Isaias officially became a named tropical storm on Wednesday night, when its wind speeds exceeded 39 mph. The storm could affect several landing areas just as Endeavour is supposed to reenter Earth’s atmosphere, deploy its parachutes, and splash into the Atlantic Ocean or Gulf of Mexico.
Three of the seven landing zones that SpaceX and NASA prescribed for the test mission, called Demo-2, lie within the “cone of probability” for the storm’s path. Those splashdown sites are located off the coasts of Cape Canaveral, Daytona, and Jacksonville, according to NASA. A July 30 map shows NASA and SpaceX’s landing zones for the Crew Dragon Demo-2 mission amid the estimated path and conditions of Tropical Storm Isaias. The outer-edge green shows a 5-10% chance of sustained tropical storm-force winds. Google Earth; NOAA; NASA; Business Insider
Depending on how large the storm grows and how nasty weather conditions become, mission managers may scrub the undocking and landing attempt. Steep waves, rain, lightning, low clouds, poor visibility (for helicopters to fly the astronauts from a SpaceX recovery boat back to land), or even winds stronger than about 10 mph can trigger a “no-go” decision.
At the moment they are go for undocking on August 1st and splashdown the next day, but that could change depending on how the weather changes.