Let's talk about the weather

gad-westy

gad-westy

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Graham
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Sorry if this topic has been discussed before. I'm trying to get clued up a bit more on predicting conditions in advance of a shoot and though I have some specific questions, I thought this might be a good place for a bit of general Q&A on the topic.

Anyway, to kick us off. I went out the other night to shoot the milky way. All my apps were telling me things would be perfect. Milky way should have arched nicely over my subject to the North. Clearoutside app was telling me that Sky was to be free of cloud at all heights at the time I was going to be shooting (3am, ouch!) and a new moon meant no moonlight to ruin the party.

But what I actually got was a fair bit of low cloud in my shots with stars visible above that. I realise now that this is likely because, although it was clear where I was and directly overhead, I hadn't really considered how far north I would need the sky to remain cloud free and clearly it wasn't.

So first question from me is really just how far away from my locations I should be looking at in terms of cloud cover? And does it depend on what height the cloud is at, I assume it must do when considering angle of view but I don't know. Although this occasion was astro stuff, I guess it's even more relevant when predicting sunsets and sunrise.

I have another question about dew points but that can wait!
 
It's hard to predict but my train of thought is, if I'm going to the Peak District for example, and rain has been passing through from west to east, but it's predicted to be clear in the Peak District and the rain is still passing through the east, I'd expect to see cloud facing east which may block out direct light at sunrise even though the skies overhead may be clear. I hope that makes sense! I'm not that scientific about it and would expect others to be able to elaborate more.

The thing is forecasts from both Met Office and MeteoGroup based apps have been so patchy of late it really is hard to know what you're getting. Just a few years ago you could look at BBC forecasts alone (when they were Met Office based) and get a pretty accurate picture. I tend to look at multiple apps now and mountain weather information service (if I'm going to one of the areas they cover) and take a punt based on all of the information. I don't find any apps to be particularly reliable now so it's an educated guess.
 
If I am checking within an hour or two of being at the location I use the Met Office observations data rather than forecasts, it's the real observed data over the last 12 hours and it is available as a map with animation so you can see which way the cloud and gaps in the cloud are moving.

And yes, cloud height and your height make a difference. https://www.skippysky.com.au/Europe/ have low medium and high cloud and https://www.meteoblue.com/en/weather/forecast/seeing has “Astomincal Seeing” with low/med/high but I have not found that to be very accurate, better than nothing for free though.
 
Cheers folks. Need to spend a bit more time researching the cloud thing. There have been times when I've gone to the coat on clear forecast days only to find cloud cover way out the east blocking any sunrise. I've started checking forecasts over mainland Europe as well but not sure just how far east I should be checking.
 
Just bear in mind............whatever weather provider you use, apart from the local witches, will use computer algorithms to translate observations into forecasts. Computers work to rules. No-one's ever told the weather what those rules are....................;)
Which is another way of say nothing will ever be perfect.
If you're working an area close to you it's worth taking the time to learn its localised weather. For example a layer of cloud along the coast where land meets water is common, but you can learn when it happens locally and when it doesn't.
Weather is fascinating.
 
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