To create its weather forecast DreiTageWetter uses the American numerical weather prediction (NWP) model WRF (Weather Research and Forecasting Model). There are two versions of the model: On the one hand the WRF-ARW (Advanced Research WRF) and on the other hand the WRF-NMM (WRF Nonhydrostatic Mesoscale Model). We use the first mentioned WRF-ARW. The version, that we currently use, is WRF-ARW V3.6.
We obtain the initial and boundary conditions for our simulations from the coarser American global numerical weather prediction (NWP) system GFS (Global Forecast System). The GFS dataset also takes observational, satellite and measurement data into account. Further information can be found on the developers' home page.
Our model domain dimensions are 2000 km in north-south direction and 2000 km in east-west direction. The model domain includes Central Europe with Germany in the mid-region. You will find a graphical overview at our weather maps. The horizontal spatial resolution of our model is about 9.2 km.
The focus of our simulations is weather prediction for Germany. Thus the variety of locations, that you can select, is limited to those, that are located in the German territory. We use two different databases: If you type a place name, a dataset of the Federal Agency for Cartography and Geodesy will be used. And on the other hand entering a postcode leads to a dataset of the project OpenGeoDB. The weather maps of the current weather prediction however show weather information for Central Europe beyond the German national border. Our weather maps are built with the visualization software GrADS.
We execute simulations two times a day that start as soon as the data from the GFS is available. Around 05:45 pm CE(S)T (Central European (Summer) Time) the first simulation is initialized. At night of the next day the second simulation is started. One simulation takes about 6 hours computation time. The second simulation provides an update of our meteorological database and is usually used from about 07:30 - 08:00 am CE(S)T. Our calculating machine occupies four AMD Opteron quad-cores, which are 16 processors altogether. The system runs on a 64-bit Linux operating system.
For further information contact us or visit the developers' home pages of WRF-ARW and GFS, respectively.