We forecast time, position and intensity of thunderstorms in an accuracy for the needs of stormchaser. Be prepared which photo spots can be hit by storm cells to shoot photogenic cloud structures or even supercells.
The parameter is based on a simulated radar image. The weather model not only forecasts a probability of thunderstorms, it exactly calculates the position of the cell. But it’s still a simulation which will differ from reality. There will be small differences in time and place of the simulated storm cells.
The unit [dBZ] is a unit of precipitation intensity. Read more below. Everything above red [50dBZ] will be a thunderstorm. When you swipe the time scale, you can see the movement of the cells. You can see at which time the storms will be in which area and from which direction they will enter.
Safety first. Be sure you can take cover when the storm is close. Open a photo spot in the area with the storm cells. Check if the field of view points in the direction of the storms movement. Check the images submitted to the photo spot, if they provide a good view into the sky.
The thunderstorm and rain forecast in VIEWFINDR shows you every hour how thunderstorm cells and rain areas are distributed. This is a computer simulation, so there will be small deviations from reality. Until we integrate this feature into VIEWFINDR it is therefore important to pay attention to the real rain radar on the day of your photo tour.
Colored markers on the map show where rain and thunderstorms are located at the given time. By changing the time, you can see how the rain areas and thunderstorm cells are shifting. It is a computer simulation of the weather radar at the given forecast time.
With the help of the scale, the colored markings on the map can be translated into an understandable value. The unit is [dBZ]. If a weather radar emits a radar beam, a part of the radar radiation is sent back to the radar by the precipitation. The denser the precipitation, the more radar radiation is returned. The unit [dBZ] indicates how large the part of the reflected back radar radiation is. From 50dBZ it is a thunderstorm cell.
A thunderstorm cell can be identified accordingly by a red core, heavy rainfall areas are shown in yellow on the map. Once you have identified a thunderstorm cell, you can change the time and see in which compass direction and especially how fast the thunderstorm will move.
Since this is a computer simulation, there will be deviations from the real position of the rain areas and thunderstorm cells. Of course, the forecast interval must also be taken into account. The shorter the time interval between the forecast and reality, the more accurate the forecast will be.
For example, if you look at the thunderstorm forecast for the afternoon at noon, the forecast will be much more accurate than if you look at VIEWFINDR the night before. The closer the date for which you are looking at the forecast, the more accurate the forecast. Every 3h the weather data in VIEWFINDR is updated.
The deviations are in the range of a few kilometers for very large rain areas and thunderstorm fronts. For single thunderstorm cells the deviation is around 20km as a rule of thumb.
For thunderstorms you need to choose photo spots that are easy to reach by car. The car is your retreat against the dangers, especially for lightning. The photo spot should offer a good distant view of the approaching thunderstorm. To do this, you can look at the angle of view on the View detail page.
Choose a photo spot in such a way that the thunderstorm is approaching you. The angle of view should therefore point in the direction from which the thunderstorm cell will approach the photo spot.
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
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.
This example show how the weather model sees the landscape. It is pixelated because of the limited resolution.
Due to limited resolution, this layer of low clouds/fog will not indicate fog in valleys with a size below the resolution.
Do only link photo spots to the “thunderstorm” parameter, if the photo spot is easy to reach by car and also provides enough shelter. Do not link a photo spot if you are not sure about this parameter.
This parameter is not a secret algorithm of VIEWFINDR, so we can tell you a little more about. The parameter is a so called “simulated radar reflectivity”. Weather radar measure the atmosphere with radio signals, which they simply send into atmosphere. Precipitation, like rain, hail, snow etc. reflect a proportion of the radio signal back to the emitting radar station, where the intensity will be measured.
The greater the intensity of the reflected radar signal, the greater the density of the falling precipitation. Hence if the intensity of the reflected signal is greater than 50 dBZ, it must be a thunderstorm to create such dense precipitation. The higher the dBZ value, the denser the precipitation. The “Thunderstorm” parameter just shows a possible situation you could find in that way on the real weather radar by the forecasted time.
The simulated radar reflectivity is a numerical calculation. Weather models use such complex equations, that there is not only one solution. Instead, there is an endless number of possible solutions.
As a result, the weather model chooses a solution which is the closest to the ideal, perfect solution (which we will never find). Instead of a probability range like in other weather parameters, this parameter just presents one solution.
The found solution will differ in place and time from reality, but just a little bit. It’s pretty damn good, but not perfect. A storm cell will for sure miss a specific photo spot by a few kilometres, but not a few hundred.