Daft weather question?

[tuxzek]

Daft question.

Well not really I hope. My question relates to the recent cloudy weather. Over the summer we had loads of clear nights and now its really frustrating to see cloudy evening after cloudy evening.

Do any of the UK astronomers here, know if certain times of the year are more susceptible to being shrouded in cloud then other times? I am basically wondering if for example October is normally cloudy while November and December are generally clearer.

I have only started to look at the night sky so have no historical memory of nights being so cloudy, that said I do seem to remember December last year seemed to have clearer nights.

Maybe I should keep a log of cloudy and clear nights.

[cantab]

I expect there's weather/climate data on this. Maybe take a poke round the met office's site.

[tuxzek]

Thanks, I will try that. I am just wondering how long I need to wait to get a nights skywatching in.

[damnut]

Hi Tuxzek,

It seems like an age since we had good viewing conditions. A lot of the weather and pressure patterns are associated with the position of the Jetstream in relation to the uk. It would be interesting to see its related plot over the last couple of years.

Cheers

[tuxzek]

Cheers damnut, yes I was just wondering if clouds might be seasonal just like we know april showers don't happen in April.

[Starblazer]

If this winter is anything like last 2 years for me, I doubt i'll be seeing any stars!! Right at the peak time where I could fit in plenty of viewing, I had to contend with grabbing gaps in the clouds, not easy with an eq6 and 10" scope lol.

[peterules]

Well it looks to me like it's getting better! I'm in London and been hating all these cloudy nights! But today has been the first time i've seen sunshine, so i'm praying that it at least stays like this throughout the night! A gap in the clouds is enough for me... Fingers crossed for all of us

[Carbon Brush]

I suspect that if you did find historical weather patterns, you would find that the last few years do not match the long term trend.

You can make predictions a few days ahead from the met office general site. Local shorter term predictions are availble from the met office aviation service.

Though at the end of the day you just have to accept there is no substitute for sticking your head out of the door early evening.

[damnut]

Hi Starblazer, similar here 10" sct, 70lb lump to take in and out!.

The jetstream seems to have wandered south of the uk during summer this gives a block to the high pressure we normally associate with summer and we get wet warmish winds from the atlantic full of cloud and rain. Normally in summer the Js is north of the uk, this pulls the highs in as in 1976 when that large high sat right over Denmark and parked itself for a while, High over denmark = stable summer condtions.

Conversly this movement south allows cold arctic air to hit during the winter - see last two winters with the JS south of the uk blocking again. This allows the heavy prolonged snowfall that we have recently experienced.

[tuxzek]

Good point about the jet stream I guess while waiting for clear skies or at least clumpy clouds I can peek into weather forecasting.

I think my question has been answered, even with historical data it wont really predict the weather for the current season.

[Capricorn]

You will have to look up data for clouds or rain for as long back as is feasible, realistically 50 years.

This will depend on where you live as well. If I remember the place for the most sunshine, so I assume least clouds, was Bognor Regis.

Looking at the weather maps over the last few days there is a lot of cloud passing over Cornwall and Devon and right up the West side of the England, Wales and Scotland. This seems to be fairly normal. I guess that Oxford falls into this.

This weather we are having will be fairly typical as we tend to talk about any long hot dry summers, or even spells like that, meaning they are the unusual ones, not the norm.

[dmahon]

Is it more likely to be cloudy at night than it is in the day?

[FraserClarke]

There is some interesting data from the metoffice here, which gives long term averages across the UK;

Met Office: Climate averages

Of course, most of this is daytime based, and I haven't yet found an equivilent for nightime data.

In my experience (~15 years), around the equinoxes (March/September) seem to be a bit better (on average) than around the soltices (June/December). I'm sure this is due to the annual variation of the jet-stream + weather patterns, but I don't know the details.

Some of the best conditions you get are during a mid-winter high pressure, where you get crystal clear skies with 14hrs of darkness for 3--4 nights in a row. That usually happens 2--3 times a year I find.

Interestingly, May has substaintially more sunshine than June/July/Aug, despite the sun being up for longer in those months. So when people say "it's a rubbish summer this year", they're usually remembering through rose-tinted glasses -- summer is usually rubbish (wet and cloudy) in the UK. Not sure how/if that translates into clear nights though.

Our all sky camera is not far from you tuxzek (central Oxford), so you can get an up-to-date view of the Oxfordshire sky if you want;

Wetton All Sky Camera, Oxford

[Dave Dubya]

I believe it used to be that the jetstream's influence would lull somewhat two or three times a year and we'd get a static high pressure area over the UK -

So December/January would have cold clear skies and the end of August/into September would have that warm clear weather.

However, I'm not sure if that's still the case.

[tuxzek]

There is some interesting data from the metoffice here, which gives long term averages across the UK;

Met Office: Climate averages

Of course, most of this is daytime based, and I haven't yet found an equivilent for nightime data.

In my experience (~15 years), around the equinoxes (March/September) seem to be a bit better (on average) than around the soltices (June/December). I'm sure this is due to the annual variation of the jet-stream + weather patterns, but I don't know the details.

Some of the best conditions you get are during a mid-winter high pressure, where you get crystal clear skies with 14hrs of darkness for 3--4 nights in a row. That usually happens 2--3 times a year I find.

Interestingly, May has substaintially more sunshine than June/July/Aug, despite the sun being up for longer in those months. So when people say "it's a rubbish summer this year", they're usually remembering through rose-tinted glasses -- summer is usually rubbish (wet and cloudy) in the UK. Not sure how/if that translates into clear nights though.

Our all sky camera is not far from you tuxzek (central Oxford), so you can get an up-to-date view of the Oxfordshire sky if you want;

Wetton All Sky Camera, Oxford

Thanks for the last link that is truly awesome. It is now a permanent bookmark in my browser. I just love the time lapse video from yesterday. Awesome.

Thanks for the info something to think about. In the end I was out last night sneaking a peek at the moon and Jupiter between the clouds. Even with the cloud passing in front of the moon is was strangely captivating.

[tuxzek]

I believe it used to be that the jetstream's influence would lull somewhat two or three times a year and we'd get a static high pressure area over the UK -

So December/January would have cold clear skies and the end of August/into September would have that warm clear weather.

However, I'm not sure if that's still the case.

Sounds like the jetstream is the thing to look for. At the moment I am doing university study in the evenings so it is a case of do I skywatch or do some study. I have quickly figured out that when we get clear skies make the most of it, as there are plenty of cloudy nights for study.

[tuxzek]

Quick link to some Jetstream data, it appears to be south of the UK and so I presume that this is why we are getting this cloudy weather. I a also presume that in summer a south Jetstream means good weather (as per damnuts post above) but in winter which I assume is to do with our tilt away from the sun a southern jet stream causes bad weather. Be interesting to know if this is true.

Link -> http://virga.sfsu.edu/gif/jetstream_atl_init_00.gif

[klaatu]

The level of cloud cover is directly related to the % of people who have just bought new telescopes. The powers that be have to make it difficult for the person with the new telescope to actually use it for at least a fortnight. If they are arranging clouds for enough people then it pretty much guarantees continuous cloud cover for the whole country. If amateur astronomers were to stop spending money the crops would wither in fields

[tuxzek]

The level of cloud cover is directly related to the % of people who have just bought new telescopes. The powers that be have to make it difficult for the person with the new telescope to actually use it for at least a fortnight. If they are arranging clouds for enough people then it pretty much guarantees continuous cloud cover for the whole country. If amateur astronomers were to stop spending money the crops would wither in fields

haha. That sounds as plausible as my take on how the jetstream affects our weather.