As usual all CET predictions to be sent to me via PM please

Deadline is 2359 on Tuesday evening (2 October).

A very average September overall but within that there was some quite warm and cold weather which largely cancelled each other out over the course of the whole month.

Historic CET summary for October

1971-2000 10.4C (30 years)

1981-2010 10.7C (30 years)

1998-2017 11.2C (last 20 years)

We have had some very warm Octobers in recent years, 12.4C in 2017 and 12.5C in both 2013 and 2014 and 12.6C in 2011. The only years recently that were significantly below average were 2008 and 2012 with 9.7C.

Here is a chart of the October CET for all years since 1961:

Direct link to larger version of the chart

Current model output

GFS (00z) - potentially warmer in week 2 after something of a cool start  

http://www.wetterzentrale.de/de/show_diagrams.php?model=gfs&var=2&geoid=49069&lid=ENS&bw=

Multi Op - generally good agreement between the runs. A brief big dip on 1st October and again on the 7th but otherwise looking a little above average.

http://www.wetterzentrale.de/de/show_diagrams.php?model=multi&var=2&geoid=49069&lid=OP&bw=

Met Office contingency planners outlook 

Not yet available

Temperature analogues

See my separate analysis of October temperatures where we have a cool end to September. This shows that October can be very cold but when we have had a warm summer then actually October tends to be close to average.

If we consider years with average temperatures in August and September there is no real trend. We have not really had many years since 1950 where an average August and September has followed a period of very warm weather. The one good match is 2009 where March to June was very warm (as compared to April to July this year). Of course 2009 was followed by a very cold winter, albeit October and November were mild. 

Going further back it is very difficult to find any other good matches. The first one I come to is 1798. In that year the August CET was 16.4C and September 13.6C so very similar to this year. July was close to average at 16.3C but April to June was very mild with 10.4C, 12.9C and 16.9C respectively. So again very similar to this year. March was 5.1C which is also similar to this year. Only July was significantly different.

October 1798 had a CET of 9.9C but then things turned very cold with 4.7C in November, 1.5C in December, 1.7C in January 1799, 2.8C in February and 5.1C in March. Warmth only returned in April when the CET exceeded 10C. Looking at the CET for late September in 1798 it was not as cold as this year but not too far off with 11.81C. Solar activity was very low in the autumn / winter of 1798/99. So actually this year is a very good match to 2018.

First look at October temperature tracker

After a cool start temperatures trend towards average by the end of the second week.

I have mentioned in another thread that we are due a notably cold October, with 1993 and perhaps 2003 (depending on what your view point is) being the last examples of especially cool Octobers. Will it be this year? Well the potential is definitely there, but whether or not we manage to pull it off remains to be seen. I think I'll go on the conservative and go for a slightly cooler than average one.

Hard one to call this October is.

The MJO is poised in a position where it may either propagate right across the Indian Ocean and drive ENSO into a positive phase at long last, encouraging warmer October patterns during the first half in particular, or grind to a halt in the western Indian Ocean, keeping the ENSO state neutral or even pushing it a little negative overall, encouraging cooler patterns generally.

Third month in a row that this 'poised' state of affairs has taken place right at the end, making CET estimates even more speculative than usual. Not fair .

Posted my prediction.

My gut feeling is that it will be a largely warm, dry month in the S & E of UK after a cold start, but we see how it goes. 

Met Office Hadley        9.8c.      Anomaly      -2.5c. Provisional to 1st.

Metcheck                     10.22c   Anomaly      -0.29c

Netweather                  9.76c     Anomaly      -0.65c

Clevedon Weather         13.1c     Anomaly     1.92c

Peasedown St John        10.5c     Anomaly     -1.48c.

Mean of my 10 watched stations   10.88c.         

Met office Hadley             11.4c     Anomaly     -0.8c. Provisional to 2nd

Metcheck                         11.47c    Anomaly     0.96c

Netweather                      12.09c    Anomaly     1.7c

Alton                               11.5c      Anomaly     -1.24c

Clevedon Weather             14.1c      Anomaly     2.3c

Hexam                              9.3c       Anomaly     -1.34c

Mansfield                          11.2c      Anomaly     0.52c

Peasedown St John            11.0c      Anomaly    -0.98c

Treviskey Redruth              12.6c      Anomaly     -012c.

1 Down .  9 Up.

Mean of my 10 watched stations  11.63c.

I went for 9.9c thinking a cold high was going to take over, but it looks like southerlies all the way at the moment . 13c cet on the cards

I decided to go against the developing model signals this time, just to see how it would go. So non-scientific, or at least much less so than has been the case so far this year!

So far... the signals are sticking, instead of vanishing like they did for both Aug and Sep. Who's betting they'll hold fast and we'll actually see the exceptional warmth this time around? 

Damn, missed the deadline!! This Months gone too fast, this year has flown!

Send me something through now and I will include it. Just about to start compiling the table.

Thanks everyone for your October predictions. A very interesting range of figures this month. We could see some significant movements in the table at the end of the month. A few people going for very mild conditions.

TABLE

Cheers GW.  < 11.0c would be most welcome from my perspective. :)

Met Office Hadley           12.3c       Anomaly      0.1c  Provisional to 3rd.

Metcheck                        12.11c     Anomaly      1.60c

Netweather                     12.71c     Anomaly      2.32c

Cheadle Hulme                11.5c       Anomaly      0.32c

Hexam                            11.5c       Anomaly     0.86c

Mansfield Weather            12.5c       Anomaly     0.78c

Peasedown St John           12.3c       Anomaly     0.32c.

All 10 Up today

Mean of my 10     12.54c.       

After a cold weekend things start to warm up next week. Nothing exceptional, although there is a possibility of something warmer than indicated below. Even with the current data the CET is expected to be 12.26C by the 18th which is 0.75C above average.

I had a feeling Darren S and Gusty would estimate a fair bit higher than me but the reality is more extreme than I ever imagined! 

I've been watching GFS closely for signs that it will allow the Atlantic to push across more by the start of the week after next. As it happens it's now showing an intrusion next Thursday which is sooner than I'd hoped as I'm off work next week... but hey, you can't have it all! ECM a bit better with a Saturday changeover, but this being having trended later with that; the 00z went for a Thu-Fri changeover.

That latest GFS run gives me a rough estimate of 10.8*C to 20th which is a bit below the long-term average. This suggests to me that GW's latest estimate (which is a heck of a lot higher for just two days prior) must be a blend of multiple runs, as the preceding few runs were much warmer, well at least until the 06z which began the climb-down - am I right or is something seriously amiss with my method?  TIA

Don't lose heart yet snowman! It's changing day by day ATM.

Aaagh! Scary! I've never been at an end of the table before- and TBH I don't do that well when I'm in the middle somewhere.

I'm worried I've not gone high enough, if anything! Last year October was 12.4C, so everyone from me downwards has gone for a cooler October than last year, and the ensembles are currently well above the average line.

Met Office Hadley          13.1c.       Anomaly      0.9c. Provisional to 4th.

Metcheck                       12.48c      Anomaly      1.97c

Netweather                    13.08c      Anomaly      2.69c

Alton                             12.6c        Anomaly      -0.14c

Canvey Island                 12.7c       Anomaly      -0.44c

Cheadle Hulme               12.3c        Anomaly      1.12c

Clevedon Weather           14.5.c      Anomaly      3.32c

Darwen                          12.6c       Anomaly      0.74c

Hexam                           11.2c       Anomaly      0.56c

Mount Sorrel                   13.1c      Anomaly      1.3c

Mansfield Weather           12.7c      Anomaly      0.98c

Peasedown St John 12.72c    Anomaly     0.74c

Treviskey Redruth   12.9c    Anomaly    0.18c.

TWO Down    TWO Steady   Six  Up    Mean of 10 10 stations  12,73c.

GFS 00z was much warmer again, probably good for a finish in the 12s.

GFS 06z was considerably cooler again, but not as cool as yesterday's 12z; likely good for a finish in the high 10s or low 11s.

ECM 00z was a bit alarming for me; due to a more counteractive MJO evolution being predicted by that model, I wasn't expecting it to produce any runs that maintained a warm continental-type feed into the UK right on through next weekend.

To be honest, I sense that the weight of probability has edged in favour of an 11-12*C CET over the past few days, and that I've taken the wacky 'let's go completely against the model guidance and see what happens' idea too far. Even the very next day I was wondering why I'd gone quite so low; something in the mid-10s made more sense to me in the light of the new day.

We'll see, though. It's possible that if we go the major anticyclone route, it expands across England enough that we see chilly nights and foggy days. I actually see that as the best chance of a CET below 11*C this month; a cool but unsettled flow would be less effective due to the milder nights, unless it was exceptionally cool by day.

Wherever you are in the range of estimations for this month - there's still reason to be hopeful. Just a little more so if you're in the upper half!

I think you are sitting pretty though with 12.64 c. I really believe the cet record is under threat some incredibly warm charts at the moment. 13.3c in 2001 to beat.

I'm not sure what the all time CET high is for October. I thought it was 13.6C

Let's not get carried away here... next week's overall pattern would have to persist well into the following week for CET records to start being challenged. 

Reason being the cool start to the month (including this coming weekend). The GFS 12z gives me an estimate that brings the CET down to 11.5*C as of 7th, then raises it a whole degree to 12.5*C as of 14th, before taking it back down by the same amount to be at 11.5*C again as of 21st.

For what it's worth, from there, long-term average conditions would lead to a final CET in the high 10s. 

The ECM 12z looks a little warmer for next Thu-Sun but might be setting up a UK high on the 10th day.

So there's still a lot of possibilities for the final CET this month, despite next week's potentially impressive balminess.

Now - just watch the models start to extend the balmy pattern into the following week .

Ive lost my CET mojo and confess to having guessed October and have temporarily lost faith in my methodology. Sods law says I will have my best month of the year.