Summer 2011

[CroatianWeather]

Opposite of last year IMO. El Nino - La Nina - QBO - NAO/AO - Current Pattern and Pressure Positioning

Average February

Cold early Spring - March, April

Cool early Summer - May, June, July

Warm end Summer - August, September

Isolated I totally agree with you ........I think you just said in few lines what will happen in next months in UK...cool spring,and big part of summer,possible little warm-up in the August.....This afternoon,in next few hours I will release my detailed summer forecast for Europe..stay tuned!

Edited January 30, 2011 by CroatianWeather

[CroatianWeather]

And finally my first official predictions for Europe summer 2011 !!!!

You have to know that it is still 5 months to start of summer,so we should wait at least two or three months for final forecast....this what I release today is just my thoughs and predictions ...

This forecast is based on :-Pacific sea surface temperature state:EL nino/La nina

-Quasi biennal oscillation(QBO)

-actual pattern situation in Europe

-other seasonal forecasts

- etc ...

I will also make Europe divisions:

SOUTHEAST EUROPE(BALKANS)-----I expect settled and pretty warm summer,but I don't think it will be extreme in any aspect(temperatures or precipitation)...It should be warmer than average around 1 or 2°C above with around normal precipitation.I expect here ridge of High Pressure very often in summer.

EAST EUROPE(UKRAINE etc...) AND WEST RUSSIA----Here won't be heatwaves long and strong as last summer but it should again be little warmer than average.Precipitation around normal.

SOUTHWEST EUROPE----Spanish,Portugal etc... should have warm summer with possible one or two strong heatwaves!Also I expect here drier than normal !This teritory should be frequently under HP.So I think CORE OF WARM WILL BE HERE(SOMEWHERE BETWEEN SPAIN AND ITALY)

NORTH AND CENTRAL EUROPE-----Especially in central Europe(Germany,Poland) I expect lot of rain,lot of disturbances from northwest,so temperatures should be around or little below average with more than normal precipitation.Simillar in northern Europe!

UK & IRELAND----Unfortunaly I predict centar of low pressure between Iceland and UK with lot of rain,storms ,and temperatures around normal(so I don't expect colder summer).....

So,after reading this you can make conclusion that stormtrack should be:Atlantic-UK-Denmark-Germany-Poland...

BUT WE MUST KNOW THAT WE ARE ALL SERVANTS OF MOTHER NATURE AND SHE WILL DECIDE !

[Alex]

If the jet stays over Scotland then the southeast is spared! If the jet stays to the north then most of uk is spared bar the far northwest.

If the jet moves to north England then is the southeast spared? Similar to early July last year?

If the jet moves to south England we are all doomed!

What happens if the jet moves over the med or France? Any ideas on this pattern and whether it's happened before in summer?

[Thundery wintry showers]

It's not just about where the jet goes, but how strong it is. A strong jet nearly always defaults the UK to a flat westerly type with the Azores High trying to ridge into the south and low pressure to the north, with fronts moving across the UK at intervals, it can end up warm, sunny and dry in the south if the Azores High ridges far north enough but north-western areas are usually cool, dull and drizzly and intervening areas are dry and windy with variable amounts of cloud. It's arguably the worst pattern to get locked into for fans of convective type weather, not great for those after blazing hot sunshine either, but good for those who like relatively settled and fairly normal summer weather and don't live in the north-west.

A weak jet can give quite a wide range of weather types depending on where the resulting blocking anticyclones end up, but in general there is more of a bias towards dry sunny weather and more of a bias towards thundery downpours rather than persistent moderate rain when low pressure dominates.

Regarding the notorious hot dry sunny summers, Summer 1976 had the pattern of northerly tracking jet and Azores ridging but a look through the synoptic archives indicate that the jet wasn't particularly strong and that this helped to allow the Azores ridges right across the country for long periods. Summer 1995 saw a different pattern with persistent blocking highs over north-western Europe, the Azores High displaced to the west of its usual position and low pressure out in the Atlantic, but again the jet was weak- otherwise we'd have seen the low pressure in the Atlantic come crashing in.

[Milhouse]

Regarding the notorious hot dry sunny summers, Summer 1976 had the pattern of northerly tracking jet and Azores ridging but a look through the synoptic archives indicate that the jet wasn't particularly strong and that this helped to allow the Azores ridges right across the country for long periods. Summer 1995 saw a different pattern with persistent blocking highs over north-western Europe, the Azores High displaced to the west of its usual position and low pressure out in the Atlantic, but again the jet was weak- otherwise we'd have seen the low pressure in the Atlantic come crashing in.

Yes, that was the difference between the first half of last summer and a classic summer like 1995. Although we did get frequant ridging of the AH the jet was still too strong for it to build across the whole country. However fortunately the track of low pressures was far enough north not to affect the SE too much.

[Alex95]

The models are now showing cold easterlies in FI - could this be the start of a cold La Nina Spring?

[Milhouse]

However i wouldnt say a mild/warm southerly is out of the question either with several of the ensemble options leaning towards one. Though as its still late winter/ early Spring it wouldnt take much of a change in wind direction to bring cold back over the UK.

[Bottesford]

And since easterlies are at the most common in early spring I'm sure we'll see one at some point. More than likely a sun blocking, raw affair which are no good for anyone really!

[MP-R]

As long as the weather isn't nice in May - I don't mind what spring brings, it tends to be the most varied season when the weather is behaving itself. Not only do I have exams in May, but I also can't help but feel that a nice May is often a bad sign of the summer to come.

May 2003 was wet and unsettled then summer 2003 was fantastic

May 2004 was dry, sunny and warm then summer 2004 went downhill radidly after June

May 2005 was about average and lead on to a decent summer 2005

May 2006 was very wet and unsettled then summer 2006 was fantastic, even it did go off half way through August

April 2007 was a gorgeous month then the return of the westerlies was well underway by May

May 2008 was not dry but often sunny and warm then summer 2008 was a disaster

I could go on and on. I've used those as recent examples.

I would be happy with a wintry first half of March, an Atlantic second half of March, a showery and changeable April with a few warm spells and much the same in May with perhaps a heatwave to end the month a la 2003.

[Alex]

Last march we started with an easterly cold sunny flow I believe?

[Milhouse]

the first half was very high pressure dominated but even in strong sunshine it remained rather cold with nighttime frosts. It wasnt until the 17th when the Atlantic broke through.

[damianslaw]

the first half was very high pressure dominated but even in strong sunshine it remained rather cold with nighttime frosts. It wasnt until the 17th when the Atlantic broke through.

Yes last March saw a cold very sunny dry first 2 weeks, with nightime frost for most areas and maxes of 5 and 6 degrees, over the highlands maxima struggled to get much above freezing.

Early March can be particularly cold and wintry still with lots of frost and snow. Early March 2004, 2005 and 2006 were all cold with northerly or easterly winds bringing snow. Early March 1995 also saw cold snowy polar maritime air. Early march 2001 began very cold with some very severe frost over scotland. Most of March 1996 was cold and raw with snow mid month and later.

Indeed early-mid March particularly in the north can be every bit as cold and wintry as December, despite the increasing daylight and strength of the sun, the ground is still very cold and the seas are also very cold.. a northerly is much more potent in its depths of cold than in Dec and Jan as the arctic is at its coldest in late feb/early march.

Never dismiss the chances of freezing weather and severe snowy conditions until late March I always say.

[Thundery wintry showers]

I think your "particularly in the north" comment is an important one- down in south-east England average maxima for March are around 11C, and snow cover rarely persists for long (although there are rare exceptions, such as the exceptional northerly outbreak in early March 1970).

Further north it is rather more common- for instance many northern and eastern regions started March 2001 with a snow cover, and despite plenty of sunshine, retained most of it until the 5th- including the Scottish Lowlands, Tyne and Wear/Northumberland and parts of East Anglia. Temperatures fell below -10C quite widely, even in some eastern coastal districts which are traditionally warmed by the North Sea. I remember seeing reports that snow stuck around for the duration of the Easter 2008 spell in the Aberdeen area with thaws during sunny intervals being offset by reaccumulations during snow showers, and the Aberdeen area was hit by some 50cm of snow in early March 2006.

That said, a lot of March snowfalls feature accumulations during snow showers and thaws during the subsequent sunny intervals with temperatures oscillating between 0 and 6C. For many convective storm lovers it's actually a pretty exciting weather pattern to be locked into, with frequent dramatic changes, but of course no good if it's sustained snow cover that you're after.

[damianslaw]

I think your "particularly in the north" comment is an important one- down in south-east England average maxima for March are around 11C, and snow cover rarely persists for long (although there are rare exceptions, such as the exceptional northerly outbreak in early March 1970).

Further north it is rather more common- for instance many northern and eastern regions started March 2001 with a snow cover, and despite plenty of sunshine, retained most of it until the 5th- including the Scottish Lowlands, Tyne and Wear/Northumberland and parts of East Anglia. Temperatures fell below -10C quite widely, even in some eastern coastal districts which are traditionally warmed by the North Sea. I remember seeing reports that snow stuck around for the duration of the Easter 2008 spell in the Aberdeen area with thaws during sunny intervals being offset by reaccumulations during snow showers, and the Aberdeen area was hit by some 50cm of snow in early March 2006.

That said, a lot of March snowfalls feature accumulations during snow showers and thaws during the subsequent sunny intervals with temperatures oscillating between 0 and 6C. For many convective storm lovers it's actually a pretty exciting weather pattern to be locked into, with frequent dramatic changes, but of course no good if it's sustained snow cover that you're after.

Yes for the south sustained daytime snow cover by early March is very difficult to achieve - but if there is a particularly deep fall it will still stick until sublimation under the sun eventually melts it all. Whereas for the north, a few inches will easily stick around even in bright sunshine for at least a couple of days, in sheltered parts obviously alot longer.

Another example of snow cover persisting in the first few days of March was 2004. I remember the last day of Feb produced some very heavy snow showers near the NE coast. I was living in Newcastle at the time and worked in Sunderland. I remember going home on the Friday evening with sky all orange and thick snow beating down. This snow stuck around in much of Sunderland until about the 5th I seem to remember.

Another example of early march snow sticking around and not just in the north was March 1986, which began on a bitter note with an ice day for some. I suspect March 1987 also delivered a few days with near or full snow cover for many.

[Alex]

Even here in February in the southeast mostly late on, snow seems to melt very quickly, one such occasion was feb 2005 where a good amount fell at times particularly overnight only to be melted by 10am the next day.

Edited February 5, 2011 by Alex

[reef]

Even here in February in the southeast mostly late on, snow seems to melt very quickly, one such occasion was feb 2005 where a good amount fell at times particularly overnight only to be melted by 10am the next day.

The February 2005 easterly spell wasnt particularly potent though, with upper air rarely much below -8C to -10C at best and conditions being pretty marginal for lying snow. Sunshine is much stronger as you get into the second half of February and into March, but if the upper air is cold enough and surface temperatures low enough then snow cover can persist even in the south.

The March 2001 spell TWS mentions is a good example. Here everyday from the 1st to 5th of the month had a snowcover despite no snowfall after the 2nd. This was due to a combination of cold upper air, no flow from the North Sea to raise dewpoints and slack conditions which allowed temperatures to drop at night. Maximum temperatures for the first 4 days were 3.5-4.1C here and those temperatures were reached only briefly.

[conor123]

As long as the weather isn't nice in May - I don't mind what spring brings, it tends to be the most varied season when the weather is behaving itself. Not only do I have exams in May, but I also can't help but feel that a nice May is often a bad sign of the summer to come.

May 2003 was wet and unsettled then summer 2003 was fantastic

May 2004 was dry, sunny and warm then summer 2004 went downhill radidly after June

May 2005 was about average and lead on to a decent summer 2005

May 2006 was very wet and unsettled then summer 2006 was fantastic, even it did go off half way through August

April 2007 was a gorgeous month then the return of the westerlies was well underway by May

May 2008 was not dry but often sunny and warm then summer 2008 was a disaster

I could go on and on. I've used those as recent examples.

I would be happy with a wintry first half of March, an Atlantic second half of March, a showery and changeable April with a few warm spells and much the same in May with perhaps a heatwave to end the month a la 2003.

Im not sure April/May really has that much of an effect on the summer, in 2003 temperatures reached 25/26c across parts of The Midlands in Mid April and still got a good summer out of it, May 2006 had some weather also, April and May 2009 were both poor months here to and things didnt improve much after then either.

But i do understand where your coming from still as when high pressure hangs around for weeks in early Spring/late Winter i do worry for the summer.

Every month since July has had below average sunshine here anyway now so if that change to above average for April - September that would be lovely.

[MP-R]

Im not sure April/May really has that much of an effect on the summer, in 2003 temperatures reached 25/26c across parts of The Midlands in Mid April and still got a good summer out of it, May 2006 had some weather also, April and May 2009 were both poor months here to and things didnt improve much after then either.

But i do understand where your coming from still as when high pressure hangs around for weeks in early Spring/late Winter i do worry for the summer.

Every month since July has had below average sunshine here anyway now so if that change to above average for April - September that would be lovely.

Yes. Of course it's not as simple as that but it's the general behaviour of weather patterns. If there are prolonged spells of anticyclonic warm sunshine in May/June, it's only predictable that a change to Atlantic conditions will ensue. And conversely. I'm aware there's probably not a direct correlation with weather in spring and its influence on summer and that are probably rarities when summery weather can last through spring and summer without interruption, but I just always get suspicious when abnormally 'good' weather conditions come before they're due (like the November cold which has given way to this mush).

As you say, let's hope for a much sunnier summer this year.

[summer blizzard]

Yes. Of course it's not as simple as that but it's the general behaviour of weather patterns. If there are prolonged spells of anticyclonic warm sunshine in May/June, it's only predictable that a change to Atlantic conditions will ensue. And conversely. I'm aware there's probably not a direct correlation with weather in spring and its influence on summer and that are probably rarities when summery weather can last through spring and summer without interruption, but I just always get suspicious when abnormally 'good' weather conditions come before they're due (like the November cold which has given way to this mush).

As you say, let's hope for a much sunnier summer this year.

I actually prefer anticyclonic/hot spells in spring as an omen as a good summer, though i do support the premise of repeating patterns.

There will obviously be summers that buck the trend in terms of cold and warmth, but for the most part i like to see hot/anticyclonic spells in May at the very least.

[Thundery wintry showers]

A large number of our recent hot summers have been preceded by one or more hot spells in the spring, for example:

1976- hot spell (mainly in the SE) during the second week of May

1984- notably warm, sunny end to April

1989- notably warm May with record sunshine totals

1990- exceptionally warm southerly mid-March, heatwave in first week of May

1995- heatwave in first week of May

2003- heatwave in mid-April

2006- hot spell in the second week of May

On the other hand the hot summer of 1975 was preceded by an exceptionally cold spring with no notable hot spells, and the hot July/August 1983 was preceded by a very cloudy wet spring with no notable heatwaves, showing that these things aren't hard and fast rules.

[Milhouse]

Also 1990, 2003, 1976 and 1989 all had May CETs over 12c so if we do get a warm May doesnt mean we should have doubts over Summer. If you look further back to 1960 and 1970 where we had 2 warm Junes, they followed on from good Mays, so did 1992. But in all 3 cases the summer deteriorated from early July. 1998 and 2008 however saw a good May followed by a poor summer.

[Bottesford]

I was thinking about our good friend North Sea Low Cloud earlier. With the North Sea SSTs quite low compared to normal - how will this affect formation of the dreaded low cloud as we move into spring?

[Thundery wintry showers]

An interesting question- one would perhaps expect more in the way of low cloud with lower SSTs, and there was a common view last year that a warm spring was desperately needed to get those North Sea SSTs in order for the summer.

In reality, though, I think the synoptics are far more important than a couple of degrees' difference in the SSTs. For example, June 2010 had below-average SSTs in the North Sea, and between 5 and 9 June, easterly winds brought plenty of low cloud to the Tyne and Wear area, yet around midmonth, north-easterly winds blew and brought plenty of sunshine. At the other extreme, June 2007 had exceptionally high SSTs, yet the easterly spell of the 1st-12th had almost continuous low cloud near the east coast.

Perhaps a more significant difference arises in the temperatures, especially near the east coast, rather than the amount of low cloud produced. Onshore winds, when accompanied by low cloud, usually result in below-average temperatures in the Tyne and Wear area with cold days and near-average nights (even when other parts of the UK are warm), but the period 1st-12th June 2007 returned a slightly above mean temperature at Cleadon with cold days more than offset by warm nights. I think had the same spell occurred in June 2010 it may well have ended up a couple of degrees colder.

[Alex]

Hey I was thinking with December having a CET below 5c what would happen in a July above 5c?? 28c every day in London with nightime lows of 19c?

Also What's the highest above avg CET month in the summer ever?

[AderynCoch]

what would happen in a July above 5c??

Do you live in Franz Josef Land? :lol:

Sorry - a July 5C above the 1981-2010 average would come in at 21.7C, which beats the hottest 30-day period on record (22nd June-21st July 1976 = 20.9C). Some hot spells for comparison:

22nd June – 9th July 1976 = 22.04

24th July – 6th August 1995 = 21.04

4-13th August 2003 = 21.69

16-30th July 2006 = 21.21