[Model Output Discussion - Mid Summer Onwards]

ECM ensemble this morning has mean 1025mb high to our NE by 19th August, which could be a sign of some sort of block emerging ... I usually consider a mean 1030mb to be "banked", but this is as close as we've got since June:

 

[Model Output Discussion - Mid Summer Onwards]

NOAA 8-14 tonight looks like a plume or bust chart - more than a sniff of a trough trying to snake down towards the Iberian west coast, minor positive anomalies over the UK, but at this stage inconclusively positive IMO:

And I'd take this ECM mean at D12 absolutely any time in the summer months, it would certainly fit the NOAA chart - now that's a recipe for hot weather, trough west, high pressure east:

 

[Model Output Discussion - Mid Summer Onwards]

1 hour ago, Uncertainty said:

12/12 reds on the eps suggests to me that a fair bit of dry, usable weather could be on offer after the weekend trough clears.

 

I note clusters 2 and 3 look primed for a plume by August 23rd. The individual members have some interesting permutations on that date (see the reds at the bottom of the pic):

 

[Model Output Discussion - Mid Summer Onwards]

1 hour ago, Snowy L said:

ECM keeps the 1015hpa line in England, central and Southern England should at least see sunny spells and the occasional shower with average temps after Friday. Not perfect but beggars can't be choosers after July.

And I note the removal of warmth was delayed slightly on some models tonight, and so a chance Friday will turn out to be the warmest day of the week - ECM with a raw max in Norfolk of 27C tonight so a possibility we might see 28C/29C after all. If the ECM is right, of course, which it may not be 

[Model Output Discussion - Mid Summer Onwards]

55 minutes ago, Addicks Fan 1981 said:

Think that we can add 2 or 3 degrees onto the suggested temperatures for the ECMWF @Man With Beard, not sure if its a downgrade to be honest.  More like its falling into line with what the ensemble mean suggested this week just gone.   

The ECM op regularly projected 27/28/29C for next Thursday/Friday as a 'raw' maximum up until 48 hours ago ... now 24/25C ... it's definitely a downgrade on that model.

[Model Output Discussion - Mid Summer Onwards]

26 minutes ago, Don said:

July?! 

Oops! I will correct if I can  

[Model Output Discussion - Mid Summer Onwards]

Quite a considerable downgrade on this week's heat has happened over the past 48 hours - at one point, a figure close to 30C looked quite possible, but tonight's ECM suggests 24/25C might be the top figure on Wednesday/Thursday, which is only slightly above average in the SE - maybe a 26C with a bit of luck. Pretty tough for heat seekers and ice-cream vendors after seeing 5 weeks of the peak of summer vanish already.

Do I back the optimistic or pessimistic view for the rest of August? Well the NOAA is miles better now than it had been at any stage in July - perhaps a few short incursions of continental air could reach us at times - the ECM ensembles certainly suggest this could happen:

But I've seen over the years the models can be over-optimistic in August, and the ECM does seem on a trend of underestimating the Atlantic in the D6-D15 period. I guess we'll have to wait and see.

[Model Output Discussion - Mid Summer Onwards]

Looks like a euro ridge might set up for the middle August according to some of the ECM clusters tonight - if it does, that would typically mean better weather south and east, though not necessarily settled, less settled further north/west.

The mean at D12 backs this up:

 

[Model Output Discussion - Mid Summer Onwards]

ECM ensembles settling down now. A brief but potent heating up for 3 days between 9th and 11th August. Not inconceivable that it will remain above average afterwards for temps, but very unlikely to be as warm/hot from 12th August onwards.

[Model Output Discussion - Mid Summer Onwards]

2 hours ago, MattStoke said:

GFS prolonging the warmth but GEM and UKMO cutting it short albeit remaining warmer than of late.

Similar on ECM 00Z - the warmth certainly coming but all a little too quick to establish really hot temperatures on this run (high 20Cs at best rather than low 30Cs), and clearing out by Saturday.

[Model Output Discussion - Mid Summer Onwards]

GFS 12Z tonight a good example of how the hotter weather could stretch several days - the trough to the west lifts north slightly and fails to completely push the heat out - 7 days with the 12C uppers line over some part the UK (and the run is still going on at the time of writing). 

[Model Output Discussion - Mid Summer Onwards]

52 minutes ago, Alderc 2.0 said:

But that’s what the model shows does not? A brief one, or two day spell, given momentum of the low pressure would be a minor miracle to the warmth to hang around any longer. 

Agreed, but the shape of developments doesn't preclude a potential extension of the warmth, I think.

[Model Output Discussion - Mid Summer Onwards]

ECM ensemble support for the warm up, at least temporarily, now very high. Looks nationwide:

Personally, 16C mean uppers are consistent with 30C being reached or exceeded in the south, either on the day shown or the day after.

[Model Output Discussion - Mid Summer Onwards]

30 out of 51 ensembles have 16C uppers or more on the latest ECM - 6 members reach 20C

[Model Output Discussion - Mid Summer Onwards]

ECM ensembles for London show where the likely warm up will occur, around 10th August, but also show it may not last long, as the greens return within a few days on many members.

[Model Output Discussion - Mid Summer Onwards]

Big improvement in temperatures on ECM extended ensembles, chance of 30C by the weekend after this one starting to come into play ... 

[Model Output Discussion - Mid Summer Onwards]

I'm finding this new facility on METEOCIEL which tabulates the ECM ensembles really helpful for spotting likely periods of rainfall or dry periods. Likely wet periods are characterised by clusterings of brighter colours at a particular timeslot - likely dry periods are characterised by white strips across the page. Useful for planning how to dodge the rain!

These are for London for the next 15 days - red arrows highlight rainy periods (although there were other potential periods too!), green arrows for dry periods (blink and you'll miss them!)

[Model Output Discussion - Mid Summer Onwards]

15 minutes ago, ANYWEATHER said:

Bullseye

And so the autumnal theme continues.

We've become accustomed to 35C in the height of summer recently, but the window for such heat usually closes by mid August, so we're nearly at the point where that possibility is over, as the current charts put heatwave potential at less than 10% chance (IMO) by 12th August. After that, the chance of any high-summer heatwave receeds quickly with time, so probably only 2/3 weeks remaining for a full turnaround. September usually has good spells, no doubt it will again this year, but 30C in early September always feels a push.

[Model Output Discussion - Mid Summer Onwards]

Today's ECM ensembles are another hammer blow. They are back to the very worst for the first 8/9 days of August, having shown promise for the first weekend of August in recent days.

I can only conclude the ensembles are not seeing something beyond the D10 point at the moment, because hints of positivity D11-D15 are routinely being swept back to Groundhog day within a few runs.

Flattens out slightly D12-D15, which I can't believe I am suggesting as a welcome improvement, but this has been happening so many times I can only take it with a pinch of salt.

I think until I see a 1025mb high over the UK in the D15 period, I'm going to struggle believe this is coming to an end, now. And, right now, even getting to 1020mb seems many moons away.

Such great summers in the last 10 years - our luck has finally run out.

[Model Output Discussion - Mid Summer Onwards]

The ECM ensembles unfortunately are getting into a cycle of not picking developments from the Atlantic in the D11-D15 period, and as a result promising situations in FI are consistently getting downgraded. Three days ago, 75% of runs had a significant warm-up (uppers above 12C) between the 31st July and 5th August. Now, it's all gone:

Regarding the perception of the quality of weather - well yes, here on the south coast we have had plenty of half-decent days this month - but in recent years you wouldn't expect more than 1 or at most 2 washout days in our region during July, and this year we're probably up to 7? It's all relative of course, but we'd come to expect long dry and hot periods here, so the month well below usual expectations. It was all top-loaded into May/June which were utterly sensational summer months here, far enough from the easterly breeze to be hot for most of the period.

[Model Output Discussion - Mid Summer Onwards]

Oh my golly giddums. The ECM clusters D11-D15 are very volatile right now.

The first is the 00Z, the second is the 12Z:

So much less settled on the 12Z set.

Can't possibly base a prediction on those.

 

[Model Output Discussion - Mid Summer Onwards]

25 minutes ago, danm said:

 

These are so much better than they used to be. Even just a few years ago, the analysis beyond a couple of days was vague and sometimes felt behind the curve in terms of model developments. Now, they are a shining example of model output discussion - worthy of the country's official and leading meteorological organisation. And, it's always comforting to see them fleshing out in detail the discussions we have already been having in this forum, as an added confirmation that we are broadly reading the charts correctly.

[Model Output Discussion - Mid Summer Onwards]

The ECM clusters for the weekend 5/6 August are perhaps the best for sometime - not heatwave quality on most, but useable for dry/sunny/warm weather at times - hopefully! 

However, the more settled conditions do not last long on most clusters, and by D15 we're back to something more changeable.

Of course, things very much subject to change at that timescale, and the ECM ensembles have been a little wobbly recently beyond D8, but encouraging to see so many clusters at D11 with positive anomalies near or over our shores.

 

[Model Output Discussion - Mid Summer Onwards]

The ECM ensembles are trying tonight - they're trying to get positive anomalies over the UK, and they're very much trying our patience!

Statistically, they now have Ireland, Wales and the South West in positive anomaly territory. Baby steps again, surely it can't be long before the green shoots of recovery start to grow.

[Model Output Discussion - Mid Summer Onwards]

10 minutes ago, CoventryWeather said:

Anyone got the link to the ECM clusters charts? Would be interesting to see whether they follow what the anomalies are showing above. 

I think, considering the outlook the past few days, that the last week of July isn't looking as bad as what it was. Subtle hints of a pressure rise in early August, but have a feeling it will be pushed backwards until atleast week two. 

Going Bournemouth end of August/early September, so kind of wanting the warmer weather towards then! 

ECMWF | Charts

CHARTS.ECMWF.INT

nothing particularly settled in any of the clusters until beyond 8 August now