December CET

[osmposm]

...and the reason we often look at it - despite its arguably unsatisfactory nature for you, and others, DXR - rather than some wider UK measure, is that it has a uniquely long and fairly consistent history of some 250 years' duration. Which makes it very interesting for comparison purposes.

[LadyPakal]

There is a Scotland average that the Meto produces (and England, Wales, N Ireland & also the UK as a whole).

Numbers to November:

http://www.metoffice.gov.uk/climate/uk/2008/november.html

[Kentish Man]

Here are the monthly stats from Climate UK after the end of week 2 of December

CET: (Dec 1-14): 2.2°C (-3.2 degC)

E&W Rain: (Dec 1-14): 53.5mm (117 per cent)

E&W Sun: (Dec 1-14): 42.0hr (195 per cent)

© Philip Eden

[Eugene]

CET: (Dec 1-14): 2.2°C (-3.2 degC)

Yes very impressive yet still some aren't happy and with ensembles going for HP domination we could be in for a very cold december, i'm sure if June was running 3.2C above average by the 15th people would be ecstatic but in winter its never enough, sunshine figures are amazing too, i doubt we`ll be recording almost 200% sunshine figures come next summer.

[Kentish Man]

Just to complete the picture Hadley is static today on 2.8C.

[johnholmes]

not strictly CET but Doncaster data

The first 15 days here show a mean of 3.0C against the long term, using RAF Finningley 1942-1995 and Cantley 1997-now, of 4.6C.

That means the next 16 days need to mean 6.2C which is almost the average for November data in the long term.

To me, given what the models are suggesting along with my view of lrf developments, I would say it is very unlikely that December in this area will be anything but below average, it may edge into the rather cold category.

I cannot remember the last month, if that happened, that fitted into that category.

Edited December 15, 2008 by johnholmes

[The PIT]

not strictly CET but Doncaster data

The first 15 days here show a mean of 3.0C against the long term, using RAF Finningley 1942-1995 and Cantley 1997-now, of 4.6C.

That means the next 16 days need to mean 6.2C which is almost the average for November data in the long term.

To me, given what the models are suggesting along with my view of lrf developments, I would say it is very unlikely that December in this area will be anything but below average, it may edge into the rather cold category.

I cannot remember the last month, if that happened, that fitted into that category.

Even if the GFS came off it's going to struggle to push the CET back to average which shows how cold it has been.

[Kentish Man]

Hadley is down by 0.1C today to 2.7C.

If the high sets up residence in a favourable position between Christmas and the New Year a sub 4C month becomes odds on despite the brief milder period coming up.

[Stu_London]

Hadley is down by 0.1C today to 2.7C.

If the high sets up residence in a favourable position between Christmas and the New Year a sub 4C month becomes odds on despite the brief milder period coming up.

Should the 6z verify - on raw data alone the CET would come out at 4.3C - However that probably underdoes the effect of any fog, or possible inversions and I would expect also that some of the strange looking data from the start of the month to be recalabrated leaving 3.5C to 4C as the most likely outcome with slightly more probability to the downside of that than to higher temps

Edited December 16, 2008 by Stu_London

[kold weather]

Yep I think something between 3.5-4.5C is looking pretty probable right now, which would be a pretty decent start to winter, if HP does set itself up over the UK then I should think we will get the coldest December since 2001.

[Eugene]

Upto yesterday the CET is running 3.1C below average, makes me laugh when i see people saying caution is needed when we see cold on model runs when the CET is currently so cold so yes cold is possible in the UK, it's not a miracle

Edited December 17, 2008 by Eugene

[Iceberg]

Have to admit the first time in a very very long time we have the real chance of a well below average month. Hope it comes off

[TEITS]

Based on the 0Z we only have 4 mild days to go.

When I say mild I refer to temps 3/4C above normal i.e max temps of 10C

[Optimus Prime]

A decent chance of the first December since 2001 to be below 4.0c. It would take a substantial cold spell to bring the CET under 3.0c, even December 1996 which had a very cold last day or so just managed this at 2.9c (CET dropped by 0.2c during the last 24 hours)

Looking at how the patterns are changing I would say anything from 5.7c (if the high sinks) 3.5c (if high pressure sits over the UK for the remainder of the month, most likely in my opinion) and 2.5c if the last week brings a very cold easterly (unlikely)

At this stage 3.9c would be reasonable.

[D KARLSON]

not strictly CET but Doncaster data

The first 15 days here show a mean of 3.0C against the long term, using RAF Finningley 1942-1995 and Cantley 1997-now, of 4.6C.

That means the next 16 days need to mean 6.2C which is almost the average for November data in the long term.

To me, given what the models are suggesting along with my view of lrf developments, I would say it is very unlikely that December in this area will be anything but below average, it may edge into the rather cold category.

I cannot remember the last month, if that happened, that fitted into that category.

Indeed i cant even be bothered to look to see the last month that came in lets say 2 degrees below par , but this month has a fair chance a coming in sub 2 degrees ,if that happens that is most definitely a sign of pattern change and colder synoptics and falls inline nicely with our falling cet over previous months positve signs for cold lovers

[Kentish Man]

Hadley - CET to 16th is 2.8C.

It has been static at around this figure for some time but we should expect rather more chopping and changing from now to month's end.

[Anti-Mild]

I believe that despite the mild days we are forecast to have this week, we still have a better than average chance of recording a sub 4c December, which is the all important figure for a sub 10.0c year.

[kold weather]

The key to a sub-4C is the high pressure block holding for a long time once it set-upss around the 22nd-24th either near the UK or to our NE. If that happens then I suspect a slow drop will ensue again and below 4C is a very real chance, would be a turn up.

[Kentish Man]

Hadley is up 0.2C to 3.0C today (Dec 1 - 17). Climate UK (Manley) is still lagging way behind on 2.4C.

We can probably factor in a minus 0.3C month end adjustment on the Hadley figure as things stand.

Edited December 18, 2008 by Kentish Man

[Kentish Man]

Hadley is now on 3.4C today (Dec 1 - 19), the last 2 days both increasing by 0.2C. Climate UK (Manley) is still lagging on 2.8C. The rolling average at this stage in Dec is 5.3C.

With the cold temps projected from Christmas Day onwards we should still manage to achieve a sub 4C month.

[SNOWPLOUGH]

Hadley is now on 3.4C today (Dec 1 - 19), the last 2 days both increasing by 0.2C. Climate UK (Manley) is still lagging on 2.8C. The rolling average at this stage in Dec is 5.3C.

With the cold temps projected from Christmas Day onwards we should still manage to achieve a sub 4C month.

my guess of 3.8c is looking good :o

SP

[Stu_London]

Raw data from the 06z suggests a finish point of 4.1

However the likely downward adjustment and the underestimation of a possible inversion leads me to believe that 3.5-3.8C is the most likely point of finish

[reef]

Another increase of 0.2C on the Hadley CET. Its now running at 3.6C to the 20th.

Today and tomorrow will be very mild, so we could be north of 4.0C by the update on Tuesday.

It seems a shame how quickly cold weather is negated by mild these days. Ill always remember March 2006, when the mean was around 3C to the 23rd but the very mild last week meant the CET increased by almost 2 degrees by ther end of the month. A sign of the times I think, the mild always seems milder than the cold is cold.

It would be an extreme disappointment not to finish below 4C when the first half has been so far below average. Hopefully the upcoming easterly wont be too cloudy and have some decent cold at the surface.

[Snowly does it]

Another increase of 0.2C on the Hadley CET. Its now running at 3.6C to the 20th.

Today and tomorrow will be very mild, so we could be north of 4.0C by the update on Tuesday.

It seems a shame how quickly cold weather is negated by mild these days. Ill always remember March 2006, when the mean was around 3C to the 23rd but the very mild last week meant the CET increased by almost 2 degrees by ther end of the month. A sign of the times I think, the mild always seems milder than the cold is cold.

It would be an extreme disappointment not to finish below 4C when the first half has been so far below average. Hopefully the upcoming easterly wont be too cloudy and have some decent cold at the surface.

I'm not sure I understand Reef - what does the final figure matter? - the cold is still cold, the fact that we have 4 or 5 days of very mild weather doesn't actually make the preceeding 4 weeks of very cold weather any warmer. The reason the mild spell is raising the figure so much is that it is at a very low base already - were this a typical December then the daily amount would rise perhaps 0.1 instead of 0.2 on a day like yesterday.

Your March example is a good one - the important thing is that for 23 days there was a very cold spell of weather, nothing changes that.

I'd expect the CET by Christmas Eve (so updating to include the 23rd) to be probably 4.3 or thereabouts, I don't expect much of a downwards correction as Phillip appears to have adjusted upwards as Manley rose an eyewatering 0.5 degrees yesterday to 3.3. From Christmas Eve to te end of the year I would expect a slight contraction and a finishing figure of 3.6-4.1 - hopefully the lower end.

3.6 for me the key figure now (after 3.9 for the sub 10 year) as this would be the first month 1.5 degrees or better below average for a very long time - we have 39.6 cumulative degrees for the last 11 days of the month to achieve it and I think you bank on 20 of those today and Monday at least - meaning the period Tuesday to month end needs to average very slightly over 2 degrees to achieve this milestone - a tough call but achievable if things turn cold after Christmas.

4 the favourite from here in summary

[reef]

I'm not sure I understand Reef - what does the final figure matter? - the cold is still cold, the fact that we have 4 or 5 days of very mild weather doesn't actually make the preceeding 4 weeks of very cold weather any warmer. The reason the mild spell is raising the figure so much is that it is at a very low base already - were this a typical December then the daily amount would rise perhaps 0.1 instead of 0.2 on a day like yesterday.

Your March example is a good one - the important thing is that for 23 days there was a very cold spell of weather, nothing changes that.

Indeed, but in reality final CET figure does matter. Part of the problem we have these days is not that cold doesnt occur, it just occurs less frequently and is less potent compared to the mild. My disappointment is that despite 2-3 week cold spells, we struggle to record well below average months like we used too and especially well below average seasons (12 years and counting).

With regards to this month, we could well be sitting at a mean of 4.2C by the 22nd. This is despite the first half of the month being the coldest start to winter for 30 years. Even then, if the last 8 days had a mean of 2C, the month would end at 3.5C. So thats another winter-month failing to get sub-3C, despite what would essentially have been 85% cold. If we cant get a true 'cold' month (sub-3C - also 12 years and counting) in that scenario, when are we realistically going to these days?

Edited December 21, 2008 by reef