Spring / Summer 2010

[kold weather]

I suspect this summer will see a fairly decent Azores high in terms of strength, and I wouldn't be all that surprised if it played a fairly large role this summer. The problem is its going to be a tough call as to exactly where it sets-up and I can't make that call right now...that said I expect a below average summer in terms of precip, bar maybe the far north.

[Eugene]

Ominous signs for the summer to be honest, good dry Aprils rarely give good summers, remember the last three good aprils and what followed, the weather has a habit of balancing itself out so the rain will come at some point as we all know which will most likely be June onwards.

[Wynn D Woo]

Ominous signs for the summer to be honest, good dry Aprils rarely give good summers, remember the last three good aprils and what followed, the weather has a habit of balancing itself out so the rain will come at some point as we all know which will most likely be June onwards.

Or the good folks of the Lakes might think the dry weather has balanced out the wet period before winter

[Thundery wintry showers]

Ominous signs for the summer to be honest, good dry Aprils rarely give good summers, remember the last three good aprils and what followed, the weather has a habit of balancing itself out so the rain will come at some point as we all know which will most likely be June onwards.

Hmm... 1955, 1984, 1990, 1995 and 2003 anyone?

[BlueHedgehog074]

Or the good folks of the Lakes might think the dry weather has balanced out the wet period before winter

I kind of wonder had we not had the very unsettled November last year, then perhaps Winter and the start of Spring may had ended up more unsettled. I agree that the weather seems to like balancing itself out. It is like you could have a few thunderstorms in a row, which bring so much rain or hail that the weather becomes "tired" and some good spells of sunny weather follow on after. Though sometimes, it has been a case that a thunderstorm has been a sign of more general frontal rain to come.

@Thundery wintry showers: I remember the 2003 one quite well where Spring, specifically April, brought a good deal of dry weather, which then brought on a very warm Summer. Although parts of July and the beginning of August brought periods of unsettled weather, the huge heat wave which followed on after was quite a shock - and at times, personally made me wish the heat would go as it really did feel like a scorcher outside.

For some of the period, my family and I were staying at our grand parents bungalow down in Cornwall, so the sea breezes helped to take away the heat a little bit.

Still a shame about all the people who had struggled through the heat as it would be something you would not want to happen everyday, although I appreciate the fact that some people would enjoy the hot weather. But, for me, temperatures which reach above 34*C is not really my cup of orange juice.

[Thundery wintry showers]

I was in northern France during the first nine days of August 2003, where it reached 35-40C daily from the 3rd onwards, resulting in the holiday being cut a day short because of the heat. I must say that I'm pleased to have had that experience, just so that I know what it was like and can say I've lived to tell the tale- but it's certainly not something I would wish upon us!

Some of the other years are also notable, 1990 had that heatwave resulting in the 37.1C on the 3rd August, and 32-34C widely even in the north, while 1995 had that remarkably hot July/August marked more by consistent hot weather over a long period of time rather than individual spells of record heat, though some date records were set during that spell.

[damianslaw]

Yes we have had a fairly sustained dry period after the huge totals we recieved in November. I am a firm believer in nature balancing itself out particularly with regard to wet and dry spells, however, we have had some fairly lengthy pronounced dry spells lasting for years punctuated by some shorter wet spells.

The period from autumn 1988 to summer 1992 was a relatively dry one, with some very dry spells such as summer 1989, winter 91/92, then we saw a very wet spell between summer 1992 and spring 1995 with very few lengthy dry periods, then a notably very dry spell between spring 1995 and spring 1997, then a lengthy wet spell lasting from summer 1997 through to mid winter 2000/2001 which culminated in the very wet autumn 2000, thereafter a fairly average spell of weather lasting right through Spring 2005 with few very wet spells or dry spells, then once againa switch to a dry period between Spring 2005 and Summer 2007 which culminated in the very dry warm April 2007 (mmm a theme is developing here) and then a fairly average spell again up until dec 2009 culminating in the very wet Nov, and since then we have entered a dry spell.

Make what you make of these observations, however, we do seem to go in cycles and periods of change have often come on the back of either very dry or very wet periods as shown in the changes below

winter 94/95 very wet, followed by a lengthy very dry period

autumn-dec 2000 very wet, then a change occured to drier weather in Jan 2001

winter 2004/2005 fairly wet, abrupt change to mostly dry period in the spring and summer and then particularly the autumn and winter

april 2007 very dry followed by a very wet summer

We could be entering a fairly lengthy dry period if such cycles continue or this could be just the start of spell which gardually becomes average though it has been fairly dry so far..then again it may just a blip..

[Bottesford]

The fear is creeping in again - we're having another stunning April with lots of sunshine and dry weather. Recent experiences of such Aprils have that wet, miserable summers have followed.

Just hoping things don't go down that road again as I'm keen to have an 'outdoor' summer again after struggling since 2006.

[Don]

The fear is creeping in again - we're having another stunning April with lots of sunshine and dry weather. Recent experiences of such Aprils have that wet, miserable summers have followed.

Just hoping things don't go down that road again as I'm keen to have an 'outdoor' summer again after struggling since 2006.

I must admit that thought has crossed my mind too regarding recent warm/dry April's being followed by mixed or wet Summers. Still, that doesn't mean to say Summer 2010 will follow suit of course, but 2007 is coming to mind!

[SP1986]

Yes I think a cool, poor summer is a good bet at the moment. In fact if does occur, another very cold winter is quite likely, if it does then it'll be unusual to have 3 very cold winters in a row, but at the moment that's what we're heading towards, if the pattern continues the same as last year/year before.

[AderynCoch]

If the past fortnight has shown us anything, it's that strong sunshine can make it feel warm even when temperatures are unremarkable. It feels very warm out just now yet it's only 12C. Last Saturday felt like a proper summer's day despite only reaching 15C.

The point is, we don't necessarily need southerly air pumped into the country to experience half-decent summer weather (though it certainly helps!). As long as the sun's out and the winds are reasonably light, I'll be happy - even with cooler air aloft, the warm sunshine should make it feel pleasant (though the CET won't be anything to write home about).

I'm no expert on the issue, but a negative AO seems to be associated with poor summers. The way I've always looked at it is that a negative oscillation means less in the way of Atlantic westerlies affecting the UK - so even if the Azores High and hot southerly air is being kept to the south, I don't see how it would make things more unsettled. Perhaps someone could enlighten me on the issue?

Edited April 22, 2010 by AderynCoch

[SP1986]

I think its the collaboration of a NAO/AO which are both responsible for poor as this indicates a northerly/northeasterly bias to the pattern. However a negative AO and positive NAO may have benefits! Who knows?

Ive actually thought the sun very weak recently, I recall many times when it's been warmer than recently over the UK, even on cool days. Maybe it's just me but the sun does seems weaker even when there is no breeze blowing.

[MR EXTREMES]

Yes I think a cool, poor summer is a good bet at the moment. In fact if does occur, another very cold winter is quite likely, if it does then it'll be unusual to have 3 very cold winters in a row, but at the moment that's what we're heading towards, if the pattern continues the same as last year/year before.

i absolutely agree its very lokely indeed.

[Thundery wintry showers]

A negative AO suggests high pressure over the pole and therefore low pressure being displaced south, and so Britain is more likely to be exposed to the full force of Atlantic lows. A positive AO suggests low pressure over the pole and therefore a belt of high pressure further south, and therefore high pressure more likely to affect the British Isles. Hence the association.

There is some argument as to what the "best" summer setup is. There is the scenario of the northerly tracking jet and ridging Azores High, which is the most reliable for sustained dry settled weather, allowing at most just weak frontal systems around the northern periphery of the high. Generally it tends to be sunny and dry wherever the ridge covers, but cloudier further north, so a lot depends on precisely how far north the jet tracks. This setup dominated the summer of 1976, while Augusts 1998 and 2009 demonstrated what happens when the high only covers the south.

The other setup has an Atlantic trough and Euro high, with the Azores High itself well out west- this tends to promote a high frequency of southerly winds. It is not as reliable for sustained dry settled weather because of the tendency for the Atlantic trough to generate Spanish plumes and thundery outbreaks, while it is more reliable sunshine wise in the north, so opinion is strongly divided (some, like myself, prefer to have some convective excitement thrown in while others would rather have no rain at all). On rare occasions, as in August 1995, the Atlantic trough can park itself so far west that it doesn't bring any pronounced thundery outbreaks, which is why that month was exceptionally dry, as opposed to July 2006 which was similarly hot and sunny but had more thunderstorms with the trough slightly further east.

[Milhouse]

On the flip side you could say that this summer could break the trend of dry spring = wet summer just because its got to end sometime due to the law of averages. If May turns out to have above average rainfall will everybody then be expecting a good summer. The fact is we just cant tell, as the Met office debacle demonstrated last year.

[Weather-history]

Hmm... 1955, 1984, 1990, 1995 and 2003 anyone?

You missed the daddy of them all

April 1976

I looked at this on UKweatherworld the other day

It has been mentioned in the past that a very dry April does not favour a good summer. Is there any truth to this? It was banted about during 2007 following that very dry April and the very wet early to mid summer period.

Just for England and Wales, the top 20 driest Aprils ranked in order and the following summers.

1938: Average summer

1817: Cool wet summer

1912: Wet summer, a very cold August

2007: A very wet June/July

1957: A wet August

1893: A warm summer

1785: Average summer

1984: A very good summer

1854: A cool dry summer

1974: A cool wet summer

1842: Warm June but cool July

1783: A hot July

1954: A cool, wet summer

1844: A cool July, August

1980: A cool wet summer

1976: Hottest on record

1855: A wettish summer

1852: A very hot July

1870: A very dry summer

1801: A warmish, dryish summer

Not surprisingly, the results are mixed.

Edited April 23, 2010 by Mr_Data

[AderynCoch]

A negative AO suggests high pressure over the pole and therefore low pressure being displaced south, and so Britain is more likely to be exposed to the full force of Atlantic lows. A positive AO suggests low pressure over the pole and therefore a belt of high pressure further south, and therefore high pressure more likely to affect the British Isles. Hence the association.

Thanks for the clarification. I think I was overlooking one important factor, namely the northward shifting of pressure belts between winter and summer. In winter a negative oscillation means blocking over the North Atlantic and Atlantic depressions tracking towards southern Europe - in summer, the blocking moves northwards towards the Pole and the Atlantic depressions move northwards towards us. That seems to make sense.

Bugger.

[kold weather]

As I said before I suspect the subtropical Belt, esp the Azores high will become a dominant feature this summer and I'd expect the -ve AO/NAO signal to reduce.

It is worth saying -ve NAOs can promote a VERY warm pattern to develop, I believe we had a decent -ve NAO in the first half of summer 06 and once again in September, both periods massivly above average.

Upper atmospheric conditions and the Pacific signals should both flip during the summer which will throw things about, I'd guess therefore we will have a really mixed summer. I'd imagine background warming that has occured globally in the last 6-9 months means we favour above average in a pattern that would otherwise be close to average. I do expect this summer to have below average precip, I'd be more confident of that right now then the temps.

[Glacier Point]

Not so convinced that the sub-tropical ridge will be a player this year Darren. For the Azores high to build, you need the blocking to our north to decline, and there are a number of factors tilted towards a continuation of blocking:

1) East QBO persistence (April's value will be around -20m/s);

2) Atlantic and Pacific SSTAs, especially the warm anomaly off Africa;

3) Analogues for tropical convection which tend to suport only a slow weakening of the current angular momentum base state.

The tropics and extratropics are nicely coupled right now. Therefore, with projected decline in El Nino (and the atmosphere lagged behind this somewhat), we should be looking at examples of angular momentum hovering around neutral - positive becoming slightly negative over time.

I really like 1958 and 2005 right now as analogues although they are somewhat conflicting weather patterns. The blended composite for what it's worth:

[North-Easterly Blast]

The true summer month i.e. July has been the greatest let down in the past three years consistently wet and cool, August has also been relatively poor i.e. very cloudy. Septembers have been much better in terms of dry sunny settled weather which is what you want from the summer not necessarily hot.

Julys 2008 and 2009 had CETs of 16.2 and 16.1. Average by 1961-90 standards or even marginally above. Not that cool.

Only July 2007 was a cool month overall.

Last August, 2009, was above average for the CET even by 1971-2000 standards.

Summer 2008 had a CET of 15.43. This is still a little above average by 61-90 standards. Not a cool summer. Summer 2009 was above average (15.83*C) even by 1971-2000 standards. Not even an average summer by any definition, still slightly on the warm side.

The truth really is, that, after the exceptionally warm summers in 2003 and 2006, the last three summers overall have basically seen a return to something a bit more normal for the British Climate, and a cool summer has never happened.

As to what this coming summer may bring, no-one can really say with any certainty. Will it be another average mixed one and wet at times, or will it be a warm one, or see exceptional heat, or will we finally see a cooler than average summer. Even the Met Office has not even produced a summer forecast yet.

[Weather-history]

I really like 1958 and 2005 right now as analogues although they are somewhat conflicting weather patterns. The blended composite for what it's worth:

2005 was the better summer out of those two. 1958 was wet.

[AderynCoch]

The truth really is, that, after the exceptionally warm summers in 2003 and 2006, the last three summers overall have basically seen a return to something a bit more normal for the British Climate, and a cool summer has never happened.

Temperature-wise, yes. Rainfall-wise and sunshine-wise, no.

A summer of average temperatures but with less rain and more sunshine would feel much better than the last three summers.

[SP1986]

Forgive me but I seem to recall the temperature were pretty awful really, even by average standards!

[Weather-history]

Temperature-wise, yes. Rainfall-wise and sunshine-wise, no.

A summer of average temperatures but with less rain and more sunshine would feel much better than the last three summers.

Yes, he's been told about this before and again he does not listen. A season is made up of three factors, temperature, sunshine and rainfall.

I hardly call June-July 2007 rainfall wise typical of the British climate, they were abnormal and when you add in that May as well, they were exceptionally abnormal.

August 2008 was abnormal, sunshine wise

[damianslaw]

Julys 2008 and 2009 had CETs of 16.2 and 16.1. Average by 1961-90 standards or even marginally above. Not that cool.

Only July 2007 was a cool month overall.

Last August, 2009, was above average for the CET even by 1971-2000 standards.

Summer 2008 had a CET of 15.43. This is still a little above average by 61-90 standards. Not a cool summer. Summer 2009 was above average (15.83*C) even by 1971-2000 standards. Not even an average summer by any definition, still slightly on the warm side.

The truth really is, that, after the exceptionally warm summers in 2003 and 2006, the last three summers overall have basically seen a return to something a bit more normal for the British Climate, and a cool summer has never happened.

As to what this coming summer may bring, no-one can really say with any certainty. Will it be another average mixed one and wet at times, or will it be a warm one, or see exceptional heat, or will we finally see a cooler than average summer. Even the Met Office has not even produced a summer forecast yet.

Granted perhaps I shouldn't have referred to the last three summers as being overall cool, they were very much near average, however, compared to the four warm summers between 2003-2006 they felt rather cool, maximum temps in general in the past three summers have been dissapointing, it has been the minimums which have helped to bring CET values close to or just above average. In the northern half of the country few days in the last three summers brought days at or above 25 degrees.

Rainfall and sunshine wise there is no escaping the fact the last three summers have been poor, 2007 and 2008 being real shockers!