3/ 4.8

1971-2000: 6.0/ 5.2

1981-2010: 6.2/ 4.8

 

The averages have really diverged in recent years owing to December's cooling trend and March's warming trend. Many of the 30 year averages were quite similar, with the 1841-1870 averages both at 4.8C. No March averages were colder than their corresponding December averages.

 

[damianslaw]

Sorry to go off topic -but thanks for posting the above stats. Yes there has been a definate warming trend in March compared to December, but there have been periods when the values were fairly close. 

[Summer Sun]

16.9 to the 19th

3.0c above the 61 to 90 average

2.4c above the 81 to 10 average

[The PIT]

Sunny Sheffield 16.3C miles above normal.

[Summer Sun]

16.8 to the 20th

2.9c above the 61 to 90 average

2.3c above the 81 to 10 average

[BornFromTheVoid]

Minimum today is 10.9C while maxima look like reaching about 19C, so a drop to 16.7C is likely on tomorrows update.

After that, the 06z GFS has the CET at:

16.7C to the 22nd (15.5: +1.7)
16.5C to the 23rd (13.1: -0.4)
16.5C to the 24th (15.6: +2.8)
16.5C to the 25th (15.9: +3.2)
16.3C to the 26th (11.9: -0.9)
16.1C to the 27th (12.5: -0.4)
16.2C to the 28th (17.5: +4.3)
16.3C to the 29th (18.3: +5.2)
16.2C to the 30th (13.3: +0.5)

Warmth continuing overall but the chances of beating 2006 (16.8C) now growing quite slim, while odds are probably against a top 3 (16.3C) finish overall too. Top 5 seems a more realistic bet (16.0C), and top 10 is almost certain (15.3C).

[reef]

Warmest extended May-Sep periods in the CET series:

2006: 16.16C
1947: 15.90C
1976: 15.76C
1868: 15.68C
2003: 15.68C
1846: 15.66C
1934: 15.62C
1911: 15.54C
1826: 15.52C
2016: 15.52C (assuming a 16.0C September finish)
1959: 15.48C
1995: 15.48C

A 16.2C finish would put us on 15.56C between 1911 and 1934. Either way, just into the top 10 in over 350 years looks likely.
 

Edited September 21, 2016 by reef

[Man With Beard]

1 hour ago, reef said:

Warmest extended May-Sep periods in the CET series:

2016: 16.16C
1947: 15.90C
1976: 15.76C
1868: 15.68C
2003: 15.68C
1846: 15.66C
1934: 15.62C
1911: 15.54C
1826: 15.52C
2016: 15.52C (assuming a 16.0C September finish)
1959: 15.48C
1995: 15.48C

A 16.2C finish would put us on 15.56C between 1911 and 1934. Either way, just into the top 10 in over 350 years looks likely.
 

That's quite an elite set of years there - 1976, 2003, 1995 I can remember well - it doesn't even include 2006 and 1983 which were hot.

So is this saying it has been a very hot year? I think perhaps we don't see it that way because we haven't had any extended heatwaves - rather, it has been a series of short ones.

(Sorry - I know this isn't quite the right thread so please move if necessary.)

[Relativistic]

We’re two thirds of the way through the month now, and using the provisional figures we’ve dropped below 2006. This puts us in 5th position.

Warmest Septembers to the 20th:

1. 1865: 17.8

2. 1898: 17.4

3. 1795: 17.0

4. 2006: 16.9

5. 2016: 16.8

6. 1780: 16.7

=7. 1926: 16.4

=7. 1947: 16.4

=7. 1949: 16.4

10. 1929: 16.2

 

Below I have plotted, for the 5 warmest Septembers for which we have daily data, the mean CETs to each date in the month. Alongside them I have plotted September 2016.

September 2016 still right in the mix.

I'll update this at the end of the month, or before should anything noteworthy occur.

Edited September 21, 2016 by Relativistic

[reef]

1 hour ago, Man With Beard said:

That's quite an elite set of years there - 1976, 2003, 1995 I can remember well - it doesn't even include 2006 and 1983 which were hot.

So is this saying it has been a very hot year? I think perhaps we don't see it that way because we haven't had any extended heatwaves - rather, it has been a series of short ones.

(Sorry - I know this isn't quite the right thread so please move if necessary.)

The top year was 2006. Now corrected, but still notable the company 2016 shares.

[The PIT]

Sunny Sheffield 16.1C 2.4C above normal.

[Roger J Smith]

(edit October 1st) _ Apologies if anyone reported this earlier ... 

Using the simplified method (average of 12 monthly means) and with a confirmed 16.0 for this month, I find that the top 18 (to get the highest values from each century) averages for October to September of following year (with the coldest for comparison) to be ... 

 

2015-16 ___ 10.96 (10.98)

2006-07 ___ 10.85 (10.88)

1994-95 ___ 10.84 (10.87)

2013-14 ___ 10.81 (10.84)

2002-03 ___ 10.68 (10.72)

2001-02 ___ 10.62 (10.64)

1989-90 ___ 10.60 (10.63)

1833-34 ___ 10.53 (10.57)

1948-49 ___ 10.53 (10.55)

1988-89 ___ 10.53 (10.57)

1997-98 ___ 10.51 (10.53)

1998-99 ___ 10.51 (10.54)

2005-06 ___ 10.50 (10.54)

1845-46 ___ 10.48 (10.49)

1821-22 ___ 10.46 (10.48)

1778-79 ___ 10.44 (10.45)

2004-05 ___ 10.43 (10.47)

1685-86 ___ 10.42 (10.45)

 

(1739-40) ___ 7.32 (7.34)

 

The values in brackets are complex averages based on length of months, these tend to be slightly higher because February is a short month, and these values are leap-year-sensitive although this is the first leap year to appear in the warm list, the coldest case ran through a leap year too (almost 4 deg colder on average). The second coldest was 1683-84 at 7.38 (7.39). Then 1878-79 came in at 7.39 (7.41). 

 

Following on from that, the warmest November to next October values calculated the same way are (or for this year, will be if we have a modest 11.0 October which was the same value as we replace in the series from 2015 so same averages) ...

 

1994-95 ___ 11.07 (11.10)

2015-16 ___ 10.96 (10.98)

2013-14 ___ 10.81 (10.84)

1778-79 ___ 10.73 (10.75)

2006-07 ___ 10.68 (10.70)

2002-03 ___ 10.61 (10.65)

1989-90 ___ 10.62 (10.65)

1833-34 ___ 10.58 (10.61)

1948-49 ___ 10.67 (10.69)

2004-05 ___ 10.65 (10.69)

1988-89 ___ 10.63 (10.68)

1997-98 ___ 10.54 (10.56)

1998-99 ___ 10.52 (10.55)

2005-06 ___ 10.49 (10.53)

1845-46 ___ 10.48 (10.49)

1821-22 ___ 10.48 (10.51)

1920-21 ___ 10.46 (10.50)

1975-76 ___ 10.36 (10.38)

2001-02 ___ 10.35 (10.37)

 

1685-86 ___ 10.21 (10.23)

 

(1739-40) ___ 6.96 (6.98)

 

From 16.0 in September, this October would need to average 12.4 to match 1994-95, and it would need to finish 9.2 or below to place 2015-16 below 2013-14 in third place on these estimates.

Because 1685-86 dropped by 0.25 when Oct 1686 replaced Oct 1685, there would be several other NOV-OCT "years" ahead of it as well as all the previous cases. I have only added those years that also moved past 2001-02, which were just two, 1920-21 and 1975-76. 

With the record cold October 1740 joining the second list, 1739-40 drops to even lower values. The second coldest NOV-OCT "year" is then 1878-79 (at 7.28) (7.31).

 

Edited October 1, 2016 by Roger J Smith

[Weather-history]

7 hours ago, reef said:

Warmest extended May-Sep periods in the CET series:

2006: 16.16C
1947: 15.90C
1976: 15.76C
1868: 15.68C
2003: 15.68C
1846: 15.66C
1934: 15.62C
1911: 15.54C
1826: 15.52C
2016: 15.52C (assuming a 16.0C September finish)
1959: 15.48C
1995: 15.48C

A 16.2C finish would put us on 15.56C between 1911 and 1934. Either way, just into the top 10 in over 350 years looks likely.
 

2016 is the poorest summer out of them in that list. Some famous summers in that list: 1911, 1947, 1959, 1976, 1995

 

[Matthew.]

7 minutes ago, Larger than average Hobo said:

Just goes to show, if a summer period can beat all of those legendary summers by being 'relatively poor', the next good summer that comes along is going to leave them trailing in it's wake, a bit like December 2015 did for that month. 

Many of the best summers didn't have the warmest May or September which brings their Summer average down. 2016 was consistently warm throughout the 5 months. As the legendary summer of 59' shows it's not all about CET but average sunshine is a bigger player in the feel of the summer. As a whole summer 2016 was no where near them legendary summers above in that respect.

[Summer Sun]

16.7 to the 21st

2.9c above the 61 to 90 average

2.2c above the 81 to 10 average

[The PIT]

No change for Sunny Sheffield still 16.1C tomorrow will be another drop though.

[Summer Sun]

16.6 to the 22nd

2.8c above the 61 to 90 average

2.2c above the 81 to 10 average

 

[NorthYorksWeather]

Steadily dropping away here currently, 15.7c to the 22nd which Is 2.2c above average. Expecting a finish around 15.0c

[The PIT]

Sunny Sheffield 15.9C a slight drop for today as well which should be cancelled out by Saturdays warm weather.  Can't see there being much change so finally figure here between 15.7C and 16C. So warmest since 2006.

[Don]

22 minutes ago, The PIT said:

Sunny Sheffield 15.9C a slight drop for today as well which should be cancelled out by Saturdays warm weather.  Can't see there being much change so finally figure here between 15.7C and 16C. So warmest since 2006.

I think it's a safe bet now that September 2016 will be the warmest since 2006.

[Summer Sun]

16.5 to the 23rd

2.7c above the 61 to 90 average

2.1c above the 81 to 10 average

[Summer Sun]

16.5 to the 24th

2.7c above the 61 to 90 average

2.2c above the 81 to 10 average

[damianslaw]

Suspect we will come in above 16 degrees, which will make it easily the mildest September since 2006. Winds have predominantly come from the south or south west all month in the south - there persistance quite startling, aided by the paths of ex tropical storm systems which have continued to pull in ridge development from the south. Its been a warm month not due to high pressure directly overhead but tropical maritime air instead.

I think we've hit peak anamolous warmth this last 12 months, and will now enter a more average 12 month period at least. In many respects similiar to the May 2006 - May 2007 period which brought persistent warmth with only very shortlived cooler spells - very shortlived..

[Summer Sun]

16.4 to the 25th

2.7c above the 61 to 90 average

2.1c above the 81 to 10 average