Met Office Hadley          13.9c.        Anomaly         -0.6c. Provisional to 10th.

Metcheck                       13.64c       Anomaly         -0.8c

Netweather                    14.07c       Anomaly         0.38c

Peasedown St John         14.19c       Anomaly         -0.53c.       

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Met Office Hadley            14.1c.        Anomaly       -0.4c. Provisional to 11th.

Metcheck                         13.83c       Anomaly       0.11c

Netweather                      14.3c        Anomaly        0.61c.

Peasedown St john       14.25c      Anomaly        0.27c.     

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Your wise wariness shows with the latest model trends... albeit with GFS and ECM finding cooler outcomes via very different paths; the former suddenly much more progressive and then flatter with the pattern, such that the really warm air barely gets a look-in before getting blasted aside, while the latter is opting for more of a UK-based high bringing the possibility of chilly nights leading to inversions and perhaps fog troubles.

I'm actually a little surprised to see this much wavering all of a sudden, despite how far away the big Euro ridge formation is in time. There's just so much working toward increasing the atmospheric angular momentum during the coming week or so. When AAM rises strongly, the subtropical high tends to get booted out of the Azores to take up residence across Western or Central Europe for at least a week. There also tends to be a broad trough digging well south in the North Atlantic, with a weaker jet stream than usual by the UK and Europe.

I suppose ECM's UK-based high is a reasonably realistic variation on the theme, but the mobile GFS solution really doesn't fit with the rising AAM, but might just about be feasible if more than one tropical cyclone in the Atlantic basin behaves in such a way as to 'turbocharge' the polar jet via a regional large increase in the temperature gradient. I don't think a single one would really produce enough of an impact to fully override the response to a big climb in AAM.

 

Hmm, why on Earth am I delving so far into this? 

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Met Office Hadley         14.3c          Anomaly        -0.1c.  Provisional to 12th.

Metcheck                      14.02c        Anomaly        0.30c

Netweather                   14.55c        Anomaly        0.08c

Peasedown St John  14.64c       Anomaly      -0.08c.

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Still not too shabby!  We’ve had two or three mild nights which I think have held up the daily mean temps.  A few warmer days to come now but I still think it’s all eyes on overnight minimum temps.  

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I think for those of us in the '15 Club' for September it's still going pretty well. But you are right, it's all going to be down to the cooler nights. A lot of the forecasts I am seeing emphasise cool/chilly nights, even local ground frost and turning cooler overall at least for a time after Sunday so the CET may not rise quite as much as we might like. If I could make my prediction again I would downgrade it a little to around 14.9C but overall I'm still happy. Onwards and upwards!

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Hmmm!  As suspected!  Single figures overnight, which is not good!  If that’s indicative of the three CET stations, we’d need a daytime max of mid twenties for the mean to benefit us ‘fifteeners’.  Some cloudy nights needed!

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Met Office Hadley         14.2c        Anomaly     -0.1c Provisional to 13th.

Metcheck                      13.90c      Anomaly    0.18c

Netweather                   14.56c      Anomaly    0.87c

Peasedown St John    14.8c    Anomaly     0.8c.    

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Now still 14.2°C to yesterday, 0.1C below the LTM

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Met Office  Hadley as already posted       14.2c.    Anomaly      -0.1c. provisional to 14th.

Metcheck              14.03c      Anomaly      0.31c

Netweather           14.52       Anomaly      0.83c

Peasedown St John  14.46c   Anomaly      0.26c.         

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Warmth is generally less prevalent in the modelling now compared to a few days ago.

The nights into each of Tue, Wed & Thu look to widely drop down into the 6-8*C range, but the days may climb widely into the 20s to compensate. It depends which model you look at; GFS is wrapping in considerably more cool air from the NE than ECM & UKMO, resulting in daytime max temps generally 1-3*C lower.

ECM continues to advertise a decent blast of warmth Fri-Sat followed by a 'gentle simmer' for Sun-Mon as the Atlantic lows struggle to make inroads. UKMO's going for a similar peak of warmth but shorter-lived with a very progressive Atlantic trough, while GFS is actually less progressive, but doesn't get as much warmth in to begin with.

So, not the clearest of pictures there...!

The following week shows signs of a more 'standard' westerly regime, temps perhaps doing alright overall, though this is assuming that GFS diving troughs down through the UK from the northwest is a consequence of its inability to capture rising-AAM periods beyond about a week's range (due to a systematic low-AAM bias).

 

Overall, I sense a mid-14s finish to the CET has started to become favoured, unless the final week of the month proves to be a warm one (no clear signals on that yet).

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Yes SC, my gut feeling is for a mid 14 finish now, with the night time minima being the deciding factor.  I expect a small rise today following a mild night but I think ending at 15c is a big ask now, given the current output. 

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12.0C (-0.4C) here at half way

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I feel that this one is starting to slip away now. There are simply not enough very warm days on offer to offset the chilly nights. Besides The Express is predicting a 2 week heatwave so that's the end of that!

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Met Office Hadley         14.3c        Anomaly       0.1c. Provisional to 15th.

Metcheck                      14.6c        Anomaly       0.44c

Netweather                   14.6c        Anomaly       0.91c

Peasedown St John     14.54c      Anomaly      0.6c.

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Met Office Hadley        14.3c        Anomaly      0.1c. Provisional to 16th.

Metcheck                     14.04c      Anomaly      0.32c

Netweather                  14.63c      Anomaly      0.9o4c

Peasedown St john        14.8c       Anomaly      0.6c.  

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The recent cold nights and coolish days have had a marked effect, with mean this morning on 11.6C here (-0.5C)

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14.2°C to 17th- that's lower than I was hoping for at this stage, with the 2-day warm spell gone.

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Me too!  Daytime temps just haven’t been enough to make up the  lows at night.  With minima around 5c we’d need to get into mid 20’s during the day, a really big ask!  What we need is cloud at night. 

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An attempt at solving a few simultaneous equations gives me:

Final CET > 14.62 - Col increases his lead with GezM up to 2nd
14.20 < Final CET < 14.63 - Col retains his lead but it decreases, GezM up to 2nd
14.10 < Final CET < 14.21 - Col retains his lead but it decreases to just 0.01c to GezM in 2nd
Final CET = 14.10 - Col and MartinG joint leaders, with GezM 0.01c behind in 3rd
13.87 < Final CET < 14.10 - MartinG takes the lead from Col in 2nd, GezM 0.01c behind Col in 3rd
13.72 < Final CET < 13.88 - MartinG takes the lead from me in 2nd, Col 3rd, GezM 4th
Final CET < 13.73 - I take the lead from MartinG in 2nd, Col 3rd, GezM 4th

I can't 100% vouch for the accuracy of the above but I don't think it's far off. In short, come on you chilly nights!

Cheers for working that lot out!

I had looked at this and realised that something around 14.6 would enable me to preserve my lead. That is right up at the top end of my expectations now though. I really need the upcoming few warm days to make a big difference, if it doesn't then I expect a big chunk will be taken out of my lead come month end.

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Your high September prediction really has offered a lifeline to the chasing pack. HP centred over the UK allowing for cold surface nights rather than humid SSW'lies with the high to our east appear to have scuppered a really warm month. Any peaks in temperature in an attempt to raise the average really are struggling against the background declining seasonal tide now.

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Met Office Hadley        14.1c        Anomaly        -0.0c. Provisional to 18th.

Metcheck                     13.85c      Anomaly        0.12c

Netweather                  14.41c       Anomaly       0.72c

PSJ                              14.6c        Anomaly       -0.16c.   

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 As we enter the final quarter of the year, predicting close to the actual always gets more tricky, just as it was in the first quarter of the year.  Cumulative errors tend to be a lot lower in the 6 months April-September, than the 6 months either side.  For me, its now about whether my 5.99 all time low  cumulative error in 2016 will be beaten.  Again this year, as last, there is a fair chance.  I am way off the pace this year, in large part due to February.  But that is what makes the competition so engrossing.  Given the volatility that is possible in the CET, particularly in November and December, its going to be an interesting few months in this great competition.

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The margin for error is most certainly greater in winter than it is in summer. I worked this out once, the difference between the absolute highest & lowest CET vakues is July is around 6C but in January more like 10C. An interesting few months indeed, my only regret is that I have been posting here since Jan 2013 yet this is the first year I have entered the CET competition!

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