what will summer 2007 bring?

[johnholmes]

summer_temps_from_1997_and_EGXI_data.xls

The above are summer temperature statistics from my weather station.

This was started 1 January 1997.

The 25 year data 1971-1995 is for Finningley.

The 1997-2006 are the figures from my station as are the 2001-2006 figures.

The temperature data for my own site and Finningley were pretty rigorously checked over about 18 months whilst I was S Met O at Finningley. Subsequent equipment changes and position have all been given the same corrections, so I'm quite happy at temperature comparisons between the two sites.

What it shows is that, similar to the post I made in the April CET thread, that the overall temperature data for any season all show a similar pattern, upwards, and by a reasonable percentage.

I am not suggesting that this trend at my station is mirrored over Europe let alone world wide but I do believe its not a bad indicator of what has happened in many parts of the UK. Probably some parts of Europe also, chiefly the western fringes probably.

Will the trend continue this summer? No one knows, although I suppose the odds are on it being above normal rather than below the 1971-2000 average.

Even more of a question to pose is what is the main driving force for these warmer summer months.

Leaving aside the discussion on GW and/or AGW what is it which is causing this? My own view, expressed last year was, still is, that its the persistence of the Euro high, both at the surface and in the upper atmosphere that is largely responsible. Is this an extension, as mentioned in a thread recently, of the basic climate zones to the south, edging north, or is it something else causing it?

I hope we can discuss this in a pleasant manner, constructive comments will be great, for or against anything I've suggested, but please no yah boo one liners or unkind digs at anyone posting their thoughts.

John

[North-Easterly Blast]

The most traditional summer weather pattern is low pressures passing northern UK with ridges of high pressure passing across the south, giving the typical pattern of short settled spells with temps into the low 20s followed by rain or showers as a low pressure passes and then another short settled spell.

What happened in July 2006 is that persistent high pressure was often over Scandinavia or Central and eastern Europe and slow moving lows stalled out west, giving a prolonged hot south to south-easterly flow over the UK. The same is true in August 2003 with frequent slow moving anticyclones over or just to the east of the UK, and also in the summer of 1995, as opposed to the traditional summer weather pattern described above.

[acbrixton]

John thanks for posting the data. Apart from the upward trend in recent years I was surprised that Finingley's summer averages were quite so warm: maxima are not that different to Greenwich 71-2000 (courtesy of UKMO):

"Jun 20.2 11.1

Jul 22.8 13.6

Aug 22.6 13.3"

Regards

ACB

[Bottesford]

Graphing your data its a very obvious trend - upwards - especially the past couple of years.

My first Office 2007 graph as well!

[johnholmes]

upwards really over the past 307 years it seems to me.

Why is the question?

[Stratos Ferric]

summer_temps_from_1997_and_EGXI_data.xls

The above are summer temperature statistics from my weather station.

...

Leaving aside the discussion on GW and/or AGW what is it which is causing this? My own view, expressed last year was, still is, that its the persistence of the Euro high, both at the surface and in the upper atmosphere that is largely responsible. Is this an extension, as mentioned in a thread recently, of the basic climate zones to the south, edging north, or is it something else causing it?

I hope we can discuss this in a pleasant manner, constructive comments will be great, for or against anything I've suggested, but please no yah boo one liners or unkind digs at anyone posting their thoughts.

John

Although I haven't checked the data my instinct is warmer, sunnier and less wet: all points to increased prevalence of HP and a northward migration of the Mediterranean climate so that here in the UK, certainly in the south, we're now on the fringes. We certainly very rarely get polar air in summer - even accepting the rut we temporarily got stuck in last August.

In our lifetime they will be rewriting the books on climate that as recently as twenty years ago would have been considered to be stable for, probably, centuries.

[noggin]

Will the trend continue this summer? No one knows, although I suppose the odds are on it being above normal rather than below the 1971-2000 average.

John

Another way to look at it is that the longer the trend goes on, the more likely it is to change. Because nothing stays the same. Result.........colder weather.

[Bobby]

Another way to look at it is that the longer the trend goes on, the more likely it is to change. Because nothing stays the same. Result.........colder weather.

Perhaps a bunch of aliens said that about Venus, which was once much like the Earth. Look what happened there...

[biddie]

Perhaps a bunch of aliens said that about Venus, which was once much like the Earth. Look what happened there...

not necessarily look at 2003

[Mr Sleet]

summer_temps_from_1997_and_EGXI_data.xls

The above are summer temperature statistics from my weather station.

This was started 1 January 1997.

The 25 year data 1971-1995 is for Finningley.

The 1997-2006 are the figures from my station as are the 2001-2006 figures.

The temperature data for my own site and Finningley were pretty rigorously checked over about 18 months whilst I was S Met O at Finningley. Subsequent equipment changes and position have all been given the same corrections, so I'm quite happy at temperature comparisons between the two sites.

What it shows is that, similar to the post I made in the April CET thread, that the overall temperature data for any season all show a similar pattern, upwards, and by a reasonable percentage.

I am not suggesting that this trend at my station is mirrored over Europe let alone world wide but I do believe its not a bad indicator of what has happened in many parts of the UK. Probably some parts of Europe also, chiefly the western fringes probably.

Will the trend continue this summer? No one knows, although I suppose the odds are on it being above normal rather than below the 1971-2000 average.

Even more of a question to pose is what is the main driving force for these warmer summer months.

Leaving aside the discussion on GW and/or AGW what is it which is causing this? My own view, expressed last year was, still is, that its the persistence of the Euro high, both at the surface and in the upper atmosphere that is largely responsible. Is this an extension, as mentioned in a thread recently, of the basic climate zones to the south, edging north, or is it something else causing it?

I hope we can discuss this in a pleasant manner, constructive comments will be great, for or against anything I've suggested, but please no yah boo one liners or unkind digs at anyone posting their thoughts.

John

I think you are spot on John. The most recent IPCC summary for policymakers makes it clear if you look carefully that changes to N Hemisphere circulation over the last 30 years cannot be explained by known ( natural or man made) forcings. i.e synoptics is probably driving the N Hemisphere changes, not GW.

Edited April 27, 2007 by Mr Sleet

[ukmoose]

Interesting question, John and clearly an upward trend there for all to see. Also, as SF has observed, not only warmer but drier and sunnier in summer and warmer of course in the winter. Strangely, it seems that the sunshine records keep being broken too, even in the winter months. But thinking about it, with increasing pressure overall, that makes sense too.

I remember 10 years or so ago the computer models were suggesting that Britain would have a Mediterranean climate in, I think it was 60 or 70 years' time. Well the means 50 or 60 years now but it looks as though the trend is moving much morfe quickly than that. Climate is the trend for weather over a number of years and there is probably no definitive time scale for this but clearly things are happening much fsater than was predicted. Could we then have a 'true' Mediterranean climate in as little as, what 10 years? Five? Three??

That brings us back to your original question -why? I think you and several other posters have hit the proverbial nail. One reason the computer models have been caught out and predicted climate change 60 or 70 years hence is because they were only fed with global warming style data.

Actually, as we have seen, changes to the movement of pressure belts has caused us to receive much more of our weather from warmer quarters for prolonged periods of time. The Euro high blocking has prevented the Atlantic lows from heading our way in the way that we were used to, reducing rainfall significantly. More high pressure means more sunshine, generally. Put all of these factors together and we have what we are now experiencing rapidly increasing warmth, increased sunshine and drastic changes to rainfall patterns.

What is alarming is that these (unforeseen pressure pattern changes) have affected our climate in a much more rapid timescale than the much-feared global warming has so far done. Put the two together and.....

Regards,

Moose

[Stratos Ferric]

Another way to look at it is that the longer the trend goes on, the more likely it is to change. Because nothing stays the same. Result.........colder weather.

Alas, that doesn't necessarily follow Noggin. It might be true in a flat climate, where a rebound would be expected, but in a warming climate it's not the case. Less warm at some point, but my choice of words is deliberate: "less warm" rather than "cold".

[johnholmes]

in a private chat within the forecasters thread Brick pointed out an interesting point. That is that the average minimum temperatures have risen much more than the average maximum temperatures.

When I get time, for my own little back yard, so to speak, I'll do the checks on the data I've quoted above.

Edited April 29, 2007 by johnholmes

[summer blizzard]

For me, June 2007 was a perfect example of global warming, warm and wet with an average minimum over 2C above average but an average maximum only 0.4C above average.