"It's scattered thunderstorms, but as far as we're concerned, we're running a marathon no matter what," said Ellis.
"We're running matter what," agreed Mathers.
And marathon veterans are offering encouragement.
"It's great fun. These kids will have something to look forward to if it rains a lot," said 19-year marathon veteran Mike Mathers.
But the forecast of rain and possible lightning is serious business for race organizers. If there is lightning at the beginning of the race, they can delay the start time for up to an hour. They can also temporary stop the race and wait for lightning to pass.
"The plan is to move people as we can, parking garage, good choice, underpass good choice," said Dr John Cianca. "Any place other than a place in a wide open place and away from a tree or whatever conducts electricity."
If severe weather forces the cancellation for the race after it's already begun, officials will move the runners to various large gathering spot, pick up the racers and transport them to the finish line.
"We've never had to do it before. W've only drawn this up on paper," said Dr. Cianca. "We think it will work, but until it happens we don't know."
Cancellation is the worst case scenario and something no one wants. So for now, everyone's staying positive.
"Right now the weather conditions are green, and if they go to black they'll cancel, but as long as they're green in the morning when I wake up, I'll go running," said Mike.
Click on this link for complete coverage of the Chevron Houston Marathon. And don't forget to watch the race starting at 7am Sunday on ABC13 and streaming live here on abc13.com.