Stormy Weather II

[DracoM]

Well, it's now teeming it down up here - selon le BBC, the depression etc wasn't supposed to reach far north at all....erm....well...it has and how.

[Flay]

Well, it's now teeming it down up here - selon le BBC, the depression etc wasn't supposed to reach far north at all....erm....well...it has and how.

Teeming down in Yorkshire too.

erm...well... the depression has certainly reached this message board. Let's hope things brighten and lighten up soon...

[Joseph K]

I didn't pay attention to the temperature yesterday, but today it's dropped to 9C... However, I'll take this over constant rain, definitely.

[Bryn]

I didn't pay attention to the temperature yesterday, but today it's dropped to 9C... However, I'll take this over constant rain, definitely.

A pleasant 16°C here, at the moment. Scheduled to rise to 18°C by 5 pm.

[oddoneout]

Goodness I'm glad I got my shopping done before lunch rather than after. There has just been a most impressive cloudburst, dry to flood in not many minutes, and not forecast to happen until later, even the weather map suggests we could have expected to miss anything from the colourful blob in the vicinity given the direction of travel. What I find interesting is that when I came home at midday the sky was black as black and large drops started to fall as I was minutes from home, enough that I stopped to put on my waterproof but in the end it didn't come to anything and I assumed that was it as the forecast was less than 50% chance anyway.This downpour has come from a sky that's just light grey and with cloud breaking to show bits of blue - no thunder either.
Much less chilly than the past couple of days( I lit the woodstove on Wednesday night because the damp and the grey made me feel chilly even though the thermometer said it wasn't cold in the house) and the weekend is supposed to be OK so I think time will be spent in the garden dealing with all the exuberant growth the rain has produced.

[Serial_Apologist]

A pleasant 16°C here, at the moment. Scheduled to rise to 18°C by 5 pm.

That we find ourselves back in the sorts of weather pattern sequencings that were commonplace throughout the poor summers of the 1950s and 1960s, with predicted temperatures of the order of ca. 19 C today, 21 C tomorrow and maybe 24 C Sunday in the centre of London as the expected HIGH traverses this part of the UK, could be instructive. Back in those days sourcings for weather types varied along with seasonality - long "fetch" in the winter half of year, when predominantly large weather systems govern longer distance travel than in summer; short "fetch" in summer as shallower lows and highs would result in a greater preponderance of local factorisation in weather mixes - produced the same ranges of daytime temperatures in similar driving conditions to those expected this weekend and into next week.

This is in marked contrast with the conditions which have been leading to record-breaking high temperatures, at least as far as the northern hemisphere is concerned, whose causes can be traced to interruptions in the normally zonal, ie broadly west to east passage of the Polar Jet, the coveyancing driver of Atlantic depressions, albeit ranging from smooth direct W-E passage to oscillating wave pattern.

In pre-global warming times these normally gradually varying patterns would mostly be prone to disruption by three main sources of blocking. Two of these examples would occur between November and March: namely southward extensions of the "Greenland High" following a family succession of translatlantic lows, or, more rarely and giving rise to "beast of the east"-type severe winters, westward extensions of the semi-permanent winter "Siberian high" forcing the Atlantic jet to bifurcate, one branch passing north-east to north of Scandinavia before fizzling out, the other stronger branch diverting into the Mediterranean. The other example would take place in the summer months with the northward displacement of the "Azores high", and either ridging from, or separate high pressure cells splitting way from this main high to bring warmer than average temperatures and dry conditions across Britain and northern Europe. King Charles's famous observation of the British summer consisting of three fine days and a thunderstorm was a reflection of the innate tendency of heatwaves to rapidly collapse at our latitude, due to the way in which the generation of a hot inland zone of strong solar heating leads to the local development of surface low pressure as ascending hot air produces an incipient vacuum on ground level. This then sucks in surrounding air to replace that which has been convected, and, given the much greater contrast between heated interior and cool inflow of maritime origin than exists the closer one gets to the equator, the more rapid the breakdown of any heatwave - usually assisted by the generation of heavy thunderstorms introducingthe cooler air and change of surface wind direction.

What now seems to be happening - and throughout the year, rather than being just restricted to the stretch from about October to May - is that with the global rise in temperatures giving rise to large, often very deep low pressure systems along the course of the polar jet, and complementarily large and intense high pressure systems extending periodically beyond their past historical positionings, the effect of the warmer airstreams and longer travel routes concomitantly associated with the enlarged air circulations has been noted as the main factor leading to arctic ice melt. Record high temperatures registered in NE Siberia last week provides a timely instance.

It is generally accepted that infiltration of cold meltwater from Greenland'sa ice cap and melting arctic ice flows today constitutes the largest factor in polar jet stream disruption, in turn leading to ever more frequent halts in the eastward progression of Atlantic depressions, and, at times, contorting otherwise "normal" fluctuations of the jet stream into reverse loops as intervening high pressure systems push back against the automatic eastward inclination consequent on the earth's revolving axis, in turn sustaining "meridional" patterns of weather system distribution, direction, evolution and decay.

What this seems to suggest - to my admittedly amateur assessment, albeit now based on 60 years' observations - is that as far as the consequences affect the UK, climate change, global warming, call it what you may, enables high temperatures to be sustained for longer periods than was the case pre-global warming, as blocks allow for prolonged warming, borne of air sourced from regions nearer the tropics than would once have been the situation, since the usually mobile circulation would have acted to intercut the heat source at an earlier stage of build-up, thus terminating the heatwave. Also suggested is that whenever what would once have been the customary pattern of atmospheric circulation is temporarily restored - as has happened across the UK in the past two days - air temperatures will return to levels that were the commonplace of your average nondescript "British summer".

[BBMmk2]

I find that the weather patterns seem to ge quite similar, for the past few years quite similar. We’d be going on holiday now and again, touch wood, the weather is again, similar. Thankfully!

[oddoneout]

It's good to wake up to sunshine even if the forecast suggests it may not stay. What isn't so welcome is mention of low overnight temperatures - 5 or 6 isn't good for my tender veg.

[DracoM]

OK, so it;s dry, still, greyish but with glimpses of sun.................
...but, suddenly, and yes, it's a summer weekend, but..........

No kid: in the last hour, 126 motorbikes have roared past on their way to and from favoured high moors 'fun runs'.
The small, tight-pavemented market town is now full of offcomers who are careless, undistanced, and almost every other one has either two children or dogs - or in three cases, BOTH.

We have had nothing like this all lockdown or since. So suddenly, we are the target..............

[oddoneout]

OK, so it;s dry, still, greyish but with glimpses of sun.................
...but, suddenly, and yes, it's a summer weekend, but..........

No kid: in the last hour, 126 motorbikes have roared past on their way to and from favoured high moors 'fun runs'.
The small, tight-pavemented market town is now full of offcomers who are careless, undistanced, and almost every other one has either two children or dogs - or in three cases, BOTH.

We have had nothing like this all lockdown or since. So suddenly, we are the target..............

Quite apart from the noise fumes and aggravation I imagine the damage the bikes are doing to those 'fun runs' must be pretty awful, especially after the heavy rain you've had.

[DracoM]

.....and snaking in five to ten bike posses through the trad stone walled roads?
At some corners, as you suggest, great puddles of completely unanticipated rain.

[Joseph K]

Well, the sun is out, and my phone says it's 16 with a high of 21 and low of 10 - quite pleasant weather indeed.

[BBMmk2]

Well, the sun is out, and my phone says it's 16 with a high of 21 and low of 10 - quite pleasant weather indeed.

Roughly the same down here, JK! I plan going on a saunter in my motobility scooter later.

[Serial_Apologist]

Roughly the same down here, JK! I plan going on a saunter in my motobility scooter later.

Watch out, BBM - I don't know about where you are, but the ants are swarming around here today - it must be their annual riot day. I've had to cancel the bike ride I'd been looking forward to.

[oddoneout]

The sun came out properly late morning and with air movement having got back to sensible levels it has become really quite warm this afternoon. Everything is going mad in the veg patch, and I might even get some runner beans now as there have been a few pollinators around to do the necessary with all the flowers and moisture at the roots will encourage the plants to hang on to the embryo beans I hope.