Will this summer be similar to the poor ones of the 1980s?

[weatherguru14]

I hope its case. But this weather reminds me of a good the summers of the past.. warm start to May then a cloudy and fairly dull 2 weeks followed for a warm up in the late May heading into the start of Summer.. I really hope it turns out this way..

[B87]

6 minutes ago, weatherguru14 said:

I hope its case. But this weather reminds me of a good the summers of the past.. warm start to May then a cloudy and fairly dull 2 weeks followed for a warm up in the late May heading into the start of Summer.. I really hope it turns out this way..

I hope we have a normal summer this year but I've given up hope already.

[weatherguru14]

19 minutes ago, B87 said:

I hope we have a normal summer this year but I've given up hope already.

One thing ive noticed is the lack of wind this year so far . Bodes well for unsettled periods to be fleeting..Ie  if we get an active Atlantic season. everything moves through quickly and  we don't get chance for longer settled periods and for the weather to settle down and warm up..

The Jet maybe further north this summer.. Of course if the Atlantic stirs up. our summer will go down the drain quickly.

[B87]

3 minutes ago, weatherguru14 said:

One thing ive noticed is the lack of wind this year so far . Bodes well for unsettled periods to be fleeting..Ie  if we get an active Atlantic season. everything moves through quickly and  we don't get chance for longer settled periods and for the weather to settle down and warm up..

The Jet maybe further north this summer.. Of course if the Atlantic stirs up. our summer will go down the drain quickly.

It's been windy here throughout April. Normally the winds are calm or light.

I do hope the jet returns to it's normal position this summer (north of Scotland), instead of it sitting directly over southern England ruining everything like it's done for the past few years.

[Evening thunder]

No idea what this summer will do.. although referring to the list of factors quoted on the previous page, the summers ending in 8 thing is of course a coincidence and if Easter had the same dates as last year it would have been warm instead.

But anyway there's the usual negative postings.. I've posted the maps before but the last 5 summers have actually been a relatively standard set for the UK.

[Frost HoIIow]

1 hour ago, weatherguru14 said:

I hope its case. But this weather reminds me of a good the summers of the past.. warm start to May then a cloudy and fairly dull 2 weeks followed for a warm up in the late May heading into the start of Summer.. I really hope it turns out this way..

Not necessarily. Late May 2012 was basically perfect for heat lovers. The Summer that followed was mostly cool. The weather will do what it wants and doesn't follow patterns.

[B87]

13 minutes ago, Evening thunder said:

No idea what this summer will do.. although referring to the list of factors quoted on the previous page, the summers ending in 8 thing is of course a coincidence and if Easter had the same dates as last year it would have been warm instead.

But anyway there's the usual negative postings.. I've posted the maps before but the last 5 summers have actually been a relatively standard set for the UK.

2013, 2014 and to a lesser extent 2017 were fairly normal here regarding sunshine. The others not so much. West has done much better than the east it seems. Most of those summers would be below even the average of the 1960-69 decade (which was extremely dull, with 570 hours).

2008: 478.7 (77%)
2009: 516.2 (83%)
2010: 492.8 (79%)
2011: 491.2 (79%)
2012: 462.7 (75%)
2013: 624.4 (101%)
2014: 650.2 (105%)
2015: 520.8 (84%)
2016: 485.9 (78%)
2017: 557.2 (90%)

Edited May 4, 2018 by B87

[B87]

Number of extremely cloudy summers (less than 500 hours) by decade in the Heathrow record.

1957-59: 1

1960-69: 1

1970-79: 3

1980-89: 1

1990-99: 0

2000-09: 2

2010-17: 4

Looking at that, you'd expect to see 2 per decade on average (balanced out by sunnier than average summers), yet this current decade has seen double that number, and could see 6 occasions by the time it ends. Maybe the 2020s and 30s will be like the 80s and 90s, and we are in a decade of duller summers now like those of the 70s?

[weatherguru14]

27 minutes ago, Frost HoIIow said:

Not necessarily. Late May 2012 was basically perfect for heat lovers. The Summer that followed was mostly cool. The weather will do what it wants and doesn't follow patterns.

why mention 2012? one of the poorest summers on record. I have not suggested its going to be 2006 summer. Just seems people look for extremes..Anyway  I said I was hoping it would follow the pattern of  summers in the past.. didn't say it was going to happen that way.. I also mentioned once the Atlantic gears up. It usually means  summers are poor.Anyhow for the record. I think 2018 will be one of the better summers in recent years.

[Frost HoIIow]

1 hour ago, weatherguru14 said:

why mention 2012? one of the poorest summers on record. I have not suggested its going to be 2006 summer. Just seems people look for extremes..Anyway  I said I was hoping it would follow the pattern of  summers in the past.. didn't say it was going to happen that way.. I also mentioned once the Atlantic gears up. It usually means  summers are poor.Anyhow for the record. I think 2018 will be one of the better summers in recent years.

I mentioned 2012 purely as an example that a warm Spring does not guarantee a hot Summer. Do yourself a favour and look at 2013 - coldest Spring for about 50 years yet it gave a decent Summer overall. July being particularly hot.

Edited May 5, 2018 by Frost HoIIow

[reef]

14 hours ago, B87 said:

2013, 2014 and to a lesser extent 2017 were fairly normal here regarding sunshine. The others not so much. West has done much better than the east it seems. Most of those summers would be below even the average of the 1960-69 decade (which was extremely dull, with 570 hours).

2008: 478.7 (77%)
2009: 516.2 (83%)
2010: 492.8 (79%)
2011: 491.2 (79%)
2012: 462.7 (75%)
2013: 624.4 (101%)
2014: 650.2 (105%)
2015: 520.8 (84%)
2016: 485.9 (78%)
2017: 557.2 (90%)

That's not the case, we're in the east and it has been as sunny as the already high 1981-2010 mean. So much so that the 1991-2020 mean will likely be higher still.

Last 11 summers here compared to the 1981-2010 average of 567hrs:

2007: 550hrs (97%)
2008: 517hrs (91%)
2009: 602hrs (106%)
2010: 573hrs (101%)
2011: 552hrs (97%)
2012: 444hrs (78%)
2013: 640hrs (113%)
2014: 619hrs (109%)
2015: 589hrs (104%)
2016: 556hrs (98%)
2017: 599hrs (106%)

All pretty close to average apart from the dire 2012. They average out at 100.1% of normal over the 11 years exactly.

Only 5 of those summers were wetter than average and 3 were cooler than average (and even then by no more than 0.3C below average). We really haven't done too badly at all, locally at least.

Edited May 5, 2018 by reef

[BruenSryan]

On 03/05/2018 at 19:41, TJM14 said:

I think this summer will be similar to 2001 atm, nothing special. Just a guess

That would be very good. Some heat, some thunderstorms. You can't go wrong. 2001 was not that bad. 2001 is one of the years that crops up the most in the analogues I've mentioned above along with 1876, 1934, 1947, 1963, 1975, 1996, 2008 and 2013. 

[BruenSryan]

16 hours ago, Evening thunder said:

No idea what this summer will do.. although referring to the list of factors quoted on the previous page, the summers ending in 8 thing is of course a coincidence and if Easter had the same dates as last year it would have been warm instead.

But anyway there's the usual negative postings.. I've posted the maps before but the last 5 summers have actually been a relatively standard set for the UK.

Not exactly. If you look at the 1st April Easter Sundays and the Summers that followed them (last occurrence of such being 1956 - terrible Summer), you'll find again a similar suit to what all those showed with a southerly tracking jet stream and northern blocking.

It was mentioned on Twitter that the constant high pressure to the east since February maybe a good sign for the Summer because it combined with a weaker zonal flow means it's unlikely to change. 

[weatherguru14]

such a lovely and warm day. without being oppressive... I hope we get ;loads of days like this

[Bristawl Si]

No it wont be.

[B87]

3 hours ago, reef said:

That's not the case, we're in the east and it has been as sunny as the already high 1981-2010 mean. So much so that the 1991-2020 mean will likely be higher still.

Last 11 summers here compared to the 1981-2010 average of 567hrs:

2007: 550hrs (97%)
2008: 517hrs (91%)
2009: 602hrs (106%)
2010: 573hrs (101%)
2011: 552hrs (97%)
2012: 444hrs (78%)
2013: 640hrs (113%)
2014: 619hrs (109%)
2015: 589hrs (104%)
2016: 556hrs (98%)
2017: 599hrs (106%)

All pretty close to average apart from the dire 2012. They average out at 100.1% of normal over the 11 years exactly.

Only 5 of those summers were wetter than average and 3 were cooler than average (and even then by no more than 0.3C below average). We really haven't done too badly at all, locally at least.

You got lucky then, as here it's been poor.

[summer blizzard]

Since 1997 the only other years which have achieved an NAO value of +1 or greater for the first half of May are 09 and 15, neither was stunning for the summer.

 

 

[Evening thunder]

On 05/05/2018 at 00:25, B87 said:

2013, 2014 and to a lesser extent 2017 were fairly normal here regarding sunshine. The others not so much. West has done much better than the east it seems. Most of those summers would be below even the average of the 1960-69 decade (which was extremely dull, with 570 hours).

2008: 478.7 (77%)
2009: 516.2 (83%)
2010: 492.8 (79%)
2011: 491.2 (79%)
2012: 462.7 (75%)
2013: 624.4 (101%)
2014: 650.2 (105%)
2015: 520.8 (84%)
2016: 485.9 (78%)
2017: 557.2 (90%)

But even for the SE and central South region, the sunshine anomalies are much higher (this is using the 1981-2010 average).
2008: 576.4 - 94%
2009: 619.1 - 101%
2010: 602.8 - 99%
2011: 550.3 - 89%
2012: 509.3 - 82%
2013: 694.4 - 112%
2014: 710.2 - 115%
2015: 599.2 - 97%
2016: 574.6 - 93%
2017: 653.2 - 105%

Average: 98.7%
Heathrow average: 85.1%

Has Heathrow really sustained a 13.6% sunshine deficit compared to even the region it's in, over a 10 year period?

Well I know I've mentioned this before but I don't think so..

Heathrow of course changed from a Campbell-Stokes recorder, to a Kipp & Zonen recorder in September 2005:
https://www.metoffice.gov.uk/pub/data/weather/uk/climate/stationdata/heathrowdata.txt

and the Met Office state on the Historic Station page that  "No allowances have been made for small site changes and developments in instrumentation"

Studies in the UK shows that CS sensors give higher sunshine totals, for Example:
https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1256/wea.99.03

This study aimed to create a conversion factor between the two sensors in the UK using an overlap of data using both instruments at 16 stations for an average of 18 months.
It found that the CS recorder overestimates sunshine due to the spreading of the burn marks, primarily with strong sun and broken cloud conditions, by an average of about 20% in summer, and 7% in winter.

It's studies like this that the Met Office use to try keep their data-sets and maps consistent (that Heathrow data often seems to disagree with).

To me this is the only logical explanation and makes perfect sense, I'm sorry but I can't see otherwise.

[reef]

2 hours ago, Evening thunder said:

But even for the SE and central South region, the sunshine anomalies are much higher...

Indeed, there's definitely something fishy about those Heathrow numbers. Looking at the figures compared to mine locally, there's no way that 9 out of the last 11 summers would be sunnier here than down there. Its just not possible when you consider how Heathrow is further south and benefits from arguably more setups when it comes to sunshine. Summer 2010 for example was generally a NW/SE split, yet Heathrow apparently had 492hrs compared to 573hrs here and 602hrs in the general south-east region. I don't buy that for a second. I suspect the Metoffice are adjusting in some way for the instrument changes on their anomaly maps pages, as this suggests closer to 560hrs for Heathrow that summer:

For summer 2017 it has closer to 620hrs, as opposed to 557hrs on the raw figures:

That's more than here and much more in line with what you would expect.

Edited May 8, 2018 by reef

[B87]

But KZ records higher values than CS in pretty much every other study conducted (by around 7% in winter and 13% in summer).

Just highlighting a few examples, the original values on the historic data page had the following sun hours (converted/current values).

July 2006: 312 hrs (266 hrs)

Feb 2008: 138 hrs (130 hrs)

Jun 2012: 132 hrs (118 hrs)

Jul 2013: 303 hrs (268 hrs)

All of those months occurred after the switch to KZ, and those original numbers would have been recorded with KZ. It is still actually noticeable on the 'Regional Climates' page for the SE; Heathrow's sunniest July is shown to be around 310 hours (though with CS, the sunniest was actually 276 or so hours in 1959 and 1999). Same with the dullest June, which is shown to be 130ish, but is actually 118 (this was before 2016 blew away 2012 in the dullness stakes with its ridiculous 101 hours).

The SE coast doesn't seem to have suffered the cloudy summers and it's vakues are relatively normal, but someone on another forum based in Bournemouth has also noticed a marked decrease in sunshine (have they changed sensor too)? 

It's not just the sun values, I remember summers as having cloudy starts but generally sunny or partly cloudy days. Since 2007, it seeme to be sunny before 11am and after 7pm, but mostly cloudy or overcast over most of thr day.

Edited May 8, 2018 by B87

[MP-R]

On 4 May 2018 at 23:06, weatherguru14 said:

 

The Jet maybe further north this summer.. Of course if the Atlantic stirs up. our summer will go down the drain quickly.

Not necessarily. The Atlantic naturally stirs the later into the summer/September we go but if that's to the north of the U.K., high pressure often gets sucked northwards towards us on the southern side of the jet. 

[B87]

Another strange example of sun hours changing is Warsaw routinely getting 2200+ sun hours using a vaisala electronic sensor (vs the average of 1570 or so). There is no way that is accurate, as Warsaw is cloudier than southern England.

Edited May 8, 2018 by B87

[hillbilly]

5 hours ago, B87 said:

But KZ records higher values than CS in pretty much every other study conducted (by around 7% in winter and 13% in summer).

Just highlighting a few examples, the original values on the historic data page had the following sun hours (converted/current values).

July 2006: 312 hrs (266 hrs)

Feb 2008: 138 hrs (130 hrs)

Jun 2012: 132 hrs (118 hrs)

Jul 2013: 303 hrs (268 hrs)

All of those months occurred after the switch to KZ, and those original numbers would have been recorded with KZ. It is still actually noticeable on the 'Regional Climates' page for the SE; Heathrow's sunniest July is shown to be around 310 hours (though with CS, the sunniest was actually 276 or so hours in 1959 and 1999). Same with the dullest June, which is shown to be 130ish, but is actually 118 (this was before 2016 blew away 2012 in the dullness stakes with its ridiculous 101 hours).

The SE coast doesn't seem to have suffered the cloudy summers and it's vakues are relatively normal, but someone on another forum based in Bournemouth has also noticed a marked decrease in sunshine (have they changed sensor too)? 

It's not just the sun values, I remember summers as having cloudy starts but generally sunny or partly cloudy days. Since 2007, it seeme to be sunny before 11am and after 7pm, but mostly cloudy or overcast over most of thr day.

You had it good,our nearest met office station gives 90 hrs for June 1990 and only 79 hrs in June 1987 !

[Evening thunder]

10 hours ago, B87 said:

But KZ records higher values than CS in pretty much every other study conducted (by around 7% in winter and 13% in summer).

Just highlighting a few examples, the original values on the historic data page had the following sun hours (converted/current values).

July 2006: 312 hrs (266 hrs)

Feb 2008: 138 hrs (130 hrs)

Jun 2012: 132 hrs (118 hrs)

Jul 2013: 303 hrs (268 hrs)

All of those months occurred after the switch to KZ, and those original numbers would have been recorded with KZ. It is still actually noticeable on the 'Regional Climates' page for the SE; Heathrow's sunniest July is shown to be around 310 hours (though with CS, the sunniest was actually 276 or so hours in 1959 and 1999). Same with the dullest June, which is shown to be 130ish, but is actually 118 (this was before 2016 blew away 2012 in the dullness stakes with its ridiculous 101 hours).

The SE coast doesn't seem to have suffered the cloudy summers and it's vakues are relatively normal, but someone on another forum based in Bournemouth has also noticed a marked decrease in sunshine (have they changed sensor too)? 

It's not just the sun values, I remember summers as having cloudy starts but generally sunny or partly cloudy days. Since 2007, it seeme to be sunny before 11am and after 7pm, but mostly cloudy or overcast over most of thr day.

That's interesting as it was CS sensors giving higher totals that I first became aware of (I believe from posts on this forum many years ago).
Maybe the UK just has a particular climate with much more intermittent summer sunshine than many places.

The logical conclusion to those figures, is the current Heathrow data is un-corrected (as they state), and they had previously published 'corrected' figures.

The paper does state that the average 170w/m2 threshold for the CS recorder compared to 120w/m2 for KZ would in theory mean the KZ gives slightly higher totals, but as radiation changes rapidly at sunrise and sunset this would only be a few minutes, and this is outweighed by the above.
I suppose you might get a scenario with weak sunshine through high cloud where a KZ sensor registers sunshine but a CS recorder doesn't.

I'm not sure if/how different KZ sensor versions vary if other studies have looked at different versions though?

Then there's variability with CS thresholds apparently ranging from 106 to 285w/m2, and human interpretation of the burn marks on the cards.

There could have been more 'sunny start then shower or cumulus infill' days due to synoptic in recent summers (not sure how easy it is to get the data to assess that), and maybe it would have also kept the coats of the SE clearer.. (but to that extent over a 10 year mean?!) However, if the deficit at Heathrow is genuine, presumably some nearby climate stations around the Home Counties/London area would show a similar decline, if any have kept using a CS srecorder to date.

That's the only thing that would stop me thinking there's something fishy really. But without that, I think that Met Office associated study of 16 stations having simultaneous recording using both sensors is pretty strong evidence supporting what's already quite apparent.

Edited May 8, 2018 by Evening thunder

[B87]

45 minutes ago, Evening thunder said:

That's interesting as it was CS sensors giving higher totals that I first became aware of (I believe from posts on this forum many years ago).
Maybe the UK just has a particular climate with much more intermittent summer sunshine than many places.

The logical conclusion to those figures, is the current Heathrow data is un-corrected (as they state), and they had previously published 'corrected' figures.

The paper does state that the average 170w/m2 threshold for the CS recorder compared to 120w/m2 for KZ would in theory mean the KZ gives slightly higher totals, but as radiation changes rapidly at sunrise and sunset this would only be a few minutes, and this is outweighed by the above.
I suppose you might get a scenario with weak sunshine through high cloud where a KZ sensor registers sunshine but a CS recorder doesn't.

I'm not sure if/how different KZ sensor versions vary if other studies have looked at different versions though?

Then there's variability with CS thresholds apparently ranging from 106 to 285w/m2, and human interpretation of the burn marks on the cards.

There could have been more 'sunny start then shower or cumulus infill' days due to synoptic in recent summers (not sure how easy it is to get the data to assess that), and maybe it would have also kept the coats of the SE clearer.. (but to that extent over a 10 year mean?!) However, if the deficit at Heathrow is genuine, presumably some nearby climate stations around the Home Counties/London area would show a similar decline, if any have kept using a CS srecorder to date.

That's the only thing that would stop me thinking there's something fishy really. But without that, I think that Met Office associated study of 16 stations having simultaneous recording using both sensors is pretty strong evidence supporting what's already quite apparent.

Here's the link to another paper that studied CS vs electronic sensors in Krakow. It found that the electronic 120Wm2 sensor recorded approx 10.4% higher values over the course of the year, versus the CS recorder. Krakow averages less than 1500 hours of sunshine per year in the 81-10 averages, so it is cloudier than pretty much all of southern England, but comparable to the Midlands.

https://link.springer.com/article/10.1007/s00704-014-1125-z

A poster on another forum (based in NZ) reports similar increases in sun hours as stations replace CS recorders with electronic sensors. I know that the below isn't a journal paper (I couldn't find a NZ based one), but it shows that there is definitely a discrepancy in favour of electronic sensors over CS.

http://nelsonweekly.co.nz/2017/01/sun-crown-shady/

 

There is an old book online in pdf form somewhere, titled 'The Climate of London'. Granted, it is fairly out of date now as it studied climate in the 50s and 60s, but I recall it saying that the average burn threshold of the CS recorder in Kew Gardens was 139.5 W/m2. Kew averages 1653 hours sun, but I don't have access to any annual data from that station, so can't be compared to Heathrow (avg 1633 hrs, now using KZ). I have noticed on totally cloudless days in summer, that Heathrow sometimes struggles to get above 11-12 hours of sun in a 15-16 hour day. I could understand if it lost 1-1.5 hours due to low sun in the early/late hours, but to lose 4 hours with 0/8 skies and no horizon obstructions is strange to say the least.

Edited May 8, 2018 by B87