RadarWatch:
An early warning system for approaching rain

The rainfall radar of the Dutch MET office both indicates where rain is falling and how much. A series of radar images at 5-minute intervals allow you to see if the rainfall is becoming heavier and the direction in which it is moving. These data are used by a new software module, called RadarWatch, which was developed in association with the online weather service ‘WeerOnline’.
 

Current and previous radar images are used to forecast the rainfall’s movement based on a mathematical method called ‘interpolation’. RadarWatch downloads the forecast radar images for the grower’s location via the Internet every 5 minutes. These forecasts are then incorporated in a grid of 5 by 5 pixels, with each pixel representing a surface area of 2.5 by 2.5 kilometres.

The user can set a weighting factor for every pixel in the grid. This enables a certain area in the grid to be weighted more heavily in calculating the rainfall index. The higher the index, the greater the likelihood that it will rain during the forecast period. The index for the next 25 minutes is shown in the weather station window.

The rainfall index for the next 25 minutes is shown at the bottom of the weather station window.

This rainfall index will soon be available as a readout in the MultiMa process computer. This means, for instance, that as soon as the index exceeds a pre-set value, the computer will be able to close the vents to a safe position before it starts to rain. In order to make sure that RadarWatch operates correctly, we recommend installing an atomic clock on the Synopta Server. Please note that RadarWatch is only available in the Netherlands for now.