The Weather Thread 2019

[gigpusher]

It depends on the forecast as to whether you can trust it. If it's all totally one type of weather either rainy or dry it's probably more likely to be right. If it's showing as being changeable or that 4 seasons in 1 day kind of weather then even at the same hour you can't trust it. 

Even if it says it's bone dry I will bring some wet weather gear because I don't like gambling with the weather gods. I have the stuff I'd rather bring it. I've seen some photos of bags packed already which just seems crazy. It could be glorious or it could be quite cold at this stage. 

[Aragorn]

20 hours ago, crazyfool1 said:

I find it incredible with all the technology these days ....... we can never trust the weather forecast ... 

I would not say so to be honest - there are so many factors involved its just not possible, anyway here are the latest precipitation ensembles for somerset upto a week away from the festival.  The thick red line mean is the one to look for rather than the operational green line. 

Shows unsettled running upto the week before the festival.  Looks like abit of a bad day on the 8th with almost all ensembles going for 6mm plus of rain  

 

 

[briddj]

Yep, think on Saturday it's going piss it down across the whole country.

That rain will mean nothing though with the forecast for the week after. The moisture will be long gone.

[tumbles]

20 hours ago, Wallace said:

For everyone asking how accurate the forecast is further out, keep an eye on your own local weather forecast for the next few days and see how close to the truth it really is.

But don't use the BBC Weather App which is the biggest pile-o-shite in the world. 

[Sasperella]

Accue definitely seems to be deteriorating. Not terrible yet though....just like it's gonna keep us on our toes 

 

 

[BambooShanks]

7 minutes ago, Sasperella said:

Accue definitely seems to be deteriorating. Not terrible yet though....just like it's gonna keep us on our toes 

 

 

Metcheck is looking better, completely dry festival apart from a 1mm shower on saturday.

There's a few days of rain (and a heavy shower or two) forecast for the next couple of weeks but with the ground being so dry, it'll do it the world of good.  

Lets hope it stays that way!

 

[Bags73]

Official Met Office Forecast today:

Forecast for Sat 08 Jun 2019 to Mon 17 Jun 2019
General Situation: Through the weekend and into the following week, the general theme of changeable
conditions is expected to continue, with showers or longer spells of rain at times, most frequent in the west.
There will be some brighter interludes, especially in the east, however temperatures will mainly be below or near
normal, with no current indications of reaching trigger criteria.

Forecast for Tue 18 Jun 2019 to Tue 02 Jul 2019
General Situation: From mid-June onward there is a trend for more settled and generally drier conditions,
although by the end of the month the potential for further changeable spells increases again. Despite drier
conditions developing, temperatures are currently signaled to remain near average across the UK, and perhaps
turning cooler in the north by the end of the month, However confidence for this period is low, with a small
chance of trigger criteria being reached.

[jfaragher]

Update on previous analysis here

Outputs now available from the Met Office seasonal model and the extended-range ECMWF model.  Caveats - these models aren't intended for this kind of stuff, the analysis method isn't intended for this kind of stuff, its still a long way away, and weather is fickle and complicated.  Don't base your plans on this or blame me when this turns out to be nonsense.  

So - the output from the models has been classified into a number of regimes that are used to describe common weather patterns in the UK (things like 'Zonal' or 'Scandinavian High') that usually hang about for a few days. We can associate typical amounts of rainfall, across broad geographic areas, with these regimes.  These regimes are (usually!) a bit easier to forecast at long lead times (i.e. for 3 or so weeks away) than specific weather at a specific location. Usually.  What you do lose is an idea of what the extremes could be, so basically, if it's going to be a 2007, this won't tell us.

I've looked at the regimes, and for the approx location of Glastonbury classified them into "low", "mid" and "high" in terms of rainfall (around <2mm, <4mm and 4mm+ per day respectively),  then looked at the percentage likelihood of each of these regimes as forecast.  The method used to get a percentage likelihood is an ensemble forecast.

Here's the analysis, in 5 day chunks starting at the dates listed.  Totals are broken by rounding errors.

Met Office seasonal

Looks pretty much ideal to me in the run up - light rain on-and-off to soften up the ground without saturating it.  Also means if we get any heavy rain, it won't immediately run off causing flooding.  The confidence in the model is below average for the last couple of periods (i.e. it doesn't think it's doing a good job), which might be why, especially in the 28-Jun column, its going for 'could be anything'.  Notably, for those who are interested, most of the 'low' rainfall is represented by a single regime, NAO- (Blocked).  

ECMWF Extended Range

This is consistently a little bit more 'medium wet', but doesn't yet give us good detail for the last few days.  If you look at the daily output (which runs to the 30th) the spread seems to narrow a bit and become more consistently dry from the Wed onwards (!!), but this is so far out, that no-one would trust daily forecasts at this point.  Again, loving that NAO-, but this model has a reputation for holding blocking, and not being very good at forecasting it breaking down, so...

TL;DR?

Looks OK, likely a bit of rain in the run up, which will help with ground state, still chance for mud and/or sunstroke.

[Thunderstruck]

Looking potentially very wet through to mid June - maybe 50-100mm of rain. Not sure how this compares to previous years? Fingers crossed things settle down by the end of the month.

[dccool]

14 minutes ago, Thunderstruck said:

Looking potentially very wet through to mid June - maybe 50-100mm of rain.

 

[briddj]

 

[tarw]

I’d be very tempted to stick with Gav. Let’s see what he is telling us come video time

[Wurzelcat]

Meanwhile, spending today at Butlins Minehead for daughters birthday. Yesterdays forecast for Minehead, dry with sunny spells.

Today's weather for Minehead: pissing it down all day.

So if yesterdays forecast can't get it right for today, I'm taking every long range one with a pinch of salt

[gigpusher]

7 minutes ago, Wurzelcat said:

Meanwhile, spending today at Butlins Minehead for daughters birthday. Yesterdays forecast for Minehead, dry with sunny spells.

Today's weather for Minehead: pissing it down all day.

So if yesterdays forecast can't get it right for today, I'm taking every long range one with a pinch of salt

Exactly it's been wrong about the very hour we are in before today. 

[Doug85]

2 minutes ago, gigpusher said:

Exactly it's been wrong about the very hour we are in before today. 

Yeah however the main forecast i'm bothered about is just to see what kind of trend or weather front we are due to have over the site that week. It was right about it being high pressure in 2017. 

If we have sustained low pressure then we know we are due a wet one however if its High we have a better chance at just the odd shower or no rainfall at all. Even in the hot years we still have a small shower at some point, 

[gigpusher]

3 minutes ago, Doug85 said:

Yeah however the main forecast i'm bothered about is just to see what kind of trend or weather front we are due to have over the site that week. It was right about it being high pressure in 2017. 

If we have sustained low pressure then we know we are due a wet one however if its High we have a better chance at just the odd shower or no rainfall at all. Even in the hot years we still have a small shower at some point, 

Yes if it says it will be glorious or it will be a shitshow it will be pretty reliable. What tends to happen though is there'll be a chance of rain everyday and some years you just seem to get all of it (2016 - I'm looking at you!) and other years you only get the odd shower and we can cope with that. 

[benc]

wasn't 2010 all to play for with a few days to go? pretty sure rain / mud was forcasted quite late on

[gigpusher]

Just now, benc said:

wasn't 2010 all to play for with a few days to go? pretty sure rain / mud was forcasted quite late on

2010 was my first festival and I think the hot weather was quite last minute as I know I rushed out a couple of days before to get some warm weather gear as we hadn't had any and it wasn't expected but in the last week the forecast showed it was coming. 

[bennyhana22]

5 minutes ago, gigpusher said:

Yes if it says it will be glorious or it will be a shitshow it will be pretty reliable. What tends to happen though is there'll be a chance of rain everyday and some years you just seem to get all of it (2016 - I'm looking at you!) and other years you only get the odd shower and we can cope with that. 

Don't (EVER!) forget that 2016 was preceded by almost unrelenting rain for WEEKS. I have recently tried and failed to find a video the day before the gates opened posted on Twitter, showing some crew bouncing on a big patch of ground at the top of one of the hills on site, that patch of ground FLOATING on a flowing, underground river!

That's why it was the Somme from Wednesday afternoon. As things stand, even with the showery stuff forecast for the next week or so, we really shouldn't even have enough time between now and gates for things to get anywhere near that, notwithstanding what actually happens during the festival itself...

Ben

[gigpusher]

1 minute ago, bennyhana22 said:

Don't (EVER!) forget that 2016 was preceded by almost unrelenting rain for WEEKS. I have recently tried and failed to find a video the day before the gates opened posted on Twitter, showing some crew bouncing on a big patch of ground at the top of one of the hills on site, that patch of ground FLOATING on a flowing, underground river!

That's why it was the Somme from Wednesday afternoon. As things stand, even with the showery stuff forecast for the next week or so, we really shouldn't even have enough time between now and gates for things to get anywhere near that, notwithstanding what actually happens during the festival itself...

Ben

Oh yes it was relentless but that was my point even during the festival there were days when it was like 20% chance of rain but we seemed to just keep getting it. I remember waking up every morning and hearing the rain and a little bit more of me dying inside. The Brexit result didn't help either. 

[Doug85]

13 minutes ago, bennyhana22 said:

Don't (EVER!) forget that 2016 was preceded by almost unrelenting rain for WEEKS. I have recently tried and failed to find a video the day before the gates opened posted on Twitter, showing some crew bouncing on a big patch of ground at the top of one of the hills on site, that patch of ground FLOATING on a flowing, underground river!

That's why it was the Somme from Wednesday afternoon. As things stand, even with the showery stuff forecast for the next week or so, we really shouldn't even have enough time between now and gates for things to get anywhere near that, notwithstanding what actually happens during the festival itself...

Ben

I remember those videos. Surely someone has a copy of them somewhere, it was all over social media and here at the time was it not? 

[SighMo]

If you think pinning down a forecast for Glasto is tough you should try Green Man in the Brecon Beacons; it changes from sun to rain by the hour ?

[bennyhana22]

10 minutes ago, Doug85 said:

I remember those videos. Surely someone has a copy of them somewhere, it was all over social media and here at the time was it not? 

If anyone does, please post it! I 'love' that short video!!

Ben

[bennyhana22]

22 minutes ago, gigpusher said:

Oh yes it was relentless but that was my point even during the festival there were days when it was like 20% chance of rain but we seemed to just keep getting it. I remember waking up every morning and hearing the rain and a little bit more of me dying inside. The Brexit result didn't help either. 

Totally this. And yet, even now, there is a significant contingent of that year's attendees who claim that 'there wasn't actually a lot of rain during the festival'...

Where the f*** were they the whole time? In the Tiny Tea Tent???

Ben

[bennyhana22]

11 minutes ago, SighMo said:

If you think pinning down a forecast for Glasto is tough you should try Green Man in the Brecon Beacons; it changes from sun to rain by the hour ?

I still get 2012 flashbacks...

Ugh.

Ben