Venus, a UFO, or a spy blimp?

At about 3:30pm today I saw a large, white, stationary object high in the Los Angeles sky. I was next to the Bird Sanctuary in Griffith Park at the time. I'm pretty sure this was too large to be a star or a planet, and anyway Venus is currently to the southwest, but the object was more SSE. I didn't take a bearing, but I'm pretty sure this wasn't to the west.

The object looked like it was at an altitude of at least a mile or two, and it did not move in the five minutes or so that I was observing it. However, after driving away and looking for it about 15 minutes later, I could not find it.

Was this Venus? Or, perhaps friends from across the galaxy coming to pay us a visit? Or, could it be a blimp or large balloon of some kind?

Perhaps it was just a weather balloon. Yeah, that's it.