June CET

[Joneseye]

up to 25C by Sunday (officially very hot)

I don't mean to be picky Richard, but I think to call 25C very hot is a bit misleading. Would have been better to say well above average for the time of the year... I did have a little search to find the exact definitions for warm, very warm, hot, very hot etc. but failed miserably.

However, I did find an interesting piece on the heat index:

http://en.wikipedia.org/wiki/Temperature-Humidity_Index

EDIT: Just read the post from Chris and I take back the bit about very hot

[Shiny_Bottom_1]

Hi Joneseye.

Met Office Explanations are HERE

Very Hot would mean an average of >7oC above average. Actually, i'm not sure if that is for the maximum during the day, or for the 24 hour period of the day?

I suspect, it could be the later, but could be used to explain the both.

[PersianPaladin]

I live in the north-east and i certainly don't find 25C 'very hot'. I consider it 18-21 to be 'warm' 22-25 to be 'very warm', 26-29 to be 'hot' and 30+ to be 'very hot'. This is in mind of my region as well as my own heat tolerance (this country gets pretty humid in the heat and i prefer dry heat).

Oh, the joy of semantics.

[Dawlish]

Mark ... there are professional metereologists employed for working on the CET, as well as Philip who is one of the country's most seasoned experts outside the Met Office. Much science goes into this, as well as experience. I think what was probably irksome for some folk was your dismissive comment about the CET - which is, afterall, a lot older than you and I and which will be around long after you and I have died. It's a superb series, and the longest running such series in the world. Whilst no-one wants sycophancy, a little respect, and a little humility wouldn't have gone amiss perhaps?

There have to be changes to the stations. With the spread of urbanisation you obviously have to adjust sites accordingly. At the moment the Met O apply a 0.1 to 0.3C adjustment for the urbanisation effect. You can read more in basic format here: http://www.metoffice.com/research/hadleyce...bsdata/cet.html

However, if you really want the definitive study of this issue, then the Met Office have made it available. You will find it here in pdf format: http://www.metoffice.com/research/hadleyce...CTN/HCTN_50.pdf

This is a 31 page document authored by David Parker and Briony Horton and should give you all the information you will ever need on the topic of CET adjustments unless you want to do a PhD on it.

(NW mods - worth a link somewhere in the NW guide to this excellent study by the Met O?)

Nice one West. Good links and very good suggestion, which i would second. May I just add to that, again, by linking to Philip Eden's take on the Met Office changes in the CET and the comparison to the continuing Manley series, which Philip uses in the CET info on his site.

I'm no stickler for the past and especially not for orthodoxy, but I'm not sure that the Met Office changes to such a long recording sequence have enhanced it. indeed, I think the opposite has occurred. I underastand the reasons for the Met Office changing the cET, but. perhaps, they should have continued the original Manley sites and monotired the two to see any differences. It has been left to others (Philip Eden especially) to do this.

I'd rather trust the original sequence and I don't put a lot of store by Netweather's CET, Metcheck's CET, or the Hadley centre's CET. I know this is a personal preference, but it is based in my belief that the continuation, of such a long statistically relevant sequence is better than fiddling with it. The present Hadley Centre CET differs, at times markedly, from Philip Eden's continued Manley CET. i know this could imply that the corrected sequence could be now more accurate, but I don't think so, for the reasons quoted by Philip Eden.

It is worth having a look at the differences. Philip is monitoring exactly what I've been talking about. I don't think a "reliable correction" is needed, as I feel the integrity of the Manley series has not been compromised to a degree that requires correction.

http://www.climate-uk.com/CETcheck.htm

I also don't think that John was OTT at all. Anyone who has worked with the CET series and has also worked with the changes in some of the Met Office sites has a wealth of experience that any of us would find hard to match. Repect and humility for Manley's work, in Meteorology, as West said, is really necessary. It is like saying Best wasn't really much kop at ball control to a Man Utd fan (or almost any football fan), without suggesting players who were better and having the knowledge to explain why you think they are/were better. It's a bit hard to justify.

I'm always quick to question something that I feel is poor science, or poor statistics and I make no apologies for doing that; but to question the relevance of the CET series, on a met forum, showed some naivity, or some balls!

Paul

[West is Best]

I live in the north-east and i certainly don't find 25C 'very hot'. I consider it 18-21 to be 'warm' 22-25 to be 'very warm', 26-29 to be 'hot' and 30+ to be 'very hot'. This is in mind of my region as well as my own heat tolerance (this country gets pretty humid in the heat and i prefer dry heat).

Oh, the joy of semantics.

I think we've had all this before PP on another thread and frankly I'm fed up with it. The Met Office have official categories, of which 25C at this time of year is very hot. http://www.metoffice.com/weather/europe/uk/guide.html

Why don't you just keep your esoteric temperature preferences to yourself? It's not just semantics. Just because I decide that the long yellow thing I'm holding in my hand is not what everyone else calls a banana, but is in fact an orange, doesn't make the debate go further. In fact it's just a pain in the I have a problem. There are official categories in these areas and subverting them is pointless. If you want them altered publish a refereed article on it.

[Shiny_Bottom_1]

To be fair to Richard, I have done some basic calculations (which may not be correct, but I dont think it would be far wrong).

For 18.06.06 in Southern England:

Max Temp Average - 18.8oC (long standing)

Max Temp Average - 27oc (On 18.06.06)*

Therefore > 7oC from average = Very Hot

Average Temp for 24hours - 14.1oC (long standing)

Average Temp for 24hours - 22oC (On 18.06.06)*

Therefore > 7oC from Average = Very Hot

* Max and min temps taken for London area (ish) and divided by 2.

What we perhaps have to remember that this is the first 1/6th of the summer months, and we have experienced temps more akin to July and August.

Its maybe worth noting that temps at night are quite high in the South, so this pushes up the average. If night temps were slightly cooler, then perhaps we would be in the hot to warm category.

Then you of course have regional variations.

It is of course possible for London to have a very hot day, and somewhere like Manchester to have a warm day (and vice versa).

If we were to take the whole of the UK for 18.06.06, I would guess perhaps a hot day, rather than a very hot day. But then again, that would require alot more further work, and unfortunately, I have some work to do (plus I cant be arsed with nit picking - Its not like a very hot day has been called, and its forecast to be a cold day by category)

Richard - Perhaps less venting might be a better option, as all it does is add fuel to a fire

[West is Best]

Chris - a good post. My point is valid though I think. Constantly re-drawing official categories just subverts meaningful discussion for no good reason. It's like posting messages about the dates of winter. We have the categories so that everyone has a benchmark from which to be able to debate, and in the case of the CET, from which to compare. So it's completely irrelevant if PP or anyone else thinks such and such a temp is or is not 'very hot' ... there are Met Office categories which are worth sticking with for the sake of reasoned debate. Where I completely agree with you of course is that this varies according to region and baseline. As a rough guide, Philip's Manley CET graphs provide this: http://www.climate-uk.com/graphs/0606.htm

It's back to the thing about a little humility. Who are we to re-draw these things willy nilly? If we want such established categories changed we should publish a refereed article on it.

[Dawlish]

I think we've had all this before PP on another thread and frankly I'm fed up with it. The Met Office have official categories, of which 25C at this time of year is very hot. http://www.metoffice.com/weather/europe/uk/guide.html

Why don't you just keep your esoteric temperature preferences to yourself? It's not just semantics. Just because I decide that the long yellow thing I'm holding in my hand is not what everyone else calls a banana, but is in fact an orange, doesn't make the debate go further. In fact it's just a pain in the I have a problem. There are official categories in these areas and subverting them is pointless. If you want them altered publish a refereed article on it.

Hang on West, are you right there? The Met Office categories are not normed against a particular temperature, it is normed against a deviation from a particular temperature. Your 25C, as very hot, for a daily max temperature, would only work if the average daily max temp for June was <18C. I think this Hadley centre graph puts the average June max above 18C, so the weather would not be classed as "Very hot" at 25C, in June.

I could be wrong! Someone please help with the Average June max temp.

Paul

PS I love semantics!......and I must get some work done!!

[johnholmes]

we all have our own tolerance to hewat in a similar manner that we all have different tolerances to cold.

I do think its best to stick to the official Met O definition of v hot, hot, v warm, warm etc. How humid it is will always have an effect and that is why if the Met O forecaster believes hot and humid as the correct term they use it. Hot, with dry heat has just the same definition but our bodies are able to cope with dry heat rather than humid heat.

John

[kold weather]

The average temp overall is indeed about 18C for the month of June. But I'm not so sure that this is the case for the 30 year rolling CET and that the figure of 18C will probably be close to 21C I suspect given the case for more often warm-hot June's.

Then again I have nothing against the Met-office classifications and I think they are generally good, though I have to admit that I doubt there are many who do find 25C very hot and i'm pretty certain even the Met-office don't stick to that list of categoires at all rigidly. Heck even the Beeb consider temps of 22-23C average at the time of year and I suspect the Met-office do now as well. I personally expect some sort of revision to extend the warm end.

Anyway still looking at a June CET above 16C. how warm it'll actually get wil ldepend more on the overnight mins then the maxes I suspect because maxes look don't look warm at all compared to what they have been recently. I still think 17C is more then possible if we can get another heatwave.

[Shiny_Bottom_1]

Perhaps (and maybe Mr Holmes could clarify?), another way of looking at how above/below a temp is, is by using the ensembles.

If the average for the 850's is say 6, and it is forecast to be x amount above/below this, then you could also use this as a guide?

Even then, the 18.06.06 for London is still very hot.

And I totally agree with what John says. We should use official definiations of The Metoffice for such debate. The same, IMO anyway, should also be used when looking at things such as regional and national CET's.

The answer for the average for June is also not clear cut. The average for a month varies from the start to the finish, therefore, for more accuracy, it should probably be looked at on a specific date.

Also, another thing to bear in mind is that our summer temperatures have some what been quite high over recent years, making it sometimes a little difficult to decifer between recetn years temps and the average.

[johnholmes]

hi again

I must stress that unless we use a constant set of forecast values one can never compare like with like. Thus using the Met O definition of hot, warm etc, does allow us to do this.

Chris is right in that the average max temp will be higher at the end of June than at the beginning. However there is absolutely no sensible reality in trying to compare the 'average' max for say the 10th and maybe that for the 23rd for instance.

The easiest way is to compare the average max for any particular month.

For instance here the June value is 19C, so anything 7C or more above that value in June is very hot.

Now for Lerwick, say for an example with very different values, there the long term June average max is 12.5C, so for Viking in Lerwick a max temp in June of 19.5C or more would be considered very hot for that part of the UK. Indeed the highest ever value for Lerwick in June is 23.3C, here it is 32.8C, I think.

To go back to my comment re the post by Chris on the value changing from the 1st to the 30th June. Here is goes from about 17.5C to about 19.5C

the more you delve the more complex you can make it!

best to keep it as simple as possible, hence use the Met O figures for each part of the country, just have a look at the nearest long term station to you, and then use the Met O hot, cold terms etc.

John

[West is Best]

Well ... I won't add to this. I'm 100% with John on this.

Now I really do take Kevin's point about going for extremes. However, Paul, as in Dawlish Paul, what odds will you offer me on the following based on the CET series:

1. This June to be the warmest June for 30 years since 1976: 16.1C to beat in 2003

2. This June to be the sunniest June ever recorded in England & Wales: 284.6 hrs to beat in 1957 (As of yesterday 147.2 hrs, which will rise today ...)

3. This June to be warmer than 1976: 17.0C to beat and therefore the warmest since 1846 (18.2C)

4. This June to take the all-time record: 18.2C to beat

For my own ha'penny's worth ... I reckon No. 1 is very much odds on. I think No. 2 is a distinct possibility. No. 3 would be remarkable, but by no means impossible, indeed I'd say better than evens. No 4. Very unlikely but not impossible.

Of course if Reef's Atlantic get-up scenario transpires the CET will drizzle down below 15C and I'll never post on here again!

(Edit - hi Chris: amended No. 1 to take in your question!)

[Shiny_Bottom_1]

1. This June to be the warmest June for 30 years: 16.1C to beat in 2003

Are you including 1976 in that Richard

The easiest way is to compare the average max for any particular month.

Hi John. Your correct actually, and as you said later down, I think I was just making it more complex.

[kold weather]

I tend to agree with you West.

I'm pretty confident that No.1 will occur , it would only need a 3-4 day intrusion of hot air to pretty much make that a certainty even at this stage as there doesn't seem to be any cooler air air about. no.2 is possible providing the high prioves to be as strong as the models expect, but it may be quite close. No.3 is also possible but would require a 30C+ plus type heatwave. No.4 is probably just about possible still if we were to get a mega heatwave but it'd require something like a 35C type heatwave that can be sustained for a good 5-7 days.

[Dawlish]

Well ... I won't add to this. I'm 100% with John on this.

Now I really do take Kevin's point about going for extremes. However, Paul, as in Dawlish Paul, what odds will you offer me on the following based on the CET series:

1. This June to be the warmest June for 30 years since 1976: 16.1C to beat in 2003

2. This June to be the sunniest June ever recorded in England & Wales: 284.6 hrs to beat in 1957 (As of yesterday 147.2 hrs, which will rise today ...)

3. This June to be warmer than 1976: 17.0C to beat and therefore the warmest since 1846 (18.2C)

4. This June to take the all-time record: 18.2C to beat

For my own ha'penny's worth ... I reckon No. 1 is very much odds on. I think No. 2 is a distinct possibility. No. 3 would be remarkable, but by no means impossible, indeed I'd say better than evens. No 4. Very unlikely but not impossible.

Of course if Reef's Atlantic get-up scenario transpires the CET will drizzle down below 15C and I'll never post on here again!

(Edit - hi Chris: amended No. 1 to take in your question!)

Hmmm, ok! Don't laugh too much!

1. No chance. No odds. I fully expect this to be at least equalled and probably beaten, from the present gfs.

2. 4/1 against. I can't see the second half of June being as sunny as the first and beating a long-standing record doesn't happen often, though with present sunshine figures, the potential is there; hence the lack of really long odds.

3. 7/1 against. That'll take some doing, though the potential is there.

4. 25/1 against. It would take phenomenal heat to do that with only 15 days left and the CET being where it presently is - hence the long odds.

The odds reflect my agreement with you on June being very warm. I don't agree with Reef, on this and I'd offer very different odds on June being that cool. I've already commented on the possibilities of some extreme heat with a plume in the last week, so I don't blame you for considering these quite extreme scenarios - and the odds you've got factor that in.

Paul

PS You're wanting that pint back aren't you......with interest!

EDIT Kold - I just read your assessment and the odds I've quoted reflect my present, almost complete, agreement! I do think that loking at forecasts, in terms of odds and possibilities, instead of absolutes is a good - and fun - way of approaching meteorology. Many USA TV stations use percentages of something happening as a matter of course, we're just not very used to it in the UK.

[West is Best]

1. No chance. No odds. I fully expect this to be at least equalled and probably beaten, from the present gfs.

2. 4/1 against. I can't see the second half of June being as sunny as the first and beating a long-standing record doesn't happen often, though with present sunshine figures, the potential is there, hence the lack of really long odds.

3. 7/1 against. That'll take some doing, though the potential is there.

4. 25/1 against. It would take phenomenal heat to do that with only 15 days left and the CET being where it presently is - hence the long odds.

PS You're wanting that pint back aren't you......with interest!

You bet I want that pint back! And I don't live far away remember! (In fact, do you ever come into Exeter?)

Right then ... I like these odds!

No. 2: 2 pints please. It's probably unlikely but worth a shot.

No. 3: 4 pints please. I reckon we'll beat June '76, but it does depend on holding the HP scenario next week

No 4: 1 pint for fun. If I win that you'll be buying me pints for some time ...!

[Dawlish]

You bet I want that pint back! And I don't live far away remember! (In fact, do you ever come into Exeter?)

Right then ... I like these odds!

No. 2: 2 pints please. It's probably unlikely but worth a shot.

No. 3: 4 pints please. I reckon we'll beat June '76, but it does depend on holding the HP scenario next week

No 4: 1 pint for fun. If I win that you'll be buying me pints for some time ...!

All accepted. I like your confidence! For 2; 2 pints at 4/1 = 8 pints. For 3; 4 pints at 7/1 = 28 pints.

You must remember that all pints are virtual, though they can be converted at the Smugglers Inn in Dawlish - mainly so I can help to drink anyone's winnings and not have to drive (I may make an exception for small wagers, in Exeter!)

Just to remind us of the virtual wagers:

1. This June to be the warmest June for 30 years since 1976: 16.1C to beat in 2003 (no odds)

2. This June to be the sunniest June ever recorded in England & Wales: 284.6 hrs to beat in 1957 (As of yesterday 147.2 hrs, which will rise today ...) 4/1

3. This June to be warmer than 1976: 17.0C to beat and therefore the warmest since 1846 (18.2C) 7/1

4. This June to take the all-time record: 18.2C to beat 25/1

Paul

PS for anyone else, these are this run's odds and they will change, either shorter, or longer, as the month goes on

[reef]

Of course if Reef's Atlantic get-up scenario transpires the CET will drizzle down below 15C and I'll never post on here again!

A bit of a cheap shot there West. Nowhere have I suggested that the CET would fall and I definitely didnt give any figures. I suggested that there would be two possible outcomes from the current setup: Either the Azores high ridges in and gives more settled and warmer weather, or the Atlantic pushes in and brings warm but wet weather (aka August 2004). I actually agree that it is looking like we are set for an extremely warm June, though I think the chances of beating 1976, 1846 or recording the sunniest June are unlikely.

In my opinion:

To beat June 1976 would require a daily CET of 17.6°C - possible, though the current pattern doesnt look robust enough to achieve this.

To beat June 1846 would require a daily CET of 19.7°C - no chance, its very rare to have such a prolonged hot spell of this magnitude in the UK.

To beat the June record sunshine amount of 284.6 hours would require every day remaining to have an average of 8.6 hours of sunshine per day. - Certainly possible, though the current high pressure is much dirtier than the previous, so I would say it looks unlikely.

[West is Best]

A bit of a cheap shot there West.

Peace my friend! I really wasn't being sarcastic - I do retain a % chance of your scenario coming off. Paul is spot on about %ages, and hence why punting has a point to it. Anyone who is 100% definite about any weather pattern in the UK is asking for big trouble! So I'm serious - if the flat Atlantic scenario did happen I'll be buying Paul lots of pints (mostly virtual, but some for real!).

By the way - virtually wall to wall sunshine here in the west today so nothing dirty about this high ridge. You should see some of the sunshine spreading east over the next couple of days as the temps build once more. Could be a warm weekend (technically very hot in parts, but I'm not going over all that again!).

To beat June 1846 would require a daily CET of 19.7°C - no chance,

Re. 'no chance' ... careful! See above. Unlikely, or very unlikely perhaps but with a possible hot spell coming up it's by no means impossible. Remember that it's perfectly possible at the end of June to have a week with CET averaging 22C or more - easily.

[kold weather]

I'd be careful of using the word easily West, its not easy to have a week with a CET of over 22C, though it is at this point certainly possible and I agree with you. Mind you I don't think its at all likely as you say West, its probably very unlikely though we HAVE presently got a base high enough to make that sort of figure possible.

I still think 17C is very much possible, more likely then us getting the record sunniest month infact, as we still have a high base and it'll warm up again by the weekend with temps probably getting upto 26-28C and night-time mins above average we should see the Cet re-stablise, even if its for a few days.

[Guest Mike W]

13.8

[West is Best]

I'd be careful of using the word easily West,

Hang on - I put about 50 caveats before that word about likelihood etc! But in mid-summer a burst of heat i.e. a week over 20C is easily achieved. One hot spell at this time of year can do it - easily. Most appropriate word.

[Guest Mike W]

13.8 is a joke BTW

[Weather-history]

Here's a list of warm Junes (CET of 16 and >) and whether the warmth was sustained throughout the rest of the summer.

The years are ranked with the warmest June first in the groupings

Junes, where the warmth was sustained

1826, 1976, 1781, 2003

Junes where the warmth was sustained into the July but not into the August

1762, 1775, 1728, 1818, 1772, 1707

Junes where the warmth was not sustained into either July or August

1822, 1658, 1726, 1940, 1970, 1896, 1950, 1785, 1786, 1804, 1960, 1672, 1683

Junes where the warmth was sustained but to a much lesser degree than in June

1846, 1676, 1798,