December CET

[Stratos Ferric]

I am actually beggining to think that even my estimate may be too high, this week will probably push the CET up to around 8.5C, but with a potent northerly next weekend knocking the CET back to around 8C and an inversion following, something in the 3C+ range is still possible, though i suspect an outcome around average is most likely.

?

Inversions are becoming this year's black. HP does not necessarily mean inversion - it needs to be cold before that particular factor kicks in. The HPs I was looking at didn't look to me like being of the cold variety. CET will drop back as the month progresses, the background is still cooling, so something 6-7C looks likeliest. I'll provide a rolling projection once we get to the 15th.

[kold weather]

I think a good indicator of whether the H will be a clear one or one of those mucky ones is the strength and where the Upper high is located. If the upper high is not there or tyoo far west then weak disturbances will be able tyo ride over the feature so to speak and helping cause instablity in the shape of cloud. However the HP being progged looks pretty well stacked up through the layers which means that while its nearby us I can see some pretty cold nights occuring, as for daytime temps I suspect they'd be below average for a while as well given the northerly flow still circulating around the high at the time.

I agree wit hthe idea of something around the 6-7C mark being most likely.

[West is Best]

Agreed SF, I'm not sure what evidence there is to suggest that there will be a temperature inversion from this projected HP set-up. Depending on the orientation, cloudy nights and weak weather fronts caught up in the flow are as likely as anything else.

Absolutely! It could well be more akin to the November 2004 high pressure, which was essentially warm.

[kold weather]

when about in November are you talking about West, because I know we had HP cell to our west for a decent part of the month?

If thats the HP system your talking about, the look at my above post, upper center was almost certainly over the mid-atlantic for the first half of the month, second half overall it moved closer to the UK but even then it only tended to ridge towards the UK in the wake of Lp's. Thats not quite the same as the progged set-up this time, as the upper high is pretty close to the UK.

A far closer set-up would be mid-late November 05, with a weak northerly and toppling HP cell over the UK with upper feature pretty close by.

Edited December 11, 2006 by kold weather

[summer blizzard]

The CET has risen according to Phillip Eden to 8.3C.

[BLAST FROM THE PAST]

The CET has risen according to Phillip Eden to 8.3C.

I am surprised about that...but of course I am not in the CET zone. 3 frosts in 4 days

BFTP

[Stratos Ferric]

I am surprised about that...but of course I am not in the CET zone. 3 frosts in 4 days

BFTP

And probably 3 in about 44 as well? I think it's fair to say Redhill is reasonably well known as being all but a frost hollow in still conditions at any time of year; foot of the downs and loamy / chalky soil...

[BLAST FROM THE PAST]

And probably 3 in about 44 as well? I think it's fair to say Redhill is reasonably well known as being all but a frost hollow in still conditions at any time of year; foot of the downs and loamy / chalky soil...

SF

Not looking back or surprised about that as my CET projections have shown...but it has been cooler than forecast and I am surprised the CET has risen as I would be very surprised if recent frosts were this localised. Yes we are prone to frosts but I live towards Gatwick and it was widespread.

BFTP

[Stratos Ferric]

SF

Not looking back or surprised about that as my CET projections have shown...but it has been cooler than forecast and I am surprised the CET has risen as I would be very surprised if recent frosts were this localised. Yes we are prone to frosts but I live towards Gatwick and it was widespread.

BFTP

I was on the train N-S through the Midlands this morning. Last night's late forecast had been for widespread ground frost but I have to say there wasn't much evidence this morning. My hunch would be that with an awful lot of standing water and flooding the ground hasn't cooled as freely as it otherwise might. It'll be interesting to see what the measured minima were and what Philip's plot has it at. Certainly at the northern end of the CET band (not far from Stratosdale) it was not particularly cold at 4:45am - my car had it at 4C - despite fairly clear skies (though with some high cloud).

[Snowly does it]

I was on the train N-S through the Midlands this morning. Last night's late forecast had been for widespread ground frost but I have to say there wasn't much evidence this morning. My hunch would be that with an awful lot of standing water and flooding the ground hasn't cooled as freely as it otherwise might. It'll be interesting to see what the measured minima were and what Philip's plot has it at. Certainly at the northern end of the CET band (not far from Stratosdale) it was not particularly cold at 4:45am - my car had it at 4C - despite fairly clear skies (though with some high cloud).

Frost was patchy in Norfolk - it dropped to 3.8 here just before dawn but places nearby had frost and therefore probably hit sub 3.

[Stratos Ferric]

Here's the first projection to month's end.

The first November projection proved too high: my guess would be that at this distance from month's end the final CET is going to fall within the projected bounds somewhere between 1:2 and 1:3 occasions. My instinct at present is this month might be one of them: if it misses it will almost certainly miss low side. The conservative projection for CET is therefore at present low 7s.

...

• 6.7 : Scorcher
  
• 6.7 : snowray
  
• 6.8 : West is Best
  
• 7.0 : weatherwise
  
• 7.1 : Stephen Prudence
  
• 7.1 : Paul
  

All in pole position for the first monthly winner. Also, with quite a spread field, this group would have more than a couple of length's start for the winter seasonal prize. Still, by Friday there'll be a huge northerly programmed, just wait and see.

On this basis the year end CET will be around 10.9, and the record will be breached - accepting that the odds on sustained freezing days are so long and against as to be not worth considering - perhaps as early as this Friday, with fully half a month of the year still to go!

[Stratos Ferric]

If December comes in at 7.4 then the last seven months will comprise the follow ranks for each month against all its predecessors:

1, 69, 1, 3, 3, 22, 7:

This simply exacerbates last night's point. There are only twelve first places available: any one year has a 1:30 chance of landing one; the odds on a single year landing two are therefore about 1:900. To have five top ten months in seven (let alone in effect five top three when averaged), where "top ten" means "from 350 previous months" all but defies statistics. The odds against this happening randomly are so huge as to be dismissable, this data should therefore be taken as proof of the null hypothesis that our climate is now warming significantly.

Step change anybody? Quantum leap?

Edited December 14, 2006 by Stratos Ferric

[West is Best]

Philip's CET is currently on 8.4C (rounded up from 8.35C), though you have to go here to find the details: http://www.climate-uk.com/graphs/0612.htm

After another amazingly mild night the NW tracker is on 8.45C and rising.

The December record of 8.1C is certainly not now outside the bounds of possibility. On balance I think something in the 7's more likely, but with the synoptic outputs the way they are any cool incursions are likely to be cancelled out by more mild.

[osmposm]

If December comes in at 7.4 then the last seven months will comprise the follow ranks for each month against all its predecessors:

1, 69, 1, 3, 3, 22, 7:

Stratos, I'm completely confused by the months you are attributing these places to - as I commented yesterday that I was by some similarly odd figures on the "Beginning of the End...?" thread.....Oh, I think I see it: I guess you really meant the last SIX months, but have mysteriously stuck in another third place in addition to October's, and shifted July Aug & Sept back by a month. Um....weird.

As you know, I do not disagree with most of your assertions and hypotheses - but I think you should double-check the stats you post to back them up!

Ossie

Edited December 14, 2006 by osmposm

[Stratos Ferric]

Stratos, I'm completely confused by the months you are attributing these places to - as I commented yesterday that I was by some similarly odd figures on the "Beginning of the End...?" thread.....Oh, I think I see it: I guess you really meant the last SIX months, but have mysteriously stuck in another third place in addition to October's, and shifted July Aug & Sept back by a month. Um....weird.

As you know, I do not disagree with most of your assertions and hypotheses - but I think you should double-check the stats you post to back them up!

Ossie

Well spotted, it was late and I edited a number without deleting one. There should, indeed, be only one third place.

[summer blizzard]

Looking at the current models, there is good agreement on the synoptic outcome for the next ten days, i am thinking that the CET may well drop a lot over the next ten days as it looks like an inversion will set in next week, though it does look like this month will come out above average and there is still disagreement over the final few days of the month.

Assuming a daily CET value of around 3C average from the 15th to the 25th and assuming an average end to December, i believe that the CET will come in between 5C and 6C.

http://www.wetterzentrale.de/pics/MT8_London_ens.png

Ensembles show good agreement on temperature and therfore synoptic outcome.

[West is Best]

Assuming a daily CET value of around 3C average from the 15th to the 25th

lol. Nothing like an assumption SB!

If the high were to sit right over central England, and if there is inversion (by no means guaranteed) then it's possible it may be low. But I wouldn't bet your house on it. The ECM synoptics as per last night's 0z looks much more likely to me: the high sliding away with a very mild finale to the month.

[Snowly does it]

lol. Nothing like an assumption SB!

If the high were to sit right over central England, and if there is inversion (by no means guaranteed) then it's possible it may be low. But I wouldn't bet your house on it. The ECM synoptics as per last night's 0z looks much more likely to me: the high sliding away with a very mild finale to the month.

If you want double or quits on that steak Richard, I am happy to say no higher than 6.7 for December on Phillip or the Hadley calcs

[kold weather]

After the CET rises over the next 48hrs it does look increasingly likely that at LEAST for a 96-144hrs period we will likely see temps a good 1-2C below the average, and maybe even more if we do see some strong inversions occuring and lots of fog, which I suspect would be likely for a time. Beyond that set-up and just too much uncertainty to make a decent call on December's final outcome. I suspect with the colder period coming up, a record December will probably be on the very upper end of what is possible.

given this I'd punt for somewhere between 6-7.5C at the end, quite a wide spread tohugh because of uncertainty over the actual set-up.

By the way, for the period of 17-23rd came out with an average of 2.75C on the ensembles, 12z operational run was a touch below that, so I don't think its too unreasonable to suggest a CET in the colder set-up between 3-4C.

[PersianPaladin]

I think any punt less than 6C is rather brave IMO.

[The PIT]

Met Office have gone average temps this weekend by the way. A lot depends whether we have clear nights or not. Nothing really low predicted by the way during the night.

[Optimus Prime]

It all depends what happens with this high pressure, it it remains slightly south of Scotland it will be cold, foggy and frosty for southern areas while Northern Ireland and Scotland will be in a South Westerly flow and could possibly look good for a very mild December.

A repeat performance of November 2005 could mean a cold second half offsetting the very warm first half in which case downwards of 6.0c is possible.

[West is Best]

Currently 8.6C on the Manley CET, not rounded up http://www.climate-uk.com/graphs/0612.htm

8.7C on NW tracker.

I'd be interested to know (Kevin?) of warmer first halves of December.

[kold weather]

CEt should drop away somewhat once today is out of the way, exactly how far is totally dependant on cloud cover and whether any fog occurs...by the 27th I expect a milder set-up so i asuspect the higher end of my range still looks the most likely to occur.

[Stratos Ferric]

Met Office have gone average temps this weekend by the way. A lot depends whether we have clear nights or not. Nothing really low predicted by the way during the night.

I suspect that will be right. Looking forwards, even under a HP, we aren't going to get extravagant cold by night, even if we do get clear nights. Two or three below zero would be the lowest I'd expect us to see widely. It's not a cold source HP and the air aloft isn't particularly cold.