Is there a reason for so much cloud?

[SniffTheGlove]

I have long forgotten when I last did some decent long hours of observing. For so many months there has been constant cloud and when the breaks have happened for the odd hour the seeing has been bad.

Is there a meteorological reason why the UK is suffering with bad weather conditions? (Don't tell me it is down to global warming)

Is it down to the placement of the jet stream being in the wrong place or just real bad luck we having been having. Now as I type this it is chucking down with rain so no clear skies tonight I expect (again)

It is very hard to persude the wife to allow me to spend £2500 on an imaging rig when I can not use my Dob for several months due to cloud

[pete_l]

I'm yet to be convinced that the amount of cloud we experience is more or less than normal.

As to why, here's my take:

Weather systems generally move west -> east (due to the direction of the earth's rotation). Since we're on the eastern side of a large mass of water, it's only natural that a lot of water is picked up as air travels across it. That's the cloud.

[Grunthos]

Is there a meteorological reason why the UK is suffering with bad weather conditions?

Yes.

Briefly (very briefly) it's down to the air masses arriving in the UK.

Sources of air mass includes polar maritime, causing cold, moist, unstable conditions, with possible convective cloud, showers and thunderstorms.

If you want more detailed info you'll need to study up on meteorology.

PS: It's not "bad weather", it's just "weather".

[JamesF]

There was an interesting Horizon programme a short while ago that I'd recommend watching. It was called "Global Weirding" AFAIR.

In the specific case of the British weather I believe the suggestion was that the shrinking size of the Arctic ice cap and other warming effects around the polar region are causing the jet stream to be pushed further south and changing the shape of the atmospheric "cells" that circulate air around the world. If the UK ends up in the wrong place relative to them we experience more extreme weather conditions and because the wind patterns change we end up receiving lots of moisture-laden air or dry, cold air when we wouldn't normally do so.

I was blissfully unaware that other parts of the world are also suffering equally from extreme weather conditions, some more conducive to good nights for astronomy than others. Texas has had (I believe) a couple of years of extreme drought, followed by exceptionally heavy rain last winter, and I believe Australia is just coming out of a very long drought period. Warming seas are apparently also leading to far more hurricanes than would normally be expected, too.

That said, sometimes extreme weather conditions "just happen", but certainly where I live I'd suggest that the weather has not really been "normal" for five or six years.

James

[Adrian]

If it carries on like this every year April will become renowned for having prolonged heavy showers... Oh Wait

[JamesF]

If it carries on like this every year April will become renowned for having prolonged heavy showers... Oh Wait

Last time I checked, "April Showers" weren't horizontal

James

[SniffTheGlove]

So is this an indication of what is to come in the future years for us here in the UK. Neither settled winter or summer periods just months of mush all mingled together with cloud? In previous years there were many many good periods of clear skies at night yet from beginning of 2011 it has reduced significantly.

Looking at the movement of the jet stream does bring that wired weather and if sure looks like it is going to stay this way here in the UK for a while

[SniffTheGlove]

If it carries on like this every year April will become renowned for having prolonged heavy showers... Oh Wait

April has been quite dry these last few years even with periods of temps in the 20's

[pete_l]

I think we've had quite a few periods of clear weather recently.

Here's a plot of clear days and clear nights from the Met Office.

It's from their historic data archive, for my local weather station. As is apparent from the black bars (number of hours of clear skies each week), while there are lots of lows - some for prolonged periods, there are also some long runs of clear nights.

January and March of this year had a lot of clear skies and while summers seem to be a disappointment - not just from the small number of hours of darkness, but because it's cloudy, spring and autumn seem to do quite well.

[JamesF]

On the one hand, it's odd that people's observations don't match the statistics, but on the other hand it isn't.

For instance, it was my habit for a long time before I owned a telescope to get a drink and sit outside watching the stars for fifteen minutes or half an hour before going to bed. I used to do it pretty much whenever possible and usually several times a week. These days it's often too cold or cloudy. But that isn't because the statistics are wrong, or that my memory is wrong, but actually because the statistics aren't "measuring" the same thing as I am (ie. how cold and cloudy it is at bedtime

People might also form the impression that it's been a very rainy month, say, when the statistics show it to have been no different from average, perhaps because rather than three or four showery days per week it has absolutely bucketed down every four or five days.

The same disjointedness occurs with these statistics, I think. There's absolutely no reason whatsoever to dispute their accuracy, but where many amateur astronomers are concerned, five hours of clear sky between midnight and 5am after a cloudy evening is a bad night because generally they'll either not know about it or not be able to make use of the time and will be remembered as a cloudy night. On the other hand, five hours of clear sky from 8pm to 1am is an excellent night. In the statistics, they both look the same. In the astronomer's memory, they're completely different.

James

[SniffTheGlove]

Yes James, you are correct. I look out of my east facing window several times an evening and if I see cloud then I sit infront of the TV/PC but if it's clear then off out I go but anything after 11pm is ignored as I am off to bed then unless I can be guaranteed 100% clear skies for 3 hours at least.

I do like that weather Chart you posted Pete, do you have a like to the page that generates it?

[pete_l]

I do like that weather Chart you posted Pete, do you have a like to the page that generates it?

The data comes from the Met Office. They collect reports from various weather stations around the country. Here's a link to my local station, you can find others that may be more relevant to where you live

Met Office: High Wycombe: latest

As for the plot, I have a iittle script that runs regularly and scrapes the tabular hourly observations data from the page and I generate the plot myself, rom that. I've been collecting this data for the past 2 years which is what you saw in the previous post.

There's a ton of "interesting" stuff that the Met Office makes availalable. Another little gem that may be pertinent is their historical monthly summaries here: Met Office: Historic station data which goes back 150 years.

Enjoy

[acey]

We've got a big low pressure system stuck over us that has been producing lousy weather. It's not so unusual. And only a matter of weeks ago there was a high pressure system that gave lovely daytime weather and a stretch of superb clear nights. As the data posted by pete-l shows (and I can confirm from experience), we've actually done pretty well so far this year, on the whole.

[ArmyAirForce]

I got my scope in the third week in February, and had five observing sessions during the rest of that month. In March, I had twelve observing/photographic sessions. In April, I had three, which included two hours on Saturday observing the Sun through gaps in the clouds! April has been poor up North!

[Mr Spock]

It's physics:- the amount of cloud is inversely proportional to the amount of kit you own.

[MadAlbert]

It's official:

http://www.bbc.co.uk/news/uk-17897982

Perhaps we can get on with summer now?

[David JM]

Yes, we live in Britain. Britain doesn't have a climate, it just has weather.

£100 to anyone who can invent a cloud filter. Until then I hear there are things called "eye-telephones" that you an put an apple on to look at the sky whatever the weather.

[E621Keith]

Remember there was a telescope shortage a few weeks ago. The weather was brilliant. However, it has been raining like cats and dogs when the shipment from Skywatcher and Celestron arrived.

I wonder why it's raining so much?

[David JM]

It's physics:- the amount of cloud is inversely proportional to the amount of kit you own.

I appear to have widdled myself laughing.

[Donkeiller]

Personally I blame the Met Office. You can pretty much guarantee they will get it wrong. The trouble is they rely on computer models.

This is the forecast.

Met Office 3-month Outlook

Period: April – June 2012 Issue date: 23.03.12

The forecast presented here is for April and the average of the April-May-June period for the United Kingdom as a whole.

This forecast is based on information from observations, several numerical models and expert judgement.

SUMMARY – PRECIPITATION:

The forecast for average UK rainfall slightly favours drier-than-average conditions for April-May-June as a whole,

and also slightly favours April being the driest of the 3 months.

With this forecast, the water resources situation in southern, eastern and central England is likely to deteriorate further during the April-May-June period. The probability that UK precipitation for April-May-June will fall into the driest of our five categories is 20-25% whilst the probability that it will fall into the wettest of our five categories is 10-15% (the 1971-2000 climatological probability for each of these categories is 20%).

This is the reality.

BBC News

30 April 2012 Last updated at 17:52

April is the wettest month for 100 years

Aerial video shows Somerset floods

Man dies as floods create havoc

Somerset’s rivers on flood alert

Badminton Horse Trials cancelled

This has been the wettest April in the UK in over a century, with some areas seeing three times their usual average, figures from the Met Office show.

And we actually pay these bozos through our taxes!!

[iwatkins]

So it's the Met Office fault the weather is poor at the moment? Come on.

Yes, it relies heavily on NWP systems to forecast the weather, as do all the leading meteorological services worldwide. Do you have a better suggestion on how to do it?

As for your comment that they are "bozos". I work for the Met Office, so thanks for that.

And only a small percentage of Met Office funding comes directly from the Treasury. The rest is contracts that are competed for.

[JamesF]

I have to admit to laughing at the video of the floods in Somerset where the car is driving along the flooded road getting deeper and deeper and eventually coming to a halt. That was stupidity of the highest order and so astonishingly predictable. I realise it's not nice to laugh at others misfortune, but really, what *did* they think they were doing?

Good to see the Badminton Horse Trials cancelled, too. Astounding waste of money. I hear they've never yet found one guilty.

James

[Joguj]

To be fair, the Met office and the rest of the forecast centres have an impossible job but really, long term forecasts are so unreliable as to be laughable. Any one of us can now look at a 3 hour roll of cloud patterns from satellite and can comfortably predict what we should expect over the next 24 hours, not like 15 years ago when the mere mortal was not privvy to such information (or not so easily in anyway).

I would never trust ANY forecast from ANY source more than 48 hours ahead. Weather is far too chaotic and continuously proves experts wrong for me to have any faith in them, at least in the UK. It's one thing predicting a 7 day sunny spell in Oman or hurricanes in the American midwest but 7 days ahead on our little island which is subject to weather patterns reacting all over the Northern Hemisphere I fear is out of our reach?

And as for even longer term forecasts over a couple of months, well, we all know how they turn out don't we? It's the very reason that weather forecasters are the butt of so many jokes in this country, they have always got it wrong because it's an impossible job to do. But we still love them!

[johnrt]

Good to see the Badminton Horse Trials cancelled, too. Astounding waste of money. I hear they've never yet found one guilty.

James

Very very good.

[Donkeiller]

To be fair, the Met office and the rest of the forecast centres have an impossible job but really, long term forecasts are so unreliable as to be laughable. Any one of us can now look at a 3 hour roll of cloud patterns from satellite and can comfortably predict what we should expect over the next 24 hours, not like 15 years ago when the mere mortal was not privvy to such information (or not so easily in anyway).

I would never trust ANY forecast from ANY source more than 48 hours ahead. Weather is far too chaotic and continuously proves experts wrong for me to have any faith in them, at least in the UK. It's one thing predicting a 7 day sunny spell in Oman or hurricanes in the American midwest but 7 days ahead on our little island which is subject to weather patterns reacting all over the Northern Hemisphere I fear is out of our reach?

And as for even longer term forecasts over a couple of months, well, we all know how they turn out don't we? It's the very reason that weather forecasters are the butt of so many jokes in this country, they have always got it wrong because it's an impossible job to do. But we still love them!

I agree absolutely.

Which is why I am astonished that politicians believe in 25, 50 and 100 year "projections" from these guys.

Predict/project and inherently chaotic system? What are they on?