September CET

[summer blizzard]

I have opened this thread to discuss the CET for September...

In recent years, we have been used to above average temperatures, commenly refered to as an Indian summer, infact, the last below average September was September 2001 with a CET of 13.4C, which is 0.3C below average however to find a September which was at least 1C below average, you must go all the way back to September 1994 which had a CET of 12.7C, which is 1C below average.

The average CET for September is 13.7C.

My teleconnections forecast points to a CET of 15.2C, continuing the trend of warm September however my seasonal forecast points towards a fairly average September however at this moment, i am going to back my teleconnections forecast as it was close in August.

Summer Blizzard: 15.2C

[Weather-history]

The last time September

..had a CET >16C

1949 16.3

..had a CET >15C

2005 15.2

..had a CET <14C

2001 13.4

..had a CET <13C

1993 12.4

..had a CET <12C

1986 11.3

..had a CET <11C

1952 10.7

..was warmer than August

1956 Aug 13.5 Sep 14.3

..was colder than October

1807 Sep 10.5 Oct 11.4

..was warmest month of the year

1890 Sep 14.6

..was cooler than May

1992 May 13.6 Sep 13.4

The longest run of consecutive Septembers with a CET >15 is 3

1729 16.6 1730 15.3 1731 15.3

The longest run of consecutive Septembers with a CET <13 is 7 from 1691 to 1697 inclusive

The longest interval between sub 12 CET Septembers is 52 years between 1705 and 1758

The longest interval between >15 CET Septembers is 48 years between 1731 and 1779

[BLAST FROM THE PAST]

Sticking with my thoughts of very warm end to Sept and an above average month anyway I'll go for 15.1C. After August i think some will be surprised with the resetting to a blocked/warm regime.

BFTP

[Stratos Ferric]

I have opened this thread to discuss the CET for September...

In recent years, we have been used to above average temperatures, commenly refered to as an Indian summer,

SB, I think "Indian Summer" generally refers to a sunny warm period, of reasonable duration, anywhere in autumn, (particularly astrological autumn in this sense, as opposed to the recording convention of Sept 1st onwards). It is quite possible to have an "Indian Summer" during an otherwise cool, below average, autumn period.

[Bham Chris]

Well it will be an above average month that will be unsettled at times but will have some warm or even very warm periods.The CET for september will be 14.7C in my opinion,1.0C above average.

[summer blizzard]

Bham Chris: 14.7C

Blast From The Past: 15.1C

Summer Blizzard: 15.2C

Strattos Ferric, what you say is true however the term is traditionally applicable in October although in recent years the term has taken a new meaning with the continued run of above average September's.

"An unseasonably warm period near the middle of autumn, usually following a substantial period of cool weather."

http://www.google.co.uk/search?hl=en&q...ummer&meta=

[Snowly does it]

I think the wheels will come off this September

13.1

[Rollo]

I tend to think that September this year will be generally changeable but with one notable warm spell (optimist?).I would go for a CET of 15.6c.

[Snowyowl9]

I`m going to go for a cool september this year at 13.7c.

S9.

[Bottesford]

14c making it slightly above average due to a few warm to hot days. Most of the month with be unsettled I think without all that blocking to the east.

[Stargazer]

I'll go for a warmish settled spell mid month to lift the average a bit, but otherwise a changeable month. Let's say 14.1.

[SNOW-MAN2006]

14.0 on early indications with unsettled spells leaving mild conditions but some cool and possibley Frosty nights (to end) as it settles down.

autumn forecast avaliable september 1st along with september forecast

SNOW-MAN2006

[The PIT]

Well it won't be an Indian summer anyway since I always get it wrong went too high last time I'll go for 15.5C

[kippure]

16C on the button

[Optimus Prime]

Recent September have been warm but have still managed to provide some low minima;

2005; Shap Recorded -1.7c on the 16th-17th. Lowest Mid September reading since 1986

2004; A few air frosts

2003; Some unusually hard frosts with -3.5c at Perthshire. Some areas having their lowest night time September readings since 1919 with a temperature reading of -2.8c at Redhill Surrey. Maxima was above average while minima was the lowest since 1993

2002; -3c at Tulloch Bridge on the 24th

2001; Cool Month, some low temperautres at the start of the month accompanied, by even some slight frosts

I'm going to a CET off 13.5c.

[SMU]

Slightly below ave is my punt.............

S

[BLAST FROM THE PAST]

Bham Chris: 14.7C

Blast From The Past: 15.1C

Summer Blizzard: 15.2C

Strattos Ferric, what you say is true however the term is traditionally applicable in October although in recent years the term has taken a new meaning with the continued run of above average September's.

"An unseasonably warm period near the middle of autumn, usually following a substantial period of cool weather."

http://www.google.co.uk/search?hl=en&q...ummer&meta=

Folks

Indian summer (also called Old Wives' summer in the United Kingdom) is a name given to a period of sunny, warm weather in autumn, not long before winter. This time can be in late October or early November (Northern hemisphere) / late April or early May (Southern hemisphere), usually sometime after the first frost. It can persist for just a few days or weeks.

BFTP

[summer blizzard]

Snowmaiden: 13.1C

Optimus Prime: 13.5C

Snowyowl9: 13.7C

Bottesford: 14C

Snowman2006: 14C

Stargazer: 14.1C

Bham Chris: 14.7C

Blast From The Past: 15.1C

Summer Blizzard: 15.2C

The PIT: 15.5C

Rollo: 15.6C

Kippure: 16C

Steve Murr, could i have an exact figure from you?

Strattos Ferric, you always seem to make well informed opinions, would you be willing to give a CET prediction?

Mr Data, can i tempt you to give a CET prediction again?

[Somerset Squall]

14.9C

[SMU]

Snowmaiden: 13.1C

Optimus Prime: 13.5C

Snowyowl9: 13.7C

Bottesford: 14C

Snowman2006: 14C

Stargazer: 14.1C

Bham Chris: 14.7C

Blast From The Past: 15.1C

Summer Blizzard: 15.2C

The PIT: 15.5C

Rollo: 15.6C

Kippure: 16C

Steve Murr, could i have an exact figure from you?

Strattos Ferric, you always seem to make well informed opinions, would you be willing to give a CET prediction?

Mr Data, can i tempt you to give a CET prediction again?

13.5

[Stratos Ferric]

Steve Murr, could i have an exact figure from you?

Strattos Ferric, you always seem to make well informed opinions, would you be willing to give a CET prediction?

Mr Data, can i tempt you to give a CET prediction again?

Steve told me off-line that his punt was 22.4; I did try to reason with him but he wouldn't have it.

Since you've tried to tempt me with flattery, go on then, but don't think it will work every time.

September is one of the least volatile months in terms of variation around its mean - to be expected, so that makes the window around 12.8-14.8 based on the recent thirty years, a bit ore than this based on the past ten. It's also warming on rolling ten year with a current mean of 14.5C, and two recent very warm Septembers; in fact four of the warmest thirty Septembers in a sequence numbering almost 360 have occurred in the past ten years, i.e. an event with a return period of thirty years has occurred almost every other year in the last ten! Through the year most months come in between 0.5-1.0c above par currently. Sequences of three consecutive years, for any given month, with excess of >1C are very rare though, and the last two Septembers have been more than 1C above par. Finally, September is the ONLY month to have more or less continuously increased in temperature over the past five years.

So, in summary: recent trend above long term mean, with some very warm months in recent years, but indications that we're overdue a downward correction of some sort. That would probably suggest something 0.5-1.0 above par, though my instinct is still higher than this.

Synoptically, after recent instability, I can't help thinking we're due some settled weather sometime in the month, and nearby waters are still warm, so even if we get a zonal flow I suspect persistent cold is unlikely; if we get clear nights though (their absence has been a partiulcar factor in recent . The trend in recent Septembers has been for HP not far off our SW, though with perhaps more westerliness becoming apparent. Taken together this suggests a month slightly above normal.

Overall then, I'm going - slightly against my instinct which is higher than this - to punt for 0.7C above the 30 year mark:

14.6

[Scorcher]

I have a feeling the renewed warmth will surprise a few people this September. The Atlantic is certainly becoming more active now in terms of tropical storms and possibly hurricanes which could have an impact. I'll go for a CET of 15.4C, so slightly warmer than last year. I wonder if there is an outside chance that September could be warmer than August. It would take some doing, but if someone had said earlier in the year that this July would be the warmest month on record I would have laughed.

[Wynn D Woo]

I think september will be marginally above average, so i will punt at 14.4

[Anti-Mild]

I was going to go with 14.4c but then windswept took it so I was going to take 14.5c but the I thought "why should I change it, just because the person directly above chose the same as me?"

Therefore, my selection is 14.4c :lol: !

[VillagePlank]

14.5C

(The moving average is for 10 years, btw)