Stormy Weather II

[un barbu]

Certainly the warmest and sunniest day this month (which has been wet and dismal in general). As I am moving house next week I have had to stay inside packing cardboard boxes. Fortunately, courtesy of Radio 4, I had two hours of the company of assorted French aristos, artists, social climbers and demi-mondaines.

[Serial_Apologist]

Certainly the warmest and sunniest day this month (which has been wet and dismal in general). As I am moving house next week I have had to stay inside packing cardboard boxes. Fortunately, courtesy of Radio 4, I had two hours of the company of assorted French aristos, artists, social climbers and demi-mondaines.

Good luck with your move, UB. Are you moving far?

[un barbu]

Good luck with your move, UB. Are you moving far?

Thank you, S-A. Just a couple of miles but it has been a draining couple of months given the process of selling and renting. The charity shops in the town have done very well out of it, however!

[ferneyhoughgeliebte]

Good luck with your move, UB.

[un barbu]

Thank you!

[Serial_Apologist]

The temperature has maxed out at 29C here in our mini island of relative coolness - same as yesterday, exept that this time I just returned from a brief cycle ride, for purposes of adjusting brakes and gears, covered in sweat. The difference is higher levels of humidity, now being expressed in some nice bulky cumulus towers building up north of London, indicating ground-up convection, as officially predicted, which will doubtless trigger some heavy showers and thunderstorms as they make their way northwards and north-eastwards across East Anglia. These types of storms are usually of short duration - each cell lasting not more than 20 minutes - but given the right conditions - convection coinciding with encountering an upper air trough, with its associated jet acting to siphon up the air at high elevations, this helping to group otherwise separate storms such as these together, this additional aggregation of causes can easily lead to larger self-sustaining storm systems which form their own mini low pressure systems, and these are the most conducive conditions in this country for funnel clouds to form. If no such convergence between lower and upper conditions arises, the storms and showers are less likely to join forces in this way, and without the necessary heat input from below will dissipate on crossing the sea.

This whole area of thunderstorm formation under different conditions is of great fascination to weather observers and the official forecasting community: Showers and storms that form over the relatively warm sea in winter and then disperse inland as they cross colder land surfaces unable to sustain convection unless with some additional forcing mechanism such as orographic uplift, ie air forced up on hitting cliffs, hills or mountains, or sudden convergence caused by a tightening of the circulation around a locally deepening low; summer thunderstorms associated with high level convection which form at the middle (altocumulus and altostratus) level, associated with more coherent (less haphazard) airmass organisation, which can be along fronts or what are called shortwave troughs; frontal thunderstorms associated with cold fronts, where the warm airmass in advance of the frontal passage is undercut by the cold airstream advancing in the wake. The structure of storms reflects their origins and the conditions giving rise to them

[Serial_Apologist]

Here we go! - thunderstorms kicking off in Herts, Cambs, Norfolk and Lincs.

And now the West Riding - along the eastern side of the Pennines, a favoured spot for localised convection.

[DracoM]

Fast moving rain here, arrived spot on 4 p.m., then went east. Sun now. Will it last?

[un barbu]

https://youtu.be/o8g71EqdroI

[cloughie]

Here we go! - thunderstorms kicking off in Herts, Cambs, Norfolk and Lincs.

And now the West Riding - along the eastern side of the Pennines, a favoured spot for localised convection.

Good to see the West Riding still exists, even if only as a meteorological zone.

[Serial_Apologist]

Good to see the West Riding still exists, even if only as a meteorological zone.

My goodness me! - one huge blob of a thunderstorm has in fact grouped together out of the separate storms, and it's about five times the size of London, covering the whole of Lincolnshire and the eastern side of Yorkshire's West Riding, and forming an arrow-headed line of advance towards Leeds. Lightning is firing off twice a second in various part of the storm: goodness knows what conditions must be like underneath it! Another line of storms has broken out, running up along the coastline from Middlesbrough north towards Edinburgh, probably a convergence line between hot rising air over the land and sea breezes feeding into it. All this lot will probably head into the North Sea as the evening progresses, though I wouldn't be surprised were there to be some back-building in the rear area to the west before it does so. Nothing was mentioned of this on the national news on Ch4 just now. Anyone in and to the south of London will either be heaving sighs of relief that the feed coming up from the south did not trigger until it got just north of the M25 on the Hertfordshire side, or bemoaning the lack of rain! It's still hot here - 28C - but there is at last a moderate breeze coming in from the south, and all the heaviness and heat haze earlier on has dissipated. Two esses, one p - had to check that!

[DracoM]

Looks like Gotterdammerung here! Skies amazing.

[Serial_Apologist]

Looks like Gotterdammerung here! Skies amazing.

Lots of dramatic accounts coming in from Cambridgeshire, Lincolnshire and Yorkshire, with talk of supercells, which revolve and are the most intense kinds of storms bar tornadic ones. Oh, and one message from Hove just saying "How disappointing!"

What will be interesting will be to see if the cold front now still out to the west, when it eventually comes through tonight and tomorrow, will have any thunder embedded in it; the official forecast merely spoke of light rain! What will be pleasant will be the return of air temperatures to near normal tomorrow and for the rest of the week: with a nice accompanying breeze I can't wait to get my windows open and refresh the air in here.

[BBMmk2]

We had a change down here. A welcome one, with rain and cooler temperatures but became quite humid. We could have a thunderstorm this evening. The temperature maxed at 30C down here.

[Serial_Apologist]

We had a change down here. A welcome one, with rain and cooler temperatures but became quite humid. We could have a thunderstorm this evening. The temperature maxed at 30C down here.

Same as here, BBM. Surprising we're so blessed up here, given that the temperature reached 33C in the centre of town yesterday, only 6 miles to the north. The sky's looking quite thundery today, but it has cooled off quite a bit, and I don't think there's enough energy up there to trigger off anywhere now: most of it is over neighbouring Belgium and Holland. From Sunday onwards temperatures will be back to normal, which means maxing at 20-21C, as we're at the start of the slide into autumn. Still, it's been a pretty good summer by usual standards, I think, and we can't rule out further warm spells.