January CET

[Weather-history]

11th December - 21st January CET: 1.2C

[kold weather]

Even at this late stage of the month there is a wide range for the final outcome. The difference between the 0z ECM and the 0z GFS could be as much as 2 degrees on the final outcome. I certainly would still not rule out something above 2.5C and I don't even think sub-3C is actually quite as nailed as most seem to assume. A mild night last night followed by a mild day today, for instance, will pull in something above 7C for the day. Much more of that and the monthly mean will rise very sharply.

On the other hand, if the easterly does actually materialise then the opposite could still be true and we could end up at around 1C. Remarkable divergence at short range.

Last night came in actually surprisingly cool, at just 1.5C, therefore we won't be reaching 7C today either...sub 3C IS nailed on now without any doubt IMO, needs over 8C now per day to reach 3C and thats simply not going to happen, esp given a few colder days seem quite probable next week. Today will probably come in around 5C, tmeps in the CET zone at the moment generally around 7-8C.

2C is now the real benchmark with about 5.3C needed per day. The next few days should reach that and probably beat it by quite some way but monday-wednesday at least will come in below this figure. Any downward adjustments makes it more likely to come in sub 2C at the end of the month. I suspect 1.8-2C actually will be about where the raw figure ends up at, maybe a touch lower, the next 10 days probably will average out between 3-4C, maybe scope for a little lower if a decent NE flow comes in like the ECM suggests.

As SM said 2.5C is the very upper marker right now given expected synoptics, 1.5C is probably the lower mark.

[Optimus Prime]

Strangely if the figure comes in below 2.0c I personally don't think it's felt like a cold month. I'd say January last year felt colder.

[Duncan McAlister]

Strangely if the figure comes in below 2.0c I personally don't think it's felt like a cold month. I'd say January last year felt colder.

It was those widespread minus double figure minima that did it I suppose, on 2 or 3 nights?

[damianslaw]

Some cold minima likely over the coming days especially early next week and low maxima as well will help to prevent anything higher than 2.5 degrees being realistically recorded. As Mr Data states, 2 degrees is a good benchmark with increasing signs that the finishing mark will be below this especially if a northerly verifies. With inevitable downward adjustments, 1.5 degrees still looks within a shout.

[Snowly does it]

1.1 (1.12) to the 22nd

3.0 requires 7.5 per day from here

2.0 requires 4 per day

1.0 requires about 0.8 per day

1.8 to 2.2 now looks the unadjusted landing zone to me

[Kentish Man]

1.1 (1.12) to the 22nd

3.0 requires 7.5 per day from here

2.0 requires 4 per day

1.0 requires about 0.8 per day

1.8 to 2.2 now looks the unadjusted landing zone to me

Yes around 2.0C looks about right now. To get something nearer to 1.0C we needed that 2-3 day spell of easterlies then the high to transfer westwards at a more northerly latitude trapping the coldest air. Unfortunately the GFS rather than UKMO were nearer the mark with no real easterlies and the high transferring at a lower latitude with westerlies covering the northern part of the UK. A northerly over the last 3 days would help but the 06z GFS doesn't go for this and they seem to have been the most accurate so far about the current evolution.

[North-Easterly Blast]

Yes around 2.0C looks about right now. To get something nearer to 1.0C we needed that 2-3 day spell of easterlies then the high to transfer westwards at a more northerly latitude trapping the coldest air. Unfortunately the GFS rather than UKMO were nearer the mark with no real easterlies and the high transferring at a lower latitude with westerlies covering the northern part of the UK. A northerly over the last 3 days would help but the 06z GFS doesn't go for this and they seem to have been the most accurate so far about the current evolution.

Looking at forecast temps, the CET should be around 1.25 after today, and around 1.5*C (unadjusted) by the 26th (Tuesday). 4.6 for the final five days will then get us to 2.0*C. We would then need 7.7 for the last five days to get us to 2.5*C, which I think looks unlikely. This month at least now looks highly likely to breach the sub 2.5 barrier at least, and sub 2.0 still looks possible but less likely. To get us a sub 2.0 month it will require today's 00z ECM to come off, of which GFS has none of it. There is however, scope for a downward adjustment, as Hadley often makes when the final figures are released replacing the provisional figures, especially as Manley are around 0.5 behind Hadley atm. If we do get to 2.0 unadjusted, which I think we will, then after adjustment we may well yet still record that magical first sub 2.0*C month since Feb 1991, which will make this month certainly an unusually cold month by recent standards at least. Prior to 1988, sub 2.0 calendar months were cold but by no means that unusual, as many months in particular the 77-87 era managed CETs below this figure.

Strangely if the figure comes in below 2.0c I personally don't think it's felt like a cold month. I'd say January last year felt colder.

Last year's January was only cold up to the 10th, then the rest of the month stayed mostly average to mild, so where are you coming from? On top of this, the cold first ten days of Jan 2009 was not brought by proper cold synoptics, it was mostly due to an anticyclonic block sat over the UK giving surface cold, not deep cold Arctic air, and for most places there was little snow about. This was unlike this year, which saw a very cold and snowy first half for many parts of the UK, with proper deep cold synoptics.

[kold weather]

I think sub 2 is still very likely after adjustments, which I suspect there will be a 0.2C drop IMO but you never quite know!

Anyway a slow cooldown should occur from now on though the next 2 days should come in above the 4C needed for a 2C month to occur...

However its worth noting the GFS is really unkeen on that northerly, most other models would deliver a stronger and longer lasting flow down and the GFS however equally the ECM is likely extreme on the other end of the scale.

Still Monday-Wednesday looks pretty cold so its quite possible we may even see a slight drop for those days, esp Tuesday and Wednesday, and if nothing else we should come in below the target needed to get a sub 2C month.

[Weather-history]

Haven't recorded a daily CET mean of 6.0 or greater since the 10th of December, 43 days ago.

Now how long ago since we have had such a stretch?

8th December 2001 - 12th January 2002: 36 days

22nd January 1991 - 22nd February 1991: 32 days

2nd January - 5th February 1987: 34 days

22nd January - 4th March 1986: 42 days

30th December 1978 - 1st March 1979: 62 days

[damianslaw]

Haven't recorded a daily CET mean of 6.0 or greater since the 10th of December, 43 days ago.

Now how long ago since we have had such a stretch?

8th December 2001 - 12th January 2002: 36 days

22nd January 1991 - 22nd February 1991: 32 days

2nd January - 5th February 1987: 34 days

22nd January - 4th March 1986: 42 days

30th December 1978 - 1st March 1979: 62 days

Thanks for these stats, proof that we are encountering the longest protracted cold spell relative to the average since 1986. Recent years have been full of long periods of 6 degree CET's, long may it continue. Its true it hasn't felt mild since early Dec, just how winter should feel.

Back to the CET for this month I still feel with adjustments we will come in just below 2 degrees, how about 1.9 degrees, hope we can record a sub 2 degree, a much more representative figure of the month as a whole.

[kold weather]

Models now in good agreement for a toppler type set-up to occur which should give another couple of days with colder temps. I suspect therefore as long as Sat+sun don't come in too massivly above the 4C needed from the 23rd till the end, that we should get the sub 2C we are all looking for!

[HotCuppa]

been a good 10C everday for pretty much the past week, would be surprised to see anything below 4C this month...the average temp as been 5C for the past several weeks.

[Jason T]

Looking at the models now, looks like its all change again to very cold and high chance of snow. Confused i am.

[Weather-history]

been a good 10C everday for pretty much the past week, would be surprised to see anything below 4C this month...the average temp as been 5C for the past several weeks.

Official stations show nothing of the sort, hasn't reached 10C in Manchester since the 9th of December, Liverpool Airport reached 10C one day.

[The PIT]

been a good 10C everday for pretty much the past week, would be surprised to see anything below 4C this month...the average temp as been 5C for the past several weeks.

Have you moved to channel isles or something ????? Very high temps you've got there.

[Snowyowl9]

Sub 2 looks very possible now a cold N-ly is coming nights like this will help and this is not the N-ly.

http://91.121.93.17/pics/Rtavn4817.png

http://91.121.93.17/pics/Rtavn7217.png

Edited January 24, 2010 by Snowyowl9

[kold weather]

I'd go further and say if the 0z models come off then we will get a sub 2C month unadjusted, the northerly flow will just seal the deal I suspect.

Anyway yesterday came in surprisngly low at just 3.7C which was BELOW what was needed to get a sub 2C CET, last nights mins were about a degree colder then yesterday so it looks highly likely we will come in below the 4C needed once again. CET at the moment is at 1.23C and from now on any rises will likely be pretty small and indeed on Monday and Tuesday and the last 2 days of the month it is possible we may even see a small drop...

[Kentish Man]

Yes the projected northerly toppler has dramatically altered the likely outturn for this month. 24 hours ago the GFS were going for mild WNW's goung round the top the high which could have added 0.5C or more to the CET. Now looking at the remaining 8 days maybe only one or two will push the CET mean up, the rest will be neutral or drag it down further. Given Manley is only on 0.7C compared to Hadley's 1.2C today there is still the prospect of a 0.2C downward adjustment as well. Sub 1.0C is still just possible and sub 2.0C a certainty barring a sudden about face by the models in the next day or so.

[kold weather]

Looking at the flow predicted 1.5C is certainly on the cards though anything below that probably is something of a long shot given we are at 1.23C now and today will likely raise that towards 1.3-1.35C.

However with adjustments a severe month certainly is well within reach even if we do end up just the wrong side of 1.5C but at the very least sub 2C now looking pretty much odds on with 1.4-1.8C seemingly being the likely bullseye zone...and a very cold month, esp by previous winters standards...

[The PIT]

According too country file we have a few mild days coming up before the northerly comes in towards the end of the week. Double figures mentioned for the mild days and if it turns up that should the CET a bit of damage. The question then will the northerly be enough to cancel the upward push.

[kold weather]

According too country file we have a few mild days coming up before the northerly comes in towards the end of the week. Double figures mentioned for the mild days and if it turns up that should the CET a bit of damage. The question then will the northerly be enough to cancel the upward push.

I think thats classic beeb going way too high, the only day that looks possibly above average next week is Wednesday and its quite possible the mins will balance that out, probably maxes of 6-8C on Wednesday as a mild sector comes in ahead of the colder thrust....the UKMO is MUCH milder then the GFS and the ECM with that set-up but I think the GFS likely has a better handle on that front....so expect the Beeb to slowly lower temps as it falls inline with the other models.

Lets put it this way Pit, even the somewhat milder temps of the last week have only managed to give temps close to average, I think for once soil/SST profiles actually will be keeping temps somewhat more surpressed then you'd expect in these set-ups.

Also...finally...a sub 3C month is here, been quite a long time in coming.

Now lets see if we can get a Severe winter month at 1.5C, really need the northerly to stay as progged with no downgrade to get this without any adjustments.

Edited January 24, 2010 by kold weather

[Snowyowl9]

Yes I can`t see any double figures as Pit said max temps were of 7 and 8c at 11.50 and that was further west.

7 and 8c years ago only just gets into the mild category.

GFS goes for this for the mildest day.

http://91.121.93.17/pics/Rtavn8417.png

The night will be mild.

Then back to a cold NW-ly

http://91.121.93.17/pics/Rtavn10817.png

[Guest North Sea Snow Convection]

Sub 3C certain, and the figure will be significantly below that with ease.

The sub 3C barrier was only an artificially imposed psychological barrier for some. It didn't exist at any time as any scientifically empiric benchmark and as long predicted by many others it has 'fallen' much sooner than later, inevitable as it was.

The truth is that we are capable of witnessing a prolonged spell of weather comparable historically, indeed this winter has already proved that, notwithstanding what Feb produces

Sub 2C quite likely and maybe within 1.5C.

The argument that will almost inevitably tried to be claimed from herein that the occasionally very cold monthly CET or more prolonged cold spell is still consistent with the extent of (A)GW will be the next fallacy to be exposed IMO

But that is for another thread and another time

[J10]

The strange this is that the 3c barrier looks like being broken with a lot to spare, after seemingly unbreakable for so long.

This just goes to show that if the synoptics are right then cold will follow.