Two methods to forecast auroral displays Fred Sigernes, Margit Dyrland, Pål Brekke, Sergey Chernouss, Dag Arne Lorentzen, Kjellmar Oksavik and Charles Sterling Deehr J. Space Weather Space Clim., 1 1 (2011) A03 Published online: 26 October 2011 DOI: 10.1051/swsc/2011003