Model Output Discussions 12z 03/05/2016

[Frosty.]

30 minutes ago, johnholmes said:

To be fair to frosty he often posts a succession of charts along with his comments. A pity more folk don't do this. Charts showing the whole UK do help those just beginning to try and understand the models, or I would think so? Of course one can 'cherry pick' charts to suit but that soon becomes obvious when anyone does that over a fairly short period.

like he's done above whilst I was typing!

 

Cheers John, I'm guilty of cherry picking but I also post a lot of average and poor charts too but I don't mind admitting a preference for hot anticyclonic and spanish plumes in the summer.

Edited June 14, 2016 by Frosty.

[Summer Sun]

Monday should see the dry weather staying for most parts of England and Wales Scotland and possibly northern Ireland could start and see some rain or showers as the center of the low tracking towards Iceland

[I remember Atlantic 252]

29 minutes ago, Summer Sun said:

Monday should see the dry weather staying for most parts of England and Wales Scotland and possibly northern Ireland could start and see some rain or showers as the center of the low tracking towards Iceland

yeah but SS dreading Tuesday, my ultimate least favourite weather, hope for a change

and why is favourite redlined? we aren't American!

[Frosty.]

The end of the Gfs 12z op run is a peach with warm anticyclonic weather covering the UK at the end of June.. I would welcome that as I'm sure most on here would. 

In the meantime we have at least another 2 very showery days with thunderstorms around during the afternoons and evenings but the trough responsible slowly fills in situ by Friday with less showers and nowhere near as heavy by then as the Azores ridge starts to slowly build in and the weekend looks better with largely dry and bright weather with sunny spells but saturday night looks cold for the time of  year, still a few showers on saturday and patchy rain spreading into the west on sunday but the s / se looks like becoming fine and progressively warmer on Sun / Mon but becoming more unsettled further n / w. Tuesday shows an active band of rain pushing in from the west but still dry and pleasantly warm across the southeast for a time and the rest of next week looks changeable with sunshine and a few heavy showers and some cool wet weather in the SE for a while too but then high pressure starts to ridge towards the sw / s with drier, brighter and warmer weather across central and southern areas with temps rising into the low 20s celsius once again. Then further into low res it all gets rather good with high pressure taking centre stage towards the end of the run...not for the first time the models show potential for a warm settled further outlook!

[knocker]

Rather early to try and pin down any detail for Glastonbury but not harm in having a look.

The GEFS 5 day period covering it doesn't look that clever with the upper trough over the UK and ridging Scandinavia indicating a rather unsettled period, As the week progresses the trough decline with faint pressure rises in the western Atlantic so basically it's a zonal flow with no strong indication of the Azores HP nudging NE. Essentially not much more one can say at this range as it will be dependent on the synoptic detail as we get towards this weekend. The obvious favoured solution would be some surface ridging from the south west.

[Frosty.]

The GEFS 12z mean shows a ridge of high pressure this coming weekend which lasts longest in the southeast, even through next Monday but further n / w  it becomes increasingly unsettled. Thereafter there is some ebbing and flowing of the Azores high (ridge) but it never has the support to build in and actually it retreats with more widespread unsettled weather taking over, quite zonal. However, the 6z mean was a little better for next week and I don't think we should write off the possibility of improvements in the coming days but at least the south would at least have some fine and pleasantly warm weather next week as things stand but with a risk of occasional rain.

Edited June 14, 2016 by Frosty.

[mb018538]

Everything looks like being in just the wrong place for anything too settled, so a continuation of sunshine and showers looks likely, with the best weather further S and E.

[Frosty.]

Sorry to say the Ecm 12z isn't a patch on last night's in terms of a settled and warmer outlook beyond T+168 hours, however, we do have an improvement at the weekend with a ridge of high pressure which slowly sinks SE by next Monday with another fine warm day for the southeast but thereafter it looks like we are open to the Atlantic with a more zonal unsettled outlook next week with the Azores ridge just out of reach but warmer air flirts with the southeast around next tues with a risk of thundery showers but this run doesn't have a happy ending, unlike 24 hours ago.

[Man With Beard]

If anything, I think the mid-term outlook has got more uncertain today rather than less. Both GFS and ECM ops at T168 see a trough splitting just before arrival to the UK. This makes me think the idea of a splitting trough is now a clear favourite. However, anyone who has studied splitting troughs in summertime knows that you cannot pin them down until T72 - ECM sometimes picks them correctly at T120. If it splits early enough, it could sink towards Biscay, leading to a possible plume, maybe even a return to the ridge dominated runs we saw yesterday. Or it may stall over the UK leading to a very wet few days.

 

[damianslaw]

Very much a typical outlook for the time of year, trough filling in situ as we end the week, a weak ridge of heights from the azores building but not robust enough and we then see a return of the westerlies so to speak, with quite a zonal flow, with the azores aligned in classic fashion to allow the jet to build over it and an airstream from between SW and W and with strong heights to our NE, the trough will only have one way to go and that's slap bang over the UK, a weaker more northerly programmed jet would allow the azores high to build NE more robustly and link with heights to the NE, hence why some of the models recently have been showing an anticyclonic outlook.

A very standard outlook.

[knocker]

41 minutes ago, Man With Beard said:

If anything, I think the mid-term outlook has got more uncertain today rather than less. Both GFS and ECM ops at T168 see a trough splitting just before arrival to the UK. This makes me think the idea of a splitting trough is now a clear favourite. However, anyone who has studied splitting troughs in summertime knows that you cannot pin them down until T72 - ECM sometimes picks them correctly at T120. If it splits early enough, it could sink towards Biscay, leading to a possible plume, maybe even a return to the ridge dominated runs we saw yesterday. Or it may stall over the UK leading to a very wet few days.

I'm sorry to say I haven't studied splitting troughs in summertime, or any other time for that matter, so would appreciate a simple explanation of the process. Ta.

[Frosty.]

35 minutes ago, knocker said:

I'm sorry to say I haven't studied splitting troughs in summertime, or any other time for that matter, so would appreciate a simple explanation of the process. Ta.

I'm only half awake but is it something to do with split flows and cut-off lows (troughs) ? :-)

[mb018538]

When they split, it depends on how much energy is sent into each portion of the trough, and this is notoriously hard to resolve without precise starting data closer to the time - and will ultimately effect things downstream. Hopefully it will split towards Biscay as stated, and hopefully promote a ridge later on.

[knocker]

32 minutes ago, mb018538 said:

When they split, it depends on how much energy is sent into each portion of the trough, and this is notoriously hard to resolve without precise starting data closer to the time - and will ultimately effect things downstream. Hopefully it will split towards Biscay as stated, and hopefully promote a ridge later on.

Like so you mean? Problem with that is there is no supporting evidence to back it. All the anomalies tonight still decaying the trough NW and looking towards zonality with the HP down to the SW

Edited June 14, 2016 by knocker

[northwestsnow]

GEM 0z gets my vote  HP pretty much all the way, pretty unlikely but nice to see anyway..

[William of Walworth]

For next week, I would bank the images on Frosty's most recent post but would sack the image above on koocker's most recent post. All still to play for.

Edited June 15, 2016 by William of Walworth

[knocker]

The offerings from the GFS this morning

The thundery low will hang around for the next couple of days before brief ridging at the weekend. Then the by Monday fronts sweep in from the west bringing some wet and windy weather leaving a westerly N/S split flow by Glastonbury week with the Azores HP nudging up from the SW which perhaps will be hopeful for GW.

Does this morning's GEFS support this latter conclusion? Well not really, ridging Scandinavia but liittle sign of ingress from the Azores

Edited June 15, 2016 by knocker

[mb018538]

Looks like from that GEFS chart we will be on the periphery for now. So not full on low pressure like we have at present, but not high pressure domination either. Better in the SE.

[Matthew.]

Yes GFS 0z not bad at all. That Azores high seems to be tantalisingly close to the Sw as time goes on next week. It just needs a nudge Ne. Mostly looking reasonable next week imo

Edited June 15, 2016 by Matthew Wilson

[wishingforsnow]

A few wet days and this story breaks http://www.telegraph.co.uk/news/2016/06/14/uk-weather-june-could-be-wettest-ever-recorded-as-wimbledon-and/

Not really acccurate at all as next week already looks like an improvement on this one starting from the South and though the models look mixed and can't decide on one outcome I don't see any outcome like June 2012 at all  Glastonbury right now is looking mixed with warm sunny periods and Wimbledon is too far off to call. There's even the possibility of further high pressure influence at the end of the month with the fact that it's been showing up on runs though uncertain of timing as the swings in outlook have been dependant on the splitting trough. Still at best we get a mixture of warm sunshine and showers with more unsettled weather further North, but not a washout for the rest of the month by any means I don't think.

Edited June 15, 2016 by wishingforsnow

[Frosty.]

1 hour ago, northwestsnow said:

GEM 0z gets my vote  HP pretty much all the way, pretty unlikely but nice to see anyway..

Yes the Gem 00z turns into a thing of beauty next week with temps into the mid to upper 20's celsius, high pressure, lots of strong sunshine...perfection!

[Matthew.]

The ECM is once again quite a joy this morning even from Tuesday! Will be interesting to see if it holds. My blood pressure on the rise once more

[mb018538]

23 minutes ago, Matthew Wilson said:

The ECM is once again quite a joy this morning even from Tuesday! Will be interesting to see if it holds. My blood pressure on the rise once more

Am I looking at the same run here?? Looks fairly innocuous to me, with a shallow trough plonked over the UK from 168 hours onwards?

[knocker]

20 minutes ago, mb018538 said:

Am I looking at the same run here?? Looks fairly innocuous to me, with a shallow trough plonked over the UK from 168 hours onwards?

That would seem a reasonable assessment

[johnholmes]

Too many switches, albeit not major pattern changes, on the anomaly charts, to be really clear just what upper air pattern will be with us 6-10 days from now. On balance probably a westerly type but fairly slack with no definite suggestion of it being cyclonic or anticyclonic being the main influence.