It now says the chances of Sunday's planned shuttle launch being scrapped are going up because of storms expected to hit central Florida.
Shuttle weather officer Kathy Winters says there's a 60 percent chance bad weather will force a scrub, up 20 percent from Friday.
Winters says they're still hoping the sea breeze will push the storms far enough away for Atlantis to take off at 4:30 p.m., Eastern.
She says the weather looks better Monday and Tuesday, in case Sunday is a no-go.
NASA officials are also checking to see if a lightning strike Friday at the launch pad caused any damage.