December CET

[Nick L]

I know they are still doing the CET, but why aren't they posting it on the usual page?

[reef]

Hadley is now 4.9C to the 18th. Yesterday came in at -0.1C.

Today will be a very cold day, the minima is already down as -5.0C, so even if the average max is above freezing we'll see a huge drop, quite possibly by up to half a degree.

[Duncan McAlister]

Yes I know but my PC won't load it up for some strange reason, keeps saying 'Open with' hence why I have to use the HADCET diagnosis site. Default programme Windows media player!

Any idea what file format they use for the individual daily CET?

I have the same problem, on a Mac.

[kold weather]

Yep yesterday was a very cold day indeed, some areas in the east stayed decently below 0C all day..I'm a little surprised the min was as high as that actually, given how widespread the -6/7/8s were, I fully expect that number to be lowered somewhat at the end of the month when al lthe adjustments are done...

I'd guess the max will come in a little above 0C given how relativly high the mins were in comprasion to the mins from from other sites, none the less it'll be one of the coldest days of the decade it seems...9 ice CET days this year so far, quite probably another one coming tomorrow as well....outside chance of having the most since 1991, though more likely is to have the most since 1996.

Edited December 20, 2009 by kold weather

[reef]

Hadley is now 4.5C to the 19th. Yesterday came in at -1.2C. Im a little suprised with the maximum which is down as 2.6C. Certainly scope for that to be adjusted downwards at the end of the month, as it seems a tad high. Today's min is down as -4.8C so another sub-zero day possible.

[kold weather]

Thier stations must have been some of the mildest in the entire country!!

I think we could see a rather big downward adjustment for that day as the mins seem a little on the high side as well compared with the stations across the rest of England...

I'd have though -2.5C region would have been more probable to be honest...

[Weather-history]

11th-19th December CET: 2.5C

[stewfox]

I am going to be blunt here and the mods may pull me up for this but I think it is about time some people start reading posts in this thread because the Hadley CET is there and yet we are still getting the tired old posts, where is it, where is it?. And its not rocket science to work it out when you know the system. Everything are to the powers of 10 and 100.

IT AINT WORKING

http://hadobs.metoffice.com/hadcet/cet_info_mean.html

Now if you want to 'work it' out each day and post it on here fine

Please stop bleating if others find after using the site for years that they make the occassional comment on the site re its STILL isn't updating.

Any reason anyone ?

[Weather-history]

It looks like the decadal average for December for the 00s could be cooler than February's

February 2000s CET: 5.03

December 2000s CET: 4.96 up to December 2008

So this December needs to have a CET of 5.7 to equal the February's decadal average.

It could also be colder than the January's decadal average as well: 5.02

In the 1870s, December was a colder month for that decade than either January or February.

[Weather-history]

.

Any reason anyone ?

Why not e-mail them?

[ukmoose]

It looks like the decadal average for December for the 00s could be cooler than February's

February 2000s CET: 5.03

December 2000s CET: 4.96 up to December 2008

So this December needs to have a CET of 5.7 to equal the February's decadal average.

It could also be colder than the January's decadal average as well: 5.02

In the 1870s, December was a colder month for that decade than either January or February.

Interesting facts re December being the coldest of the winter months. I'm not surprised - most Januarys and Februarys seem to have been a big let down in terms of cold wintry weather and there have been quite a few particularly mild ones I think.

By the way (sorry if I have missed it somewhere) but how does the winter index work? I am assuming points for days of lying snow and/or reaching certain temperatures? Thanks.

[Weather-history]

By the way (sorry if I have missed it somewhere) but how does the winter index work? I am assuming points for days of lying snow and/or reaching certain temperatures? Thanks.

Thats right

Its 10 x [(number of days with lying snow at 9am)+(number of days with falling sleet/snow)+(number of days with minimum at or below 0c)] divided by the winter mean maximum temperature up to that particular date

[ukmoose]

Thats right

Its 10 x [(number of days with lying snow at 9am)+(number of days with falling sleet/snow)+(number of days with minimum at or below 0c)] divided by the winter mean maximum temperature up to that particular date

Thanks very much Mr D

[Snowly does it]

Hadley at 4.3 (4.27) to the 20th

Manley at 4.0 to the 20th

Last night shows on Hadley at -2.9 so it will be tight as to whether the run of sub-zero CET days continues (were today to succeed, I would think we would manage 7 on the bounce possibly)

The GFS 06z would see us come in just under 3 for December I fancy, I think sub 4 is now very likely unless the blowtorch breaks through as we should be comfortably into the low 3s before the slightly milder air breaks through and a correction is now looking relatively likely (some of the recent marks seem rather high but we shall see)

An extension of widespread frosts to somewhere around the 29th will make that first sub-3 of the century a close prospect and I would say it is now 50/50 to be below last years 3.5 and hence the biggest negative anomoly versus the 71-00 average of the century (so far!)

[reef]

Hadley at 4.3 (4.27) to the 20th

Manley at 4.0 to the 20th

Last night shows on Hadley at -2.9 so it will be tight as to whether the run of sub-zero CET days continues (were today to succeed, I would think we would manage 7 on the bounce possibly)

The GFS 06z would see us come in just under 3 for December I fancy, I think sub 4 is now very likely unless the blowtorch breaks through as we should be comfortably into the low 3s before the slightly milder air breaks through and a correction is now looking relatively likely (some of the recent marks seem rather high but we shall see)

An extension of widespread frosts to somewhere around the 29th will make that first sub-3 of the century a close prospect and I would say it is now 50/50 to be below last years 3.5 and hence the biggest negative anomoly versus the 71-00 average of the century.

it would be quite something if the last month of the decade manages to record a sub-3C CET as well as the largest negative anomoly. Also interesting is that 6 of the 10 Decembers could end up below average, hence as Mr Data says, such a low decadal mean.

[Snowly does it]

it would be quite something if the last month of the decade manages to record a sub-3C CET as well as the largest negative anomoly. Also interesting is that 6 of the 10 Decembers could end up below average, hence as Mr Data says, such a low decadal mean.

It will definitely be below average, I think sub 3 is probably just out of reach (need some really low minima over the next few days to help accelerate the decline) but the biggest negative anomoly I think will happen - 3.2 or 3.3 seems about the mark to me unless mild wins out by the 27th, then it will push the high 3s perhaps.

[kold weather]

I'm willing to bet we will just miss it provisionally but given I think several days will be adjusted downwards at the end of the month I'm willing to bet we will end up below 3C...

Either way its going to come in below 4C I'd have thought, also looks nailed on that this December will be one of the coldest months since Jan 1997...maybe not the most impressive feat but we will see!!

Also could well see the coldest 20 day period since December/Jan 1997, though Dec/Jan 2009 probably will keep that title.

Something in the low-mid 3s seems the best call right now...so a fair chance IMO of being the coldest December since 1996.

Edited December 21, 2009 by kold weather

[Optimus Prime]

Manley;

Mean Max 6.4c (-1.7c)

Mean Min 1.7c (-0.9c)

[Lettucing Gutted]

Assuming the December 2009 CET finishes at 3.5C the December 2010 CET will have to be cooler than 7.6C in order for the 1981-2010 December CET average to be cooler than the 1971-2000 December CET average of 5.1C.

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Assuming the December 2009 CET finishes at 3.5C the December 2010 CET will have to be cooler than 7.6C in order for the 1981-2010 December CET average to be cooler than the 1971-2000 December CET average of 5.1C.

I have a feeling your guess will be a bit on the high side.

[Nick L]

Will the Met Office ever use 1981-2010 though? Don't they still use 1961-1990?

[AderynCoch]

It looks like the decadal average for December for the 00s could be cooler than February's

February 2000s CET: 5.03

December 2000s CET: 4.96 up to December 2008

So this December needs to have a CET of 5.7 to equal the February's decadal average.

It could also be colder than the January's decadal average as well: 5.02

In the 1870s, December was a colder month for that decade than either January or February.

Yep, the 1870s had four Decembers below 1C - this only happened once throughout the entire 20th century.

This time round of course, it's more to do with December being not as above average as January and February. Very mild Decembers have been rare in comparison to other months in the past 20 years - in fact I think Decembers in the 90s were on average colder than in the 80s (1981 being a true anomaly).

As an aside, does anyone reckon we'll manage five sub-zero CET days in a row (provisionally we're on three at the moment)? This hasn't happened since January 2001 - surely the longest such drought in the daily CET series?

[Snowly does it]

As an aside, does anyone reckon we'll manage five sub-zero CET days in a row (provisionally we're on three at the moment)? This hasn't happened since January 2001 - surely the longest such drought in the daily CET series?

It's all down to today I think - last night is down as minus 2.9 Hadley so we need today's maxima to have been less than 2.7 - looks like we may just sneak it as Pershore and the area around Rothamstead have been under 2 all day - the NW one may be a little higher.

Tomorrow looks highly likely to be sub zero so we could theoretically manage a week of sub-zero.

[AderynCoch]

As I thought:

December average CET 1980-9 = 5.16C

December average CET 1990-9 = 4.6C

Take 1981 out of the equation and you get 5.7C for the eighties.

December average CET 2000-8 = 4.96C

December 2009 would have to finish below 1.4C for Decembers in the noughties to be colder than in the nineties (very unlikely), and above 7C to be warmer than in the eighties (not going to happen).

Edited December 21, 2009 by AderynCoch

[damianslaw]

At this juncture we could be heading for our coldest December since 1996, all will depend on how mild the post christmas period turns out to be.

Certainly we will have a close battle with last years values, and I am expecting to downward adjustment at the end of the month - finishing mark unlikely to be any higher than 4 with 3.5 degrees a good benchmark but very good potential for something very close to 3 degrees, sub - 3 seems just out of reach.