They are exceptionally complex and take years to develop, Droegemeier declares. Some have been retired and are obsolete, having been tried and found wanting. However, dozens more based on the numerical weather prediction concept are currently in use and are being refined every day. When errors occur, those errors can increase exponentially as the models run. Coming to a weather forecasting station near you is a rather new methodology called the Ensemble Approach.
Ensemble forecasting is a sophisticated technique that meteorologists now are putting to good use.
Droegemeier explained why. The use of ensembles, or multiple models, stems from the fact that the atmosphere is chaotic, and we never know exactly what the state of the atmosphere is when we start a forecast. Somewhere Over the Rainbow . . . Yes, we have extremely powerful supercomputers. The software versus hardware debate continues.