UEFA on alert as weather warning hits Nations League: Will Germany vs Cristiano Ronaldo’s Portugal be called off?

An unexpected variable is silently threatening the spectacle—an approaching storm system that has put UEFA on alert.

A battle between European heavyweights looms large in Munich on Wednesday night as Germany hosts Portugal in the UEFA Nations League semifinals, with a place in Sunday’s final on the line. But while tactical duels and star power dominate pre-match talk, an unexpected variable is silently threatening the spectacle—an approaching storm system that has put UEFA on alert.

This highly anticipated encounter pits Germany...