The northern lights may appear across the skies of Washington and northern Oregon on Sunday night. It promises to be an electrifying rarity for the region. A severe geomagnetic storm alert is in effect through Monday, triggered by G4 storm conditions detected Saturday. The Space Weather Prediction Centre confirmed the storm's intensity, which could push the aurora far south of its usual haunts. Visibility, however, will depend on only one thing: cloud cover. If the skies stay clear, the show could be spectacular. The National Weather Service warned that geomagnetic activity is erratic. It rises and also fades. Expect sudden shifts in intensity as the storm plays out. Want a shot at catching the spectacle? Get away from urban glare. Move closer to a darker area. The storm should taper off by Monday night. The window is brief. All eyes should be up to see it.