Published on: March 15, 2009 at 8:39 AM

STS119-S-001 [Converted]

Forecasting the weather for Space Shuttle launches and landings is a critical part of the process.

The weather rules for a shuttle launch are very clear and the launch weather officer and her team will call for a no-go if any of them are violated.

Fortunately for us hoping to watch the Shuttle lift off tonight at 07:43:46 p.m. EDT, the meteorologists say there is an 80% of acceptable weather conditions at launch time.

According to NASA, the main concern is for a slight chance of a low cloud ceiling at Kennedy Space Center. Two transatlantic abort landing (TAL) sites are forecast to have acceptable weather today. Only one TAL site is required to be “go.” There are no weather concerns at the alternate landing site at Edwards Air Force Base in California.