Stormy Weather II

[Serial_Apologist]

Currently 25°C, bright sunshine and fluffy cumulus. The wind direction (currently S) seems to change constantly these days.

That tends to be the case right in the centre of low pressure systems. I can remember, once, as the centre of a deep low passed overhead, turning to my left, and the clouds were going from right to left. Turning to the right, the clouds were going from right to left. So that proved it for me. Don't ask me about in front and behind, because in both directions tall buildings were blocking the view.

Big puffy cumulus clouds building into anvil-topped cumulonimbus: reportedly storms have already delivered over E and NW London, but they are once again skirting our area. Thursday looks to be the best day for going outside this week - after that it's downhill and into a meteorological pre-announcement of autumn for the weekend, unfortunately.

[oddoneout]

The wind direction (currently S) seems to change constantly these days.

During the night the wind direction managed to get round between N and S, but avoiding W. It actually managed to rain during that time - a useful amount and in a sensible fashion, ie straight down, fairly heavy but not torrential. The sun got out after lunch and the temperature shot up, but then cloud built up and some of it is sort of leaking but not convincingly so I put the last bits of washing out anyway. So long as the breeze continues the creases will be shaken out if nothing else. Some thunder grumbles which fits with the weather map.

[DracoM]

Mini-monsoon, in ominous yellow, deepest grey skies as I post.

[cloughie]

Pleasant evening here now.

[BBMmk2]

21C, today, sunny intervals and a moderate breeze, according to BBC.

[DracoM]

Here, fells invisible in mist/rain/yuk/dreich.

[Serial_Apologist]

It feels stifling here in London today, despite the temperature being what it is supposed to be at this stage in the year - which is when I start feeling depressed at the thought that fresher days to be welcomed are not long in the offing, but mean that another summer has passed, all to quickly.

[Serial_Apologist]

My goodness! Quite a lively thunderstorm currently crossing the Edgeware district of NW London as I write - which, I have to admit, I had not been anticipating. The anvil from this storm spreads right out, revealing an odd scalloped edge, which is right overhead. I had assumed the altostratus which had spread across the skies earlier, reducing the sun to a blob, was just debris from old showers or frontal systems, but it must be forming part of this. More piled up cumulonimbus are looming up to the SW, so I had better get out and do my shopping before running the risk of being caught out! No wonder if feels so heavy out there today!

[Joseph K]

Yep, first signs of leaves yellowing etc.

[oddoneout]

Yep, first signs of leaves yellowing etc.

A response to the drought here rather than seasonal change. If there is something approaching reasonable moisture for the next little while it won't progress further and there may even be some regrowth.

[Serial_Apologist]

A response to the drought here rather than seasonal change. If there is something approaching reasonable moisture for the next little while it won't progress further and there may even be some regrowth.

In London and the SE we also have the sadly disfiguring effect of a parasite, which for some years now has been damaging our horse chestnut trees, making the leaves yellow and brown halfway through the summer. They then exfoliate at around the same time as other deciduous varieties, so that while the trees are not killed, the consequences in terms of limiting their energy sustaining ability to photosynthesise must presumably be life shortening, one would have thought. Ironically this along with the newer ash die-back are thought to be the result of importing foreign plants from regions where these pests are endemic.

[oddoneout]

In London and the SE we also have the sadly disfiguring effect of a parasite, which for some years now has been damaging our horse chestnut trees, making the leaves yellow and brown halfway through the summer. They then exfoliate at around the same time as other deciduous varieties, so that while the trees are not killed, the consequences in terms of limiting their energy sustaining ability to photosynthesise must presumably be life shortening, one would have thought. Ironically this along with the newer ash die-back are thought to be the result of importing foreign plants from regions where these pests are endemic.

At the moment I think the effects of the horse chestnut leaf miner are to limit growth rather than cause actual harm. In an urban environment that may not be such a bad thing but the downside is the ability to cope with additional challenges such as damage, other pest attack and adverse/perverse weather. The threats from imported pests and diseases are a lost cause in my view. Little to nothing effective was in place pre Brexit(plant passports etc notwithstanding) and so the chances of anything worthwhile(or even maintaining the status quo) are zilch after Jan 2021 when regulation that limits trade will be discarded. Extreme weather events will likely add to the problem of exotic threats by making plants more vulnerable to existing pests, diseases and physical damage. Even healthy trees can suffer if waterlogged ground and high winds loosen their roots' grip and given that so many trees have root systems compromised by agricultural practice, urban concreting, utility trenching etc they are even more vulnerable.

[Bryn]

In London and the SE we also have the sadly disfiguring effect of a parasite, which for some years now has been damaging our horse chestnut trees, making the leaves yellow and brown halfway through the summer. They then exfoliate at around the same time as other deciduous varieties, so that while the trees are not killed, the consequences in terms of limiting their energy sustaining ability to photosynthesise must presumably be life shortening, one would have thought. Ironically this along with the newer ash die-back are thought to be the result of importing foreign plants from regions where these pests are endemic.

Is Cameraria ohridella really best described as a parasite? The larvae feed by mining the leaves of Horse Chestnuts but does that constitute parasitism? I think the same applies to Ash Dieback, where Hymenoscyphus fraxineus is the fugus involved.

[Serial_Apologist]

At the moment I think the effects of the horse chestnut leaf miner are to limit growth rather than cause actual harm. In an urban environment that may not be such a bad thing but the downside is the ability to cope with additional challenges such as damage, other pest attack and adverse/perverse weather. The threats from imported pests and diseases are a lost cause in my view. Little to nothing effective was in place pre Brexit(plant passports etc notwithstanding) and so the chances of anything worthwhile(or even maintaining the status quo) are zilch after Jan 2021 when regulation that limits trade will be discarded. Extreme weather events will likely add to the problem of exotic threats by making plants more vulnerable to existing pests, diseases and physical damage. Even healthy trees can suffer if waterlogged ground and high winds loosen their roots' grip and given that so many trees have root systems compromised by agricultural practice, urban concreting, utility trenching etc they are even more vulnerable.

In addition, the effects of increasingly frequent strong winds on branch shedding, especially in the seasons when trees are in full leaf, have been greatly in evidence around these parts, where clear-up operations have become frequent with regards to two mature sycamores adjacent to our block. Upstairs frequently complain about the proximity of branches from these trees to their windows, arguing that the trees should be felled, surely? To which I have pointed out that in the London Clay that makes up the low escarpment on which our flats are situated could well be being held in place by the trees' root systems, helping to support our foundations!

[Joseph K]

Rain.