Cause Of The UK Heatwave?

[Sunny76]

4 hours ago, CreweCold said:

Well I, for one, would like to see a proper freeze up in December and January rather than the rather belated effort seen this year.

A Siberian style early-mid January freeze up thank you very much!

I think we will get one before christmas this year. Things will start off very mild in November, with days of cloudy and mild weather, then from mid December onwards the temps will plummet, with freezing conditions lasting all the way until mid February. 

It will be the first winter to rival 63 or 79. 

[WhiteFox]

On Monday, July 30, 2018 at 08:11, Sunny76 said:

A good summer shouldn’t be defined by having to exceed 30c. A lon dry spell of 24-27c for example, as opposed to two weeks of 32c is still better. 

2015 had the hottest July day on record, but what good was it, as the summer that followed was awful.

Indeed. A better measure would be the average temperature over a period and the amount of PPN. A single hot week mixed in with weeks of average to below average temperatures is not as good (subjectively of course) as weeks of above average temperatures and dry weather.

Also, the highest temperatures tend to lead to a breakdown from the west. 1976 didn't have record breaking temperatures, but was regarded as the best summer.

[Methuselah]

On 30/07/2018 at 08:11, Sunny76 said:

A good summer shouldn’t be defined by having to exceed 30c. A lon dry spell of 24-27c for example, as opposed to two weeks of 32c is still better. 

2015 had the hottest July day on record, but what good was it, as the summer that followed was awful.

Which, in and off itself, proves that the much-held belief that (for the setting of new temperature records) we need sit under static, very warm uppers for several days prior - is not actually true?

[danm]

On 30/07/2018 at 00:58, 38.5*C said:

A very poor heatwave in my opinion for Manchester because its not had a single day hitting 30C. All the other big heatwave years, 76, 83, 90, 95, 2003/06 saw 31 or 32C get hit across a number of days, 2018 very poor here as far as heat is concerned.

This summer will be remembered mainly for its dryness.

Quite surprised to hear you say that Manchester hasn’t had any day hitting 30c. Just looked at the records for this summer for the official Manchester weather station and it says it hit 30c on 26th July but that’s the only day so far this summer. 

[Fourty Point Three Degrees]

3 hours ago, danm said:

Quite surprised to hear you say that Manchester hasn’t had any day hitting 30c. Just looked at the records for this summer for the official Manchester weather station and it says it hit 30c on 26th July but that’s the only day so far this summer. 

I don't recall 30C last Thursday? It was 27C according to the BBC weather app when I was in the city centre. I'm still very surprised how we've lacked in heat this year compared to other big summers. Im not saying Manchester should be getting the high temps that SE England get but we should be seeing at least 28C days during heatwaves by now and not stuck in the low to mid 20's all the time. Very poor.   

[danm]

16 minutes ago, 38.5*C said:

I don't recall 30C last Thursday? It was 27C according to the BBC weather app when I was in the city centre. I'm still very surprised how we've lacked in heat this year compared to other big summers. Im not saying Manchester should be getting the high temps that SE England get but we should be seeing at least 28C days during heatwaves by now and not stuck in the low to mid 20's all the time. Very poor.   

The offical Manchester weather station recorded 30c last Thursday: https://www.weatheronline.co.uk/weather/maps/city?LANG=en&CEL=C&SI=mph&MAPS=over&CONT=ukuk&LAND=UK&REGION=0003&WMO=03334&UP=0&R=0&LEVEL=150&NOREGION=1 

Shows that being the only day this summer that station has reached 30c.

Edited August 1, 2018 by danm

[Frost HoIIow]

29 minutes ago, 38.5*C said:

I don't recall 30C last Thursday? It was 27C according to the BBC weather app when I was in the city centre. I'm still very surprised how we've lacked in heat this year compared to other big summers. Im not saying Manchester should be getting the high temps that SE England get but we should be seeing at least 28C days during heatwaves by now and not stuck in the low to mid 20's all the time. Very poor.   

I wouldn't say it's been "very poor" for those who like summery temps. Everyone you talk to say it's been a long summer. It's been consistently very warm. Dull cooler days like today have been few and far between. 

[Interitus]

2 hours ago, danm said:

The offical Manchester weather station recorded 30c last Thursday: https://www.weatheronline.co.uk/weather/maps/city?LANG=en&CEL=C&SI=mph&MAPS=over&CONT=ukuk&LAND=UK&REGION=0003&WMO=03334&UP=0&R=0&LEVEL=150&NOREGION=1 

Shows that being the only day this summer that station has reached 30c.

There is no 'official' Manchester weather station and those figures should be taken with a very large pinch of salt. They appear to be taken from the airport METARS but are incomplete, compare with the wunderground site for example - https://www.wunderground.com/history/monthly/gb/manchester/EGCC/date/2018-7

The ridiculous 16°C max on the 20th is at least six degrees lower than the actual temperature! Two problems with METARS is that on the one hand they are rounded values and on the other they are instantaneous and unlikely to capture absolute maximum and minimum values. So a value of 30 degrees may not actually be so because of rounding, though because of underestimating the maximum is probably that high or more so. However 30°C has been recorded twice this summer from these.

By comparison with the 16°C max, that day at nearby Rostherne less than five miles away, the maximum was 25.1°C. This site has recorded 30°C three times this year according to the SYNOP data, here on ogimet - http://www.ogimet.com/cgi-bin/gsynres?lang=en&ind=03351&ano=2018&mes=8&day=1&hora=6&min=0&ndays=50

As for the summer overall in this region it is a bit churlish to regret lack of extreme high temperatures as has been consistently very warm. Looking at the now defunct Ringway climate data and the METARS it is possible that June was the warmest on record beating 1976, and July looks like it may be the 3rd warmest month (for maximum temps) behind July 2006 and August 1995, maybe just pipping July 1983.

Edited August 1, 2018 by Interitus

[danm]

12 minutes ago, Interitus said:

There is no 'official' Manchester weather station and those figures should be taken with a very large pinch of salt. They appear to be taken from the airport METARS but are incomplete, compare with the wunderground site for example - https://www.wunderground.com/history/monthly/gb/manchester/EGCC/date/2018-7

The ridiculous 16°C max on the 20th is at least six degrees lower than the actual temperature! Two problems with METARS is that on the one hand they are rounded values and on the other they are instantaneous and unlikely to capture absolute maximum and minimum values. So a value of 30 degrees may not actually be so because of rounding, though because of underestimating the maximum is probably that high or more so. However 30°C has been recorded twice this summer from these.

By comparison with the 16°C max, that day at nearby Rostherne less than five miles away, the maximum was 25.1°C. This site has recorded 30°C three times this year according to the SYNOP data, here on ogimet - http://www.ogimet.com/cgi-bin/gsynres?lang=en&ind=03351&ano=2018&mes=8&day=1&hora=6&min=0&ndays=50

As for the summer overall in this region it is a bit churlish to regret lack of extreme high temperatures as has been consistently very warm. Looking at the now defunct Ringway climate data and the METARS it is possible that June was the warmest on record beating 1976, and July looks like it may be the 3rd warmest month (for maximum temps) behind July 2006 and August 1995, maybe just pipping July 1983.

Fair enough. 

I use this for the Heathrow figures mainly which look bang on. 

[Interitus]

16 minutes ago, danm said:

Fair enough. 

I use this for the Heathrow figures mainly which look bang on. 

Yes, they look similar to the values on wunderground though these METARS underestimate the average maximum temperature - for July 28.06°C compared to the SYNOP value of 28.46°C - http://www.ogimet.com/cgi-bin/gsynres?lang=en&ind=03772&ano=2018&mes=7&day=31&hora=18&min=0&ndays=31

[Interitus]

37 minutes ago, Interitus said:

By comparison with the 16°C max, that day at nearby Rostherne less than five miles away, the maximum was 25.1°C. This site has recorded 30°C three times this year according to the SYNOP data, here on ogimet - http://www.ogimet.com/cgi-bin/gsynres?lang=en&ind=03351&ano=2018&mes=8&day=1&hora=6&min=0&ndays=50

 

Just a small correction the maximum was 24°C on the 20th, 25.1°C was previous day, had wrong recording hour set

http://www.ogimet.com/cgi-bin/gsynres?lang=en&ind=03351&ano=2018&mes=7&day=31&hora=18&min=0&ndays=31

[Evening thunder]

19 minutes ago, WhiteFox said:

Indeed. A better measure would be the average temperature over a period and the amount of PPN. A single hot week mixed in with weeks of average to below average temperatures is not as good (subjectively of course) as weeks of above average temperatures and dry weather.

Also, the highest temperatures tend to lead to a breakdown from the west. 1976 didn't have record breaking temperatures, but was regarded as the best summer.

I'm being pedantic perhaps but 1976 saw the June record with 35.6C at Southampton (tied with Camden Square in 1957 although the Met Office indicates there's reservations about that record) and saw 35.9C at Cheltenham on the 3rd July.

In my location it's above the rest with 33.5C being the record at Exeter Airport, and an 11 day stretch with 29-33C (9 of those 30C+).
1983 and 1990 also saw over 32C.

A major heatwave is one element that's been missing for central-west/SW England IMO. Ok we have scraped 30C but the big heatwaves in 76, 83, 90, 95, 03, 06 etc got higher (sometimes 35C+ in places).
This had been suggested by the modelling a few times but it didn't verify. As such even this year almost everywhere at our latitude including parts of Ireland/Scotland, and of course parts of the Arctic circle e.g. north Lapland, have got hotter).

That doesn't stop it being a great summer overall of course, but for someone like me it's just a box left unchecked on the 'all time greatest' criteria sheet.

[The PIT]

If the weather had been like May it would have made a perfect summer. Not to hot dry with nice temps at night for sleeping in.

DSoesn't seem like anyone really talking about the cause of the heatwave. I read somewhere it was due to that cool blob out in the Atlantic and a similar setup happened in 76 although the high then was placed in a different position. 

[BLAST FROM THE PAST]

On 30/07/2018 at 03:28, CreweCold said:

Well I, for one, would like to see a proper freeze up in December and January rather than the rather belated effort seen this year.

A Siberian style early-mid January freeze up thank you very much!

Aaron

 

ALL IN.  Mega general warmth into Autumn (Oct). This December to be a big shock and very cold.....snowfall I’ll leave to now casting.....but a big wintry December coming.....and a few frosts won’t cut it....ice days and well below average.  Early taster of my thoughts....tipping point period

 

BFTP

[Sunny76]

15 hours ago, BLAST FROM THE PAST said:

Aaron

 

ALL IN.  Mega general warmth into Autumn (Oct). This December to be a big shock and very cold.....snowfall I’ll leave to now casting.....but a big wintry December coming.....and a few frosts won’t cut it....ice days and well below average.  Early taster of my thoughts....tipping point period

 

BFTP

I think Feb 2018 was the start of returning to colder winters for at least the next couple of years. Like Feb 2009, gave us our first cold winter for a number of years, then the following two Decembers were bitterly cold. 

Something similar to December 2009 or 10 could be on the cards this year. I’ll bet there’s a mild or very mild interlude for a few days at a time in between the chilly spells. 

[Mike Poole]

I think that one significant factor in this heat wave is sea surface temperatures (SST) in the North Atlantic.  The significant aspects of this are cold temperatures just south of Greenland, and warm temperatures close to he UK, this quite significant considering quite how cold they were in March! These can only really have an effect on seasonal time scales if the the weather they increase the chances of feeding back to the SST anomaly i.e. a positive feedback loop.  The Met Office contingency planners forecasts earlier in the year highlighted this,  May update in particular.  

Here the SST anomaly for the 1st of the last four months:

Edited August 7, 2018 by Mike Poole