April CET

[Metomania]

For it to get 8.5 by the end of the Easter weekend as Roger intimated, it would need a daily CET mean of 12.9C, I got to say it doesn't seem that likely especially if the nights are not especially mild.

Yes I'd agree that 8.5C might be pushing it. I suggested it might be around about average by the end of the Easter weekend. As you'll know the averages for April are as follows:

1961-1990 7.9

1971-2000 8.1

1906-2005 8.1

Something around 8C by Monday night looks fairly reasonable to me.

[kold weather]

As the others have said it'd be a long shot for it to reach 8.5c by Monday. Daytime maxes do look to be pretty high, probably reaching 14-15c on most days upto Monday but night-time mins should be more then enough to moderate it so even 8c will probably be quite hard to reach.

Beyond that and we see a cooler NW/N flow setting in, quite how cold and how long it'll last is subject to debate and the models are very unsure presently with some going for a classic warm day cold night set-up, and the 06z GFS going for the cold through option!

[Weather-history]

Well whatever happens with this April, there is one certainty though, the first half of Spring 2006 is going to be below the 1971-2000 average

1st March - 11th April: 5.3C (1.4C below the 1971-2000 norm)

[Guest Mike W]

It looks like April is going to strat of again with row after row of above average CET's, by negative side keeps thinging emmit loads of SO2, emmit loads of SO2... etc, in my head, I wish it wouldn't. Don't worry my possitive side thinks trams, nuclear power, wind, hydrogen fuel, etc.

[Metomania]

As the others have said it'd be a long shot for it to reach 8.5c by Monday.

As I said, it should be near average which is either 7.9C or 8.1C depending on which benchmark you use. I'd agree that 8.5C might be a tad much.

Night-time temps don't look particularly cold to me. GFS always under-estimates temps in these conditions.

Edit - Mike W: I have no idea what your post means?!

Edited April 12, 2006 by Metomania

[kold weather]

I think Mike is stating that we've had abnove average after above average April's in the past due to the reduced rates of SO2, though I'm not sure if I buy this idea to be honest.

Anyway March did a grand job proving that just because there are reduced SO2 levels and increased CO2 don't mean we can't have below average months.

Thats fair enough Metomania, though I've noticed that in fact the Beeb tend to under-do night-time mins by a good 1-2c and also daytime maxes a little. Of course GFs hasn't got fine enough resoultion to find the little pockets of slightly warmer air that are present so sometimes places will be both a little codler and little warmer on a local level then the models suggests.

Mr.Data, is that the coldest since Spring 96 or 01???

[BLAST FROM THE PAST]

Meto

Excellent statistically informative post...its what helps to make this such a good forum

BFTP

[Guest Mike W]

I agree that you can't count all the above average months down to reduced SO2 as I think So2 and soot in the old days reduced the Annual CET more than anything, but it's academic as we don't do that anymore, Another warming record we have broken is the longest gap between a CET below 2, which was 14 years 10 months, it's now 15 years 2 months and counting. The other is longest run of 10.** Annual; CET's which is 1997 - 2000, this run is equaling it, if this year finishes at 10.** it beats it, no reason why it won't, no masking effect you see. I'm not advocating the stuff, just think we put the cart before the horse so to speak, i.e getting rid of cooling gases first when our problem is warming gases, hence Global Warming, I think instead taking one type of pollutant out we should have reduced the lot out, through the alterantive enrgies we/I mention alot. I can'tt see us getting annaul CET's like 1993 let alone 1986 one's, I think 2001 annaul is probably as low as it gets. I want to be wrong on this.

Edited April 12, 2006 by Mike W

[kold weather]

Well its early days yet and a warm summer/Autumn would ruin this but I suspect we have a real shot at a sub-10c yearly mean.

I don't know how far below the 71-00 average we are presently but I'd guess its about 0.5c upto mid-April.

So overall we are about 0.75 below the target of 9.99 which is a good start, though one really warm month will soon see to that. still you must admit Mike so far this year has been quite abit cooler then recent ones which means we at least have a shot I'd have thought.

Actually, I think this year will have a turn-out very similar to 2001, that also had a weak La nina, fairly similar temps through the winter and March also. So i'd probably go for a overall yearly CET of 9.90C

[Weather-history]

Mr.Data, is that the coldest since Spring 96 or 01???

Coldest since 1996. The first part of April 2001 was warmer than the first part of April 2006. Maxima got over 20C on the 2nd of April 2001

[Anti-Mild]

Actually, I think this year will have a turn-out very similar to 2001, that also had a weak La nina, fairly similar temps through the winter and March also. So i'd probably go for a overall yearly CET of 9.90C

I'm going to go for a slightly cooler annual CET of between 9.7c and 9.8c. This is largely based on my assumption of a cooler and wetter summer than we have become accustomed to.

[summer blizzard]

With the current CET at 6.1C according to Phillip Eden, which is 2C below average, the GFS12z ensemble average would produce a CET around 6.3C by the 28th April, which is 1.8C below average.

The daily average from now to easter monday will be around 8.4C, which is 0.3C above average and should result in a CET around 7.6C by the 17th April, which is 0.5C below average.

[Weather-history]

Here's the daily CET mean that is needed to reach these values by months end

Anti Mild: 5.9C 5.6

drfeelgood: 6.4C 6.5

Steve Murr: 6.4C 6.5

Sunshine: 6.5C 6.6

Connor123: 6.6C 6.8

Shuggee: 6.7C 7.0

Snowprincess: 6.9C 7.3

Ragnarok: 7.1C 7.6

Rikki: 7.2C 7.8

Helly Hanson: 7.3C 8.0

AtlanticFlamethrower: 7.3C 8.0

Great Plum: 7.5C 8.3

Noggin: 7.5C 8.3

Matty M: 7.5C 8.3

Joneseye: 7.6C 8.5

Terminal Moraine: 7.7C 8.6

Evo: 7.7C 8.6

ChrisL: 7.8C 8.8

Mr Data: 7.9C 9.0

Glacier Point: 7.9C 9.0

SNOW-MAN2006: 8C 9.1

Peter Tattum: 8.1C 9.3

Stephen Prudence: 8.1C 9.3

Foggy: 8.2C 9.5

Thundery Wintry Showers: 8.2C 9.5

Rollo: 8.3C 9.6

Optimus Prime: 8.4C 9.8

Scribbler: 8.4C 9.8

Phillip Eden: 8.4C 9.8

Supercell: 8.4C 9.8

Londonsnow: 8.5C 10.0

bartlett_hi: 8.6C 10.1

Blast from the past: 8.7C 10.3

Reef: 8.8C 10.5

Snowmaiden: 8.9C 10.6

Kold Weather: 8.9C 10.6

SteveB: 8.9C 10.6

stricklands: 8.9C 10.6

Bottesford: 9C 10.8

The PIT: 9C 10.8

Metomania: 9.1C 11.0

Summer Blizzard: 9.3 11.3

phil n.warks: 9.6C 11.8

button-wales: 9.9C 12.3

Summer of 95: 10.1C 12.6

Roger J Smith: 10.2C 12.8

[Metomania]

With the current CET at 6.1C according to Phillip Eden, which is 2C below average, the GFS12z ensemble average would produce a CET around 6.3C by the 28th April, which is 1.8C below average.

The daily average from now to easter monday will be around 8.4C, which is 0.3C above average and should result in a CET around 7.6C by the 17th April, which is 0.5C below average.

SB I have to question your ability to make definitive statements about temperatures in the future. Using the GFS runs in the way you do is very inaccurate.

The CET is now rising fast. Philip had it at 6.3C to yesterday (not 6.1) and the NW tracker which is several hours ahead is approaching 6.7C. The tracker CET should be somewhere around 8C by the end of the Easter weekend, or average. Thereafter we will need to see what the synoptics produce, but if second-guessing synoptics that far ahead is fraught enough, stating temperatures is folly.

[kold weather]

Yeah temps are rising now very fast in terms of CET, should be upto 6.6-6.9c range by the end of the day on Philip Edens site. Will probqably reach about 8.2c by the end of this warmer spell.

Where we go from there, I haven't a clue but I suspect now something between 0.5c above or below average is looking right as I don't see any sustained spells with mins and maxes at roughly average it seems.

[Joneseye]

SB I have to question your ability to make definitive statements about temperatures in the future. Using the GFS runs in the way you do is very inaccurate.

The CET is now rising fast. Philip had it at 6.3C to yesterday (not 6.1) and the NW tracker which is several hours ahead is approaching 6.7C. The tracker CET should be somewhere around 8C by the end of the Easter weekend, or average. Thereafter we will need to see what the synoptics produce, but if second-guessing synoptics that far ahead is fraught enough, stating temperatures is folly.

SB is only using the information that is available to him. Do you suggest an alternative to using the GFS?

[Metomania]

SB is only using the information that is available to him. Do you suggest an alternative to using the GFS?

Yes. Don't use it for long-range temperature guestimates.

Seriously, model outputs are wayward enough past T+5 days on synoptics. To try and use them to second-guess actual temperatures that far out, and then state 'this is what the CET will be' is about 4 leaps of faith too far. If forecasters caution about synoptic certainty at that range, it is quadruply dangerous to use them for temperature certainties.

[Joneseye]

Yes. Don't use it for long-range temperature guestimates.

Seriously, model outputs are wayward enough past T+5 days on synoptics. To try and use them to second-guess actual temperatures that far out, and then state 'this is what the CET will be' is about 4 leaps of faith too far. If forecasters caution about synoptic certainty at that range, it is quadruply dangerous to use them for temperature certainties.

Fair enough and I agree with you that using the models to predict temperatures and CET is not the best method. What would you suggest using as an alternative method of predicting the CET?

[Metomania]

Fair enough and I agree with you that using the models to predict temperatures and CET is not the best method. What would you suggest using as an alternative method of predicting the CET?

Others may have some views, but it's ok as long as we just make clear it's really tentative and rough. The uncertainty though is what makes this monthly CET thread (and now I see an annual one creeping in!) such a piece of fun. It's a bit of a lottery really!

It all makes the Met Office winter forecast so impressive ...

[Stratos Ferric]

Others may have some views, but it's ok as long as we just make clear it's really tentative and rough. The uncertainty though is what makes this monthly CET thread (and now I see an annual one creeping in!) such a piece of fun. It's a bit of a lottery really!

It all makes the Met Office winter forecast so impressive ...

I agree with the sentiments of your point MetO, but it's just another example of the perennial tension on sites like this between professional standard precision at one extreme and "wannabe" enthusiasm at the other. Digressing slightly one of my loves on here is people citing their own "CETs" (misnomer no.1 - but I think I know what they mean) to 2dps, presumably based on instruents that measure to only 1dp: hey-ho.

I think accepting the fun element, then the sensible course is to try to ensure that semantics around data do not imply a degree of precision that really cannot be assured: as you suggest, therefore, and it is largely a semantic point, SB might be better served caveating his phrasing with a few more words and phrases like "assuming that", "making some wild assumptions" and "might be somwhere in the general vicinity of"...

Then again, there goes another winged pig out for its evening constitutional...

[BLAST FROM THE PAST]

I think my 8.7C is looking good :lol:

BFTP

[summer blizzard]

According to Phillip Eden, the current CET is 6.6C, which is 1.5C below average.

Assuming that the average of the GFS6z ensembles came off, and that there were no inversions, then the average of the GFS6z ensembles may produce a daily CET in the vicinity of 9.5C, which is 1.4C above average and may result in the monthly CET being in the vicinity of 8.2C, which is 0.1C above average.

Just to show the scale of the GFS6z operational run outlier, assuming that there were no inversions then on its own, it may result in a daily average in the vicinity of 15.8C, which may result in a monthly CET in the vicinity of 12C, which is almost 4 above average.

[Anvil Crawler]

I am currently running at 6.8°C .

[Thundery wintry showers]

in the vicinity of 8.2C, which is 0.1C above average.

Go 8.2C!

[Stratos Ferric]

According to Phillip Eden, the current CET is 6.6C, which is 1.5C below average.

Assuming that the average of the GFS6z ensembles came off, and that there were no inversions, then the average of the GFS6z ensembles may produce a daily CET in the vicinity of 9.5C, which is 1.4C above average and may result in the monthly CET being in the vicinity of 8.2C, which is 0.1C above average.

Just to show the scale of the GFS6z operational run outlier, assuming that there were no inversions then on its own, it may result in a daily average in the vicinity of 15.8C, which may result in a monthly CET in the vicinity of 12C, which is almost 4 above average.

SB,

I think it's fair to say that the prospect of inversions once we get out of the deep winter months are so negligible as to not be worth mentioning really. An inversion only impacts the CET because a dense cold pool of stagnant air develops close to the surface so that low lying sites are cooler than higher ground - of course normally the reverse prevails.

Like the caveats! Out of interest, just how do you project from GFS to temperatures, or do you use the 2m charts?

Go 8.2C!

It's certainly looking more likely to turn out cooler rather than warmer than average as things lie right now. None of the real warmth that has tended to be a feature for at least part of the month in recent years.