Thunderheads
When the cumulus turned into real clouds, one thing in the sky was left behind: the storm. Its front was still built from translucent grey slabs, and a wall of masonry marching across the island never quite looked like weather. Today the storm gets the same clouds as everyone else.
A front you can read from across the map
On storm rounds a line of thunderheads walks across the map: a low, ragged, rain-black base you can fly under, towers boiling up through it, and a flat anvil sheet spreading at the top and leaning the way the storm is heading. They're cut from the same soft puffs as the fair-weather cumulus and lit by the same sun, so the storm looks like part of the sky rather than something parked in front of it.
Where the front walks, it swallows the fair-weather cumulus in its path, and gives them back once it has passed. The rain under it falls in soft grey curtains now, feathered at the edges, and the streaks still come down around your canopy when you fly into it.
Lightning from the inside
Every stroke lights up the cloud it comes out of. The puffs around the flash flare blue-white while the cells beside them stay dark, and a strike three kilometres away still lights its belly through the rain. After dark that's how you find the storm at all: a black shape on a black sky, until one tower lights up from within.
Same storm, every theater
The tank crews on the Brick Steppe watch the same line of thunderheads come over the grass, and the captains on the Brick Sea see it coming across the water. Every player sees the same storm at the same moment, flash for flash.
Keep an eye on the horizon.