Clouds Tutorial

Low, Mid, High Clouds Parameter

This parameter shows the cloud cover between 0% and 100%. The parameter is divided into the Low, the Medium and the High clouds. These correspond to specific altitude ranges, which can be taken from the figure.

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Color overlay

When a time is selected, the color overlay loads. Loading is indicated by a small loading icon at the bottom right of the map. If there are no clouds in a region, then the map remains empty. The denser the white color overlay is at a location, the denser the sky at that location is covered with clouds.

The scale can be used to translate the color overlay into a numerical value and thus determine how high the degree of cloud cover is at a location.

In order to be able to see the cloud forecast well, it is useful to use the “Satellite” background map. The background map can be changed on the corresponding icon.

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Opacity

The degree of coverage indicates what percentage of the sky is blue and what percentage is gray. With an opacity of 50%, this means that 50% of the sky is covered by solid clouds. The other 50%, however, is clear blue sky.

It does not mean that the sky is covered with a single layer of clouds, 50% of which are transparent. In the example photo you can see a coverage of about 50%. There are blue portions and cloudy portions of the sky in equal measure.

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Forecast accuracy

This is a forecast generated by computer calculations, therefore there will always be deviations. The clouds will not appear exactly as the forecast indicates. The forecast is more precise for large, connected cloud fronts than for small, local cloud fields.

Therefore, there will be deviations of a few kilometers. For large cloud fronts this deviation is not noticeable, but for local cloud fields it is. Therefore, the forecast for large cloud fronts is always somewhat more accurate.

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Common things about weather forecast you should know!

Computer Simulation

The weather forecast in VIEWFINDR is a computer simulation that very realistically forecasts the coming weather. However, the forecast is not exactly the reality and there will be deviations.

In VIEWFINDR new weather data is provided every 3h. For example, if you check for the probability of afterglow after sunset in the morning hours, the forecast will change several times over day. This is perfectly normal and that’s a good thing!

The closer the deadline, i.e. the sunset in the evening, the smaller the deviation of the computer simulation from reality becomes. The forecast becomes more precise. Before you finally set out to take pictures, you should therefore take another look at the current forecast.

You should therefore check the forecast again before you start your photography tour to see, if the probability is still high. Don’t be mad if the forecast probability changed into worse, it probably saved you from a bad outcome!

The weather forecast in VIEWFINDR is limited to 24h for local weather models and 72h for continental weather models. It is not useful to look into the future for a longer period. The forecast becomes inaccurate and is not reliable. Weather apps that allow forecasts of more than 3 days but do not provide any indication that the forecast is extremely inaccurate are a disgrace. This gives the

Weather Data Resolution

Just as the resolution of your camera is limited, i.e. it cannot take an “infinitely” sharp photo, the resolution of the weather model is also limited. This is 2.8km for Central European weather data and 7km for European weather data.

Structures and features of the landscape that are not that large are averaged by the model. For example, if a mountain is 800m high, and the valley next to it is 400m high, then the landscape for the weather model in that “pixel” is 600m high, corresponding to the average altitude.

This means that small structures, like narrow mountain valleys or local small river valleys cannot be properly captured by the model. This is not a problem, you just have to learn to deal with it. If a valley in the mountains is much smaller than the resolution of our weather model, then you have to interpolate.

Small valleys always end in larger valleys. You can therefore use the weather in the next larger valley as a good reference for the weather in a smaller, adjacent valley. In the example, you can see that the large valley is filled with fog. It is almost certain that the small valley is also filled with fog.

Due to the limited resolution, it makes sense not to use too much zoom. It is important that you look at the overall context. Therefore, consider the weather forecast not only for your location, but at least for the entire region where you are shooting.

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This example show how the weather model sees the landscape. It is pixelated because of the limited resolution.

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Due to limited resolution, this layer of low clouds/fog will not indicate fog in valleys with a size below the resolution.