Thunderstorm alley

[Len]

We in this part of Devon are experiencing a line of thunderstorms.

First one here at 0500 hrs ,  and recently 0955 hrs.

Such excitement.

Len

Wembury, SW Devon

[Paul from Dawlish]

Thunderstorms, what thunderstorms?

Dawlish has missed every single one. Just a few drops of rain, not enough to wet the ground... yet.

[Brian Wakem]

It's very frustrating to see areas that have not been particularly hot get all the thunderstorms.  It's seems to happen every year.  We in the SE suffer all the heat and then storms spring up everywhere except here.  I've only had 1 decent thunderstorm in the 8yrs I've lived here and that was in the middle of the night when trying to sleep.

Now 31.1C

-- 

Brian Wakem

Lower Bourne, Farnham, Surrey

http://www.brianwakem.co.uk/weather

Live obs @ 12:17:56 : 31.1C, DP 20.4C, RH 53%, 0.0 mm

[Julian Mayes]

I agree completely!   All part of the thunderstorm 'drought' that has affected the SE for decades now - probably attributable to the synoptic changes I referred to in the 'not having a heatwave' thread.    It looks as though Wembury is right in the firing line now. 

[Len]

Well yes. On the western edge of firing line.

Not much rain. Just brief heavy spells.

Plenty of rumbles of thunder. A couple of really loud, shake the wall types of thunderclaps.

Line of storms moving a little east now letting us have a glimpse of that Cornish sunshine.

Thanks Graham.

Len

Wembury

[Graham Easterling]

To be honest Len, I'd enjoy a thunderstorm, I'll just have to make do with the sunshine!

The N wind's got quite blustery this morning. F4 N surface wind with the earlier medium / high level cloud streaming north at quite a rate.

Graham

Penzance

[Tim Furdui]

the SE of UK very bad at thunderstorms - it really is unlucky

and despite being more prone to heatwaves not the same can be said to thunderstorm

the only ever good thunderstorm this corner will get are the imported ones from France - but with those ones a) some lose their strength over channel, some just dont come this way (veer to NE)

the main issue i see with at least london - is that the cold water to the east and south inhibits formation of thunderstorms or leads to decay in the ones imported

as for home grown, most circulation is south(sw/se) to north (nw/ne) - that puts us in bad place as storms begin forming over us - or just after m25 - they grow as they advance north - meaning we miss most if not all of it 

the only scenario london will get a huge thunderstorm is if its moving NW/SE over london or if some supercells move over from france - S-to-N over London 

I also notice if/when they happen they tend to be at night - as you know night time stors are driven by very moist and warm air aflot and not daily heating - meaning they can sustain for long periods of time and are less influenced by geography 

night storms are also much more destructive - exactly because the energy required for them to exit is not based on sun, so the CAPE tends to be massive - resulting in plenty if energy to develop and grow 

I think for London the best chance of a good thunder during this spell is european imported and night time - have only lived in London for 15y and i remember one or 2 vivid night time storms but none produces violent winds or hail - however - back home we have violent thunderstorms in summer, with large hail, violent winds and even tornados and yes most of them happened at night

In many ways - i wouldnt wish one of those to anyone - they can be very destructive 

[Nick Gardner]

Nowt 'ere. Not even a drop of rain to damp the dust.

[Tudor Hughes]

       Where is "back home", Tim?

        The contrast with the past is very marked.  Night-time storms were almost part of Surrey folklore, if there is such a thing.  I can remember some rather good ones in the 50's and 60's and also some powerful local late-afternoon storms which also seem less common now.  Even allowing for distance lending enchantment I think the change is real.

Tudor Hughes, Warlingham, Surrey.

[Dave C]

It is real Tudor. It is not my imagination that I remember as a child seeing a man canoeing down our road after a vicious storm and flash flood. And it wasn't substance  induced as I was still a bit scared of thunder at the age I was!

[Julian Mayes]

Tudor: The contrast with the past is very marked.

I was planning to write the same thing. Turning Tim's phrase around, the South East 'used to be very good' at thunderstorms.  Traditional climatology told us that the two most thundery parts of the UK were the South East in general and the Trent valley. The latter is still quite a thundery area - especially if you extend it to Lincolnshire and Yorkshire!    

As for the South East, you only have to peruse the 'heavy falls' sections of any year's issue of British Rainfall to see the concentration of such events in the SE. This was probably true until about 1973, with a minor recurrence perhaps around 1980-82. Indeed, years 1968 to 1973 saw a return to the high levels of thunder and heavy falls here that some may remember from earlier times.   

I do wonder if thunderstorm alley now is in the process of shifting to Scotland and the western fringes of the UK - maybe not frequent but severe when they occur and changing the seasonal distribution of lightning in these parts - the winter peak now accompanied by a weak summer peak of severe storms. This is a concern to power supply industries in these parts. 

British Rainfall online   https://digital.nmla.metoffice.gov.uk/SO_29627928-7fb1-43b2-b7ad-f63509127917/

- though for me that's no match for the actual issues bought secondhand. 

[Len]

The Hampstead storm of Aug 1975 was a goodly one. Over 6 inches of rain in a couple of hours.

The underground flooded in places.

I know, I was there.

Read all about here:

https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/j.1477-8696.1976.tb04382.x

Len (moved out west in 1980)

Wembury Devon

[Tim Furdui]

Back home is south-east Romania

summers there can be scorching but also thundery

past 2-3 years they had almost monsoon season with may-june or june-july very wet thundery and colder than usual and august/sept/oct warmer and drier

but one thing i miss is the big summer storms - esp my village is sub-mountain so loads of activity there in afternoons or around cold fronts

i've seen hail bigger than a golf ball - truly terrifying 

i learned to spot hail by cloud colour - if the cloud turns greenish/blueish under the main dark sky - thats a sign of hail, i learned from my grandparents and they didnt had any meteorological training :) it helped sheltering animals and fragile plants 

as for tornados only had one - by far the scariest thing after earthquakes (we have those too a lot)

a few times we had derechos too - quite interesting and also quite damaging 

and very rarely we get something called a dry lightning storm -  no rain, no wind, just cloud to ground lightning - nearly go hit by one - i can still remember the smell of burned grass and the hair on my body standing up - oh and the loud bang - 

but the british weather has its own charm - surely it doesnt have such big summer storms but you get tropical activity here, albeit just the remnants and amazing wind storms - and i even remember some memorable winter snow events

 and of course i can certainly say the summer are becoming hotter and the hot spells longer

when i moved to london i remember if you got few days with 25C in the summer that was a good summer - most of the times i couldnt even wear shorts by my standards

but then it changed - last 3 summers have been very hot and dry and almost reminiscent of romanians summers 

the funny thing is the hottest day so far this year in romania was 38.7C few days ago - and thats probably it for this summer as temp will be going downwards soon - if you think about - thats not very far from UK's highest temp this year - and we all know how much further south romania is to UK and also how much closer is to the big heat reservoirs africa and the middle east

so who knows maybe UK is the new spain - and spanish people will soon come to UK to spend summers 

speaking of - anyone know is water temp are warmer than normal for this time of the year?

[Tudor Hughes]

     I have had a feeling for some time that the focus of thunderstorm activity has moved mainly north and to some extent west.  Thunderstorms in Scotland now seem quite routine whereas in the past they would have been regarded as against the natural order of things.  I wonder if there is any documentation to prove this shift.

         The south-east seems to have moved into a warmer, less disturbed climatic zone, rather like northern France but without that area's capability of generating its own storms.  This may be partly due to the distribution and land and sea.

         Thanks for the link to British Rainfall.  When I was in the Met Office Editing Section at Bracknell (1964-66) I would spend lunchtime in the Library scouring its pages.

Tudor Hughes

[Tudor Hughes]

You couldn't canoe along the road I was brought up in.  It had a steep slope and was un-made-up, the surface being sand, gravel, flints and other stones with bits of chalk poking through.  On Monday July 16 1956 a  thunderstorm with about 2 inches of rain in just over an hour washed most of that road surface away and deposited it a few hundred yards down the road on the made-up part which now looked like dirty beach.  It also gouged a channel in the exposed chalk opposite our house that was deep enough to have grounded a car.

      This all took place around six in the evening, the rest of the day having been fine.  It was purely local storm and there was another lesser one two days later.  I was only 13 so it was all great fun.

Tudor Hughes

[Dave C]

Date sounds about right for my one. Usual happening this morning. Two heavy outbreaks of rain one 5 miles to my East and on towards Southend, the other larger one drifting 5 miles to my East. Looks like I might get some drizzly stuff in the corridor between. Still, might at least hold the temperature down for a bit.

[Graham Easterling]

In the last decade thunderstorms have shown a marked decline here in west Cornwall.

Looking at 'thundery' years, which here means 10 or more storms. (Since 1991)

1990s 3 years  (most 1994 -11)

2000s 3 years (most 2006 - 13) 

None since 2006.

I don't think the number of extreme storms has declined. I do keep a record of all those of around 75mm & above, so I must find time to check. Although Boscastle is notable, it's the geomorphology & NT tarmac carp park in the flood plain that makes things so severe. There have been several >100mm storms in north and west Cornwall since 1991 

The last severe storms were 200mm near St Ives in 2009. I looked at that one in detail http://www.turnstone-cottage.co.uk/StIvesFlood.pdf Almost entirely ignored by the press, cars were washed off the road into the sea near Zennor, by a stream normally far smaller than that in Boscastle. The EA had just opened a new flood defence system to a big fanfare in St Ives, but when the storm struck someone forgot to turn on the pumps, or they failed miserably. Then of course Coverack, again 200mm storm.

Graham

Penzance