This new format is based on the post of Monday in the main Glastonbury thread on the forum, and this reflects the movement into the long term range of the main models.
[url="http://forum.netweather.tv/topic/76531-glastonbury-wed-26-to-sun-30-june-2013/page-3"]http://forum.netweather.tv/topic/76531-glastonbury-wed-26-to-sun-30-june-2013/page-3[/url]

[b]GFS Operational Charts [/b][based on 12Hz 12th June run]

Signs of High Pressure slowly re-establishing itself from Tuesday next week according to the GFS 12Hz run. The High Pressure lasts to a growing extent for most of the run, however a brief blip on the first Wednesday of the festival.Charts shown in order (240, Sat 22nd June, 312 Tue 25 June, 336 Wed 26 June, 384 Fri 28 June)
[attachment=174104:GFS 12 1.JPG] [attachment=174103:GFS 12 2.JPG] [attachment=174108:GFS 12 4.JPG] [attachment=174102:GFS 12 3.JPG]

So if the GFS op were to be believed not looking that bad, and probably mostly dry as well leading up to the festival, however other charts are not so promising.

This shows 12mm of rain, however this understates the rain compared compared to all the ensembles.

[attachment=174121:Rmgfs144sum.gif]

[b]GFS Ensembles[/b] [based on 12Hz 12th June run]

The trends continue to be pressure ridging from the south, from as early as mid next week to around 1015mb, and steadily rising to 1020mb, however the op run a little bit progressive in increasing pressure too quickly, also a slight tendency for pressure to drop around the start of the festival. Most ensembles agree of heavy rain over next weekend, but after this signs of rainfall total dropping.

[attachment=174120:GEFS 12 1.png] [attachment=174119:GEFS 12 2.png]

[attachment=174118:GEFS Som 12 1.png] [attachment=174117:GEFS Som 12 2.png]

[b]NOAA Upper Charts [/b][based on run published 11th June]

Both shown an upper trough over the UK, but with Pressure slowing increasing to the South West.

[attachment=174110:610day.03 11 1.gif] [attachment=174109:814day.03 11 2.gif]

[b]NOAA Upper Charts [/b][based on run published 12th June]

[attachment=174130:610day.03 12 1.gif] [attachment=174129:814day.03 12 2.gif]

If anything this shows the High Pressure moving further away to the South west,

[b]ECM[/b] [based on 12Hz 12th June run]

This shows a lot of unsettled weather over the UK this weekend, however this also shows the trough moving northwards, with High Pressure for Southern areas by mid next week, before ending with low pressure one again. (in contrast to earlier runs which showed Low Pressure further south for much of the run).

Charts shown in order (120, Mon 17 June, 192 Fri 25 June, 240 Sun 27 June)

[attachment=174112:Recm1201 11 1.gif] [attachment=174111:Recm1921 11 2.gif] [attachment=174116:Recm2401 11 3.gif]

[b]Summary [/b]

Things looking a bit promising tonight was High Pressure slowly ridging up on the main models next week, however these op runs are slightly progressive in doing so, however in the run up to Glastonbury festival period, it looks like drying up.

If this is the case, the heavy rain for this weekend makes a big difference.

If the rain is very heavy over, say 40mm, it could make the ground sodden for the festival, meaning a increased risk of a mud bath festival
If the rain is under 20mm, then it would wet the ground the ground but allowing the festival site to dry up before the festival.
Current guidance is for the latter in terms of this coming weekend, but this can easily change.