The three-days-out launch range forecast has been issued for Orbital ATK’s Antares rocket with Cygnus cargo spacecraft on the company’s CRS-9 resupply mission to the International Space Station. There is a very slight chance of thick clouds over the region for the launch attempt, scheduled for 5:04 a.m. EDT on May 20 from the Mid-Atlantic Regional Spaceport at NASA’s Wallops Flight Facility on Virginia’s Eastern Shore.
The main weather concern for the launch attempt is sky screen. Low-level cloudiness (1,000-foot ceilings) is expected for the launch window on the morning of May 20.
A persistent wet and unsettled weather pattern will remain over the Wallops region through Saturday, providing numerous chances of showers and thunderstorms. A quasi-stationary frontal boundary will move north of the Wallops region Saturday as a warm front, while a final piece of upper level energy will move through the Wallops region Saturday morning and afternoon, with a chance of showers and possibly thunderstorms.
Weak upper level energy will move east of the Wallops Region Saturday night into Sunday morning in combination with a Bermuda high pressure system building into the Wallops region to end precipitation chances. However, there will be a slight chance of a lingering rain shower during the beginning of the count.