December CET

[Stu_London]

Interesting that the 06z was one of the milder solutions in FI - not without support, but with less support that other GFS runs over the last 24 hours.

If the trend is back to colder then we could be looking again at sub 0c or close to it.

What we really need after the cold spell is a big fat high over us for a week. Wouldn't please the snow lovers but would deliver the 0C cet.

[kold weather]

EVen the 06z isn't mild really, most days are close to average and the final couple of days would probably cool things down again so the period between between the 20-31st likely would only end up between 4-5C and even that maybe a little high given the first 3 days are still severely cold...

Either way looking very likely we will be below 1.5C and I think the odds are we will end up below 2C...Sub Zero is still very possible, esp if the colder solutions on the ensembles come off...

[summer blizzard]

This December is certainly looking like an exceptional month, and i believe that we will not get above 1C now given that GFS maintains the freezing conditions to the 22nd, GEM maintains them throughout its output as far as the 23rd, (at 240 hours out it has proven to be the most reliable) and ECWMF also maintains below freezing conditions throughout. Within the 240 hour timeframe, only the GFS is running scared, and of the three log range models, GFS has had the worst record over the past three months.

On a side note, i do think that the current charts are similar to late December last year with the low too far west at first, though if you recall, cold conditions were maintained.

Also, GFS aside, there is great snow potential for most of England on sunday/monday.

[kold weather]

Well most models have the surface cold lasting now to the 23rd in the CET zone so even if we do see an attempt to push milder air into the south it looks to me like we will continue to pull in -2/3/4C CET days the whole of the 18-23rd period and maybe a bit longer.

Chances of getting a sub zero CET starting to increase again, though still a long way to go and the period between the 25-31st could easily be enough to push us above 0C...

[Roger J Smith]

By the 23rd, I would need a few mild days to get up to 0.8 C ... but I'm a sport, let's hope for the negative outcome. Hell, we came this far, let's go for the coldest December.

By the way, imagine saying anything like that in say 2006? You'd be taken off to a mental hospital.

[Optimus Prime]

By the way, imagine saying anything like that in say 2006? You'd be taken off to a mental hospital.

I remember discussing March of that year being one of the coldest of the last century...then came the southerly blast for the final week, I don't think it will happen this time. Below February 1991 70% odds I would had thought. First 4.0c below average CET since 1986 about 30%. Keep having to bear in mind how much warmer the earth is.

[kold weather]

That warm earth didn't exactly stop the coldest last week of November being from 2010 did it OP

Anyway I think the odds are pretty high that we go below Feb 91 and probably below Jan 10...how low we go though is still very much up for debate and clearly depends on the upcoming cold spell....

Anything above 2.3C is now just about out of the question given the synoptics and therefore its pretty much nailed on we are going to have the coldest December since 1981...its just whether we get close to December 1981 thats the question...

[Stu_London]

18z would probably get us up to somewhere above 1.5C by the end with a more zonal flow.

That said, until this weekend is resolved, things could go any number of ways.

I would think sub zero is looking slightly more unlikely - I would have liked to have stayed below zero during the milder spell we have until Wednesday (which wont be the case) for that to happen.

guesses around 0.5C to 1C would be favourite at this stage, but there is a lot less confidence than usual at this stage of the month and the spread of possible outcomes remains quite wide.

[kold weather]

I totally agree Stu that range is looking pretty solid at the moment but really there is still maybe as much as 3C range...but that little range you mentioned is probably the most likely at the moment IMO as well...

[Weather-history]

Mid November to mid December period is going to be interesting. Could be the coldest since 1879.

Looking at Philip Eden's anomalies since the 21st of November to the 13th of December results in that period of having an anomaly of about -5.4C

[Isolated Frost]

I think RJS' 0.8C prediction is the best so far, but we'll see, it could oscilliate from -2C to 4C to be honest.

For me, it'll be about whether we get a mild snap around Xmas, or the cold continues, sub 0C could be possible if the latter prevails.

[Cymro]

I think RJS' 0.8C prediction is the best so far, but we'll see, it could oscilliate from -2C to 4C to be honest.

For me, it'll be about whether we get a mild snap around Xmas, or the cold continues, sub 0C could be possible if the latter prevails.

I would say it's neon impossible to get above 2 going by what the models are progging.

[paul tall]

I would say it's neon impossible to get above 2 going by what the models are progging.

"Nigh on"

[Cymro]

"Nigh on"

Oh dear I do apologise my English can be very poor at times . Second language you see!

[BornFromTheVoid]

-0.1C to the 13th.

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

Yesterday was 1.3C. Minimum for today is a cool -1.8C while maxes look like being around 4C, so will probably be at 0C by tomorrows update. After that, going by the 06z GFS, we'll be at...

0.3C to the 16th,

0.0C to the 18th,

-0.2C to the 20th,

-0.3C to the 21st.

If we are on -0.3C to the 21st, we'd need 5.3C/day to reach 1.5C, 3.7C/day to reach 1C, 0.63C/day to reach 0C, -1.9C/day to beat the lowest December on record -0.8C.

[NorthNorfolkWeather]

-0.1C to the 13th.

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

Yesterday was 1.3C. Minimum for today is a cool -1.8C while maxes look like being around 4C, so will probably be at 0C by tomorrows update. After that, going by the 06z GFS, we'll be at...

0.3C to the 16th,

0.0C to the 18th,

-0.2C to the 20th,

-0.3C to the 21st.

If we are on -0.3C to the 21st, we'd need 5.3C/day to reach 1.5C, 3.7C/day to reach 1C, 0.63C/day to reach 0C, -1.9C/day to beat the lowest December on record -0.8C.

It's all up in the air after the weekend, but a couple of days with a slack flow could give us some impressive lows, having forecast 2.9, I reackon 0.0 to 0.3 is going to be near the mark.

[Stu_London]

-0.1C to the 13th.

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

Yesterday was 1.3C. Minimum for today is a cool -1.8C while maxes look like being around 4C, so will probably be at 0C by tomorrows update. After that, going by the 06z GFS, we'll be at...

0.3C to the 16th,

0.0C to the 18th,

-0.2C to the 20th,

-0.3C to the 21st.

If we are on -0.3C to the 21st, we'd need 5.3C/day to reach 1.5C, 3.7C/day to reach 1C, 0.63C/day to reach 0C, -1.9C/day to beat the lowest December on record -0.8C.

Hi BFTV

I think you may be a little conservative with your figures. Decent chance of being below -0.5C by the 22nd I would have said. A lot will depend on where the breaks in any clouds are - GFS very bullish about some very low minima, although I do accept these are on the north edge of the CET area on some nights.

[kold weather]

Yep Stu I have few doubts the CET zone will be back getting -7/8/9s and maxes are likely to be sub zero as well so I fully expect at least 3-4 -3/4C type days which are going to shunt the CET downwards.

Anything above 2.4C now looks impossible, realistically anything above 1.5C is looking increasingly like a big ask as well at the moment though still enough uncertainty not to rule it out...

Even if we had a week like the last week of December 74 we'd still end up a little below December 1995 and thus the coldest since 1981...it really is now just a case of how severely cold we end up...

[BornFromTheVoid]

Hi BFTV

I think you may be a little conservative with your figures. Decent chance of being below -0.5C by the 22nd I would have said. A lot will depend on where the breaks in any clouds are - GFS very bullish about some very low minima, although I do accept these are on the north edge of the CET area on some nights.

Hello Stu!

The GFS has been downgrading the cold closer to the time, yesterday the 06z would have had us at -0.6C to the 20th, today it's down to just -0.3C.

I usually increase the minimas a bit (~1-1.5C) from what the GFS shows as it tends to overplay them a little at times. Also, if this slow moving frontal snow/sleet event comes off during the weekend or early next week it would keep the mins up quite a bit across the CET zone imo.

Edited December 14, 2010 by BornFromTheVoid

[BornFromTheVoid]

The 12z GFS would have us at -0.6C to the 21st.

Game is still on for coldest on record!

[Stu_London]

The 12z GFS would have us at -0.6C to the 21st.

Game is still on for coldest on record!

Definately a colder run from the 12z

Still progging a milder outlook through christmas, however I am far from convinced of the breakdown from the south west, they are almost always wrong, especially from the GFS.

We have three days of small rises to get through with the CET and then at least 5 or 6 days of sharpish falls.

[summer blizzard]

This December is certainly looking like an exceptional month, and i believe that we will not get above 1C now given that GFS maintains the freezing conditions to the 22nd, GEM maintains them throughout its output as far as the 23rd, (at 240 hours out it has proven to be the most reliable) and ECWMF also maintains below freezing conditions throughout. Within the 240 hour timeframe, only the GFS is running scared, and of the three log range models, GFS has had the worst record over the past three months.

On a side note, i do think that the current charts are similar to late December last year with the low too far west at first, though if you recall, cold conditions were maintained.

Also, GFS aside, there is great snow potential for most of England on sunday/monday.

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.

[Weather-history]

Very cold first halves to December (CET <1C)

1981: 0.9

1890: 0.4

1882: 0.9

1879: -1.6

1878: -0.8

1846: 0.0

1844: -1.2

1819: 0.2

1796: -0.8

1791: 0.8

1788: 0.2

1784: 0.3

1782: 0.9

[NorthNorfolkWeather]

Very cold first halves to December (CET <1C)

1981: 0.9

1890: 0.4

1882: 0.9

1879: -1.6

1878: -0.8

1846: 0.0

1844: -1.2

1819: 0.2

1796: -0.8

1791: 0.8

1788: 0.2

1784: 0.3

1782: 0.9

So, IF we beat 1981, we go back 120 years to the next lowest.

Interesting little run between 1878 and 1882, wonder if we'll have a few years like that. Krakatoa in 1883, so surprised that didn't impact CET, I wonder if the 1819

was a delayed reaction to Tambora

Whoops, just noticed you were only talking of the first two weeks of December. What were the overall CET's like for the years you mention in that list? Or if you can tell me where the link is, I'll look it up

Edited December 14, 2010 by NorthNorfolkWeather

[BornFromTheVoid]

19 day mean since the 25th of November is -0.74

30 day running mean is down to just 1.3C.

If the 12z is right and we're at -0.6C to the 21st the 30 day mean will be at -0.3C, though we should be below 0C by the 20th.