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

[BornFromTheVoid]

The minimum today is 6.7C, while maxima look like reaching the low 11s, so remaining on 9.8C on tomorrows update.

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

9.7C to the 29th (9.1: +5.2)
9.7C to the 30th (9.4: +5.2)
9.6C to the 31st (5.9: +1.5)
 

A sightly cooler final day, but still no day this month below average. At this stage, a finish of 9.4 to 9.8C before corrections, and 8.9C to 9.8C after correction is likely

[snowray]

Incredible stuff that final projected figure.

To think that we have recorded far lower temps in June than many of this months Max temps, I can remember some very cold early Junes with sleet and even wet snow reported as far South as the Chilterns one year. And of course we had heavy snow that settled in the home counties around North London in late October not that long ago. We had the best snowfall and ice days around here in November, 4 or 5 years ago.

No real seasons any more.

Edited December 28, 2015 by snowray

[Summer Sun]

9.8c to the 28th

5.1c above the 61 to 90 average

5.1c above the 81 to 10 average

[The PIT]

Sunny Sheffield 8.6C finally figure likely to be 8.5C rounded up

[cheeky_monkey]

2 minutes ago, The PIT said:

Sunny Sheffield 8.6C finally figure likely to be 8.5C rounded up

im guessing London has to be 10c + 

[BlueSkies_do_I_see]

Say it finishes 9.6C, that is 1.5C more than the previous highest record CET for the month (1934,1974). I believe the highest a record CET has ever been beaten by?

I know this is a difficult question to answer, but what CET figure would we be talking about for a July CET value to finish as far off the scale as Dec 2015?

I am talking roughly the same weather setup as we have had this month - I.e almost total southerly or southwesterly systems the whole month with a warmer than normal Atlantic and very warm continental Europe.

Edited December 29, 2015 by BlueSkies_do_I_see

[North-Easterly Blast]

I believe that the warmest 31 day period on record in the CET since 1772 is around 20.3-20.4, from July 24th to August 23rd 1995 or thereabouts.  I also believe that a similar figure was reached from around June 21st to July 20th 1976.  So it is a tall order for the warmest 31 day period on record to fit neatly into a calendar month.  We just managed the warmest calendar month on record in July 2006, as the heatwave exactly coincided with the calendar month - if the heatwave had have started two or more days earlier or later than it did at the time, we probably wouldn't have quite broken the record.  So a July with a CET of over 20*C is theoretically possible but would be fully dependent on an exceptionally hot 31 day period fitting neatly into the calendar month.

I still feel that it is easier for a winter month to be further above the average than a summer month.  Winter months in general show greater variation in both the amounts that they can be above and below average than summer months.

13 minutes ago, BlueSkies_do_I_see said:

Say it finishes 9.6C, that is 1.5C more than the previous highest record CET for the month (1934,1974). I believe the highest a record CET has ever been beaten by?

I know this is a difficult question to answer, but what CET figure would we be talking about for a July CET value to finish as far off the scale as Dec 2015?

I am talking roughly the same weather setup as we have had this month - I.e almost total southerly or southwesterly systems the whole month with a warmer than normal Atlantic and very warm continental Europe.

 

[Timmytour]

19 minutes ago, BlueSkies_do_I_see said:

Say it finishes 9.6C, that is 1.5C more than the previous highest record CET for the month (1934,1974). I believe the highest a record CET has ever been beaten by?

I know this is a difficult question to answer, but what CET figure would we be talking about for a July CET value to finish as far off the scale as Dec 2015?

I am talking roughly the same weather setup as we have had this month - I.e almost total southerly or southwesterly systems the whole month with a warmer than normal Atlantic and very warm continental Europe.

Think we would be talking about getting on for a mean CET of 23.4C for a similar percentage increase on the current July record of 19.7C from 2006

[Timmytour]

A couple of very general questions on mean CETs.......

I have the a download of the monthly mean CETs from Hadley, which also provides the annual CET for each year.  By process of obtaining the sum of multiplying the CET of each month by the number of days in that month and dividing by the number of days in that year, I come to exactly the same annual CET except for one exception....2014.   I calculate this to be 10.94C but Hadley say it's 10.95C....why would this be the only year that doesn't match exactly?

1752 was the year when the calendar lost 11 days of September as we moved from the Julian calendar to the Gregorian.  But the calculation looks as if it was based on a fully year to give an annual CET of 9.21. Should this have rather been based on a 19 day September and a 354 day year to give a CET of 9.07 instead?
 

[Timmytour]

Even if this month ends up at 9.6C, the average December mean CET over the last 25 years (1991-2015) will have been cooler than the previous 25 years (1966-1990)

[Froze were the Days]

9 hours ago, cheeky_monkey said:

im guessing London has to be 10c +

At least - I've been winter recording since 1983 and have found this weather well mind boggling, I live out on the Essex coast and I'd guess out here we're running at least 10.5c so Londinium I would have thought would be higher. Unbelievable.

[BornFromTheVoid]

10 hours ago, North-Easterly Blast said:

I believe that the warmest 31 day period on record in the CET since 1772 is around 20.3-20.4, from July 24th to August 23rd 1995 or thereabouts.  I also believe that a similar figure was reached from around June 21st to July 20th 1976.  So it is a tall order for the warmest 31 day period on record to fit neatly into a calendar month.  We just managed the warmest calendar month on record in July 2006, as the heatwave exactly coincided with the calendar month - if the heatwave had have started two or more days earlier or later than it did at the time, we probably wouldn't have quite broken the record.  So a July with a CET of over 20*C is theoretically possible but would be fully dependent on an exceptionally hot 31 day period fitting neatly into the calendar month.

I still feel that it is easier for a winter month to be further above the average than a summer month.  Winter months in general show greater variation in both the amounts that they can be above and below average than summer months.

 

20.31C from is the figure, from July 24th to August 23rd, 1995. The warmest 31 days in 1976 was 20.22C, from June 22nd to July 22nd

[The PIT]

Back up to 8.7C in Sunny Sheffield.

[Summer Sun]

9.8c to the 29th

5.1c above the 61 to 90 average

5.1c above the 81 to 10 average

[J10]

23 hours ago, cheeky_monkey said:

im guessing London has to be 10c + 

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

This shows Heathrow to be at 11.5c for the month so far.

[cheeky_monkey]

5 minutes ago, J10 said:

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

This shows Heathrow to be at 11.5c for the month so far.

portland is at 12.1c !! 

[Harve]

1 hour ago, J10 said:

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

This shows Heathrow to be at 11.5c for the month so far.

This ain't the rainfall thread, but 44mm in Wick, 777mm in Shap and less than 30mm in many southern England sites? That's quite something.

[The PIT]

There's going to be a huge difference across the country. We've just gone over 100mm today and we've missed out on nearly all the heavy rain.

[Timmytour]

34 minutes ago, The PIT said:

There's going to be a huge difference across the country. We've just gone over 100mm today and we've missed out on nearly all the heavy rain.

I'd imagine the rainfall for the UK as a whole during the month is about average.   The problem has been the distribution of it!

[AderynCoch]

6 hours ago, cheeky_monkey said:

portland is at 12.1c !! 

Also a mean minimum this month of 11.2C and a lowest minimum of 8.3C. Horrendous.

[BornFromTheVoid]

Minimum today of 8.3C, while maxima were in the mid 11s, so remaining on 9.8C on tomorrows update.

The minimum tonight looks like being in the mid 5s, with maxima in the mid 8s, so a drop to 9.7C is likely before corrections. After corrections, 9.2 to 9.7C is the most likely range.

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.

[J10]

I have put the first draft of the December scores in the rules thread so if you want to have a look and make comments please do so in the other thread.

Link-> https://forum.netweather.tv/topic/84491-cet-competition-2015-2016-rules-thread/?do=findComment&comment=3311033

Edited December 30, 2015 by J10

[Roger J Smith]

On December-29-15 at 6:02 AM, Timmytour said:

A couple of very general questions on mean CETs.......

I have the a download of the monthly mean CETs from Hadley, which also provides the annual CET for each year.  By process of obtaining the sum of multiplying the CET of each month by the number of days in that month and dividing by the number of days in that year, I come to exactly the same annual CET except for one exception....2014.   I calculate this to be 10.94C but Hadley say it's 10.95C....why would this be the only year that doesn't match exactly?

1752 was the year when the calendar lost 11 days of September as we moved from the Julian calendar to the Gregorian.  But the calculation looks as if it was based on a fully year to give an annual CET of 9.21. Should this have rather been based on a 19 day September and a 354 day year to give a CET of 9.07 instead?
 

My understanding (and I can't recall how I determined this many years ago, perhaps Hubert Lamb mentions this in his books somewhere) is that the CET values we see for 1752 and previously are calculated from Gregorian calendar data, in other words, what they say is January 1740 is actually something like 21 Dec 1739 to 20 Jan 1740, etc. So the temperature data for the day of the Daniel Defoe storm (as you may know in O.S. dates was 26-27 Nov but new style 7-8 Dec 1703) would be in December 1703 not in November 1703.

I can't help you with the other question. Maybe it's (shock) their error? I assume humans enter into the picture somewhere in those lofty realms.

[Roger J Smith]

Another way of comparing this month to a July record warm outcome would be to consider how the mean temperature compares to the average value of daily record highs. This past month is about 1.5 deg below the average of record daily highs. For July, that would be around 23.2, assuming a somewhat narrower variance then perhaps 22.0 would be a reasonable estimate of how extreme this month would look in summer conditions. It is hard to compare because a big factor this month has been cloud cover preventing any radiational cooling at night. That much cloud cover in July would pretty much guarantee a rather low CET even in warm, humid air masses.

The other question about breaking the record by a certain amount, is not that hard to compare, just look at the ranked CET values and choose your earlier cases. If you allowed a very generous 15 years minimum and top 20 current ranking, so that cases would have to be later than 1674 to count, and reasonably warm by modern standards, then these are the most significant record-breakers I could find:

JAN ___ 0.9 C (Jan 1733 vs 1708)

FEB ___ 1.1 C (Feb 1779 vs 1739)

MAR __ 0.9 C (Mar 1938 vs 1750)

APR __ 0.6 C (Apr 2011 vs 2007, also 2007 vs 1865)

MAY __ 1.3 C (May 1833 vs 1788)

JUN __ 1.1 C (Jun 1676 vs 1672) -- lame but nothing else available, 1846 only beat 1676 by 0.2

JUL ___ 0.7 C ( July 1983 vs 1783)

AUG __ 0.5 C (Aug 1747 vs 1736)

SEP ___ 1.6 C (Sep 1729 vs 1708)

OCT __ 0.8 C (Oct 1731 vs 1685)

NOV __ 1.1 C (Nov 1730 vs 1729)

DEC ___ 1.4 C (Dec 2015 vs 1974) est

In some ways then the step up in September 1729 was almost equally impressive given time available vs variance. It may retain the record for this quirky statistic if you accept my limits (actually top 2 and at least 70 years available to beat would be the limits defined by 1729).

 

 

[Summer Sun]

9.8c to the 30th

5.2c above the 61 to 90 average

5.2c above the 81 to 10 average