White sphere rises to dock with momentarily uncloaked cylindrical ship, then both vanish.

While walking on my ranch a white balloon caught my eye as it floated upward.  Thought it was just a party balloon that got loose as I've seen before.  It was too round, so I figured a weather balloon or a test balloon that the hot air balloonists use around here to measure wind currents.  
No reference as to size, it could have been a half-mile or more away.  I was concerned because commercial aircraft regularly fly over around 20-30k feet on one leg of the instrument approach to San Francisco Bay area airports.  
I continued to watch and noticed a couple of black bands around the balloon at angles to each other that I thought was odd but at the distance it now was any detail was lost.  The balloon continued it's assent and I noticed a few small wispy clouds in a clear sky above where it looked like it was heading.  It reached the clouds and stopped it's ascent and appeared to move back and forth horizontally in short movements.  (In hindsight what appeared to be horizontal was probably a small circular "holding" pattern).
Directly above the balloon appeared what looked like a fuselage, cylindrical in shape, military gray/silver, like cold-war aircraft.  However just the bottom of a cylinder, no wings or tail and the clouds obscured the ends of the cylinder.  Then the balloon disappeared as well as the cylinder.
So a craft ascending to the rendezvous marker clouds to meet a cloaked ship that had to become visible for a few seconds so the spherical craft could see to dock to the cylindrical ship....
Witness indicates that the date of the sighting is approximate.  PD