NASA says the weather prediction will decide whether it makes a third try to launch its Artemis 1 round-the-moon mission next week, after a successful test .
This isn't just old weather; a tropical depression in the Caribbean Sea has the potential to develop into a hurricane that will strike the Florida coast.
At the moment, NASA is continuing with launch preparations for next Tuesday's launch from Florida's Kennedy Space Center.
Ideally we're calling it Plan A since the cryo test was a success, and right now we don't have a prediction that violates our weather criterion."
The latest forecast computer models from the National Weather Service for the storm system now labelled as Tropical Depression 9 may force a modification in that strategy.
Wednesday was spent testing the fixes and new processes that have been implemented.John Blevins, NASA's chief engineer for the SLS programme.