Think it'll stabilize and then maybe tick up early this week before more cold nights on Wed and Thu night bring it lower again.

Anything from mid-September completely up for grabs so where we finish up is anyone's guess but it's certainly not looking like an excessively hot month at the moment.

After that very hot run from April to July things seem much more "typical" again for now.

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Met Office Hadley         14.9c.   Anomaly     0.3c.  Provisional to 8th.

Metcheck                      14.75c   Anomaly     1.03c

Netweather                   15.35c   Anomaly     1.66c

Mansfield Woodhouse     15.6c    Anomaly      1.82c

Peasedown St John        15.62c   Anomaly     0.65c.

 

Mean of 10 stations     15.41c.   

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This has certainly been quite a collapse in the CET which we have been seeing recently, to the point where we can more or less say now that the provisional average CET is now running close to average, even going by the old 1961-1990 30 year average (which is what the Hadley figures go by for the anomaly).

Not too long ago, Gavin P. in his September 2018 forecast had gone for this month to be warmer than average. With the way that things are going just now though, the chances of a colder than average CET for this month have to be getting better all the time (which would then, bust Gavin P.'s forecast for yet another warmer than average month for the CET region at least), especially after the usual downwards corrections are applied at the end of the month.

It would therefore be interesting to see what the odds are, of that actually happening.

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Point of order M'lud    I wasn't the only forecaster to go for a warmer than average September - In fact at the start of the month pretty much nobody "saw" a colder than average month coming - For example:

https://www.netweather.tv/weather-forecasts/uk/long-range/monthly

https://www.theweatheroutlook.com/twoother/twocontent.aspx?type=hpnews&id=4493&title=September+prospects

But yes it does look as though my September forecast, along with everyone else's, could be in a bit of trouble!

Edit: And at least I did say September wouldn't be anywhere as "straightforward" in terms of being warm and dry as the CFS and BCC were showing - This is the forecast here for anyone who wants to have a butchers; 

https://www.gavsweathervids.com/month-ahead-forecast-2018.php

 

 

 

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Well, I’m not holding my breath yet!  We all know how quickly things can change and change again, where the weather’s concerned.  Looking further than a week ahead is futile, so we still have an uncertain second half of September!

I’m thinking my 15c guess is too high but I don’t think by a lot!  Wishful thinking again!  

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You sound surprised, and yet actually there was a lot of uncertainty expressed from the end of August; that's why I went for a CET in the 14s. In fact, I believe Gav & I had a little chat about being overdue a more average September. I'm still not convinced there will be a colder than average September.

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I think there was enough evidence at the end of August to suggest that a cooler than average month was possible. There were plenty of occasional runs dropping a trough into Scandinavia bringing NW'ly flows at times. Things can and will flip at times. It all makes for an interesting competition.

I'm looking forward to seeing what everyone has predicted. 

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Sorry I was very busy last week and am now on holiday. So won’t be able to post the list of predictions for at least another week.

That makes it even more exciting. We wait with happy anticipation GW!

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Longer-range guidance is suffering yet again now, as the atmosphere has missed another opportunity to establish an El Nino-like environment which has long been anticipated to arrive late summer/early autumn (originally last third August!) and bring about a downstream sequence of events that takes the UK weather back toward a warmer variety.

Not only is the long-range guidance proving too keen time and time again to get the change underway, but the analysis tools appear to be awry as well, with CFSv2 raw data suggesting that the Nino-like atmosphere is evolving as I type this, but genuine observation-based analysis showing the opposite; a very weak La Nina-like setup.

The modelling trends of late have been away from the CFSv2 take and toward the observational data implications, as the models have caught on to the fact that the Nino forcing remains AWOL.

It's a real shame, as we had a genuine prospect of unseasonable warmth dominating a large swathe of this month. I almost went very warm again but reigned my estimate in a great deal after what happened last month... and I'm very glad I did! I still went a bit above average though and even that will be under threat unless either the atmosphere takes the next opportunity for a Nino transition, occurring about three weeks in, and we see a warm final week by way of response or a tropical cyclone shakes things up in just the right way to send a lot of warmth across us.

 

The usual expectation when a tropical signal fails to do as expected is that there is a delay due to a complication - but on this occasion, there's now been so many delays that I begin to wonder whether the El Nino state will ever truly emerge. Given how useful a weak manifestation of it would be for exciting winter prospects, I hope I won't still be wondering this in a couple of months time! 

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Have a good holiday GW!  

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Met Office Hadley       15.1c         Anomaly      0.5c.    Provisional to 9th.

Metcheck                    14.80        Anomaly      1.08c.

Netweather                 15.48c      Anomaly      0.36c.

Alton                           14.9c.       Anomaly      O.36c.

Clevedon Weather       17.0c.      Anomaly       0.88c.

Hexam                       14.0c       Anomaly        0.84c

Mansfield Woodhouse      15.5c     Anomaly       1.72c

Peasedown St John        15.71c    Anomaly       0.74c

Treviskey Redruth        15.9c      Anomaly       1.16c.

 

Mean of My Watched   10 Stations   15.39c.  

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Okay - so some suggestions of a warmer or even much warmer flow regime coming together by this weekend or early next week and lasting for 4-8 days. Maybe a little longer.

A slight rise in AAM with the GWO into phase 3 looks to be working together with tropical-extratropical TC movements amplifying the Euro ridging response. There is some scope for exceptionally warm conditions as per the ECM 00z but at this stage that's the wildcard; it depends on the TCs moving in the right ways.

Taking the 00z ECM, it's slower to warm up but then brings a run of three days with mid-teens CET minimums and low-mid 20s CET maximums. As a result my CET estimate jumps up from a mediocre 14.5*C as of 17th to a healthier 15.2*C as of 20th.

Bolting on the GFS 00z numbers, it holds steady for a couple of days, then falls away very gradually overall but with a few jolts as a result of chilly nights - which having failed to achieve as warm a first half to the month as the signs once strongly indicated, will be the main enemy of those who've predicted a warm month. 

 

There's a chance that the AAM rise will actually prove to be the harbinger of the long-awaited transition to Nino-like, in which case the door opens to a more prolonged unusually warm period and final September CETs in the 15s, but the signs are tenuous at this time.

To be honest, even 11 days into the month, I still see anything from low 14s to high 15s as plausible for the final figure .

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Have a feeling we'll spike the temperature early next week in response to Helene (course the danger with these patterns is the low pressure ends up being pushed east which means we get the wind and rain and the hot/tropical air plumes north through central Europe) but it'll be relatively short-lived then back to westerlies by mid-week.

Every little helps to keep us on the warmer side of average by months end though! 

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Met Office Hadley         15.1c.       Anomaly      0.6c.  Provisional to 10th.

Metcheck                      14.96c      Anomaly      1.24c

Netweather                   15.5c        Anomaly      1.81c

Canvey Island               16.7c        Anomaly      0.0c

Clevedon Weather         17.1c        Anomaly      0.98c

Mansfield Woodhouse 15.8c      Anomaly   1.08c

Peasedown St John   15.71c     Anomaly    0.76c.

 

Of my watched 10 stations 4 remain the same as yesterday  whilst 6 are up slightly.

Mean of my 10 stations   15.57c.            

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It’s still holding steady!  

We’ve had some really mild nights here, if not particularly warm days but I think it will be the night temps that will affect the CET most this month.  

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Well for what it's worth, the 12z runs have seen GFS and ECM crank up the heat a notch further.

GFS takes the CET estimate from 14.5*C as of 15th to 15.0*C as of 20th. Further bouts of warmth in lower-res take it all the way up to 15.5*C as of 27th.

ECM takes the estimate from 14.6*C as of 16th to 15.1*C as of 21st.

 

Interesting to see further amplification being added to the pattern for the middle of next week onward. Question is then whether we stay on the warm side of the trough-ridge duo.

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Met Office Hadley           15.2c.        Anomaly       0.7c. Provisional to 11th.

Metcheck                        14.91c       Anomaly       1.18c. 

Netweather                     15.63c       Anomaly       1.94c

Cheadle Hulme                15.0c         Anomaly       0.96c

Hexam                            13.9c        Anomaly        0.74c

Mansfield Woodhouse  15.4c       Anomaly    1.74c

Peasedown St John   15.73c   Anomaly  0.76c.

 

2 stations same as yesterday.  2 are up.  6 are  down

Mean of my 10 watched stations   15.44c.                                

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Met Office Hadley     15.0c.   Anomaly   0.6c.  Provisional to 12th.

Metcheck                  14.65c   Anomaly   0.93c

Netweather               15.42c   Anomaly   1.73c

Clevedon Weather      16.6c    Anomaly   0.48c

Hexam                      14.0c    Anomaly   0.84c

Mansfield Woodhouse  15.4c    Anomaly   1.62c

Peasedown St John   15.34c  Anomaly   0.34c

1 station up on yesterday  9 down.

Mean of 10 stations 15.19c.           

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Looks like we're shaping up for a very warm second half to September? 15C+ CET September looks likely to me now (although under high pressure in September you never know if your going to get cool nights)

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Met Office Hadley      14.8c.    Anomaly    0.5c  provisional to 13th.

Metcheck                   14.57c   Anomaly    0.85c

Netweather                15.21c   Anomaly    1.52c

Hexam                       13.9c    Anomaly     0.74c

Mansfield Woodhouse 15.3c  Anomaly  1.52c

peasedown St John    15.31c  Anomaly  0.34c

Treviskey Redruth   15.2c  Anomaly  0.46c

 

9 Stations down on yesterday i remains the same.

Mean Of My 10 Stations 15.07c

 

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It is indeed tricky with high pressure across the UK in the second half of the month. The GFS 06z for example has some notable warmth for a while but late on there is some evidence of cooler nights leading to inversion formation and in turn fog, which really holds the day temps down in a few places. An estimate from the run sees the CET rise from a low point of 14.6*C as of 15th to the low 15s by 19th (thanks to ex-Helene's influence - a very warm night or two for the time of year and some warmth by day too*) and then climb further to a peak near 15.3*C to 26th, before falling to finish at around 15*C.

The 00z was quite similar in the broad sense, but the cool-warm boundary was 100-300 miles further south for days 12-16 and this made for a final CET estimate several tenths lower despite days 9-11 having been warmer than the 06z.

 

Just how much ex-Helene kicks the CET up remains under question as the timing and path have varied by as much as 24 hours and 400 miles during the past four sets of runs. * This has brought about modelled minimums ranging from widely mid-teens to widely high-teens, and maximums ranging from widely low-20s to widely high-20s (now that would be something to remember!).

Then, for most or all of the remainder of the month, a strong cool-warm boundary looks to be across the UK in some form or other, as is usual for the time of year, but with ridging dominant the potential variations in temperature are larger than when troughs are dominant; anything between chilly nights + cool days and mild nights + very warm days is possible, as opposed to the much narrower range of cool nights + cool days to mild nights + very mild days.

 

...good luck everyone .

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Thanks for the analysis Stormchaser! 

I'm still hoping we can string together a few cold nights somewhere and get a 14C+ finish as we've not had one for 9 years! 

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Im far from confident of the specific eventuality, but something in the 14's looks probable as a finish.  So 14.5 would be a nice place to be.  Im not there sadly.

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Sounds perfect with my guess of 14.45C  

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