Screening smoke

Fog forecast

When it comes to fog in landscape photography, photographers get picky. Our Fog Veil algorithm detects fine, localized layers of fog that can appear after clear nights in grasslands or over bogs, for example, as well as dense fog in river valleys. Just search for a photo spot when the parameter suggests it to you.

Wetterparameter Viewfindr

Check screening smoke parameter

From the parameter menu choose screening smoke. The weather parameter will now be an overlay of the map. The more transparent the map, the higher the probability for screening smoke. Best chances are at sunrise.

Choose “Outdoor” map background

Screening smoke will be found in valleys or flat land. You will see that the probability is higher in valleys, compared to the surrounding hills.

Choose the right photo spot

For the most success, choose photo spots located in valleys or with a good view over a valley. Simply click the photo spot icon on the map. VIEWFINDR only shows photo spots which are suitable for screening smoke, when chosen. Choose photo spots in the areas with a transparent map.

“Screening Smoke” Tutorial

Play Video about Screening Smoke

Fog forecast with VIEWFINDR

Fog Parameter

The fog parameter predicts fine fog veils on meadows, moors, lakes. In narrow river valleys in the mountains, the “fog” parameter indicates whether they are filled with fog. For supra-regional dense fog, which also penetrates into cities and fills whole areas, see the “Dense fog” parameter. The transition from soft veils of fog to dense fog is smooth. If you want to predict fog, look first at the “Fog” parameter and then at the “Dense fog” parameter to estimate the thickness and height of the fog

smoke screening App
The right time of day

In most cases, fog forms overnight. The probability of fog is highest at sunrise. The fine veils of fog dissipate shortly after sunrise. Sometimes fog veils can occur in the evening as well. Use the timeline to change the time of the forecast shown. Look for fog first at sunrise.

Probability

The scale indicates how likely fog haze will occur at a location if it meets the conditions (meadow, bog, heath, floodplain, lakes, and river valleys). The overlay works like a template. The more visible the background map, the higher the probability.

The yellow color marks places with especially high probability. This is a numerical calculation of fog fields by the weather model.

The red color marks places where fog appears below freezing point temperatures, resulting in hoar frost deposit.

weather forecast made easy
Fog with the "Fog" parameter

The “Fog” parameter always indicates a much larger area covered by fog compared to the “Dense fog” parameter. If the fog layer has a thickness of less than ~50m in clear, visible sky or if it is only small fog swaths on a meadow, the fog is predicted only with the parameter “Fog”. 

fog heigh forecast for landscape photographers

The fog will always be most thick in the center of the predicted area that will be covered with fog. There is always a smooth transition between fog-free areas and the center of the fog layer, where the densest fog is located. 

Fog with the "Dense Fog" parameter

If a fog layer with a thickness of more than ~50m is predicted, the layer will be covered by the weather parameter “Dense fog”. It is important to always compare both parameters to know how thick the fog layer will be. In this example, the “Fog” parameter covers a larger area than the “Dense Fog” parameter. 

weather fog map
Hoar frost with the "Fog" parameter

If fog occures in air which is below the freezing point of 0°C, the undercooled droplets will freeze, if they hit surrounding structures, like trees, grass, and stones. If the fog continues while the temperature stays below freezing point, the deposited hoar frost thickens. After several hours a nice layer of hoar frost built up, resulting in a nice winterly landscape.

Over the years we discovered some rules of thumb, regarding the amount of time a landscape needs to stay within freezing fog to have a useful amount of hoar frost built up:

> 6h the hoar frost is noticeable
> 12h the hoar frost is good visible
> 24h the hoar frost is utterly beautiful

If you want to visit a photo spot, you need to check the weather data hourly and count up, how many hours one place will stay inside the ice depositing fog. You need to check the fog parameter every day, when the period is more than 24h.

As soon as the fog will dissolve for the place where hoar frost deposit was forecasted, the hoar frost will start falling of the trees. You have to visit the place asap after.

Respect the terrain

The biggest factor in predicting fog is the terrain in which the fog is predicted to occur. It’s best to think of fog as a liquid being poured onto the landscape. So be sure to note which of the categories your photo region fits into:

1. vast flatlands

If our “fog” parameter shows a high probability or even the yellow color markers, then you can expect fog veils up to a height of ~50m above the ground on meadows, moors, lakes and in the floodplains. The fog layer is uniform for kilometers. The higher the probability and the more yellow areas shown, the denser the fog. Fog that reaches a thickness of >50m is covered by our “Dense fog” parameter.

2. hilly terrain

In hilly terrain, fog accumulates in the valley bottoms. Therefore, at photo spots that are located in a local valley bottom, there will be significantly denser fog. Hills may locally peek out of the fog, although the weather forecast looks like the fog is uniform across the landscape. The local weather model has a resolution of 2.8km x 2.8km, structures of the landscape smaller than this are not resolved.

3. narrow river valleys and lakes in the mountains

Narrow river valleys and lakes in the mountains are an exception. The water increases the humidity in the valley enormously, so that if there is a high probability of fog, the river valley is often completely filled with fog, while there is much less fog in the flat surrounding area.
The problem: Those very river valleys are often much smaller than the weather model can resolve. Therefore, it looks like there is the same probability in the river valley as in the surrounding area. In reality, the probability of fog in the river valley is always significantly increased!

smoke screening app

High probability of fog in the plains of northern Italy. Even if it indicates fog inside closed cities, there won’t be any. 

Fog in the mountains

The weather model can detect low clouds clinging to mountain peaks and interprets them as fog. In this case, isolated yellow markings appear on the map in mountainous regions. With the help of the background map “Outdoor” it is possible to recognize which mountain peaks will be covered by fog. With the eye tool, the overlay can be easily hidden, making it easier to examine the map.

The background map should be set to “Outdoor”. Now valleys and hills can be seen. The fog will always gather in the valley.

fog in the mountains

Local yellow color overlay over a mountain top indicates that this specific top will be covered with fog. Compare with the altiude indicator lines.

Choosing the right photo spot

The weather model sees the landscape idealized and cannot resolve small towns and villages. Even if there is a high probability in the forecast for your city, there will not be any delicate fog patches in urban landscapes. Therefore, it is important to choose the right location.

Seek out places in valleys and lowlands if the probability is high. Choose places like bogs, meadows, floodplains and lakes. In narrow river valleys with steep slopes, the fog may well be very dense; in the flat country, it is more likely to be fine veils of fog. A high probability refers exclusively to these landscapes.

Set the filter for the views to “Weather specific” to get only views shown that can be photographed well with fog veils.

Small local valleys

Due to the limited resolution of the weather model, small local valleys cannot be captured. However, the weather is stable over short spatial distances and there is a deviation that you can neglect.

If fog is predicted in the next larger valley, then the same probability applies to the small, local river valley that cannot be captured by the weather model if the large and small river valleys are similar in nature: Elevation, vegetation, amount of grassland, etc.

fog forecast in a valley

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.

best app for photo spots

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

weather forecast for photo spots

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

Link a photospot

When uploading a new photospot you guide other photographers. Connecting a photospot to the screening smoke parameter is not “making a wish”. Only connect photospots which actually can be photographed with screening smoke. Look at our example images.

How the algorithm works

You probably know those kind of sunrises with a thin layer of fog over the grassland. When we enter a night with a clear sky, the surface gets cold. The earth radiates heat into space and cools down as a result. After some time, a thin layer of smoke arises.

For the smoke layer to not be destroyed by wind, it need to be calm. VIEWFINDR developed a weather forecast algorithm to forecast the probability of screening smoke for the needs of landscape photographers. We calculate cloudiness, wind speed and air humidity into out screening smoke parameter.

Weather parameters

Burning red sky

Burning red sky

Based on 3D cloud, rain and sun position we calculate red afterglow propability.

Fog layer height

Know which mountaintops to visit for “over the cloud” shots of photospots.

Thunderstorm cells

Numerical calculation of storm position relative to photospots.

Clear night sky

See which nightscape photospots will have a clear night the next days.

water reflection

Find perfect water reflections for your landscape photos.

Visible sunriseset

Cloudfree sunrises are more beuatiful than grey skies in the morning! We forecast them.

Structured sky

We forecast the perfect amount of cloud cover for long exposure photography.

Photo contrast App

You don’t need grey skies. We forecast when the sun is shining at your photospot.

Blue hour

Forecasting when the blue hour has no clouds in the sky with perfect light conditions.

Screening smoke

A fine layer of fog in the grassland is pretty nice to shoot. We forecast the propability.

Our Weather parameters

Burning red sky

Based on 3D cloud, rain and sun position we calculate red afterglow propability.

Fog layer height

Know which mountaintops to visit for “over the cloud” shots of photospots.

Thunderstorm cells

Numerical calculation of storm position relative to photospots.

Clear night sky

See which nightscape photospots will have a clear night the next days.

water reflection

Find perfect water reflections for your landscape photos.

Visible sunriseset

Cloudfree sunrises are more beuatiful than grey skies in the morning! We forecast them.

Structured sky

We forecast the perfect amount of cloud cover for long exposure photography.

Photo contrast App

You don’t need grey skies. We forecast when the sun is shining at your photospot.

Blue hour

Forecasting when the blue hour has no clouds in the sky with perfect light conditions.

Screening smoke

A fine layer of fog in the grassland is pretty nice to shoot. We forecast the propability.

M.Sc. Stefan Engel

Founder, developer

M.Sc. Stefan Engel
B.Sc. Bastian Werner

Founder, CEO

B.Sc. Bastian Werner
Dipl. Met. J. Lang

Founder, meteorologist

Dipl. Met. J. Lang
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