  To improve the forecasts of weather extremes, we propose a joint spatial
model for the observations and the forecasts, based on a bivariate
Brown-Resnick process. As the class of stationary bivariate Brown-Resnick
processes is fully characterized by the class of pseudo cross-variograms, we
contribute to the theorical understanding of pseudo cross-variograms refining
the knowledge of the asymptotic behaviour of all their components and
introducing a parsimonious, but flexible parametric model. Both findings are of
interest in classical geostatistics on their own. The proposed model is applied
to real observation and forecast data for extreme wind gusts at 119 stations in
Northern Germany.
