Today's launch window is still set for 18:07 to 20:07 GMT.
The launch window includes two Collision Avoidance blackout periods, at 18:20 and 19:55, because of the possibility of collision with orbiting satellites.
The thermal Chilldown of the mobile launch platform has begun prior to the cryogenic fuel being loaded.
Today's launch attempt has been cancelled. The New Horizons mission control centre at the Johns Hopkins University Applied Physics Laboratory suffered a power cut this morning due to thunderstorm activity in the area. Launch Pad winds will are from the east at 12 to 18 knots, and low ceiling clouds are moving in from the Atlantic associated with the easterly flow.
Tomorrow's launch window extends from 18:08 to 20:07 GMT (1:08 to 3:07 p.m. EST).