UK Weather - Summer 2016

[Simon Culling]

Today (Monday 18th July) was a hot and sunny day here in Milton Keynes with a maximum temperature of 28*C and virtually no wind. It was even hotter in and around London with the highest temperatures from the SYNOPS of 30.0*C at St James Park and Kew Gardens, both in central London, and 29.7*C at RAF Northolt in the NW suburbs.

Tomorrow is forecast to be considerably hotter with the expected high now put at 33/34*C from London into the Midlands and East Anglia with wall to wall sunshine over most of England and Wales and with the heat nudging into Scotland. Some severe storms are expected to break out in the west and north Tuesday night into Wednesday but nothing down here in the south east. We will have to wait until the end of the week when the heat has gone for some showers.

EDIT: This blog entry from a forecaster from a private UK weather company is very informative re this current hot spell:

http://www.netweather.tv/index.cgi?acti ... 7493;sess=

[NZstorm]

The blogg entry was a great read. Its good to see a forecaster explain why they think the thunderstorms will be severe.

Interesting that UK UV peaks at 7.
And the Med. region gets to 10.

NZ gets UV summer readings to 12 with 13 in the far north.

[Simon Culling]

Glad you liked the blog, NZstorm. Yesterday was very warm and sunny over most of the UK with the highest temperatures in the south of the country on the 19th, viz:

33.5*C at RAF Brize Norton (Oxfordshire)
33.4*C at Pershore (Worcestershire)
33.2*C at London Heathrow Airport
33.0*C at Bristol Filton Airport + RAF Northolt

The highest temperatures were actually in the Channel Island which are just off the NW French coast. The mercury hit 35.2*C at Maison St Louis Observatory in St Helier, Jersey which I think is an island record for July.

Overnight and into this morning there has been a lot of thundery activity over N England and Scotland and it has been a very warm (and unpleasant) night here in the south with many places recording a minimum of 19-21*C.

Attached is a great satellite photo from mid morning yesterday showing most of the UK bathed in sunshine!

[Simon Culling]

Wednesday (20th July) was a very active day electrically speaking over a large part of the UK, although some areas (including MK!!) missed out on the storms and the rain. I have not seen any large rainfall totals, but the storms that developed over E Anglia in the late afternoon produced some torrential rain and hail in the 30-35mm range in a number of locations - big enough to dent the odd Beemer - shame!

The map below (courtesy of Blitzortung) shows the distribution of lightning strikes over the UK for the 24 hour day of Wednesday - well over 100,000 were recorded and most of those in the west were overnight so a good display was put on by nature.

[tunster]

3 years ago pretty much exactly was also a heatwave. I think it was both hotter and much longer than the current one though (summary here: https://www.wunderground.com/history/ai ... .wmo=03772 ).

[Simon Culling]

Tunster, we did have a much longer 'heatwave' in July 2013 and more details can be found in this thread:

http://www.weatherforum.org.nz/phpBB3/v ... f=9&t=5000

NZstorm, the UV scale that the Met Office uses for UK exposure goes up to 11 as a maximum - which seems a strange cut-off point.

http://www.metoffice.gov.uk/guide/weath ... uv-symbols

It is a scale developed by the WMO - see this link for more details:

http://www.who.int/uv/intersunprogramme ... _index/en/

Note that the WMO scales shows 11+ at the top of the range and if you go to page 4 where it provides a list expected UV levels for various cities of the world it does quote figures up to 13. I would imagine that the UK would struggle to get above 9-10 on this scale, although we do get to see many very red people when we do get these hot and sunny days! The sun can still burn us here in the UK.

[tunster]

Tunster, we did have a much longer 'heatwave' in July 2013 and more details can be found in this thread:

http://www.weatherforum.org.nz/phpBB3/v ... f=9&t=5000

NZstorm, the UV scale that the Met Office uses for UK exposure goes up to 11 as a maximum - which seems a strange cut-off point.

http://www.metoffice.gov.uk/guide/weath ... uv-symbols

It is a scale developed by the WMO - see this link for more details:

http://www.who.int/uv/intersunprogramme ... _index/en/

Note that the WMO scales shows 11+ at the top of the range and if you go to page 4 where it provides a list expected UV levels for various cities of the world it does quote figures up to 13. I would imagine that the UK would struggle to get above 9-10 on this scale, although we do get to see many very red people when we do get these hot and sunny days! The sun can still burn us here in the UK.

Yes, I was living in Reading in July 2013, the weather was simply lovely. And it was possible to "enjoy the sun" too, which is almost unthinkable in January in NZ.

My understanding of the UV scale is that it's linear. So a UV index of 14 implies double the radiation of a UV index of 7. So when you compare NZ's higher sunshine hours than those of the UK, along with substantially higher UV index, there must be a big difference in cumulative radiation we get exposed to down here.

The WHO list looks bizarre. The Australian cities, as well as Wellington are all underdone. Wellington is given a "maximal" UV of 7 in January, which would actually only happen with a cloudy day here. A typical mid January UV index in Wellington would be around 11. Maximal UV of 7 is more like mid March.
Alarm bells are ringing when Wellington looks pretty much identical to Paris (though with seasons reversed of course), which is plainly wrong.

8 or perhaps 9 might well be the theoretical maximum for UVI in the UK; it will always be limited by the high latitude and probably the atmospheric pollution too.

Back to UK weather, although a westerly breakdown of sorts appears imminent it looks like something more "default" for summer and warmer than a few weeks ago just based on eyeballing the 564dam line on the MetOffice prognosis charts.
So when showers do occur, might be time to trot out that controversial line "at least it'll be mild"!

Further out in the 10 day period, the EC ensemble seems really keen to keep an upper trough in the vicinity of the British Isles. The chances for >30C again look very slim in the next 10 days.

[RWood]

Wellington and Nelson (as just 2 examples) catch out foreign visitors time and time again as they get fried by staying out on sunny summer days when the Tmax may only be about 21-23C. Having said that, I like to see proper blue skies, not feeble ones with a washed-out look. Adelaide and Perth are good examples of largeish cities where pollution is low enough to allow deep blue skies. I was amazed at how feeble the sun felt in early September in both London and Paris, even bearing latitude in mind.

[spwill]

Wellington and Nelson (as just 2 examples) catch out foreign visitors time and time again as they get fried by staying out on sunny summer days when the Tmax may only be about 21-23C..

The high UV is a feature of NZ Summer, very high skin cancer rates here. Being outside on a cloudy day in Southland in Summer can lead to sunburn.
When I come back from USA in May I notice Auckland has brighter sunlight compared to early Summer Mid West USA.

[RWood]

Wellington and Nelson (as just 2 examples) catch out foreign visitors time and time again as they get fried by staying out on sunny summer days when the Tmax may only be about 21-23C..

The high UV is a feature of NZ Summer, very high skin cancer rates here. Being outside on a cloudy day in Southland in Summer can lead to sunburn.
When I come back from USA in May I notice Auckland has brighter sunlight compared to early Summer Mid West USA.

My common tactic when outdoors at risky times for a while is to sit in locations where there is lots of sunlight close by but very little if any direct sunlight on me. And of course to wear a hat when in direct sunlight and watch the dosage on any uncovered parts.

I did notice that as expected UV is much higher in semi-desert locations like Sedona in Arizona than it is nearer to LA and other large centres.

[Simon Culling]

Thanks Gentlemen for your comments on the UV index. I have seen a level of 8 in the UK forecast but nothing higher than this. As has been said, we have the limitations of latitude, but the pollution issue will only arise when the winds come off the continent - normally they get our pollution if the winds are off the Atlantic. When the wind swings round more to west or north we get some very clear air and this would be when the sun appears to be at its strongest (especially in summer) and we get very clear blue skies away from any showers. These are good days for photographing clouds and landscapes but also for being aware of the burning potential of the sun.

The warm weather came to and end overnight and Monday (25th July) was much cooler and fresher and the forecast for the week ahead is a continuance of this fresher air with showers at times.

The CET for July was 17.0*C (+1.0*C) up to the 24th and the EWR was 32mm up to the 23rsd which is only 51% of the monthly average. This figure disguises quite a dry southern half of the UK and a very wet north and west.

[Janos]

Tunster, we did have a much longer 'heatwave' in July 2013 and more details can be found in this thread:

http://www.weatherforum.org.nz/phpBB3/v ... f=9&t=5000

NZstorm, the UV scale that the Met Office uses for UK exposure goes up to 11 as a maximum - which seems a strange cut-off point.

http://www.metoffice.gov.uk/guide/weath ... uv-symbols

It is a scale developed by the WMO - see this link for more details:

http://www.who.int/uv/intersunprogramme ... _index/en/

Note that the WMO scales shows 11+ at the top of the range and if you go to page 4 where it provides a list expected UV levels for various cities of the world it does quote figures up to 13. I would imagine that the UK would struggle to get above 9-10 on this scale, although we do get to see many very red people when we do get these hot and sunny days! The sun can still burn us here in the UK.

Yes, I was living in Reading in July 2013, the weather was simply lovely. And it was possible to "enjoy the sun" too, which is almost unthinkable in January in NZ.

My understanding of the UV scale is that it's linear. So a UV index of 14 implies double the radiation of a UV index of 7. So when you compare NZ's higher sunshine hours than those of the UK, along with substantially higher UV index, there must be a big difference in cumulative radiation we get exposed to down here.

The WHO list looks bizarre. The Australian cities, as well as Wellington are all underdone. Wellington is given a "maximal" UV of 7 in January, which would actually only happen with a cloudy day here. A typical mid January UV index in Wellington would be around 11. Maximal UV of 7 is more like mid March.
Alarm bells are ringing when Wellington looks pretty much identical to Paris (though with seasons reversed of course), which is plainly wrong.

8 or perhaps 9 might well be the theoretical maximum for UVI in the UK; it will always be limited by the high latitude and probably the atmospheric pollution too.

Back to UK weather, although a westerly breakdown of sorts appears imminent it looks like something more "default" for summer and warmer than a few weeks ago just based on eyeballing the 564dam line on the MetOffice prognosis charts.
So when showers do occur, might be time to trot out that controversial line "at least it'll be mild"!

Further out in the 10 day period, the EC ensemble seems really keen to keep an upper trough in the vicinity of the British Isles. The chances for >30C again look very slim in the next 10 days.

We were living down in Cornwall during this time and I recall the temps in Berkshire being so much warmer and sunnier that Lostwithiel. Our two daughters were living in Caversham at the time and they were suffering because of the high humidity and heat. I must admit the heat of last week was hard work, or rather the humidity was.

[Simon Culling]

I suppose it depends upon your own personal preferences with regard to weather and temperatures but I would agree that generally speaking it does get rather humid here in the UK when the temperatures heads north of about 25*C and this is especially noticeable at night in the towns + cities. To me, our best 'summer' days here in the SE of the UK are brought by west or north westerly winds which give scattered Cu and plenty of sunny periods with the temperature around 20-23*C and about 40-50% humidity. You can get out and about and be active in those sort of conditions. Further north and west they will have showers to contend with so these synoptic conditions are not best for Ireland, Wales + Scotland.

It has been a bit more humid this week with some showery rain but also sunny periods - normal July weather really with a decent weekend to come - should get some cricket in tomorrow!

[Simon Culling]

It has remained rather humid and generally dry here in the southern half of the UK and it was quite a breezy day today (Weds 3rd Aug) with sunshine at times and a humid max of 23*C. Monday into Tuesday saw the first general rain for England and Wales for quite a while with 10-20mm in many places and more than double this amount in S Wales and parts of SW England. In the 24hrs to 0600GMT on Tuesday 52mm fell at The Mumbles Lighthouse (S Wales) and 47mm at nearby Pembrey Sands. 44mm also fell on Cardinham which is on Bodmin Moor, Cornwall.

A very photogenic waterspout was observed off the east coast of E Anglia - more specifically at Thorpeness, on Saturday 30th July - I have not seen any better photos of a UK spout than this one:

http://www.bbc.co.uk/news/uk-england-suffolk-36941468

The final CET for July was 16.9*C which is +0.8*C above the long term average. The EWR was just 44mm which is just 71% of the monthly average. The year as a whole remains considerably wetter than normal.

[tunster]

I suppose it depends upon your own personal preferences with regard to weather and temperatures but I would agree that generally speaking it does get rather humid here in the UK when the temperatures heads north of about 25*C and this is especially noticeable at night in the towns + cities. To me, our best 'summer' days here in the SE of the UK are brought by west or north westerly winds which give scattered Cu and plenty of sunny periods with the temperature around 20-23*C and about 40-50% humidity. You can get out and about and be active in those sort of conditions. Further north and west they will have showers to contend with so these synoptic conditions are not best for Ireland, Wales + Scotland.

It has been a bit more humid this week with some showery rain but also sunny periods - normal July weather really with a decent weekend to come - should get some cricket in tomorrow!

I think truly humid days in the UK are quite rare. It's very rare to see dewpoints over 20C - only happens a few times of the year usually.

On the really hot 30C+ days, which are also quite rare, the dewpoint will usually be quite low. For example, the hottest day of the 2013 heatwave saw 33C with a dewpoint of 14C at Heathrow. Then the famous August 2003 hot and humid spell - on one of the 35C days the dewpoint was 16C, on the hottest day of all the temperature reached 37C but the dewpoint was 9C at the same time.
Contrast that with truly humid conditions such as in the tropics where dewpoints are routinely around 25C or higher whilst the temperature is in the low or mid 30s. Or somewhere like the UAE, where the temperature could be 40C and the dewpoint is 22C. You might think it won't feel humid because of the almost 20C dewpoint depression but that's because we should not be using "relative humidity" to measure how humid people feel. "Moistness" would be a better descriptor and we could use dewpoint (or wet bulb) for that. So a 22C dewpoint will always feel humid, regardless of the temperature.

I think the reason people in the UK find it humid in summer is because the dewpoints peak overnight and at the same time the temperature is lower, so the difficulty in sleeping comes to define the overall feel. Then when it's hot in the middle of the day (and the dewpoint correspondingly drops), people just aren't used to heat and perhaps call it humid regardless? Not sure, speculating here.

[Simon Culling]

Hello tunster, thanks for your recent comments - I agree with your general point that those of us normally resident in the UK cannot fully appreciate the meaning of humidity unless we have visited the tropics, for example. The level of discomfort in the UK is an order of magnitude below that - and I have direct experience of a few months in north Queensland to compare to.

I suppose it depends on what you are used to and I think the medical term is 'your physiology' or how you perceive your surroundings or environment. Here in the UK really humid days (for us) with a dew point north of 18*C are thankfully rare, but nights with high humidity, as you suggest, are much more frequent - even in the depths of winter the temperature and dew point can lift to 15-16*C overnight as tropical maritime air floods in from the Atlantic.

We had a warm and sunny weekend here in the south (up to 25-28*C on both days) but the north was affected by strong winds and rain, particularly on Sunday. No rain at the Test Match at Edgbaston as England defeated Pakistan to go 2-1 up in the four match series.

The CET for August was 17.1*C (+1.1*C) up to the 7th and the EWR was 19mm up to the 6th, which is 25% of the monthly average of 77mm. Most of this has fallen in the north. Another spell of hot weather is predicted for this coming weekend and into next week with the mercury into the low 30's again.

[Simon Culling]

We had a change of airmass on Monday to a NW feed and this has brought much cooler weather with two chilly mornings for Tuesday + Wednesday. This morning (Weds 10th Aug) there was quite a widespread air frost in the Glens of Scotland with the lowest recorded temperatures being:

-1.0*C at Tulloch Bridge + Dalwhinnie
-0.9*C at Cromdale
-0.6*C at Loch Glascarnoch
-0.4*C at Aviemore

The grass minimum at Aviemore was -3*C. These compare to the August record low of -4.5*C at Lagganlia (Highlands also) on 21/8/1973. A lot of these old stations are now closed.

The weather will warm up at the end of the week, although there has been a bit of a downgrade on the likely maximums next week to about 30*C. Before that, the NW of Scotland is looking at one of those 'atmospheric rivers' giving it two to three days (from today) of continuous rain with at least 100-150mm up on the higher ground. Dry with sunshine at times here in the South!

[Simon Culling]

The forecast for a 'heatwave' has been progressively downgraded over the last few days and will just be a nice sunny and warm spell of weather with only a small potential for a few storms later in the week. It was very warm yesterday (Fri 12th Aug) with a max of 28.8*C at Cavendish (Suffolk) and 27.7*C at London Heathrow and this may rival the forthcoming warm spell. It was sunny again this afternoon (Saturday) and nice and warm here in MK at 24*C. Despite the dry weather of the last couple of months everywhere still looks very green as evidenced by the photo below taken at 6pm today - sunny and 22*C with a moderate west breeze.

It was indeed wet in the NW of Scotland in the latter part of the last week with some quite high rainfall totals at low ground stations. In the 72 hours to 0600GMT today (Sat 12th Aug) 109.4mm was recorded at Achnagart, 70.4mm at Lusa (Isle of Skye) and 53.0mm at Aultbea. I would imagine nearly double that would have fallen higher up the mountains.

[Simon Culling]

Whilst not a heatwave it has been warm and mostly sunny here in Milton Keynes for the last 5 days with the temperature reaching 23-25*C daily, although the longer nights have been refreshingly cool. The sunshine and warmth has extended further north in the last couple of days and the highest temperatures have been recorded in Scotland rather than England with 26.9*C recorded at Kinlochewe yesterday (Tues 16th Aug) and 27.3*C at the same site today (Weds 17th). The high pressure responsible was situated a bit further north and east than forecast and gave us a feed from the east rather than the south and hence temperatures in the thirties were not seen.

As the high drifts away further east a particularly deep low (for the time of year) will be approaching the UK this weekend giving us a return to cooler and wetter/windy weather.

The CET for August was 16.6*C (+0.6*C) up to the 16th and the EWR was 25mm up to the 15th which is just 32% of the monthly average - and most of this has fallen in the north.

[Simon Culling]

It was indeed windy and much cooler over the weekend and sadly six individuals got into difficulty in the sea and perished. Unfortunately some of us underestimate the power of waves and currents and suffer the consequences:

http://www.bbc.co.uk/news/uk-37148196

On a brighter note, it was a glorious sunny day here in Milton Keynes today (Tues 23rd Aug) with a maximum temperature of 29*C. It will be a bit warmer tomorrow but the sunshine is likely to be a bit hazy as weather systems gather to our south and west with a thundery period due from Wednesday night onwards. The charts are a bit muddled at the moment but there is the potential for quite a few thunderstorms over much of the south eastern half of the UK into the weekend and it will become much more humid from tomorrow onwards.

EDIT: Highest temperatures on Tues 23rd Aug were 31.0*C at London Heathrow + Cambridge NIAB and 30.5*C at RAF Northolt.

[Simon Culling]

Wednesday 24th August was the warmest day of the year so far and seems likely to retain that title. The highest recorded temperatures were:

33.9*C at Gravesend (Kent)
33.8*C at Cavendish (Suffolk)
33.5*C at Andrewsfield Aerodrome + Writtle (both in Essex)
33.1*C at London Heathrow
33.0*C at St James Park, Central London

Tragically another person injured in last weekend's coastal accidents has passed away and 5 young men lost their lives in another sea-side accident yesterday - they appear to have been caught out by tidal changes.

http://www.bbc.co.uk/news/uk-england-sussex-37182791

A few thunderstorms broke out yesterday evening, but the expected activity into today has not yet transpired but may get underway later on into Thursday (25th Aug) evening as the plume edges across the UK and exits to the east. It has been very humid today with dew points reaching 18-20*C in places so there is plenty of moisture around.

[Orion]

Shocking tragedies there, Simon - is that kind of toll unprecedented?

[Simon Culling]

Hello Orion, it is certainly unusual to see 12 casualties in a few days as a result of drowning incidents around the UK coasts, but sadly all too often people take unnecessary risks with waves and tides and suffer the consequences. This might seem strange as the UK is historically a nautical nation, but perhaps knowledge of the sea is no longer part of our make-up. I spent the first twenty years of my life living on the coast and was taught at an early age to respect the sea and how to understand the tides, but I would suspect that day 'visitors' to the beach might not possess this information. Let us hope that these incidents make more of us aware of the dangers even on what can seem to be a calm and benign day.

Weatherwise, the predicted storms did not really materialise yesterday and today (Fri 26th Aug) was another warm and sunny day in Milton Keynes with a max temperature of 24*C. However, a warm front will push northwards from the continent on Saturday to bring some needed rain to southern parts.

The CET for August was 17.1*C (+1.3*C) up to the 25th and the EWR was 52mm up to the 24th which is 68% of the monthly average - but most of this has fallen in the northern half of England + Wales.

[Simon Culling]

Saturday (27th Aug) provided the best thunderstorm day this year for a fair part of England as a frontal wave appears to have developed and MCS type system as it moved NNE from Dorset through the Midlands and into the North Sea via Lincolnshire. The map below shows the progression from late morning when it formed to about tea time when it excited the country. Of the total lightning strikes displayed about 90,000 were over the England land mass. Very heavy rain (and hail up to about 25mm) and squally winds were reported by many observers as was the frequent lightning and thunder as well as a funnel cloud near Oxford. There were also numerous pictures of the 'asperatus' clouds that some are trying to get recognised as a new cloud genus - its is the rolling and chaotic Sc/As that you often see near thunderstorms - particularly the elevated variety - as these were.

The storms skirted round me here in MK but we did get some well needed rain and a few rumbles!

After a few showers on Sunday it has been back to quiet and sunny weather today which looks set to hold for much of the week with a few 25*C+ days.

[Simon Culling]

The last few days of the meteorological summer have been dry with plenty of sunshine and still on the warm side with nothing exciting to match the weather of last weekend. Overall it has been a reasonable summer with above average temperatures and roughly average rainfall and sunshine. The week ahead as we move into the meteorological autumn still looks warm and mostly settled with some particularly good days in the middle of next week.

The CET for August was 17.3*C (+1.3*C) up to the 30th and the EWR was 67mm also up to the 30th which is 87% of the monthly average.

EDIT: Some provisional figures for the summer from the Met Office - it always puzzles me why they release preliminary figures before the summer has ended - can't they wait 2 days?

http://www.metoffice.gov.uk/news/releas ... statistics