Houston interstates help form clouds overhead

If you were driving through Houston on Tuesday morning, you likely would have seen concentric circles and a grid of clouds over H-Town. We aren't talking about crop circles or aliens here, but about interstate-induced clouds.

On the loop below, you can pick out many of the city's freeways, especially on the west side of town. You can even pick out the curvature of Interstate 69 around Rosenberg on the southwest side. I-45, the Northwest Freeway, the Tomball Parkway, I-10 and multiple of the city's beltways are all visible.

These clouds were kick-started by the heat of the interstates themselves. The asphalt warms considerably faster than the greenspaces around them. The morning traffic likely contributed by adding more heat through the friction of the tires on the warming pavement.

(Watch: Shelf cloud signals the arrival of a storm)

But you need moisture for clouds, too.

A trip to your car was likely sweat-inducing and that is exactly what led to this strange arrangement of clouds. The dew point was in the muggy mid-70s and temperatures were climbing through the upper 70s and low 80s. That's a relative humidity falling from 100% to 85% as the temperature was rising.

Winds near the interstates were light and out of the east, allowing towering clouds to rise vertically with a slight westward or southwestward lean. They weren't quite tall enough to reach the jet stream with winds screaming toward the east, or those same clouds above the streets would have been pushed east, too.

(Not the same thing: Cloud streets seen over Georgia)

Unfortunately, the same air you can wear is what led to the interstate clouds' demise. Thunderstorms erupted over Galveston Island and swept inland to Baytown before sending out a cooling outflow boundary toward Houston. The map in the sky was no more after that mini-cold front took away all of the ingredients that made it possible.

Quarter-size hail was later reported in Harris County as daytime heating really caused storms to flare up.

You can see the full loop of these clouds here.

Jonathan Belles has been a digital meteorologist for weather.com for 10 years. His favorite weather is tropical weather, but also enjoys covering high-impact weather and news stories and winter storms. He's a two-time graduate of Florida State University and a proud graduate of St. Petersburg College.