It's still more than two hours until liftoff time, but conditions aren't looking great.
Brevard County, home to the Kennedy Space Center launch site, was briefly under a tornado warning. That warning ended at 2:15 pm ET without any visible twisters coming near the launch site.
Flashes of lightning and thunder claps are a common occurrence, but weather officials are hoping it will pass before takeoff at 4:33 pm ET.