Nailed on 

Jetstream resumes S of the UK Tue 18th but folds up into a S-ward dipping loop from Wed 26th which breaks up by Mon 31st.

GFS - LP works in from the W this week, shallow at first but much deeper Thu 20th, from 980 mb off SW Ireland then to Scotland filling by Tue 25th. Mid- Atlantic ridge of Hp then drifts across from the W but giving way to LP moving into the SW from Spain by Sat 29th.

GEFS - In the S small heat blip Fri 21st otherwise mean temp is close to or below (esp Mon 24th) seasonal norm< Rain around from time to time, Scotland temps similar (but no blip) but rain more concentrated with peaks 19th/21st/ 27th

ECM - a deeper LP on Fri 21st and the ridge of HP generates more of a N-ly flow as it approaches

Getting one of those of model periods where the ops are consistently very different (in this case cooler) than the other ensemble members on both ECM and GFS (and GEM).

In all 3 cases the ensemble mean gives us a mini heatwave next weekend - ECM 12C 850s, GFS and GEM both 14 with some members up closer to 20, but the ops peak at 10, 12 and 12 respectively and only fir a few hours, associated with a load of rain.

Typical of this time of year when tropical storms are getting into the Atlantic - the models always have problems with these.

I'd missed that http://www.wxmaps.org/pix/temp4 is now doing a 16-day forecast even though it still calls itself a 10-dayer; however, it's showing a big cool-down for Europe N of the Alps (that's us as well) for the last week of August. Rain in the west to start with, then a large amount moving SE across France in that last week and catching the S Coast.

Take a quick look at the snow and ice chart https://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow_asiaeurope.gif both the NW and NE Arctic passages well clear of ice.

Current computer models:

GFS - LP moving in from Atlantic Thu 20th (though briefly bringing up some warmth as it approaches, the mini heat wave referred to elsewhere) and after visiting the NW coast eventually end up in Norway Mon 24th; spell of westerlies resolving into deep LP Fri 28th 985 mb Hebrides which leaves a legacy LP moving S 990 mb Brittany Mon 31st. Between them these last two Lp drag in a lot of cool N-ly air.

GEFS - Mini heat wave for S Thu 20th otherwise most runs agree on a decline into a cool spell through to Fri 28th after which much disagreement between runs. Rain peaks Mon 17th and Fri 21st and then more generally from Mon 24th. Fo Scotland and N England the mini-heat wave is only just detectable though the rest of the temp profile is similar, and rain occurs fairly frequently throughout.

ECM synoptics follow GFS at least to Tue 25th (the chart for 26th is still yesterday's 12z at time of posting)

FAX keeps pressure generally low throughout and the LP on Thu 20th is deeper (969mb) and hints at heading more to our SW.

Looking very bleak for the rest of August here.

Central Europe looks to be keeping the Warmth in the North too, probably more High pressure to that area.

Tomas Sch... you-know-who has just mentioned on the BBC that the remains of tropical storm Kyle will be mixed with the LP arriving on Wednesday adding some initial warmth and later more persistently disturbed weather.

And after that the jet stream is diving down south of the UK. That could be it for the extreme heat this summer - here's hoping anyway.

It's just the op GFS run - and those "temp4" charts have been run out to 16 days since at least 2008. (I have some from 2004 and earlier which were only 10-days, but they changed at some point in th einterim).

The thing that strikes me with those charts is just how hard it is to get blues over the UK during summer. I guess it's not too much of a surprise as we all know things are warmer than they were, especially compared to the 1901-2000 base period that those charts inexplicably use!

GFS - LP moving in from the Atlantic and deepening withthe aid of remnants of tropical storm Kyle 985mb off W Coast of Ireland Fri 21st, moving to Norway Sun 23rd, some warm air being drawn up in front and in advance of it, cooler and following it. Next Atlantic LP over UK Wed 26th. Brief ridge of HP Sat 29th collapsing to W-lies backing NW-ly Wed 2 Sep. Final chart looks quite autumnal with procession of large depressions Newfoundland - Iceland- Russia.

GEFS Warm briefly in S Thu 20th then cool Mon 24th then seasonal norm but lots of scatter towards end of run; rain quite frequent, some agreement on 20th and 25th for best chance of significant amounts. Much the same in the N & Scotland but warmth on 20th suppressed and more rain either side of the dates above

ECM similar to GFS, LP on 26th not as deep

I spotted that too. Some significant warm runs in the Ensembles. Some of those would get temperatures easily back into the thirties again. A new trend or just white noise? Worth keeping track of for sure.

Might be a good hot start to September too after a bad August had pass by. Sept date line now appearing on ensembles.

September in recent years has basically been a continuation of summer warmth anyway for the most part.

September is very often the loveliest summer month.

Interestingly, this weekend doesn’t look half bad down here either.

Certainly a far cry from some of the more extreme predictions.

Jetstream running across or close to S England with occasional loops in the stream until Fri 28th when a bigger loop changes its direction to SW-ly and it then breaks up before resuming in strength with a tight loop enclosing the UK.

GFS - deep LP off Ireland Thu 20th moving to N Norway by Tue 25th with a legacy of N/NE winds persisting through the week,  ridge of HP over the weekend of 29th before new LP from Atlantic moves in, becoming quite deep on the Channel Thu 3rd

GEFS generally temps above norm Thu 20th, below Sun 23rd, both by a small amount; mean of runs then stays on norm but with even more divergence between run than yesterday, quite often a difference of 17C between top and bottom forecasts. Rain around in next couple of days, briefly dry then in the S irregular amounts from time to time and also in the N but more frequent. 

ECM LP on 20th/21st deeper and closer than GFS, but more W-ly than N-ly to follow with shallow LPs in these W-lies

Is this low the remnants of TS Kyle?

Yes to some extent; Kyle has given it a big injection of heat and humidity which has meant that things are going to be wet (tomorrow Wed) and with strong winds (Thu/Fri). But it started out as an ordinary depression.

I think the period 2007 to 2012 was the longest autumn ever (punctuated, admittedly, by some fine wintry spells in 2009 and 2010)

Was a dry warm month here.. yet another poor start to the mushroom season. The last few day's of the month were very wet & cool though.

Had some cool nights early in the month, down to 4.1c on the 8th, but dry and mild to warm in general. We were down in Devon until the 21st which was warm all week culminating in 25c, the next day the ark descended for the 6 months of autumn.

Back OT, sneaky High pressure showing on the ECM in FI for the 28th. Looks strong enough with a good directional flow to indicate a nice BH weekend.

GFS Op and GEFS having none of it however, but happy with the Op as it seems whenever it goes out on a limb in terms of low 850s/2m or Pressure in FI (the latter being the case now), the opposite happens so looking good...

Arpege 12z continuing to show the risk of damaging winds during the next few days in parts of the UK. https://t.co/meE4sDv0IO pic.twitter.com/YeUsm9ehjW

— TheWeatherOutlook (@TWOweather) August 18, 2020