September 2015 CET forecasts

[Summer Sun]

12.9c to the 9th

 

1.7c below the 61 to 90 average

 

2.2c below the 81 to 10 average

[The PIT]

Sunny Sheffield back up 12.3C

[Summer Sun]

13.1c to the 10th

 

1.4c below the 61 to 90 average

 

1.9c below the 81 to 10 average

[BornFromTheVoid]

The minimum today is 9.4C, while maxima look like hitting about 21C, so an increase to 13.3C is likely on tomorrows update.

After that, the 06z GFS has the CET at:

 

13.5C to the 12th (16.0: +1.5)

13.5C to the 13th (13.8: -0.1)

13.6C to the 14th (15.3: +1.6)

13.6C to the 15th (13.4: -0.2)

13.6C to the 16th (12.8: -0.9)

13.6C to the 17th (13.6: -0.2)

13.6C to the 18th (14.3: +0.4)

13.7C to the 19th (14.5: +0.9)

13.7C to the 20th (13.5: -0.5)

 

So not as dramatic a warm up now as originally forecast, with the CET remaining below the 81-10 average for the foreseeable future (81-10 to the 20th is 14.5C)

[summer blizzard]

Close to average is probably favoured but it would not be too difficult a task to get a fairly cold CET or one that's a little above.

[Midlands Ice Age]

GW over on the other forum has posted today that he had the CET at 12.1C  on the 8th, when the provisional was showing 12.8C.

He attributes this to very cold early morning temps over the previous few days and he is expecting a very large downward correction  at the end of the month for the final figures. As discussed previously on this thread low temps at dawn seem to cause the provisionals to have problems.

 

So unlikely it will get above average this month

 

MIA.

 

Edit...

 

Have changed the post - it actually was a whole degree lower (12 rather than 13) than I had posted.   

(Perhaps I was thinking of my guess this month!!)

 

 

Yarmy --- Re your post below...

 

Being a golfer I have shorthened/changed 'provisional' to 'provos'.              Golfers will understand!!

Edited September 11, 2015 by Midlands Ice Age

[Yarmy]

GW over on the other forum has posted today that he had the CET at 13.1C  on the 8th, when the provisional was showing 13.8C.

He attributes this to very cold early morning temps over the previous few days and he is expecting a very large downward correction  at the end of the month for the final figures. As discussed previously on this thread low temps at dawn seem to cause the provos to have problems.

 

So unlikely it will get above average this month

 

MIA.

 

???

 

[Midlands Ice Age]

???

 

 

Nothing political Yarmy..... :oops:

 

See my edited note above.

 

MIA

[Summer Sun]

13.3c to the 11th

 

1.2c below the 61 to 90 average

 

1.7c below the 81 to 10 average

Edited September 12, 2015 by Summer Sun

[Summer Sun]

13.5c to the 12th

 

1.0c below the 61 to 90 average

 

1.5c below the 81 to 10 average

[Summer Sun]

13.5c to the 13th

 

0.9c below the 61 to 90 average

 

1.4c below the 81 to 10 average

[BornFromTheVoid]

The minimum today is 8.8C, while maxima look like reaching above 17C, so a drop to 13.4C is likely on tomorrows update.

 

After that, the 06z GFS has the CET at:

 

13.4C to the 15th (13.2: -0.4)

13.4C to the 16th (12.4: -1.4)

13.4C to the 17th (13.8: +0.0)

13.3C to the 18th (12.6: -1.3)

13.4C to the 19th (13.6: +0.0)

13.4C to the 20th (13.5: -0.5)

13.4C to the 21st (14.1: +0.4)

13.4C to the 22nd (13.3: -0.5)

13.3C to the 23rd (11.8: -1.7)

 

So a close to average/slightly cool period coming up it seems. Coolest September since 1994 (12.7C) is still a possibility.

[Stu_London]

A couple of little interesting nuances for this month.

 

Looks quite likely that the CET in running will not breach 14C on any given day in the month. Quite a rare occurrence in recent times (1992 the last September this happened)

 

Similarly to 1992, the CET looks like operating in a particularly narrow range (in 1992 the CET in running was always between 12.2C and 13.4C) Based on the provisional data for 2015, the range is currently 12.8C to 13.7C - this might of course get blown off course with revisions (particularly if the comments earlier in the thread hold any water) but quite interesting none the less.

[damianslaw]

Yes at the half way juncture and given the outlook it looks an increasingly tall order to record an above average month, more so as the month on average sees a cooling trend. A very good chance it will end up the coolest since 1994 and possibly cooler than that. Not sure of correlation, but the last time I believe we had temps like we have in the NE atlantic in Sept was 1994, 1992 and 1993 also saw cool anomalies, all three Septembers were cooler than average. Autumn 1992 and 1993 were notably cool especially 1993, 1992 saw a mild Nov, likewise 1994 after a fairly cool October.

[Summer Sun]

13.4c to the 14th

 

0.9c below the 61 to 90 average

 

1.4c below the 81 to 10 average

Edited September 15, 2015 by Summer Sun

[The PIT]

Sunny Sheffield 12.5C likely to be the same tomorrow unless we have a mild night which isn't looking likely.

[Timmytour]

Trying to have an early look at a mean CET relationship between August and September

One angle I've looked at is where the difference is 3C or greater (Aug-Sept) AND the September CET is 13C or lower....as we could get that situation this year

I wouldn't have thought this was too unusual an occurence and up until 1952 it occurred an average of once every four years.

However since then there's only been 1972, 1974, 1994 and 2012. there's three gaps there of 20 years, 20 years and 18 years. Since 1659, apart from a 21 year gap between 1829 and 1808, no other gap had been more than 12 years bar a 16 year gap which ended in 1758.

Hard to draw any winter conclusion however. What slightly concerns me at this stage is looking at 1974. That would be a gap of 2 years after a 20 year gap. If it happens this year that a three year gap after 18 years. 1974 was pretty average up until September, on the cool side without being spectacular. It reminds me a little of this year. There followed a very cold October, but a very warm December and January after that.

It would go against the recent talk of a very cold winter, but if I had to hang my hat on a peg at the moment, I'd go for something similar happening this year and into the winter.

[BornFromTheVoid]

13.4C to the 15th

http://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

 

The minimum today is 7.9C while maxima look like reaching the high 16s, so we might drop back to 13.3C on tomorrows update.

After that, the 06z GFS has the CET at:

 

13.3C to the 17th (13.0: -0.9)

13.3C to the 18th (13.4: -0.5)

13.3C to the 19th (12.3: -1.3)

13.2C to the 20th (12.7: -1.4)

13.2C to the 21st (13.3: -0.4)

13.2C to the 22nd (12.7: -1.1)

13.2C to the 23rd (13.3: -0.2)

13.2C to the 24th (13.3: +0.5)

13.1C to the 25th (11.7: -1.0)

 

The cool conditions are forecast to continue. At this stage, I think we can rule out anything above 14C or below 12C after corrections.

[Summer Sun]

0.8c below the 61 to 90 average

 

1.3c below the 81 to 10 average

[The PIT]

Sunny Sheffield at 12.4C another drop tomorrow as well.

[summer blizzard]

Good to see a decent chance of a pretty cool September.

[Relativistic]

Good to see a decent chance of a pretty cool September.

 

Indeed, I always remain very cautious at this point in the month however. So many times have things looked promising mid-month, only then for things to go pair-shaped. May and June this year being classic examples. I still have nightmares about May 2012...

[Timmytour]

Good to see a decent chance of a pretty cool September.

Septembers coming in at 13C or below (let's define them for the purpose of this post as "Cold Septembers") have been pretty few and far between in recent years, though if we do get one this month, it will be the second time in three years after 2012 ended a 18 year run without one.

Whether it means a colder winter follows is a moot point. Although there was a Cold September in 1962 and a fantastic winter (for cold lovers) followed, the average winter following Cold Septembers since then has been over 0.7C warmer than the average for all winters since and including 1963-64.

Edited September 16, 2015 by Timmytour

[Summer Sun]

13.3c to the 16th

 

0.9c below the 61 to 90 average

 

1.4c below the 81 to 10 average

[The PIT]

Yup down to 12.3c Probably bumping along the bottom right now and probably won't be any further shifts downwards.