Weather promising for Discovery's Tuesday launch

The forecast is promising for the planned 1:36 a.m. Tuesday launch of space shuttle Discovery from Kennedy Space Center.

Air Force meteorologists predict a 70 percent chance of good weather conditions for the launch, with a slight chance of clouds or showers too close to launch site.

You can read the official forecast here.

A possible concern is the 30 percent chance of lightning within five nautical miles of launch pad 39A when fueling is supposed to begin around 4:20 p.m. Monday.

NASA rules say there cannot be more than a 20 percent chance of lightning during the first hour of fueling, as more than 500,000 gallons of explosive liquid hydrogen and liquid oxygen begin pumping into the shuttle's 15-story external tank.

The launch countdown officially begins at 11 p.m. today.

A first pre-launch news briefing is set to begin shortly, starting at 10 a.m.

NASA Test Director Steve Payne will update progress preparing Discovery for its 37th flight, a 13-day supply mission to the International Space Station that will include three spacewalks.

You can watch the briefing live here - click on the NASA TV still image at right to launch a viewer.