December CET

[Optimus Prime]

Yes it is strange.

[kold weather]

This week does look like making quite a large correction to the CET and back above normal, after that however I do think we will see some cold, the exacts of it are pretty tough to call though IMO and thus we could still be looking at either a cold CET or a mild one, just too early to call.

Anything from 3.5-6.5C is still possible!

[reef]

Hadley now on 4.9C to the 5th. Yesterday came in at 7.2C.

We could well see a half a degree rise tomorrow, as today's min is at 7.2C aswell.

[Evening thunder]

Can't see why it can't be included....but the penalty is now (until midnight) -30 points.

In October, even without being late I scored just 17 points or so....so beware, you can end up (I assume) effectively having a negative score. I presume that's what happened to Backtrack the same month - I think he had a -60 penalty, amazingly, and since he only scored around 25 before the deduction that was an expensive entry!

In case you didn't realize, you are permitted to miss up to two entries over the year (Dec 09 - Nov 10) and still be included in the annual competition.

On which subject, does anyone else think it might be an idea to have a small bonus for entering in all twelve months?

Ossie

Thanks for that osmposm

I didn't realise that you can miss up to two entries over the year, I think ive missed a couple but I cant remember exactly how many!

Think I should go for it despite the -30 penalty as then it might mean I could be included in the yearly comp, although I better not change my guess or ill get a -60 penalty as well, so better not do that :lol:

Edited December 6, 2009 by StormMad26

[osmposm]

Thanks for that osmposm :lol:

I didn't realise that you can miss up to two entries over the year, I think ive missed a couple but I cant remember exactly how many!.....

You couldn't have missed a couple yet, as this is the first month of the new 12-month competition! It starts each year with the beginning of the meteorological winter, December, and runs until the November of the following year. Jackone gave the finishing scores for the last year in the November CET thread.

Ossie

Edited December 6, 2009 by osmposm

[Evening thunder]

Oops forgot that - for some reason I was automatically assuming that it ran from the start of a calender year:doh:

[reef]

Hadley now 5.5C after yesterday came in at 8.4C and caused an increase of 0.6C in the mean.

Another mild day today as the min is down as 6.6C. We could well be within touching distance of 6.0C on tomorrow's update.

[kold weather]

Yep indeed Reef, a big correction has occured, saying that looks like we will see something of a downturn between Friday-Sunday at the very least...and beyond that then just about anything could happen, including the holy grail of cold. Anything from 2C to 6C is possible IMO.

[Thundery wintry showers]

I suggest that if the shortwaves scupper the evolution to the "omega block" then my punt of 6.5 would still be feasible if we were then to evolve into a mild SW'ly pattern around Christmas.

However the odds do currently favour my punt being on the high side. I agree with the large range of possibilities (personally I'd go for a 2.5 to 6.5 range) given the uncertainty over the upcoming weather.

[J10]

The irony is that if we do get a very cold month, very few entries have really gone for it.

[Optimus Prime]

The irony is that if we do get a very cold month, very few entries have really gone for it.

I guess very cold for December we're talking about 3.0c or below?

[Mark Bayley]

The irony is that if we do get a very cold month, very few entries have really gone for it.

We was all useing reverse psychology <_<

[reef]

I guess very cold for December we're talking about 3.0c or below?

That would be quite a feat. Assuming tomorrow's number is 6.0C, then it would already require the remaining 24 days of the month to post a mean of 2.1C to average 3.0C.

[kold weather]

Yeah 3.0C would require quite a big adjustment. It can be done however its a bit of a long shot unless we get the most sustained cold on the models.

Until we know more about the evolution of the possible cold spell there has got to be a big range, however does look like the models are now swinging towards a below average month...I'm beginning to think a sub 4C month is possible, esp if we can get a sustained cold period. Just as possible however to get a 5 day incersion high followed by a zonal flow re-establishing...in which case a TWS has said anything is possible really.

edit---the period between the 20th of December and the 10th of Jan managed to achieve that figure...with 2 days that averaged 10C per day, we got a CET of 1.94C in that period..but I grant you its still a long shot.

Indeed that was the only time in the last decade where we got a 15 day that was close to 0C, came out at just 0.07 between the 27th of December and the 10th of Jan...the 6th of Jan was also the coldest day in the CET series ince the 28th of December 1995...with -3C.

Edited December 8, 2009 by kold weather

[Optimus Prime]

Well the first half of December 2008 averaged just 2.3c. So 2.1c for the second half isn't too much to ask for.

Looking at the models it could be our best shot at a sub 3.0c month since January and February 2009 (and only January and February 2009 looking at the CET tracker since 1997)

[kold weather]

Still way too early to call though to be fair OP, esp given what the eCM shows would be a likely breakdown by the 20th...granted its all up in the air still.

IF we do get a decent cold set-up like the GFS is progging then certainly a chance we could get close to that sort of figure, I personally think its still a long shot for us to get that low.

[reef]

Well the first half of December 2008 averaged just 2.3c. So 2.1c for the second half isn't too much to ask for.

Looking at the models it could be our best shot at a sub 3.0c month since January and February 2009 (and only January and February 2009 looking at the CET tracker since 1997)

Theres a big difference between 15 days with a mean of 2.1C and 24 days though. I may be wrong (Hadley seems to be down so I cant check) but I dont think we've had that since early 1997?

[kold weather]

The closest we have come to anything like that probably was the cold December/early Jan of 2009, I think we must have been fairly close to a 24 day period around that...but none the loess I think even that was higher then 2.1C...I know we got a 21 day period at 1.94C...

[Stu_London]

06z suggests an outcome of around 4.1 to 22nd December

Temps being progged are not that much below normal

[reef]

Hadley is available again and has yesterday down as 8.3C, taking the running mean to 5.9C to the 7th.

This could be the peak depending on what happens. If the easterly fails and we end up with high pressure over the UK which gradually sinks, then we could go milder.

[kold weather]

depends how long that process takes Reef, I'd bet at this time of year 5 days of inversion high pressure could be colder then a half baked easterly flow given the warmth of the North Sea.

Stu-very true, though if we could get low a sub 4C December would still be a decent return IMO.

[reef]

Hadley is now at 6.1C after a suprisingly mild day again yesterday. To give some idea how difficult it would now be to record a sub-3C month, the remaining 23 days would have to average 1.85C. A return of 3.3C would be required to finish at 4C.

[Thundery wintry showers]

Manley running at 5.8C for 1st-7th December- so far Manley & Hadley in close agreement:

http://www.climate-uk.com/

Not far above the early-December average. I was expecting around 6.5-7.0 by this time, but the recent Atlantic regime has been rather less mild than I expected.

[kold weather]

I think just about anything is still on the table given the models. If the UKMO is right then a 6C plus is odds on, if the ECM/GFS is right then whilst the ultra cold air takes a while to get here, if it did then it would knock chunks out of the CET.

C

The intial cold shot looks chilly but nothing too extreme, probably will average close to the 3.3C required for a sub-4C month, after that anything is possible.

[Weather-history]

Just looking at some December CETs which dropped after being fairly high mid-month.

December 2000 had a CET of 9.1 by mid-month and ended up as 5.8 whilst December 1979 was 8.7 mid-month also ended as 5.8 and December 1831 had a CET of 8.5 by mid-month and that too ended as 5.8

It is clear that this December will not be as mild as that by mid-month.

December 1938 had a CET of 7.1 by mid-month and ended as 4.4