<p>It's something I've thought about myself a fair bit over the years, wondering if such is possible.</p>
<p>I'd think:</p>
<ul>
<li><p>Cloud coverage would be the firstmost factor.  Especially in the sun setting/rising direction (which of course does vary a bit by latitude/season).  Too thick should tend to often mean little beauty.  Though the one caveat is that the sun could peak through underneath the clouddeck minutes before sunset/after sunrise and lead to some of the more spectacular surprises, with all the complex reflection surfaces.  So I'd think the most negative factor of all would be thick low level cloudcover extending far into the western (or whatever the sunset/sunrise direction is) sky.  Such that you'd see little to none of the sun.<br />
On the other hand the right clouds in other areas of the sky may lead to more interesting sunsets/sunrises.  I'd think some clouds in other directions, particularly in bands, may increase the beauty at times due to the more complex shapes leading to coloring variety.  Or even some more limited, somewhat nearer, clouds that tend towards having higher bases might work (<a href="https://x.com/NWSPittsburgh/status/1865524431663358254" rel="nofollow noreferrer">backed up by this Tweet</a>)</p>
</li>
<li><p>Particulates will also be important.  Distant volcanic eruptions and smoke are <a href="https://www.youtube.com/watch?v=Kzlbr6AaLu4" rel="nofollow noreferrer">well known enhancers</a> of sunrises and sunsets as they improve scattering via the variation of particle sizes in the right range.  Does the wind advect heavy doses of it into the direction of the sun?  Great!<br />
Whereas pollution lower in the atmosphere and near the observation point tend to attenuate the light and dull the sunset.</p>
</li>
<li><p>Lower humidity (at low levels) likely helps a fair bit.  Drier days makes the sky <a href="https://www.rochesterfirst.com/weather/weather-blog/fact-or-faux-are-skies-really-more-blue-during-fall-than-in-summer/" rel="nofollow noreferrer">bluer</a>, which could aid in contrast, and get you those really classic <a href="https://x.com/CSG1973/status/1865799321360175189" rel="nofollow noreferrer">orange to blue gradients</a>.<br />
Whereas greater humidity at low levels tends towards more condensation droplets that can absorb light [about universally the greatest absolute moisture levels are found in the low levels of the atmosphere]; foggy days aren't good for sunrises or sunsets.  Of course clouds are connected with station humidity, but more-so low-level cloudiness than upper (and so more humidity again hints at clouds being more of an issue than a positive)</p>
</li>
<li><p>PBL height is an interesting one.  Low PBL height suggests lighter winds and tend to be correlated with sinking winds, meaning less low-level cloudcover.  But they also then concentrate particulates in that more confined region nearer to the ground... and such conditions often stack up to multiple stale days in a row when under persistent high pressure [the general cause of such conditions], which will grow in haze and negative types of pollution over time.  On the other hand, larger PBL can mean the wrong particulates are higher in the atmosphere, and so a larger range of angles near the rise/set will have the light passing through the hindering haze before reaching you.<br />
So not sure which is best.  Perhaps low PBLs for the first day or two?</p>
</li>
</ul>
<p><a href="https://www.spc.noaa.gov/publications/corfidi/sunset/" rel="nofollow noreferrer">Here's a great discussion that hits on many of these ideas</a> by severe weather forecaster Steve Cordfidi that may add further insight.</p>
<p>I'm thinking one more key to what we perceive as fantastic sunsets is variety.  If we've had overcast for days with little sun, any decent sunset may seem very eyecatching.  And if we've seen a long string of clear sky blue-to-orange gradient sunsets, a day with some cloud coverage mixing up the shading some may really draw our attention.</p>
<p>And of course different people may like different sunsets.  Thunderstorm lovers like me may find a sunset like the left one more interesting, landscape lovers may find the middle one more interesting, and darker color fans may find the right one more interesting:<br />
<a href="https://i.sstatic.net/YFv8qQqx.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/YFv8qQqxs.png" alt="enter image description here" /></a> <a href="https://i.sstatic.net/woTtzKY8.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/woTtzKY8s.png" alt="enter image description here" /></a> <a href="https://i.sstatic.net/mddgCGHD.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/mddgCGHDs.png" alt="enter image description here" /></a></p>
<p>But the big thing is then: how far can you reliably forecast the position/thickness of clouds for a location?  Usually weather models in preceding days will be off a bit with timing and coverage of clouds for such good blend days [they are often more solid at predicting clear or overcast days].  So you may be able to say &quot;someone in this region will likely have a great sunset&quot;... but probably not the specific locations that will wind up with such.  And often other nearby areas in your potential region may wind up being total busts (under too thick or too little cloudcover).<br />
And either way, it's going to be a bit more involved than knowing just what the direct site's cloudcoverage or other atmospheric parameters are/will be.  Sunset/sunrises are all about how the sunlight has traveled to reach your eyes, and with the low angles at those times, it's all about the many miles to your east (sunrise) or west (sunset) before it reaches you, as all that intervening atmosphere is what makes the colors in the first place.  So you'll probably need more than just an API.  (Cloud coverage percents at heights can give you an idea of the right types of values, but not which direction they'll be in).</p>
<p>But it's reasonably feasible on your computer to download a global NWP model and run some calculations on the national or global output via packages like GrADS or python.  Then each user would just have to query your derived grid of percentage of quality to see what value they have, rather than hit an API and then have it do an instant computation.  And with the added bonus that you could produce maps of probability.</p>
<p>That said, it looks like <a href="https://sunsetwx.com" rel="nofollow noreferrer">someone is already trying this </a>!  His methodology page hits on some of the same concepts... though not sure they're using the best variables (I'd think using cloud layer forecasts themselves are probably much better than loosely inferring it from RH values), so you could try to see how successful you are!</p>
<p>But whatever you do, it's a neat endeavor!</p>
<p>Hope you let us know of your results/page if you do decide to do it!</p>

CC BY-SA 4.0
2024-12-14T10:48:28.547Z
2024-12-14T10:48:28.547Z
JeopardyTempest
<p>Mostly for coding fun, and also because I appreciate the clouds, I am wondering, how could one forecast that clouds will form a beautiful scenery in the sky?</p>
<p>Ideally, I would like to derive it from some &quot;lightweight&quot; weather api, like OpenMeteo, without drilling into more resource consuming upper atmosphere parameters extraction or machine learning, if it can be avoided.</p>
<p>Parameters readily available, and seem to be relevant, among others, are low, medium, high and total cloud coverage, cape and lifted indices, PBLH, visibility, precipitation probabilities and weather code. Sunset and sunrise times, of course.</p>
<p>The aim is to calculate a probability or degree to which today's sunset is going to be a worthy spectacle :)</p>
<p>How do you think this can be achieved, to some feasible level of accuracy?
And if there are upper air params, that would make it more precise, what would they be?</p>

<weather-forecasting><clouds>
Forecasting cloud vista for sunset
Fima Rotter
# Forecasting cloud vista for sunset

(Asked by: username_0 on 2024-12-11)

Mostly for coding fun, and also because I appreciate the clouds, I am wondering, how could one forecast that clouds will form a beautiful scenery in the sky?

Ideally, I would like to derive it from some "lightweight" weather api, like OpenMeteo, without drilling into more resource consuming upper atmosphere parameters extraction or machine learning, if it can be avoided.

Parameters readily available, and seem to be relevant, among others, are low, medium, high and total cloud coverage, cape and lifted indices, PBLH, visibility, precipitation probabilities and weather code. Sunset and sunrise times, of course.

The aim is to calculate a probability or degree to which today's sunset is going to be a worthy spectacle :)

How do you think this can be achieved, to some feasible level of accuracy?
And if there are upper air params, that would make it more precise, what would they be?

**Tags:** weather-forecasting, clouds


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## 1 answers

### Answer by username_1 on 2024-12-14. Score: 1 | Accepted answer

It's something I've thought about myself a fair bit over the years, wondering if such is possible.

I'd think:

* Cloud coverage would be the firstmost factor. Especially in the sun setting/rising direction (which of course does vary a bit by latitude/season). Too thick should tend to often mean little beauty. Though the one caveat is that the sun could peak through underneath the clouddeck minutes before sunset/after sunrise and lead to some of the more spectacular surprises, with all the complex reflection surfaces. So I'd think the most negative factor of all would be thick low level cloudcover extending far into the western (or whatever the sunset/sunrise direction is) sky. Such that you'd see little to none of the sun.  
  On the other hand the right clouds in other areas of the sky may lead to more interesting sunsets/sunrises. I'd think some clouds in other directions, particularly in bands, may increase the beauty at times due to the more complex shapes leading to coloring variety. Or even some more limited, somewhat nearer, clouds that tend towards having higher bases might work ([backed up by this Tweet](https://x.com/NWSPittsburgh/status/1865524431663358254))
* Particulates will also be important. Distant volcanic eruptions and smoke are [well known enhancers](https://www.youtube.com/watch?v=Kzlbr6AaLu4) of sunrises and sunsets as they improve scattering via the variation of particle sizes in the right range. Does the wind advect heavy doses of it into the direction of the sun? Great!  
  Whereas pollution lower in the atmosphere and near the observation point tend to attenuate the light and dull the sunset.
* Lower humidity (at low levels) likely helps a fair bit. Drier days makes the sky [bluer](https://www.rochesterfirst.com/weather/weather-blog/fact-or-faux-are-skies-really-more-blue-during-fall-than-in-summer/), which could aid in contrast, and get you those really classic [orange to blue gradients](https://x.com/CSG1973/status/1865799321360175189).  
  Whereas greater humidity at low levels tends towards more condensation droplets that can absorb light [about universally the greatest absolute moisture levels are found in the low levels of the atmosphere]; foggy days aren't good for sunrises or sunsets. Of course clouds are connected with station humidity, but more-so low-level cloudiness than upper (and so more humidity again hints at clouds being more of an issue than a positive)
* PBL height is an interesting one. Low PBL height suggests lighter winds and tend to be correlated with sinking winds, meaning less low-level cloudcover. But they also then concentrate particulates in that more confined region nearer to the ground... and such conditions often stack up to multiple stale days in a row when under persistent high pressure [the general cause of such conditions], which will grow in haze and negative types of pollution over time. On the other hand, larger PBL can mean the wrong particulates are higher in the atmosphere, and so a larger range of angles near the rise/set will have the light passing through the hindering haze before reaching you.  
  So not sure which is best. Perhaps low PBLs for the first day or two?

[Here's a great discussion that hits on many of these ideas](https://www.spc.noaa.gov/publications/corfidi/sunset/) by severe weather forecaster Steve Cordfidi that may add further insight.

I'm thinking one more key to what we perceive as fantastic sunsets is variety. If we've had overcast for days with little sun, any decent sunset may seem very eyecatching. And if we've seen a long string of clear sky blue-to-orange gradient sunsets, a day with some cloud coverage mixing up the shading some may really draw our attention.

And of course different people may like different sunsets. Thunderstorm lovers like me may find a sunset like the left one more interesting, landscape lovers may find the middle one more interesting, and darker color fans may find the right one more interesting:  
[![enter image description here](https://i.sstatic.net/YFv8qQqxs.png)](https://i.sstatic.net/YFv8qQqx.png) [![enter image description here](https://i.sstatic.net/woTtzKY8s.png)](https://i.sstatic.net/woTtzKY8.png) [![enter image description here](https://i.sstatic.net/mddgCGHDs.png)](https://i.sstatic.net/mddgCGHD.png)

But the big thing is then: how far can you reliably forecast the position/thickness of clouds for a location? Usually weather models in preceding days will be off a bit with timing and coverage of clouds for such good blend days [they are often more solid at predicting clear or overcast days]. So you may be able to say "someone in this region will likely have a great sunset"... but probably not the specific locations that will wind up with such. And often other nearby areas in your potential region may wind up being total busts (under too thick or too little cloudcover).  
And either way, it's going to be a bit more involved than knowing just what the direct site's cloudcoverage or other atmospheric parameters are/will be. Sunset/sunrises are all about how the sunlight has traveled to reach your eyes, and with the low angles at those times, it's all about the many miles to your east (sunrise) or west (sunset) before it reaches you, as all that intervening atmosphere is what makes the colors in the first place. So you'll probably need more than just an API. (Cloud coverage percents at heights can give you an idea of the right types of values, but not which direction they'll be in).

But it's reasonably feasible on your computer to download a global NWP model and run some calculations on the national or global output via packages like GrADS or python. Then each user would just have to query your derived grid of percentage of quality to see what value they have, rather than hit an API and then have it do an instant computation. And with the added bonus that you could produce maps of probability.

That said, it looks like [someone is already trying this](https://sunsetwx.com) ! His methodology page hits on some of the same concepts... though not sure they're using the best variables (I'd think using cloud layer forecasts themselves are probably much better than loosely inferring it from RH values), so you could try to see how successful you are!

But whatever you do, it's a neat endeavor!

Hope you let us know of your results/page if you do decide to do it!


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