Model Output Discussion 18z 28/07/13

[Tamara]

I'm not sure any real 'standoff' actually exists.  The pattern going forward looks very clear to me, that is slowly but surely becoming more and more unsettled from the NW as next week unfolds, but never really becoming properly unsettled away from the far northwest.  Temps close to average for 70% of the UK, but a bit higher for 10% in the E/SE and a bit lower for 20% in the N/NW. Rainfall following a fairly similar spread, the only real anomalous deficiency being in sunshine values, which looks set to be below average for 95%.

In terms of what the spread of the models currently show, there is a difference quite clearly. The UKMO has gone from full support of the GFS last night to dropping the jet stream a fair way further south and extending unsettled weather much more widely across the UK. The ECM continues with the changeable half way house suggestion, whilst the GFS has continued to suggest a more definitively settled picture further south.

 

Taking an overview and reading between the lines, then much as stated, the half way house scenario is perhaps most favoured - but this is not the same as stating what the various models actually show.

 

The GFS 06z is simply a slight adjustment closer to that half way house suggestion. Nothing more or less significant than that.

Edited August 8, 2013 by Tamara Road

[Frosty.]

There has been little change in the Ecm 00z ensemble mean since yesterday, low pressure is persistent to the northwest of the BI and the core of the azores anticyclone stays in the azores but with weak ridging spreading across southern areas and pressure always higher to the southwest/south throughout with the warmest, driest and sunniest weather across southern britain and especially the southeast with warmer uppers occasionally encroaching into southern england with temperatures into the mid 20's celsius, but generally low 20's celsius in the south which trend downwards the further north you are, more like mid to high teens celsius, it's a broadly westerly pattern with occasional splashes of rain and showers for the southern half of the uk but more generally unsettled for n.ireland, cumbria and scotland with only shortlived warmer and brighter intervals between, it's normal august weather, coolest and most unsettled for the northwest corner of the uk, warmest and driest across the far south/se but with slight adjustments north to the PFJ, a more summery outlook could easily be achieved, as the gfs 00z op run shows with incursions of hot continental air.

Edited August 8, 2013 by Frosty039

[shedhead]

In terms of what the spread of the models currently show, there is a difference quite clearly. The UKMO has gone from full support of the GFS last night to dropping the jet stream a fair way further south and extending unsettled weather much more widely across the UK. The ECM continues with the changeable half way house suggestion, whilst the GFS has continued to suggest a more definitively settled picture further south.

 

Taking an overview and reading between the lines, then much as stated, the half way house scenario is perhaps most favoured - but this is not the same as stating what the various models actually show.

 

The GFS 06z is simply a slight adjustment closer to that half way house suggestion. Nothing more or less significant than that.

You call it a standoff, I call it a fairly typical difference of evolution at the kind of range involved. A standfoff over next week imo would be one of the big two refusing to drop a cell of HP over the UK, while the other refuses to drop LP. Actually agree with you that we'll probably end up with a halfway house solution between what is currently shown, but as has been said all Summer ECM has been generally more consistent. Moreover it has support from UKMO, albeit with a rather more extreme version and a tangible move towards it from the 06 GFS...we just now need to see it that continues. 

Edited August 8, 2013 by shedhead

[Tamara]

A few days ago I think it might have been snowking (?) in one of his very good analysis summaries who referred to the GFS as promising the best scenario with its Higher pressure solutions, but believing that the more changeable solutions as equally consistently suggested by the ECM as being more likely. Such a view being the one that is seemingly also widely supported by most on here.

 

That division in the models has,actually therefore, persisted for quite an impressive time period. As recently as the 12z last night, the UKMO also supported a better ridging solution in accordance with the GFS - so I think, semantics and hair splitting of words and phrases notwithstanding, there has been something of parellel different suggestions running amongst the models - even if the consensus, including the METO, has consistently favoured something more changeable. And that changeable outlook is continued to  be favoured today - albeit with the driest/wettest estimates as already suggested by many.  As said above - I think the GFS has simply adjusted more in line with the changeable half way consensus - but, at the time of typing, it still remains a considerable distance from the latest UKMO.

Edited August 8, 2013 by Tamara Road

[shedhead]

A few days ago I think it might have been snowking (?) in one of his very good analysis summaries who referred to the GFS as promising the best scenario with its Higher pressure solutions, but believing that the more changeable solutions as equally consistently suggested by the ECM as being more likely. Such a view being the one that is seemingly also widely supported by most on here.

 

That division in the models has,actually therefore, persisted for quite an impressive time period. As recently as the 12z last night, the UKMO also supported a better ridging solution in accordance with the GFS - so I think, semantics and hair splitting of words and phrases notwithstanding, there has been something of parellel different suggestions running amongst the models - even if the consensus, including the METO, has consistently favoured something more changeable. And that changeable outlook is continued to  be favoured today - albeit with the driest/wettest estimates as already suggested by many.  As said above - I think the GFS has simply adjusted more in line with the changeable half way consensus - but, at the time of typing, it still remains a considerable distance from the latest UKMO.

Yes it does and imo UKMO post T+120hrs has been pretty woeful this summer, so as I said it's T+144hr does appear to be a rather extreme version of events to say the least. On balance I still think the most likely outcome across the next 24-36hrs is for ECM to remain fairly consistent re next week, whilst GFS continues edging towards it and UKMO backs off quite a bit.

[Captain Shortwave]

GFS ens still keeping low pressure well north of the UK, though a more mobile ECM-esque set up has been show with the trough moving ENE which of course means that it's harder to get heights in more favourable positions.

 

Whilst yes it's more mobile, the track of the low is north of east as opposed to the UKMO which is south of east and would if it went to T168 would show the low plowing through Scotland bringing nationwide unsettled weather. Something the UKMO has been showing on nearly every T144 chart for the last 2 weeks.

I know it's a long long way out but the ensemble mean perhaps hinting at more settled weather towards the last third of August?

 

It's a long way off but that's quite a strong signal at that timeframe. Will update this when the full 06z ensemble is out.

Here we go

Edited August 8, 2013 by Captain shortwave

[Tamara]

GFS ens still keeping low pressure well north of the UK, though a more mobile ECM-esque set up has been show with the trough moving ENE which of course means that it's harder to get heights in more favourable positions.

 

Whilst yes it's more mobile, the track of the low is north of east as opposed to the UKMO which is south of east and would if it went to T168 would show the low plowing through Scotland bringing nationwide unsettled weather. Something the UKMO has been showing on nearly every T144 chart for the last 2 weeks.

I know it's a long long way out but the ensemble mean perhaps hinting at more settled weather towards the last third of August?

 

It's a long way off but that's quite a strong signal at that timeframe. Will update this when the full 06z ensemble is out.

That is a good post and outlines and explains the differences well

[Frosty.]

The Gfs 06z is another very acceptable late summer run, it's pretty similar to the 00z with a much warmer and more settled spell developing during next week as the azores/atlantic anticyclone ridges northeastwards across southern britain with temperatures nudging into the low 80's F across the south/se and mid 20's celsius for central areas for a time, nearer high teens to low 20's for northern britain, however, low pressure continues to have the upper hand across more northwestern parts of the uk and occasionally, unsettled and cooler weather does spread southeast to all areas but followed by rapid recovery across the south, whereas the northwest doesn't change much overall but it's not a washout by any means, there would be some warmer and sunnier spells between the rain and showers, but again the further south/se you are, the more summery it looks, temperatures generally around average so that's low 20's c but the 564 dam line does encroach into the south and southeast of england with very warm continental air flirting with the south/se, it could be a whole lot worse, luckily for most of us the PFJ is further north than last summer which means at least the southern half of the uk gets to enjoy some fine and warm spells and not just the southeast corner.

[Bristawl Si]

Reading the analysis from the above posts it seems to me that the easiest way of summing up the next week or so is "More of the same". i.e. not much change from the last week or so. Decent days, not so decent days. Not particularly unsettled but not completely dry all the time either. Temps around normal for August - days where they're slightly above.

Sorry, my simple way of putting it.

Edited August 8, 2013 by Bristle boy

[049balt]

Summer Sun, on 08 Aug 2013 - 07:25, said:

So today's Daily Express is running a front page story that a new heatwave is coming and it could see the hottest temperature of 2013 god knows where there "forecasters" have got this from the best I can find is this

 I know where they got it from. Ken Ring of Predict Weather.

[mushymanrob]

the differences in opinion between the gfs and ecm are also apparent on todays anomaly charts, with the gfs insisting on a warmer outlook with higher pressure to our south as the current op runs show. the ecm and noaa still stick with an atlantic driven zonal theme, however subtle changes suggest the azh becoming closer to the uk, to our southwest, this is a change from northwesterlies previous runs suggested might occur.

 

so it might not be too wet, less/lighter showers, not so much precipitation on frontal boundaries, sunnier and a tad warmer.

 

maybe that isnt so far removed from the gfs's solution, and as ever reality will be somewhere in between...

[Jax]

Reading the analysis from the above posts it seems to me that the easiest way of summing up the next week or so is "More of the same". i.e. not much change from the last week or so. Decent days, not so decent days. Not particularly unsettled but not completely dry all the time either. Temps around normal for August - days where they're slightly above.Sorry, my simple way of putting it.

Looking at the 06 GFS and reading the posts here I think that is a pretty fair summary for the hi-res output, FI edges to similar but slightly cooler.

[Methuselah]

Reading the analysis from the above posts it seems to me that the easiest way of summing up the next week or so is "More of the same". i.e. not much change from the last week or so. Decent days, not so decent days. Not particularly unsettled but not completely dry all the time either. Temps around normal for August - days where they're slightly above.

Sorry, my simple way of putting it.

Well put, BB...

[Captain Shortwave]

Aside from the next 5-10 days. I think for once maybe a casual glance at GFS FI might be quite handy. I watch a few forecasts of youtube from certain amateurs/professionals who do have access to the various longer term forecasts. It's interesting to see that there is quite a strong signal from models like the CFS for a fine and warm end to August starting around the 20th. Also note that the ensemble mean from the GFS also has the Azores high building around this time so I think Events from about the 20th August onwards are worth monitoring if proper summer weather is what you want. Note it is just a signal and might disappear as we approach the time, but there are signs quite similar to July present. 

Edited August 8, 2013 by Captain shortwave

[Captain Shortwave]

The good news is, the UKMO has dropped it's shocker

 

Bad news is 

 

GFS has moved to the ECM solution

Edited August 8, 2013 by Captain shortwave

[Summer Sun]

The further south you are the more settled it looks according to UKMO

 

 

GFS aint too bad so far some rain, some sunshine, some cooler spells but also some warmer ones

Edited August 8, 2013 by Summer Sun

[Milhouse]

The GFS shows alternating cool and warm airmasses with bands of rain/showers likely to spread west to east as it alternates from cool to warm. Temperatures will vary between slightly below average and average/slightly above for the forseeable future.

[Paul_1978]

The GFS shows alternating cool and warm airmasses with bands of rain/showers likely to spread west to east as it alternates from cool to warm. Temperatures will vary between slightly below average and average/slightly above for the forseeable future.

Music to my ears. Much better than wall to wall heat.

[Frosty.]

I think the Gfs 12z has been reading the Daily Express   FI becomes absolutely sensational with record breaking heat, hotter than we saw in July and the beginning of this month, that massive wall of continental heat pushing northwestwards into the uk would be astonishing if it verified, records would go tumbling, yes it's awesome.

 

Anyway, back to the reliable, it's average with sunny spells but some splashes of rain and a scattering of heavy showers but the further southeast you are, the more prolonged the drier and sunnier spells will be with temperatures generally into the low 20's celsius, sometimes pushing towards the mid 20's but mostly around 70-72F, further northwest, more and more unsettled and cooler with rain interspersed with sunshine and showers with stronger winds at times, mainly westerly but occasionally S'ly to SE'ly, and then we have FI....this would be the perfect send off to summer 2013, with another record breaking HEATWAVE.

[mushymanrob]

, and then we have FI....this would be the perfect send off to summer 2013, with another record breaking HEATWAVE.

 

theres nothing id like more.... but...... :lol:

[Frosty.]

theres nothing id like more.... but......

I believe in miracles after what happened in July, that wasn't supposed to happen either, oh yeah and 1st August ...34.1c 93 f

[legritter]

Evening gang well having just had my Appendix removed and other surgery im glad to report that i can now spend some time catching up with the gang at NET Weather ,just looking at charts today and not much happening but going by some posters and listening to chat there is the possibility of some warm or hot conditions further out in outlook .i must admit last week when in hospital we had snow all night ,but this turned to rain as the  MORPHINE and other drugs wore off ,did miss the gang ,please keep the charts coming and all that regular posting from the more technical ,regards and  .

[Captain Shortwave]

theres nothing id like more.... but......

Ah but from small acorns like this mean chart

 

Big displaced Azores highs grow 

[Tamara]

The good news is, the UKMO has dropped it's shocker

 

Bad news is 

 

GFS has moved to the ECM solution

I think that taking all that into account, the half way house is indeed becoming the way ahead. However, good hints of some more widespread summer like weather to come further down the line

[mushymanrob]

I believe in miracles after what happened in July, that wasn't supposed to happen either, oh yeah and 1st August ...34.1c 93 f

tbh frosty, it wouldnt surprise me if we did get a late heatwave, even in september. theres been alot of extreme records being broken, its perhaps overdue for something hot late on....and im talking a decent spell, not the odd few days.

totally unscientific of course, just a hunch that something might happen late aug or sept.

there, thats me with a glass half full, take note itll be a long time before i get positive again! back to grumpiness! :lol: