December CET

[Great Plum]

Roger, wouldn't anything as severe as you mention there still be extremely unlikely? Yes it will be cold, but that is freezing!

[kold weather]

The 00z model suite is frankly amazing with al lthe models going for a major cold spell..

I can't believe I'm going to say this...but...Sub 0C may well be the most likely option now...

I can't believe we are going to have a real shot at being colder then the legendary December 1981...we have a new legendary month developing right in front of our eyes!

[BornFromTheVoid]

-1.7C to the 9th

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

Yesterday was 0.8C. Minimum for today is 0.5C, maxima look to be around 7C, so CET should be around -1.1C or -1.2C tomorrow.

Going by the 06z GFS we'll be at;

-0.4C to the 12th,

-0.2C to the 14th,

-0.2C to the 16th,

-0.6C to the 17th.

If the lower resolution part of the run is anywhere near correct, we'd be around -1.2C to the 20th.

[Cymro]

-1.7C to the 9th

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

Yesterday was 0.8C. Minimum for today is 0.5C, maxima look to be around 7C, so CET should be around -1.1C or -1.2C tomorrow.

Going by the 06z GFS we'll be at;

-0.4C to the 12th,

-0.2C to the 14th,

-0.2C to the 16th,

-0.6C to the 17th.

If the lower resolution part of the run is anywhere near correct, we'd be around -1.2C to the 20th.

That would mean not once in december has the mean gone above zero :o! When was the last time that happened if ever? Could be talking a record breaking month here in any standards! Colder than 62!

[Weather-history]

A below average month is virtually guaranteed now, it would require the rest of the month to be exceptionally mild just to get up to 1971-2000 average and that is not going to happen.

Edited December 10, 2010 by Mr_Data

[Harve]

I'm sure most will be tired of the "this spell has been exceptional!" talk, but we can clearly see that from this, the November/December cold spell has been colder than the January cold spell of this year. After that who would've thought that in terms of severity of cold, it would've been beaten in less than 12 months time?

[kold weather]

Based on todays models I'd say we would struggle to get above 2C....

Even with a week averaging 8C from Xmas day through to the 31st (I don't think we wil get any breakdown before then) we still would stay sub 2C...

Therefore now it just becomes a case of how far up the cold rankings we go really...I see no reason why we don't go sub 1C overall and sub-zero is certainly a good option still!

[Weather-history]

Coldest Decembers on record

-0.8 1890

-0.5 1676

-0.3 1788

-0.3 1796

-0.3 1878

-0.2 1874

0.3 1784

0.3 1981

0.4 1844

0.5 1673

0.5 1678

0.5 1846

0.6 1870

0.7 1879

1.0 1680

1.1 1742

1.1 1791

1.2 1950

1.3 1799

1.3 1840

1.3 1853

1.4 1819

1.4 1829

1.5 1715

1.5 1798

1.5 1801

1.5 1860

1.6 1728

1.6 1822

1.6 1859

1.6 1933

1.7 1765

1.7 1812

1.8 1726

1.8 1830

1.8 1892

1.8 1962

1.9 1807

1.9 1886

1.9 1916

[North-Easterly Blast]

Coldest Decembers on record

-0.8 1890

-0.5 1676

-0.3 1788

-0.3 1796

-0.3 1878

-0.2 1874

0.3 1784

0.3 1981

0.4 1844

0.5 1673

0.5 1678

0.5 1846

0.6 1870

0.7 1879

1.0 1680

1.1 1742

1.1 1791

1.2 1950

1.3 1799

1.3 1840

1.3 1853

1.4 1819

1.4 1829

1.5 1715

1.5 1798

1.5 1801

1.5 1860

1.6 1728

1.6 1822

1.6 1859

1.6 1933

1.7 1765

1.7 1812

1.8 1726

1.8 1830

1.8 1892

1.8 1962

1.9 1807

1.9 1886

1.9 1916

Regardless of what happens between now and the end of the month, surely we can say that this will highly likely be one of the coldest first halves of December on record. The record is 1879, where the first half had a CET of -1.4*C, so surely this year must likely be the second coldest first half of December ever if not thereabouts.

[Cymro]

Looks highely likely to me that providing what the gfs has progged comes to frutition could very well be the coldest december on record!

[kold weather]

I think its highly probable the top 20 coldest December's on record list is about to get a new entry into its ranks...2010....

Indeed a real contender for top 10 as well...and if the cold spell can hang on tlll post Boxing day then the sky really is the limit.

I'm fully expecting some more -2/3/4C days in the CET zone between the 17-23rd...and maybe longer....

[Weather-history]

One interesting fact, the last occasion that both January and December were sub 2C in the same year was 1879

[Isolated Frost]

06Z looks amazing.

-2C again by Xmas day?

This mild spell really has been underdone, I think we'll get above freezing sometime soon.

[kold weather]

Mins last night looked fairly mild compared to what we've had before, I suspect we may well have an above average day today in the CET as the models have slightly underdone the mild as IF said above.

We may well briefly scrape above 0C by Tuesday as temps do reduce back to well below average but still milder then 0C, but after that at least for a few days we go back into the freezer again.

I think odds of getting below 0C have legenthened alot in the last 24hrs again, esp with certain synoptic changes occuring by the 24-26th which should put us back in a milder spell before the end of the month, its just how long it takes to get into that set-up...

Either way though I still can't see anything above 1C really...

[Weather-history]

The CET for the 24th November -23rd December period (30 days) is going to be very interesting, that is going to be low as you don't have the last week of December doubts to consider.

Even if the rest of that period were exceptionally mild, then the CET is still going to be sub 3C

This period is more likely to be sub-zero than the calendar month.

[Paul T]

-0.5oC to 11th

frcst to go to +0.4oC to the 16th, then another drop.

[kold weather]

Chances of getting a sub zero month have really gone down, the 06z GFS would likely still do the job but I think now given the way most models seem to be steadily shortening the cold spell its getting unlikely...

Odds now favour something between 1.5-2.5C, still very cold but a severe month is suddenly much more uncertain then even a few days ago where it looked like the northern blocking would last till xmas (now it barely gets to the 20th!)

[Kentish Kiwi]

Chances of getting a sub zero month have really gone down, the 06z GFS would likely still do the job but I think now given the way most models seem to be steadily shortening the cold spell its getting unlikely...

Odds now favour something between 1.5-2.5C, still very cold but a severe month is suddenly much more uncertain then even a few days ago where it looked like the northern blocking would last till xmas (now it barely gets to the 20th!)

Kold, with the recent changes in models, notably the GFS, increasing the tendancy to have the trough further west and then settle over the top of the UK with very cold upper air and slack winds, would it not be the case that overnight lows will be a lot lower than if we continued with a moderate/strong northerly flow? Could this not help to aid chances of a lower CET, especially if inversion/freezing fog conditions come into play in the CET zone to keep day time temperatures below zero for a few days?

I agree the length of the cold spell is becoming shorter and shorter on the various models, most probably to do with the section of the polar vortex likely to be dropping further west and less south than was modelled a few days ago, but could this slack set-up that results not make the period Mr Data mention of the 24th of November to the 23 of December even colder? (if you can get what I'm trying to say here)

[AderynCoch]

A lot of uncertainty for sure, though the Met Office are sticking to their guns on their Day 6-15 forecast saying that "it will stay mostly cold or very cold," the only caveat being that "some southern and perhaps central parts may become less cold for a time."

I've noticed that Weatheronline are forecasting maxima between -2C & -5C on Saturday and -3C & -6C on Sunday - I've never seen them forecast this low before.

Edited December 12, 2010 by AderynCoch

[BornFromTheVoid]

Going by the 12z GFS we'll be at:

-0.1C to the 12th,

0.3C to the 14th,

0.6C to the 16th,

0.2C to the 18th,

-0.1C to the 19th.

[damianslaw]

Still looking like we will see our coldest December since 1981, we should beat 1995. Very good potential we may even beat Dec 1981 and get our first sub zero CET month since Feb 1986 but alot can happen with nearly three weeks left of the month. If we see the month finishing like last year and going by the synoptical evolution there is every chance of this happening then a sub zero CET would be very likely.

[Weather-history]

but could this slack set-up that results not make the period Mr Data mention of the 24th of November to the 23 of December even colder? (if you can get what I'm trying to say here)

Besides yourself, no one else seem to have picked up on my point. It is possible that the 24th November-23rd December could be the coldest 30 day period since Jan-Feb 1991 or even around the February 1986 period.

[kold weather]

Yeah Mr.Data, looks highly likely to be the coldest period since 1986, indeed it looks colder then the coldest period would be...

The only reason its being overlooked is because there is a very real risk of this being up there with the big hitters in terms of the coldest December's in a long time.

Anyway a fairly cold day looks likely but nothing too exceptional outside maybe the far SE with the CET zone p[robably being the mildest in the country at the moment.

[BornFromTheVoid]

-0.2C to the 12th

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

Yesterday was just 2.1C and minimum for today is 0.1C. Will be at 0 or -0.1C by tomorrow.

After that, going by the 06z GFS, it looks like...

0.2C to the 15th,

0.1C to the 17th,

-0.4C to the 19th,

-0.6C to the 20th.

More realistic that we'll be around -0.3C or -0.4C by the 20th methinks.

[kold weather]

Yeah Saturday's maxes look a little extreme don't they...

Then again this set-up is rather close to Dec 81 and whilst there is no snowcover yet with a PV over the top of us and real deep cold wouldn't shock me if the models are underdoing the mins and thus it may end up balancing out anyway close to what the GFS suggests.