Updated: Sep 26, 2019
A cloud with a fat, rolled rim at the top is promising sign of a thunderhead in development.
An even more promising indicator are rings spreading away from the cloud top, signaling classic supercell anvil formation is well underway and a thrilling sky show is about to play out.
As the cloud swells into multi-layered magnificence, it makes the heart swell with excitement.
Lightning flashes in its core and the air rumbles in response from explosive heat expansion.
Counting seconds from flash to rumble tells me the storm is still more than seven miles away. Close enough to warrant retreat inside the house. Lightning travels a long way in short time.