This is the 8th forecast blog for Glastonbury 2015.

The 4th blog (Issued 10 June) was mostly positive.
The 5th blog (Issued 13 June) was positive and scored 3 out of 10 on the Dustbowl - Mudbath rating. Things were looking positive.
The 6th blog (Issued 15 June) was slightly positive and scored 4.5 out of 10 on the Dustbowl - Mudbath rating.
The 7th blog (Issued 17 June) was slightly negative and scored 6.0 out of 10 on the Dustbowl - Mudbath rating.

So a definite trend towards a wet festival. Is today the day to stall or reverse this trend. Today's forecast will only contain today's runs.
As we move closer to the festival, the operational charts become more important, and I will start with these, although the other forecast methods will still be shown.

[b]1. Operational Runs from GFS[/b] (06Hz and 12Hz) [b], ECM [/b][b](00Hz and 12Hz)[/b][b] and UKMO [b](00Hz and 12Hz)[/b][/b]

From today as the final day of the festival moves into the T+240 range I will show the available charts for this day. So a complete picture of the festival will be shown.

[b][size=3][b]Monday 22nd June [/b][/size][/b]
[attachment=253289:GFS 18th June 06Hz + 96.JPG] [attachment=253293:GFS 18th June 12Hz + 96.JPG][attachment=253282:ECM 18th June 00Hz +96.png] [attachment=253297:ECM 18th June 12Hz +96.png]
[attachment=253299:UKMO 18 June 00Hz + 120.gif] [attachment=253298:UKMO 18 June 12Hz + 120.gif]

There is a general theme, Low Pressure to the North East, with slightly higher pressure to the South. However it looks generally unsettled and each of the 12Hz run look similar synoptically so some rain seems likely over Glastonbury, perhaps 10mm of rain possible - enough to dampen the ground and this could effect things later on.

The theme then is on Tuesday, or the Low Pressure to edge away, so a transient day, which should be drier, and allow the ground to dry off a bit after Monday's rain.
[size=3][b]Wednesday 24th June[/b][/size]
[attachment=253288:GFS 18th June 06Hz + 144.JPG] [attachment=253292:GFS 18th June 12Hz + 144.JPG] [attachment=253285:ECM 18th June 00Hz +144.png] [attachment=253296:ECM 18th June 12Hz +144.png]

For Wednesday the theme is for low pressure to the west of the UK to start edging closer to the UK itself. With the exception of the GFS 12Hz run, Wednesdays looks mostly dry, indeed the ECM 12Hz run has a mini HP over South Eastern areas.

For Thursday the theme is for Low Pressure to continue to edge closer to the UK, but a largely dry day seems quite likely.

[size=3][b]Friday 26th June [/b][/size]
[attachment=253287:GFS 18th June 06Hz + 192.JPG] [attachment=253291:GFS 18th June 12Hz + 192.JPG] [attachment=253284:ECM 18th June 00Hz +192.png] [attachment=253295:ECM 18th June 12Hz +192.png]

Friday is currently the problematic day, there is currently decent agreement between the models that a wet day is likely, with South Western areas bearing the brunt of the rainfall, with current estimates suggesting over half an inch of rain possible. If this were to occur, this would certainly cause issues with mud, possibly even mudbath conditions.

Saturday continues to look unsettled with further rain or showers.
[b][size=3]Sunday 28th June[/size][/b]
[attachment=253286:GFS 18th June 06Hz + 240.JPG] [attachment=253290:GFS 18th June 12Hz + 240.JPG] [attachment=253283:ECM 18th June 00Hz +240.png] [attachment=253294:ECM 18th June 12Hz +240.png]

A bit of a disagreement for Sunday, ECM keeps things unsettled with further rain, while he GFS moves the low pressure out of the way quickly and a mostly dry day would probably ensue.

[b]Rainfall Charts[/b]

I am not a massive fans of these charts as they can over do rainfall amounts, but these show the heavy rain for Monday, and then for Friday, and the moderate rain in between for Wednesday based on GFS12Hz ).

[attachment=253323:Rhgfs9014.gif] [attachment=253322:Rhgfs10814.gif]

[attachment=253324:Rhgfs17714.gif][attachment=253325:Rhgfs20414.gif]

[b]Ensembles[/b]
[attachment=253327:Ensemble Temp 18 June 06Hz.png] [attachment=253317:Ensemble Temp 18 June 12Hz.png]
Generally quite cool for time of year, with the average never getting above 7c (850HPa) So no real warm weather likely however.

[attachment=253328:Ensemble Rain 18 June 06Hz.png] [attachment=253318:Ensemble Rain 18 June 12Hz.png]
Both runs are wetter than yesterday suggested especially for Monday and Friday.

[attachment=253326:Ensemble Pressure 18 June 06Hz.png] [attachment=253319:Ensemble Pressure 18 June 12Hz.png]
Interesting that both runs show ensemble Pressure dropping on Friday but moreso on the 12Hz, but large variations still present.

[b]CPC Charts[/b]
This covers the festival period 24-28 June and shows Low Pressure bang on top of the UK.

[attachment=253330:610day.03 from 18 June.gif]
[b]Summary [/b]

A lot to take in above, but some moderate rain seems likely on Monday in itself not too much of a problem. Some models suggest some rain on Wednesday but the majority do not go for this. Possibly then dry until Friday when some heavy rain is expected. This has the real potential to cause a lot of mud related problems. Perhaps a little drier and brighter for the weekend but further uncertainty.

The General theme of it being rather unsettled seems very likely and some rain does seem likely for the festival at times, however maybe a straw to hold onto is that perhaps there is a slight theme of the heavy rain being put back, perhaps this may happen and that by tomorrow the rain will be forecast for Saturday.

Despite this the trend towards a wet festival continues so a 7.0 on the Dustbowl - Mudbath Rating.

[attachment=253321:Glasto Rating 18th June.JPG]

Whatever you do, remember to pack your wellies.