UK Weather - Summer 2017

[Simon Culling]

A little warmth persisted into the first few days of the meteorological summer, but these triggered quite a few thunderstorms on Friday (2nd June) afternoon into the evening on a convergence line over south east England. The mercury had reached 26.8*C at Gravesend in the warm humid air ahead of a cold front orientated SW-NE over western and central parts of the UK and this combined with some sunshine in these parts and a clear convergence line was sufficient to trigger the storms which produced quite a bit of lightning and hail to about 2cm. The Twitter page at this link gives a good representation on the convergence zone:

https://twitter.com/danholley_/status/8 ... 8044545026

The weekend has started cooler and fresher here in Milton Keynes with plenty of sunshine today (Saturday) and a temperature of 20*C. However, we will see quite a deep depression (for the time of year) pass over the southern half of the UK Monday into Tuesday giving us plenty of rain and wind and some much cooler temeperatures.

[Simon Culling]

The weather duly went down the pan on Monday and a quite deep low (986mb) crossed England curving northwards through the western edge of the North Sea. It gave a windy and wet first three days of the week to the whole of the UK with some places seeing 50-100mm of rain and wind gusts of up to 50-60mph, even inland. It has felt more like autumn than summer. Another low is on its way for the weekend, but this one will take a more northerly track and will therefore have minimal impact on most of us. After that there are signs of the weather settling down again and getting warmer into early next week.

The CET for June was 14.2*C (+0.9*C) up to the 7th and the EWR was 43mm also up to the 7th, which is 65% of the monthly average of 65mm.

[Simon Culling]

We have dried out a bit over the last few days and we have had one of those 'one day heatwves' today over most of England and Wales with plenty of sunshine and a max of 27*C in London. It will be cooler Thurs/Fri after a weak cold front passes over in the morning, but it will become warm and sunny again from Saturday with a good chance of the first 30*C temperature by Sun/Mon. Let's enjoy it while it lasts.

The CET for June was 14.7*C (+1.1*C) up to the 13th and the EWR was 52mm up to the 12th which is 80% of the monthly average.

[Simon Culling]

It has become very warm and sunny in much of the UK with the 30*C mark broken on Saturday (17th June) with the possibility of 32*C/33*C on Sun/Mon. We have high pressure (1027mb) over southern England and very warm air has slowly filtered north from the continent (44*C in Spain on Saturday afternoon) and this set up looks set to continue for the next few days and possibly until next weekend. Highs for Saturday were:

30.1*C at London Heathrow Airport
29.7*C at Gravesend (Kent - far east of London)
29.5*C at St James Park
29.3*C at Santon Downham (Suffolk)
29.2*C at Charlwood (Surrey) + Pershore (Worcs)

[Simon Culling]

The synoptic map shows a ridge of high pressureo over sourhern England today so there is not a direct feed off the continent - it is rather a case of locally generated heat today due to prolonged sunshine as well as warmer air aloft slowly drifting north east from south of 20 degrees south. Wherever the source, it has been very warm today (Sunday 18th June) with the highest temperatures in and around London - 32.1^C at Hampton Waterworks, 31.7*C at London Heathrow and 31.3*C at both Gravesend and RAF Northolt. The heat will continue for much of this coming week with increasing humidity not helping the comfort levels. Not much prospect of any storms in the computer models at the moment.

At 10pm this evening, it is still 24*C at London Heathrow Airport and the dew point has crept up to 17*C. It is not much cooler here in Milton Keynes (22-23*C), so an uncomfortable night ahead.

[Simon Culling]

Monday 19th June was slightly warmer with 32.5*C recorded at Hampton Waterworks and 32.4*C at RAF Northolt, both in western London. The wall to wall sunshine persisted over much of England + Wales, but poor old Scotland has been on the north side of a weak front and been much cooler - a max of just 18*C in Aberdeen and 13*C on Shetland.

Today, with the centre of the high moving north, a light easterly flow has developed over the southern half of the UK and the hotest weather has shifted westward, although it is still what we would consider hot in most places - except Scotland again. We will have an even warmer day tomorrow (Weds 21st June) as the wind backs southerly as a low moves to near NW Scotland and we could see the mercury reach 34*C in and around the London area. However, this will be the last of the hot days and a few storms are likely into Thursday to be followed by much cooler weather into the weekend.

EDIT: Max temps on Tues 20th were 32.4*C at Jersey Airport (Channel Islands), 31.4*C at London Heathrow Airport, 31.3*C at RAF Northolt and 31.2*C at Chivenor (north caost of Deven).

[Simon Culling]

Wednesday 21st June proved to be the peak of the heatwave and the highest temperatures were recorded mostly in and around London. Hot and humid air was drawn across the UK as a low moved northeast past Scotland and triggered a few storms in the evening over northern England and parts of Scotland. Highest temperatures were:

34.5*C at London Heathrow Airport
33.8*C at RAF Northolt
33.3*C at Charlwood (Surrey)
32.9*C at St James Park
32.8*C at RAF Benson (Oxon)
32.5*C at Bristol Filton Airport

Much cooler (Atlantic) air is spreading across the UK today (Thurs 22nd June) and we will not see these sort of temperatures again for a while.

[Simon Culling]

Whilst the really hot weather has moved away, it has remained quite muggy here in the UK and the lauded Atlantic air has not reached us yet and the mercury has reached 25*C in places, including today, Saturday 24th June. However, the forecast for next week is certainly cool and changeable with rain or showers at times and daytime temperatures struggling to reach 20*C. These forecasts can sometimes be rather too pessimistic and I am sure there will be some good days, weather wise.

The CET for June was 16.5*C (+2.6*C) up to the 23rd reflecting the recent hot spell and the EWR was 54mm up to the 22nd, which is 83% of the monthly average.

The British Lions were well beaten this morning - the All Blacks were just too good. Let's hope the next two matches are a bit closer and we can have some cold and wet weather to make them feel more at home!!!

[Simon Culling]

The weather this week is a million miles away from last week as areas of low pressure have dumbelled around the UK giving us much cooler and wetter weather. Not much in the way of thunder but quite big areas of persistent rain have certainly lifted any fears of drought conditions. In the 24 hours to 0900GMT today (Weds 28th June) 90.2mm has fallen at Santon Downham (in East Anglia) with 64.2mm at nearby RAF Marham and 63.0mm at Houghton Hall.

Here in Milton Keynes we had a wet night (about 15mm) but a mostly dry and cloudy day with a moderate northerly breeze and a maximum temperature of just 14*C.

The forecast for the rest of the week is for the cool and unsettled weather to persist as these low pressures remain over the UK, although there is a hint of warmer and drier weather over the weekend.

[Simon Culling]

The rain and cold persisted for much of the week, but the weather has improved for the weekend with sunny spells and temperatures into the low twenties - this to me is good summer weather, where you can get out and do things but not get too hot. For us in the south of the UK this weather will persist for much of the new week, although it could be quite warm by the end of the week. Not much rain in the forecast.

Despite the fears of drought at the begining of summer, June turned out to be quite a wet month although much of the rain did fall on 6-8 days and the rest of the month was dry.

http://www.metoffice.gov.uk/news/releas ... to-a-close

[Simon Culling]

The weather will be warming up a bit more than earlier forecasts suggested and we could see 30*C on Thursday and Friday this week. With a feed of air from the south comes the threat of some significant showers on storms later on Thursday and into Friday and if they can engage the boundary layer we could see some heavy point rainfalls as there will be little wind around to move them on. It has been nice today and yesterday with sunny intervals here in Milton Keynes and a max of around 23*C on both days, but the humidity has increased a bit today. We should be nudging 27*C tomorrow as the sun will be shining a bit more.

The final CET for June was 16.0*C (+1.9*C) making this the seventh warmer than average month in a row. The final EWR was 93mm, which is 143% of the monthly average.

Here are a couple of photos of the Hampshire Downs on a sunny early evening last Sunday - it was around 22*C at the time with only a few cumulus and cirrus and a light breeze.

[Simon Culling]

It warmed up a bit more than original forecasts had suggested with the temperature hitting the 90*F mark again on Thursday (6th July) with the highest temperatures again in London, with 32.2*C at London Heathrow and 31.8*C at RAF Northolt. The high temperatures were again confined to England + Wales and some significant storms broke out in the morning and later on in the late afternoon and evening. Hail up to 30mm was observed at Oakham in the old county of Rutland. The much cooler air to the north has not made it to the south and it remains very warm and humid - it is the night lows of 15-17*C (even in the countryside) that I find most uncomfortable, but we are trying to enjoy this spell of good summer weather as it is Wimbledon and we will only complain when more normal summer weather returns.

The CET for July up to the 7th was 17.9*C (+2.3*C) and the EWR (also up to the 7th) was just 5mm which is 8% of the monthly average of 62mm.

Off topic I know, but despite the Lions getting an overall draw, I still think the All Blacks were the better side and looked the most likely to score. The interesting statistic for the last game was 2 tries to the All Blacks (plus another disallowed) and none to the Lions. It is a shame that there is not a return series here in the UK as it is probably true that the Lions are the only team that could trouble the All Blacks at the moment. All the merchandise was falling in price yesterday, so some good bargains in the next few weeks.

[Richard]

Your temps sound so nice given the week we have coming up.

It was a good series alright and they certainly tested the AB's

[Simon Culling]

Hello Richard - I agree about the UK temperatures, but I do like the cold and snowy weather when it arrives, and it has been a bit of a stranger here in the UK for the last few winters.

We have had a short break in the warm and sunny weather with a depression crossing southern England on Tues/Weds this week giving 10-30mm of rain in many places and up to 40-50mm to the north of London and up into East Anglia. However, the low pressure has moved away and after a couple of cooler days with a more NW flow, temperatures are set to rise again this weekend. The latest model output suggests another quite long warm and dry spell for England and Wales.

[spwill]

Off topic I know, but despite the Lions getting an overall draw, I still think the All Blacks were the better side and looked the most likely to score. The interesting statistic for the last game was 2 tries to the All Blacks (plus another disallowed) and none to the Lions. It is a shame that there is not a return series here in the UK as it is probably true that the Lions are the only team that could trouble the All Blacks at the moment. All the merchandise was falling in price yesterday, so some good bargains in the next few weeks.

The All Blacks had the home advantage so well done to the Lions.

[Simon Culling]

Fair point spwill - I hope the tour lived up to everyone's expectations as I gather much of the nation was looking forward to the arrival of the Lions. All of the games were tough and some of your provincial sides would give the major test nations a run for their money.

The weather has been rather non-descript here for the last few days, but another warm up is now underway and the humidity is increasing. We will break the 30*C mark again this week and there is a better chance of the south catching some storms Tuesday evening and into Wednesday. After that the models are not very sure with the consensus suggesting more unsettled weather and cooler, but this will have changed by tomorrow!

The really hot weather to our south over Spain will not make it this far north and the heat has tailed off there in the last couple of days. The mercury hit 47.3*C at Montoro on Thursday (13th July) and 46.9*C at nearby Cordoba Airport. These, if confirmed, both break the Spanish national record.

[Simon Culling]

Plenty of thunder and lightning over the southern half of England on Tuesday into Wednesday with some parts receiving continuous lightning for many hours. Here in Milton Keynes we were treated to a decent light display on Tuesday (18th July) evening with shotgun thunder that made the windows rattle!

There was a significant flash flood event on Tuesday afternoon in the Cornish village of Coverack, which is on the Lizard peninsula. A helocopter was needed to rescue people trapped in a building following torrential rain over the hills to the north of the village. The village was also hit by quite large hailstones at the start of the storm with some stones cracking windows - probably 30mm+ in size.

http://www.bbc.co.uk/news/uk-england-cornwall-40650406

[Richard]

The Coverack flooding was on our news tonight, looked bad

[Simon Culling]

Yes indeed Richard, although the flooding was a very localised event. Unfortunately there is not an official Met Office gauge anywhere near the affected area, although an Environment Agency site at nearby at St Keverne did record 105mm - this site is about 3km to the north of Coverack. Rain radar cumulative estimates give a figure of about 200m just to the north and north west of the village and this is backed up by two very crude measurements from empty buckets of 160mm and 170mm in the area affected. The land to the north and north west of Coverack is only 'hilly' at best with the highest points being 100-110m amsl so this was not a case of orographic enhancement and appears to be due to the intensity of the rain and the fact it was very slow moving for a while.

A few more pictures of the flood aftermath:

https://www.piratefm.co.uk/news/latest- ... ake-weeks/

[Richard]

In what time frame did that fall in Simon

[Simon Culling]

Hello Richard, from contemporary accounts and the rainfall radar data it looks like the bulk of the rain fell in no more than 2 to 3 hours. The attached link to a Twitter page shows a rainfall radar composite and this appears to suggest that the storm was back building over the far south of the Lizard Peninsula which had the effect of keeping the precipitation in the same place - this is between 15:00 and 17:30 in the afternoon.

https://twitter.com/Gary_Bywater/status ... 5825766400

These sort of storms are comparatively rare in the UK, but the SW of England does seem more prone to them.

[Richard]

Quite a number of storms along the southern coast line that day but only one that was as you say 'back building'

[Simon Culling]

Yes Richard, not quite sure why that one cell remained almost stationary for a couple of hours.

The weather here in the UK has been cooler since the hot spell of last week with showers or longer periods of rain which have helped to freshen up the grass etc. This theme looks set to continue over the next 5 days with rather cool and breezy weather and showers at times, although here in the south we should see 20-22*C on most days.

The CET for July was 17.3*C (+1.3*C) up to the 25th and the EWR was 72mm up to the 24th, which is 116% of the monthly average.

Here is one of those approaching showers last Sunday (23rd July) afternoon just outside the village of Hythe, in Hampshire.

[Simon Culling]

It has remained a bit on the cool side with plenty of showers or longer spells of rain - as a result July will be quite a wet month. Yesterday, Sunday 30th July, a line of showers developed along a convergence line which ran up the spine of the SW peninsula of the UK and persisted for many hours with some areas getting shower after shower whilst many areas remained dry. The showers also moved to the NE over time in the general flow up into the south Midlands and into E Anglia by the early evening. However, it was the SW that was particularly badly affected and the Met Office site at East Okement Farm, Okehampton (up on Dartmoor) recorded 84.5mm in the 24 hours to 2100GMT on Sunday as it was right in the middle of the shower line. The following tweet gives a good representation of what happened:

https://twitter.com/danholley_/status/8 ... 5070930945

The term 'Brown Willy Effect' is a reference to the usual initiation place for the showers - Brown Willy is the highest point on Bodmin Moor (at 420m) and both elevation and convergence combine to start the shower line.

The unsettled theme continues this week with more heavy rain due on Weds/Thurs.

[Richard]

No thunder in that convergence line of showers?