Weather 2017

[justperfect]

15 minutes ago, ThomThomDrum said:

At what point last year in the run up to the fest did the weather forecasts start to get it right that it was going to be shite?

Also has anyone ever done an analysis on what medium/long term forecasts are the most accurate? Or is it actually random more than 7 days out as most suspect?

I'd say march when all of southern England was under water

[p.pete]

Just now, SwedgeAntilles said:

Yeah, let's not forgot that last year the focus was still on the festival itself, which wasnt actually too bad. What few of us realised/were prepared to accept was that the damage was already being done. 

Yep, thick mud of last year and 2011 was mostly due to saturation pre-festival.  We should be confident of not getting those conditions - but absolutely not confidence of avoiding a wash-out yet - my fingers are still firmly crossed!

[The Nal]

We knew it was going to be a bit ropey on site but the horror show pics didn't start rolling in until the weekend. 

The forecast for the actual festival wasn't accurate even on the Tuesday of the festival. 

Its a fucking waste of time.

Here was the Met Office forecast from this day last year

When I saw this day, it was from the 13th but the festival starts on the 21st this year as opposed to the 22nd last year. 

On 6/13/2016 at 0:50 PM, Thunderstruck said:

On Saturday most of the United Kingdom will be dry with sunny spells, although eastern England will continue to be affected by some showers. From Sunday and into next week the latest indications are that unsettled and often windy conditions will return from the west, although there is a fair chance that much of southern and eastern England will be dry and bright this Sunday. In general bands of cloud and rain are expected to move eastwards across the British Isles, interspersed with brighter, showery conditions. The most frequent spells of rain are likely across the northwest, whilst the southeast should see more in the way of drier weather. Temperatures will generally be near average, but perhaps on the cool side at first, and turning locally warm in sunnier spells.

We had severe flash flooding 4 days later which made utter unrecoverable shit of the site.

 

Ooh, heres the Met Office forecast from this day in 2010.

UK Outlook for Friday 18 Jun 2010 to Sunday 27 Jun 2010:

 

For the start of the period up to the beginning of the new week, it should be largely dry for most areas of the UK, with variable cloud and sunny periods. The exception being some occasional cloud and light rain at times in the far north, and some light showers in eastern parts, perhaps extending to other areas for a time. Feeling warm in any prolonged sunshine, especially further south and west in light winds. Temperatures should be near or above normal, however, feeling cooler on northern and eastern coasts with a fresh north or northeasterly breeze. Conditions perhaps turning a little more unsettled for most parts later next week and into the weekend, with spells of rain or showers. Temperatures are expected to remain near or slightly above normal.

 

Updated: 1204 on Sun 13 Jun 2010

Fucking time wasters.

Thread here if anyone wants a root

 

Edited June 12, 2017 by The Nal

[Nobody Interesting]

So what we are looking at is dry up to, and including, Wednesday - then Thursday onwards  a likely breakdown with the worst weather effecting the north west of the UK which if like the norm that means showers or a weak weather front down south.

Can I stick please. I will take that over any chance of a repeat of last year.

[Mr.Tease]

So now we've gone from 'neutral weather' to 'anti-cyclones' - this year's weather thread is just messed up

[The Nal]

6 days before the gates in 2010 opened

00z ensebles out for Somerset, not overly good I am afraid - many of the different data runs going for lower pressure around the festival

[p.pete]

1 minute ago, The Nal said:

6 days before the gates in 2010 opened

00z ensebles out for Somerset, not overly good I am afraid - many of the different data runs going for lower pressure around the festival

Almost as if you don't care  

[General Lee]

1 minute ago, The Nal said:

6 days before the gates in 2010 opened

00z ensebles out for Somerset, not overly good I am afraid - many of the different data runs going for lower pressure around the festival

No ticket for me this year unfortunately - but nice to see the traditional Nal forecasts never change

[The Nal]

That wasn't my forecast.

Just pointing out what a load of complete shite it is.

[dingbat2]

There was flooding the weekend before glasto last year, which caused lots of issues with the site build if I remember correctly. Anyone remember exactly how much rain fell that weekend? It meant the festival site was waterlogged and muddy in lots of areas before  punters had even arrived

 

[Thunderstruck]

8 minutes ago, The Nal said:

6 days before the gates in 2010 opened

00z ensebles out for Somerset, not overly good I am afraid - many of the different data runs going for lower pressure around the festival

There's still absolutely no consensus for the festival period. For example the 00z run was a horror show (emphasis on the horror), and this mornings 06z was pretty much dry for the whole festival.

[The Nal]

4 minutes ago, Thunderstruck said:

There's still absolutely no consensus for the festival period. For example the 00z run was a horror show (emphasis on the horror), and this mornings 06z was pretty much dry for the whole festival.

Which has always been my point. Why do people bother? This thread started in March. 

[Thunderstruck]

Just now, The Nal said:

Which has always been my point. Why do people bother? This thread started in March. 

yeh, It's fun I suppose to try. In some circumstances we would have a good idea of the weather next week, but it's so changeable at the moment that it's impossible really. I genuinely think we will have a decent idea of which way it could go wednesday/thursday this week.

[Simpo]

6 minutes ago, dingbat2 said:

There was flooding the weekend before glasto last year, which caused lots of issues with the site build if I remember correctly. Anyone remember exactly how much rain fell that weekend? It meant the festival site was waterlogged and muddy in lots of areas before  punters had even arrived

 

I think it was around 50mm over that one weekend, or something stupid like that.

[richy24]

6 minutes ago, The Nal said:

Which has always been my point. Why do people bother? This thread started in March. 

Because talking about the weather is what we do best!

[Ohinever]

That mud at Glasto is Jurassic mud. I read this on the Somerset live website last week, so it must be true. It makes me happy as I like to take  newbies to the top of the hill of death on a Tuesday night, look at the astonishment on their faces as they begin to comprehend the scale of the scene laid bare below them, before beckoning to that gorgeous vista and gently whispering, "Welcome, to Jurassic Park". 

And I didn't even know.. 

Edited June 12, 2017 by Ohinever

[Aragorn]

14 minutes ago, Thunderstruck said:

There's still absolutely no consensus for the festival period. For example the 00z run was a horror show (emphasis on the horror), and this mornings 06z was pretty much dry for the whole festival.

The 0z was not a horror show. The operational was an outlier at numerous points. The mean was good

[Gnomicide]

[Thunderstruck]

Just now, Aragorn said:

The 0z was not a horror show. The operational was an outlier at numerous points. The mean was good

yes, to clarify I was referring to the operational. 

[Deaf Nobby Burton]

19 minutes ago, The Nal said:

Which has always been my point. Why do people bother? This thread started in March. 

You could say there is no point discussing anything, we discuss the lineup to death but ultimately none of us have any control over it and it will be the same weather we talk about it or not.

[FuzzyDunlop]

24 minutes ago, The Nal said:

Which has always been my point. Why do people bother? This thread started in March. 

Just to get your "We're fucked" forecast.

Edited June 12, 2017 by FuzzyDunlop

[jfaragher]

Just to chip in - I've taken output from the 15 day forecast from the ECMWF as this now has the whole weekend in range.  This is an ensemble forecast - it is run 51 times, with slightly varied starting conditions to try and capture some of the uncertainty inherent in medium range weather forecasts.  The 'spread' of outcomes typically increases over time, as you would expect.

Completely arbitrary methodology:

1.  Each forecast (member) has been assigned to one of 30 typical weather "regimes" or patterns for the UK.  Why - you tend to get the 'right' regime more often than you get a correct specific location forecast.  This can make it more useful for forecasts where you are trying to get the likelihood of something occuring.
2.  Each regime (pattern) has been assigned a 'raininess in the Glastonbury area' rating from 0 to 5, based on the typical rain for the regime for the time of year.  This has been done using the most advanced visual analysis tools, with additional expert intervention to determine certainty (I looked at the plots on a map, and made a decent estimate).  Broadly, the raininess rating is:
0 - Very low likelihood of any rain
1 - Low likelihood of any rain
2 - Likely some rain, but won't be much of it (<2mm/24hr ish)
3 - Very likely some rain, still not much of it (<4mm/24hr ish)
4 - Likely to get quite a bit of rain (>4mm/24hr ish)
5 - Very likely to get plenty of rain (>6mm/24hr ish)

Note that there is no indication of how this will fall - could be all in a sharp shower (in which case 2mm will leave you soaked) or in persitant and annoying drizzle.
3.  I then use the number of members to give a percentage for each one of these raininess ratings (in the table below)

Use this as you will. I will try to update over the next week.

[across97]

2 minutes ago, jfaragher said:

Just to chip in - I've taken output from the 15 day forecast from the ECMWF as this now has the whole weekend in range.  This is an ensemble forecast - it is run 51 times, with slightly varied starting conditions to try and capture some of the uncertainty inherent in medium range weather forecasts.  The 'spread' of outcomes typically increases over time, as you would expect.

Completely arbitrary methodology:

1.  Each forecast (member) has been assigned to one of 30 typical weather "regimes" or patterns for the UK.  Why - you tend to get the 'right' regime more often than you get a correct specific location forecast.  This can make it more useful for forecasts where you are trying to get the likelihood of something occuring.
2.  Each regime (pattern) has been assigned a 'raininess in the Glastonbury area' rating from 0 to 5, based on the typical rain for the regime for the time of year.  This has been done using the most advanced visual analysis tools, with additional expert intervention to determine certainty (I looked at the plots on a map, and made a decent estimate).  Broadly, the raininess rating is:
0 - Very low likelihood of any rain
1 - Low likelihood of any rain
2 - Likely some rain, but won't be much of it (<2mm/24hr ish)
3 - Very likely some rain, still not much of it (<4mm/24hr ish)
4 - Likely to get quite a bit of rain (>4mm/24hr ish)
5 - Very likely to get plenty of rain (>6mm/24hr ish)

Note that there is no indication of how this will fall - could be all in a sharp shower (in which case 2mm will leave you soaked) or in persitant and annoying drizzle.
3.  I then use the number of members to give a percentage for each one of these raininess ratings (in the table below)

Use this as you will. I will try to update over the next week.

So for what I've made of this, we're likely to have a low likelihood of rain across the weekend.

 

Looking likely that showers will be common, but no too heavy

[barkley87]

Every time I look at Accuweather the rain gets worse...

http://www.accuweather.com/en/gb/pilton/ba4-4/june-weather/710458

Edited June 12, 2017 by barkley87
Added accuweather link

[The Nal]

8 minutes ago, barkley87 said:

Every time I look at Accuweather the rain gets worse...

http://www.accuweather.com/en/gb/pilton/ba4-4/june-weather/710458

Shit Shit Shit

2007 anyone?