Looks ominous, doesn’t it, this supercell in Julesburg, Colorado, USA.
The plains of Nebraska are no strangers to extreme stratospheric conditions, as these clouds in West Point demonstrate.
Deep blue sky to the left, but a huge bank of cloud heralds an oncoming storm in Hampton, Arkansas, USA.
Noctilucent cloud as the name suggests is a bright cloud at night-time. When an aurora backdrop is added to the scene, as happened recently in Scotland, the effect is stunning.