At first there were just big puffy clouds - sitting atop their pillars of warm air
Gathering together and getting darker
Some of the clouds began snaking out from behind the dark cloud bank
Darker and swirling
At last the sky was dark - it was time to pack up and go home
Where the skies were still blue (20 miles south) and then we looked up and noticed the edge of the storm front passing right over our house.
The storm was coming to greet us.
All photos are SOOC - no post editing - taken with my Canon PowerShot SX30IS - which zooms to 140x.