July 2013 CET Forecasts / Competition

[BornFromTheVoid]

Based on Met forecasts I see it at.16th 17.9 (19.5)17th 18.0 (20.5)18th 18.2 (20.8 )19th 18.3 (21)20th 18.4 (19.75)GFS 6z ensemble mean would see it rising slightly further to around 18.5 on the 24-25th before falling back slightly at the end of the month to 18.1-18.2.

 

12z GFS op run would have us on 18.8C by the 23rd, with the week of the 17th to 23rd averaging 20.8C.

 

A finish of between 17.8 and 19.8C before correction is my best guess at this stage.

[AWD]

18.3 please

Could be close here, although perhaps a tad low. Expected a warm one, but this month is running and looking like being at the top end of my expectations.

[Weather-history]

It's the maxima that is pushing the CET up, the minima haven't been that impressive which is probably ideal for a summer month. High daytime temperatures but minima not especially, so more comfortable nights.

I don't think we have recorded a single CET minimum of 14.0C yet for this year.

Edited July 16, 2013 by Weather-history

[Scorcher]

The warm nights seem to have been restricted to the South East so far. That might change next week. How are we doing on the Manchester Summer Index so far W-H?

[Weather-history]

The warm nights seem to have been restricted to the South East so far. That might change next week. How are we doing on the Manchester Summer Index so far W-H?

223You can see it in my signature.

[Scorcher]

223You can see it in my signature.

 

Yeah of course, thanks.

[summer blizzard]

223You can see it in my signature.

Where does that rank?

[Stu_London]

A little interesting titbit.

 

Between 1778 and 1807, widely accepted as the period of the last (Dalton) solar minimum, there were no less than 17 occasions when the average temperature for July or August was above 17C.

 

Between 1981 and 2010 accepted as the warmest CET decades there were 16 occasions when the average temperature for July and August was above 17C.

 

Therefore as well as a solar minimum offering long cold winters in Northern Europe, they appear to support shortish hot summers too.

 

Happy days.

[BornFromTheVoid]

A very warm 18z GFS.

It would have the CET at about 19.2C by the 24th, with the week of the 18th to 24th averaging around 22C.

 

If the 18z GFS CET estimate turned out correct, and the final 7 days also averaged 22C, we'd equal July 2006 before corrections...

[SomeLikeItHot]

17.9 to the 16th - Yesterday came in at 19.3 a little lower than I expected.

Min today of 13.2, and max likely around 27 then with Met forecast out to 5 days gives,

17th 18.0 (20.1)

18th 18.2 (21.1)

19th 18.3 (21.1)

20th 18.4 (19.7)

21st 18.4 (19.7)

the GFS 0z ensembles then take it to 18.6 around the 14-16th, before a cooler last few days sees it falling back to as low as 18.2.

Generally we've seen upgrades to the end of month cool down - However it seems that the continual relatively low minimums are keeping the mean daily average down below most of our shorter term estimates.

The maximum anomoly is currently +3.3 where as the minimum anomoly is only 0.7.

Edited July 17, 2013 by SomeLikeItHot

[Methuselah]

I'm looking for 1C downward adjustment. 

[March Blizzard]

I'm looking for 1C downward adjustment. 

 

Even I might need that and I went for 17.9C!

[BornFromTheVoid]

With a minimum of 13.2C and a maxima of around 28C, the CET should increase to 18.0C on tomorrows update.

 

After that, the 12z GFS operational has the CET at

18.2C to the 18th (21.1)

18.3C to the 19th (20.2)

18.4C to the 20th (19.8[

18.5C to the 21st (21.5)

18.7C to the 22nd (23.2)

19.0C to the 23rd (23.8]

19.2C to the 24th (24.2)

 

After that, a continuation of the heat after the 24th would take us into the high 19s,  a breakdown to near average temps could drop us into the mid to high 18s, while a breakdown cooler temperatures could drop the CET to about 18C

[summer blizzard]

Manley still 0.6C lower and sunshine headed above 200.

[Scorcher]

It seems crazy that Manley is only running 1.0C above average- we've been several degrees above average here virtually every day for almost 2 weeks now, and it's been even hotter in the South with several days above 30C in London. Alright the nights haven't been exceptionally warm but they've still been mostly average to above.

[Roger J Smith]

For reference, these are the July 18 to 31, and 1 to 15 August, daily records in the CET daily means:

 

18 Jul ... 23.3 (1825) ... 10.1 (1863)
19 Jul ... 24.5 (2006) ... 10.6 (1892) 
20 Jul ... 22.9 (1878) ..... 8.7 (1836) 

21 Jul ... 23.1 (1868) ... 11.3 (1902) 
22 Jul ... 23.2 (1868) ... 11.5 (1902) 
23 Jul ... 22.4 (1989) ... 10.1 (1843) 
24 Jul ... 23.9 (1818) ... 11.1 (1843) 
25 Jul ... 22.7 (2006) ... 10.9 (1920) 

26 Jul ... 23.2 (2006) ... 11.0 (1884) 
27 Jul ... 21.9 (1948) ... 10.6 (1867) 
28 Jul ... 23.7 (1948) ... 11.8 (1886&1891)
29 Jul ... 25.2 (1948) ... 11.0 (1816) 
30 Jul ... 23.1 (1948) ... 10.6 (1786)

31 Jul ... 23.4 (1943 ..... 10.9 (1841)
.. .. .. .. .. .. .. .. &1995)

01 Aug ... 24.9 (1995) ... 11.9 (1888)
02 Aug ... 24.6 (1995) ... 11.6 (1822)
03 Aug ... 24.4 (1990) ... 10.5 (1912)
04 Aug ... 23.4 (1975) ... 11.3 (1812)
05 Aug ... 23.1 (2003) ... 11.3 (1812)

06 Aug ... 22.5 (2003) ... 11.2 (1823&1860)
07 Aug ... 22.8 (1975) ... 11.6 (1898) 
08 Aug ... 23.7 (1975) ... 11.5 (1823) 
09 Aug ... 23.9 (2003) ... 11.0 (1931) 
10 Aug ... 22.5 (1773 ..... 10.8 (1892)
.. .. .. .. .. .. .. .. &1997)

11 Aug ... 22.6 (1997) ... 10.8 (1902)

12 Aug ... 22.2 (1911) ... 10.5 (1912)
13 Aug ... 23.6 (1911) ... 10.5 (1881) 
14 Aug ... 21.3 (1911) ... 10.8 (1912) 
15 Aug ... 22.1 (1893) ... 10.3 (1829) 

 

These are from the thread linked below in my signature portion ... also from there, I recently did a study of notable heat waves and found there were 13 occasions with six or more consecutive days at 20.0 or above, so if we get into that sort of a run, I can compare as we go. So far we haven't reached that level. AderynCoch posted in the same thread a list of all five-day spells where each day was at least 18.0 ... I edited that down to all ten-day spells where each day is 18.0 or above, and found there were 28 in total (over 241 past years). You can see that work in the thread linked below, and as we move forward I will compare this current spell should it reach ten days. We had five in a row, missed on the 11th and now have five more (above 18.0) from provisional CET numbers, today would be a sixth on the trot, so we're not close yet to reaching the list of 28 either. But we could reach it and then I have ranked the top ten of those by mean temperatures from AderynCoch's table.

 

The 1976 heat wave figures prominently in both of our different heat wave tables.

 

I currently estimate 18.9 as a finishing value for July 2013 after corrections and think we could be on values as high as 19.4 to 19.7 in the provisional before perhaps a slight cooling after 26th. Daily records are coming into view and even the all-time daily max of 25.2 is under some pressure if the 20C 850-mb contour really does edge north into Britain. Looking back at previous record heat waves, the 20C contour on average was located near the Channel and 18C is sufficient to sustain a record hot temperature in some cases. I did not find any values above 22C in Britain on these dates. There's really no reason why higher values could not exist with the Saharan source region available, in North America 850-mb temps are often well into the high 20s or even low 30s coming out of the central plains states and into regions almost as far north as Britain. I would guess 24C is the upper limit and that could produce the 40C surface reading that another thread is discussing.

 

 

 

_______________________________________________________________________

Edited July 17, 2013 by Roger J Smith

[SomeLikeItHot]

It seems crazy that Manley is only running 1.0C above average- we've been several degrees above average here virtually every day for almost 2 weeks now, and it's been even hotter in the South with several days above 30C in London. Alright the nights haven't been exceptionally warm but they've still been mostly average to above.

The Manley series as I understand it is an average of two measurements, oxford area and Lancashire plain. Hadley CET is average of Hertford, Worstershire and Lancashire. The Lancashire measurements ahave been so far typically around 2 degrees cooler than the average of the southern measurements from what I have observed. As I understand it in Manley these are weighted at 1/2 the total, in Hadley CET only a third. This would go someway to explaining the difference.

[summer blizzard]

The Manley series as I understand it is an average of two measurements, oxford area and Lancashire plain. Hadley CET is average of Hertford, Worstershire and Lancashire. The Lancashire measurements ahave been so far typically around 2 degrees cooler than the average of the southern measurements from what I have observed. As I understand it in Manley these are weighted at 1/2 the total, in Hadley CET only a third. This would go someway to explaining the difference.

Does Manley not also have coastal observations.

[SomeLikeItHot]

Does Manley not also have coastal observations.

No, he doesn't have any coastal sites. Edited July 18, 2013 by SomeLikeItHot

[Summer Sun]

18.0c to the 17th

[SomeLikeItHot]

18.0 to the 17th. (20.4)

Min today of 14.2 and max around 28

This and Met forecasts for the next five days give.

18th 18.2 (21.1)

19th 18.3 (21.0)

20th 18.4 (18.9)

21st 18.4 (20.3)

22nd 18.6 (21.9)

After that the GFS ensemble mean would see it rise towards 18.7-18.8 by the 26th before falling to around 18.3 at the end of month.

If we take the 5 day forecast to the 22nd as reasonalbly accurate, would need to average around 22 or slighlty more for the last 9 days to beat the month record.

Edited July 18, 2013 by SomeLikeItHot

[The PIT]

18.1 in sunny Sheffield but won't beat the record set in 2006 which was 20.0C and was a remarkable month.

[BornFromTheVoid]

18.2C to the 18th

http://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

 

Yesterday was 21.5C. The minimum today is 14.6C, while maxima look like reaching about 28C, so an increase to 18.4C is likely tomorrow.

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

18.4C to the 20th (19.4)

18.5C to the 21st (20.9)

18.6C to the 22nd (21.0)

18.8C to the 23rd (21.3)

18.8C to the 24th (18.9)

18.8C to the 25th (19.0)

18.8C to the 26th (18.5)

 

 

GFS vs ECM with regard to whether we reach above 19C this month

[SomeLikeItHot]

18.2 to the 18th. (21.5) and the highest daily cet so far.

Min today of 14.6 max likely 28

we should see

19th 18.4 (21.2)

20th 18.5 (20.5)

21st 18.5 (19.7)

22nd 18.6 (21.2)

23rd 18.7 (20.7)

After that GFS 0z ensemble mean then sees it rising slightly to 18.8 on the 24th then falling slowly to 18.4 at the month end. It seems a likely ending range is 19.2 - 18.0.

Again taking the 23rd estimate as reasonably accurate, the last 8 days would need to average 22.7 to beat the month record, 22.3 to equal it, 22-19.2 to finish second highest.

[Roger J Smith]

Notice back a few posts in my list of records, today is the anniversary of the hottest day in 2006 (mean 24.5). Tomorrow presents perhaps the easiest record to break in this spell at 22.9 (1878) but I think the monthly record low of 8.7 in 1836 is safe (probably forever until the next ice age anyway). Hard to imagine a July day that chilly now.

Edited July 19, 2013 by Roger J Smith