From an article in today's OC Register:
"The largest rocket ever to be launched from the West Coast blasts off Thursday afternoon with a secret payload from Vandenberg Air Force Base, and the contrail should be visible from Orange County.
The unmanned Delta IV Heavy Launch Vehicle at 235 feet is 51 feet taller than the space shuttle and its propellant tank on the launch pad.
It's scheduled to soar into space at 1:08 p.m. on what should be a mostly clear, windy afternoon. Orange County residents who look to the northwest should be able to see the white contrail of the rocket.
'It's the largest vehicle ever launched from the West Coast, including the Titans launched in 2006,' said Vandenberg spokeswoman Jennifer Green. 'Definitely, you guys might be able to see this one.'
Read the rest of the article here.