December CET

[damianslaw]

Expecting some quite low minima by the end of the week into early next week as we a slack flow develop, over deep snow cover temps should drop like a stone.

I full expect the CET to be at around -1 degrees by Tuesday next week. Odds on beating Dec 81 I say..

[kold weather]

Still too early to make that call, a couple of 7-8C days at the end of the month could be enough to take us above 0.3C...still alot of uncertainty as to how long the cold even last for, still could breakdown by the 23rd yet...

[Stu_London]

CET to 14/12/00 0.0C

15th and 16th will be rising days

17th to 22nd (at least) look like falling days.

A lot will hinge on the last week, but anything above 1C looks unlikely

Philip Eden's site has Manley running -0.2C below Hadley at present, so downward adjustments look likely also.

[kold weather]

GFS op run suggests a very mild last week once we shunt that cold air out of the way, however personally I think the cold hangs about a little longer then some of them expect.

The 06z GFS suggests an insanly cold period between the 18th-24th...It'd be well worth looking to see the coldest CET weeks for December, I know mid 81 may well be close to the top but if the 06z came off that period wouldn't be far short of it....

[Stu_London]

The 06z GFS suggests an insanly cold period between the 18th-24th...It'd be well worth looking to see the coldest CET weeks for December, I know mid 81 may well be close to the top but if the 06z came off that period wouldn't be far short of it....

Just to put this in context GFS 06z (my interpretation of) is predicting the week from 17/12/10 to 23/12/10 to average -5.6C

Mean Min during this period -7.9C

Mean Max during this period -3.3C

Some other notable cold weeks in December

1796 - 21st to 27th -3.6C (christmas day managed -10.8C that year)

1798 - 24th to 30th -4.5C

1859 - 13th to 19th -4.9C

1870 - 21st to 27th -4.4C

1981 - 8th to 14th - 3.5C

GFS may of course be over egging the cold and individual stations could come into play, but it was quite accurate with the last week in November.

Seems remarkable that having had one of the coldest November weeks ever, we may be about to have one of the coldest December weeks ever

[Cymro]

Just to put this in context GFS 06z (my interpretation of) is predicting the week from 17/12/10 to 23/12/10 to average -5.6C

Mean Min during this period -7.9C

Mean Max during this period -3.3C

Some other notable cold weeks in December

1796 - 21st to 27th -3.6C (christmas day managed -10.8C that year)

1798 - 24th to 30th -4.5C

1859 - 13th to 19th -4.9C

1870 - 21st to 27th -4.4C

1981 - 8th to 14th - 3.5C

GFS may of course be over egging the cold and individual stations could come into play, but it was quite accurate with the last week in November.

Seems remarkable that having had one of the coldest November weeks ever, we may be about to have one of the coldest December weeks ever

What a huge turnaround.

2010 with out doubt will be a year to remeber regarding cold temperatures and below average months what is it now 7 out of the 12?

[Weather-history]

Mid-November to mid-December looks like having a CET of about 1.1 or 1.2, lower than the CET for January (1.4).

The period 24th November-23rd December looks even lower possibly sub-zero.

Edited December 15, 2010 by Mr_Data

[kold weather]

I suspect we will go sub 0C for that period Mr.Data...

Anyway I have to think the GFS is a good deal too lo BUT if we do get snowcover like the models are heavily suggestive then we are going to have some very low mins and once you start the cycle off the days and nights only get colder.

[BornFromTheVoid]

The GFS 06z really is stunningly cold for the CET zone. We could easily be at -1.2C to the 22nd or -1.4C to the 23rd!

If we did reach that for the 23rd, we'd need 4C/day for the rest of the month just to reach 0C, or 0.65C/day for the rest of the month to be the coldest on record!

[kold weather]

THe 06z GFS looks too cold to be honest but I have few doubts we'll get a solid 4-6 days where we are averaging -3/4s and maybe the odd -5/6C type day.

[summer blizzard]

Further to my post yesterday, GFS has extended its breakdown by a day to the 23rd, and GEM and ECWMF both have northerlies on the 24th which is far as their ouput goes, so there is basically an extra day at least added to the cold spell. At this stage, i would say that the coldest December since 1981 and an anomoly of -4C is 90/10 in favour, a colder December than 1981 is 50/50 and the coldest on record is 80/20 against.

In regards to my side note, models now prog this weekend to be snowy for everybody, so minimums should certainly be interesting, especially early next week.

Further to my post yesterday, GFS6z has fallen into line, GFS, GEM and ECWMF all maintain sub zero daily CET values right through to and including day 10 (25th). Below 1981 is now 60/40 in favour, December 2010 will be the coldest December in over 100 years!

[kold weather]

Well the models have yet again swang to a cold solution deeper into FI with most runs developing a high pressure cell of some sort near the UK and we keep a southerly jet of some sort.

Anything above 1C now once again looking very unlikely and there is increasingly good shout at sub 0C...

06z probably would take us down to aobut -1C by the end of the month and maybe even lower...

[BornFromTheVoid]

It's amazing to think that we *could* beat the coldest December on record by quite some way if things go the way they're looking at the moment.

To go from people thinking we'd be lucky to ever register another sub 3C month to being in with a shout of beating coldest December on record in just a few years is quite remarkable and some turn around.

[coram]

Well the models have yet again swang to a cold solution deeper into FI with most runs developing a high pressure cell of some sort near the UK and we keep a southerly jet of some sort.

Anything above 1C now once again looking very unlikely and there is increasingly good shout at sub 0C...

06z probably would take us down to aobut -1C by the end of the month and maybe even lower...

Bearing in mind how warm winters have been over the last 20 years, this is highly unlikely Kold. But then so was the cool May of 2007 after the boiling summer of 2006 and warm April of 2007, as was the snowfall in April and October of 2008, as was the heavy snowfall in central London in

February 2009, as was the snowfall prior to Xmas 2009, as was the freezing and snowy spell in January 2010 and the fact that the winter of 2009/10 averaged under 3*C ( the coldest for over 30 years), as was the record breaking cold in the last week of November 2010, as was the heavy snow in the first week of December 2010............

[trickydicky]

Bearing in mind how warm winters have been over the last 20 years, this is highly unlikely Kold. But then so was the cool May of 2007 after the boiling summer of 2006 and warm April of 2007, as was the snowfall in April and October of 2008, as was the heavy snowfall in central London in

February 2009, as was the snowfall prior to Xmas 2009, as was the freezing and snowy spell in January 2010 and the fact that the winter of 2009/10 averaged under 3*C ( the coldest for over 30 years), as was the record breaking cold in the last week of November 2010, as was the heavy snow in the first week of December 2010............

Do you think something broke in April 2007? That was the peak of the silly warmth and it has been after that month that things started to turn round with the wet, cool summer that followed and the cool relatively snowy winter after that. Its almost as if April 2007 was the straw that broke the camels back!

[kold weather]

It's amazing to think that we *could* beat the coldest December on record by quite some way if things go the way they're looking at the moment.

To go from people thinking we'd be lucky to ever register another sub 3C month to being in with a shout of beating coldest December on record in just a few years is quite remarkable and some turn around.

EVen if weren't to beat the record the fact we have a real good shot at going sub 0C is just unreal compared to as you said a few years back, when some people were thinking even sub 3C needs the perfect synopitcs...

No doubt the last 3 years have been much closer to the 80s...

Just as an aside, IF we do get a December close to 0C then we have a real good shout at recording three winters which is colder then anything the 80s could produce...08-09/09-10/10-11 may well end up colder then 84-85/85-86/86-87...and those are known as the glory years of the 80s along with Dec 81 for cold winter months...

[BornFromTheVoid]

If the temperature today gets lower than the CET minimum (2.8C), will the minimum for today be changed?

Anyway, looks like we will be somewhere around -0.5C the 23rd, though if some of the very low minimas predicted come to fruition, then we could be closer to -1.0C by the 23rd.

Imagine if this was January we're looking at being within a few tenths of a degree from the record low going into the final third of the month!

[The PIT]

Do you think something broke in April 2007? That was the peak of the silly warmth and it has been after that month that things started to turn round with the wet, cool summer that followed and the cool relatively snowy winter after that. Its almost as if April 2007 was the straw that broke the camels back!

Yup the sun decided to start winding down.

Bornfromthevoid. The min once recorded won't be altered unless it's clearly in error. Any new lows with be taken with the next recording.

Just looking at Hadley (Should be rise today then some big drops again) and has there ever been a ten degree drop from October to December before ????

[kold weather]

1969 had October up at 13C and December came in at 3.3C...so not far off and there may well have been one or two such cases.

1968 also had something very similar...1995 wasn't far off and 2001 dropped by about 9C as well...

So its not that uncommon to drop say 9C, 10C is a little more rare but I'm sure there have been cases...

[The PIT]

1969 had October up at 13C and December came in at 3.3C...so not far off and there may well have been one or two such cases.

1968 also had something very similar...1995 wasn't far off and 2001 dropped by about 9C as well...

So its not that uncommon to drop say 9C, 10C is a little more rare but I'm sure there have been cases...

The drop maybe bigger than 10C yet though. If we get some really cold nights as well things could get really interesting. Actually needed new glasses. Just noticed in 95 we dropped 10.8C we ain't going to beat that here. However in the CET zone it could be a different story.

Edited December 16, 2010 by The PIT

[Optimus Prime]

CET to the 16th is likely to be around 0.5c

With the latest GFS run for the period 16th-20th comes in at -1.1c. CET by the 20th should be around 0.2c.

[Weather-history]

.

Just looking at Hadley (Should be rise today then some big drops again) and has there ever been a ten degree drop from October to December before ????

Yes, 3 examples

1874: a 10.6C drop

1878: a 10.5C drop

1890: a 10.2C drop

At the other end of the scale, there was only a 0.2C difference between the October, November and December of 1852

It went from a very cold October, to a very mild November, to an exceptionally mild December with little change.

Its odds on now that 24th November-23rd December is going to be sub-zero.

[Roger J Smith]

We seem to be outdoing the Maunder. If this doesn't last very long, it will be the Very Little Ice Age.

[kold weather]

Well the models can't decide whether to go for a Xmas breakdown, in which case something between 0.5-1C looks likely, or if we can shunt off the breakdown till close to New Years, in which case sub 0C is very possible still...

Today almost certainly will be a sub zero day in the CET zone with some places getting Ice Days from the looks of things...

[reef]

Hadley is on 0.6C to the 16th, yesterday was 5.1C.

Today's min is at -3.9C and many places are struggling to get above freezing. 0.4C or 0.5C likely to be the number tomorrow.