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Offline GezM  
#441 Posted : 13 August 2019 14:02:51(UTC)
GezM

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Originally Posted by: Rob K Go to Quoted Post
6Z GFS op run gets increasingly warm/hot in the south towards the end, although not a huge amount of support from the GEFS.


Indeed. The ensemble average has actually dropped for that period since yesterday. The reason for this is an increasing divergence amongst the members from the 21st onwards. We need more members to follow the Op run before there can be any real confidence. 

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Offline DEW  
#442 Posted : 14 August 2019 06:10:27(UTC)
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Synoptics look good for BH weekend with HP at least to start with, and a greater number of above seasonal average temps in the ens runs. Sporadic rainfalli n some ens so perhaps a shower or two


For the nearer future, this weekend's depression following a track off NW Scotland; windy but not much rain in the NW, rather more in the south presumably from the fronts shown dragging their heels in the fax chart late Friday/early Sat

It was most foule weather ... and so we went into an alehouse - Samuel Pepys
Offline Bertwhistle  
#443 Posted : 14 August 2019 07:07:48(UTC)
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Originally Posted by: DEW Go to Quoted Post


Synoptics look good for BH weekend with HP at least to start with, and a greater number of above seasonal average temps in the ens runs. Sporadic rainfalli n some ens so perhaps a shower or two



Yes, there's a recurring signal in increasing GFS ENS members for a warm-up from about 23rd. Many members keep it going till the end of the run but it might be concerning that both the Op and Control drop again after Sunday.

Bertie, Itchen Valley.
Remember Finlake!
Offline Downpour  
#444 Posted : 14 August 2019 07:29:35(UTC)
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Originally Posted by: Bertwhistle Go to Quoted Post


 


Yes, there's a recurring signal in increasing GFS ENS members for a warm-up from about 23rd. Many members keep it going till the end of the run but it might be concerning that both the Op and Control drop again after Sunday.



Although the Friday, Saturday and Sunday of the bank hol are the key days. The Monday is travelling home day so I suspect most would take a rainy day there! 

Chingford
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Offline Ally Pally Snowman  
#445 Posted : 14 August 2019 08:09:44(UTC)
Ally Pally Snowman

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Stunning ECM means this morning from 144h to 240h settled and warm for all the UK. 

Offline doctormog  
#446 Posted : 14 August 2019 08:17:43(UTC)
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Originally Posted by: Ally Pally Snowman Go to Quoted Post


Stunning ECM means this morning from 144h to 240h settled and warm for all the UK. 



Which coincides beautifully with the last of the pupils north of the border returning to school, so is therefore an almost certain outcome. 


It certainly looks like a continuation of the signal for more summery conditions in the medium term.

Offline Ally Pally Snowman  
#447 Posted : 14 August 2019 08:23:45(UTC)
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Originally Posted by: doctormog Go to Quoted Post


 


Which coincides beautifully with the last of the pupils north of the border returning to school, so is therefore an almost certain outcome. 


It certainly looks like a continuation of the signal for more summery conditions in the medium term.



 


Always seems to be the way. Hopefully it's prolonged settled spell the north certainly needs some respite. 


 

Offline David M Porter  
#448 Posted : 14 August 2019 08:37:33(UTC)
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I have said on a few occasions over recent weeks that as long as pressure remained fairly high over the Greenland region, there would be little chance of a meaningful rise in pressure over the UK giving us the kind of sustained settled spell that many people have been hoping for. My recollection of following the model output regularly ever since late May/early June this year is that pressure over Greenland has more often been high than low, hence the mostly unsettled weather many areas have had.


Should things verfify as shown, it will be good news for those areas of the UK that have recently been affected by flooding, and will allow repairs to be carried on the dam in Derbyshire that was close to collapse a couple of weeks ago.

"Sometimes what we accept as the truth may not be the full story".
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Offline Downpour  
#449 Posted : 14 August 2019 14:17:44(UTC)
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Bank Holiday weekend now coming into the semi-reliable and looking pretty good. 

Chingford
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Offline TimS  
#450 Posted : 14 August 2019 17:03:16(UTC)
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Yes, the late August pattern change looks strong on repeated runs and in the ensembles. Just as the early August pattern change to low pressure has been long heralded. Jet stream heading north.

As analogues for the summer go, it looks like we won’t be far off 1999. going to be closest:

June 1999: average temps, generally very wet and stormy

July 1999: warm and sunny, pretty dry in many places

August 1999: wet and stormy, flooding in Lancs and North East, slightly warmer than average. Weather improved markedly in the final week leading to a very warm and sunny Sept.
Brockley, South East London 30m asl
Offline Downpour  
#451 Posted : 15 August 2019 10:23:17(UTC)
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Originally Posted by: TimS Go to Quoted Post
Yes, the late August pattern change looks strong on repeated runs and in the ensembles. Just as the early August pattern change to low pressure has been long heralded. Jet stream heading north.

As analogues for the summer go, it looks like we won’t be far off 1999. going to be closest:

June 1999: average temps, generally very wet and stormy

July 1999: warm and sunny, pretty dry in many places

August 1999: wet and stormy, flooding in Lancs and North East, slightly warmer than average. Weather improved markedly in the final week leading to a very warm and sunny Sept.


Yes, that's probably the form horse as an analogous year. 


The September Banker could come into play again – always nice to have a sweet September. 

Chingford
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Offline Bertwhistle  
#452 Posted : 15 August 2019 17:57:36(UTC)
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Here's an FI chart from GFS 12z; no way can that setup be relied upon at that range, but I thought it was a super synoptic artwork that illustrates how significant changes can potentially occur over a short timescale. The changes won't have happened by this chart, but in the previous days, HP had been building strongly across the BIs with 10C + 850s widely established. By early on 30th it looked as if something special from the warm side was afoot; then two things happen:



  1. Heights build over Greenland leading to a very cold late summer/ early autumn set up there;

  2. HP over BIs started to sink back westwards, opening the flood gates potentially for the N'lies that were setting up to the E of the Greenland HP.


If this chart was followed through, I suspect that by 3rd Sep we would all feel the influence of that cold inflow.


Comment made for hypothetical illustrative purposes only. Note the long fetch NElies W of France and Spain that would upset attempts by the LP off the Labrador coast to intrude on that cold setup. I think this is a fascinating chart, notwithstanding the need to preempt challenges to the lack of probability at that range. Personally I think GFS has got into a habit of late of assuming N blocking in one form or another, possibly because of its frequency this summer.


No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.

Bertie, Itchen Valley.
Remember Finlake!
Offline DEW  
#453 Posted : 16 August 2019 06:07:48(UTC)
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This morning optimists should look at the ECM ( a big chunk of warm air, over theBH, especially to the west, under HP); pessimists should look at the GFS 0z (gone downhill since yesterday, UK in shallow trough between two HP, cooler and persisting into the following week); averagists can have the have the GEFS ens whose runs generally are now more clustered around the seasonal mean.


More frequent rainfall now appearing in the ens generally for a week ahead, nothing dramatic but persistent; and that disagrees with  http://www.wxmaps.org/pix/prec4  (which I believe is based on GFS) 


All of which explains why weather watching is so fascinating

It was most foule weather ... and so we went into an alehouse - Samuel Pepys
Offline Bertwhistle  
#454 Posted : 16 August 2019 07:33:10(UTC)
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I find all the charts disappointing tbh. The ECM 240 looks fragile and is too far out anyway. The GFS0z didn't concern me until I went to the ENS, expecting the green to be low in the range, which it wasn't really. In the Op, seems the HP belt alignment is more WSW-ENE instead of SW-NE which allows it to collapse more easily when the next low pushes in. The overdue Nward shift of the jet was still being prophecied by the Beeb yesterday, but the northerly loops rippling across the Atlantic seem to break up on reaching the uk, then reestablish over Europe.


No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.

Bertie, Itchen Valley.
Remember Finlake!
Offline doctormog  
#455 Posted : 16 August 2019 07:57:37(UTC)
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As the 00z ECM run is not fully out until just before 8am it shows a slightly different and unfortunately more unsettled outlook than the one shown in the 12z run to which DEW refers. Even allowing for that the medium term still shows a generally improving picture albeit not prolonged warm settled conditions.
Offline Ally Pally Snowman  
#456 Posted : 16 August 2019 08:01:02(UTC)
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Yes a bit of a wobble on of the Uber settled conditions for next week looks more like a NW - SE split this morning. Still better than what many have had recently though. My hunch is this is just a wobble and a much more significant settled spell for all of the UK will return to the output over the next couple of days.


 

Offline Gusty  
#457 Posted : 16 August 2019 08:01:41(UTC)
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Consensus for an improvement next Tues/Weds as high pressure nudges up to give us a fine and warmer spell. A new signal to drop a trough SE'wards across the country to sit over the near continent by the BH weekend appears to have fairly good agreement now.


In a nutshell and based on this mornings output its likely that any improvements around midweek will be brief.

Steve - Folkestone, Kent
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Offline Ally Pally Snowman  
#458 Posted : 16 August 2019 16:53:16(UTC)
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As suspected the 12s are much better. Warm and settled for a significant length of time.

Offline Bertwhistle  
#459 Posted : 16 August 2019 18:17:37(UTC)
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The 12z GFS Op is not that well supported after the first week; it's riding high again. It swings so emphatically from one run to the next that, although I've always treated it with caution and not in isolation from the members, I do wonder why it ever qualifies as the operational run, and I'd be interested to know if the Control is more accurate over a timeframe.

Bertie, Itchen Valley.
Remember Finlake!
Offline Downpour  
#460 Posted : 16 August 2019 21:24:30(UTC)
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Originally Posted by: Ally Pally Snowman Go to Quoted Post


As suspected the 12s are much better. Warm and settled for a significant length of time.



Fair shout. B/H weekend looking decent if not very decent down south. Good weather when it’s wanted.

Chingford
London E4
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