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Why Can We Have Weeks Of Rain, But Not Weeks Of Sun?

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Hey all,

I'm just wondering why it's possible to have weeks on end of rain and low pressure systems, but when it comes to sun & warmth, it's hard to get it for a sustainable amount of time?

Obviously the position of the country doesn't help, but surely it's possible?

I created this topic as I really am fed up with the seemlingly endless unsettled theme! Even the Met Office do not seem confident of a warm up any time soon, and looking at the models, I can see why..

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your second sentence is your own answer!

Simply down to the position of the UK; look at similar areas around the world with large oceans upwind of them, they get similar weather to this country.

Take a look at any climat atlas for sunshine, rainfall totals etc it all fits.

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Due to our situation at the downwind end of the Atlantic and being surrounded by water it is hard to get weeks and weeks of warmth and sunshine.

If it's warmth, sun and dryness you're after then a high pressure area sat over or to the east of Britain, or perhaps to the north-east if the resulting easterlies are not very moist, will usually do the trick, but it is hard to get high pressure sitting around in those areas for a sustained length of time- the "default" position for summer high pressure is towards the Azores which introduces greater chance of cooler cloudier weather on the northern/eastern flanks of the anticyclone. For warmth and sunshine in relatively changeable conditions, a generally cyclonic/southerly type without much frontal activity will generally suffice, but again, with us being at the downwind end of the Atlantic it is difficult to sustain that setup without fronts subsequently piling in from the west.

On the other hand it is easy to get weeks upon weeks of dull, cool and wet- a succession of Atlantic fronts will usually suffice for that. However, the first half of this June has been somewhat unusual for high rainfall and lack of sunshine, and last year's June produced a better example of something more "normal" from the Atlantic.

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further to my post

compare Shannon and Vancouver, you will find they are not that different in rainfall and temperatures

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further to my post

compare Shannon and Vancouver, you will find they are not that different in rainfall and temperatures

But a key difference being that Vancouver experiences over double the July sunshine that Shannon does.

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As said above its the position of the uk.. If you want "decent" summer weather dont expect to see it in the united kingdom.

Apart from 8/9 days at the end of May the weather as been dire for almost 3 months..

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But a key difference being that Vancouver experiences over double the July sunshine that Shannon does.

yes to every cloud etc or glass half full/empty approach to life

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To be fair in the last few years I can remember several unusually long periods of dry sunny weather. Usually it's not come in the summer though. Last year for example I recorded almost no rain March-April and the previous year barely any rain from April to June, with some unusual warmth and sun too. April 2007 also comes to mind. We've also had some unusually dry settled weather in the Autumn in recent years. Then we've had some very wet periods which have unfortunately often come in the summer. The Northern Blocking in recent years seems to have messed up our weather patterns a bit.

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So changing it a little, is this the same reason we can get weeks of rain but not snow?

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in brief yes

height shows this nicely, check the temperature and type of precipitation at higher level stations compared to low level ones. In continental type climates height is of less significance. Have a look at Toronto or Onario compared to Vancouver?

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Hey all,

I'm just wondering why it's possible to have weeks on end of rain and low pressure systems, but when it comes to sun & warmth, it's hard to get it for a sustainable amount of time?

Obviously the position of the country doesn't help, but surely it's possible?

I created this topic as I really am fed up with the seemlingly endless unsettled theme! Even the Met Office do not seem confident of a warm up any time soon, and looking at the models, I can see why..

Hiya,

Yes it is possible to have sunny, dry and warm weather for a sustainable period of time.

The favourable synoptic set occurs far more frequently than most people think. However, out of the three variables the warmth part of the equation is the least likely to fall into place. The reason being that to experience a sustained period of sunny, dry and warm weather all at once we would only have a window of opportunity for about a third of the year. Two thirds of the year would not offer the warmth under favourable synoptics.

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Hey thanks for the great answers guys, appreciate it.

Never actually thought about us being at the downward wind end of the Atlantic, but it does make a lot of logical sense when you think that the prevailing wind is West, and what's out West? The Atlantic is.

Learnt a lot, thank you! :)

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As said above its the position of the uk.. If you want "decent" summer weather dont expect to see it in the united kingdom.

Apart from 8/9 days at the end of May the weather as been dire for almost 3 months..

I think you're forgetting the spell at the end of March, which in some ways was more exceptional than May's.

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Oh yeah i forgot that.. sort of makes up for April 85% of May and now June..clapping.gif

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Well I'm not complaining, I'll be more than happy if it stays like this until early October and then turns really unsettled.

Of course it is possible to get several weeks of generally sunny weather, you only have to look at the summers of 1959, 1976, 1989, or 1995 to name but a few but it's certainly not the norm in this part of the world.

Nor is it the norm to get weeks of generally cloudy and wet weather although there are a number of summers where it did happen such as 1954, 1956, 1980 or 1985, for instance.Most summers fall somewhere in between with a number of shortish dry warm and settled spells interspersed with unsettled periods lasting from a couple of days to a week.

As several other people have commented being downwind of 3,500 miles of ocean is the determining factor of our climate.

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I think you're forgetting the spell at the end of March, which in some ways was more exceptional than May's.

It was only warm in the southern half of England though, It was very warm everywhere in May's spell

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^^ Did you forget Scotland's record breaking March temperatures? Reached 22C widely across northern England.

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The late-March spell was more a case of certain areas of the country, including west Cumbria, missing out on the high temperatures. The Tyne and Wear area got up to 20-22C away from the extreme coastal fringes- about as warm as it got during July/August 2011.

It's worth noting that prolonged sunny weather is actually most likely during late spring and summer. This is because when we import cloudy moist airmasses from around our shores, the strong sun often burns off associated banks of cloud quite rapidly, so many anticyclones that start off cloudy become clear and sunny shortly after their arrival. Conversely, prolonged dry sunny weather is unusual during the winter months because although anticyclones often start off clear and sunny, once we get cloud trapped inside them it is remarkably hard to shift it.

The main issues during recent summers is that we've had frequent setups with frontal systems piling in off the Atlantic, and then when we've had high pressure, it's often ended up in the "wrong" place (in the sense of promoting a sustained airflow from a moist source giving relatively cloudy conditions despite the strength of the sun). Statistical quirks like this crop up quite often in the British climate- most summers during the 1990s had the opposite situation, with anticyclonic spells tending to be reliably sunny and warm and cyclonic spells often not having a succession of fronts sent our way.

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Yes the March spell this year, April 2011, April 2007 and most of the spring of 2003 are examples of sustained periods of sunshine. It can and does happen, I think we just need more factors to go in our favour than are needed for sustained spells of wet weather.

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Why Can We Have Weeks Of Rain, But Not Weeks Of Sun?

Maybe we don't deserve weeks of sun, so haven't been rewarded?

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UK - island on the edge of the Atlantic, primary flow of weather systems is east - west, Atlantic is moist, guess what that means for us?

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do you not mean west to east? although the April to June period I would have thought the main wind direction is East

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Yes the March spell this year, April 2011, April 2007 and most of the spring of 2003 are examples of sustained periods of sunshine. It can and does happen, I think we just need more factors to go in our favour than are needed for sustained spells of wet weather.

May 1990 was exceptionally sunny

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I think it's more the fact that we can never get the right weather at the right time of the year at the moment. If we had February and March's synoptics in summer it would have been a corker. October and November last year's synoptics would have also led to very decent summer conditions. Unfortunately though, our weather has become somewhat topsy turvy.

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do you not mean west to east? although the April to June period I would have thought the main wind direction is East

Oops , yes I do, my bad, it's been a long day!

February - May is the driest time of the year for most of the country.. July is usually rather dry too. But the point is the prevailing wind direction is west, so we're more likely to be cloudy than not

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