At least 6 large circular craft hovering in thin cloud cover move across the western sky.

WHILE TRAVELING 1 MILE NORTH OF UKIAH, CALIFORNIA, 1000 FEET BEFORE THE NORTHBOUND LAKE MENDOCINO OFF-RAMP, LOOKING DUE WEST TOWARD THE SUN, THERE WAS A THIN LAYER OF CLOUDS MOVING TO THE EAST.  
THE CLOUDS WERE NOT THICK OR SOLID, I LOOKED AT MY CAR CLOCK AND NOTICED THAT IT WAS 4:43 P.M.  I TURNED BACK TO CHECK OUT THE SUNSET ABOUT 2-3 MILES IN THE DISTANCE (APPROXIMATELY) AND NOTICED (3) THREE SHAPES COMING OUT OF THE CLOUD COVER, THE FIRST ONE WAS FULLY VISABLE AND I THOUGHT IT WAS POSSIBLY A HOT AIR BALLOON COMING OUT OF THE CLOUDS, BUT THEN IT BECOME FULLY EXPOSED AND I SAW IT WAS AN EXTREMELY LARGE CIRCULAR GRAY SHAPE WITH A MASSIVE DOME TOP, THE OTHER 2 WERE THEN EXPOSED AND I SAW THE THREE HUGE SHIPS JUST BEFORE THE CLOUDS CAME AROUND THEM AGAIN. INSTANTLY THEY SHOT ACROSS THE SKY TOWARD THE SUN AND THE COAST AT A SPEED THAT I CAN'T EVEN DISCRIBE.
AS I SAT AND WATCHED, THERE APPEARED 3 MORE HUGE CIRCULAR SHAPES HOOVERING IN THE CLOUDS AND THEY ALSO SHOT RAPIDLY IN SUCCESSION TOWARD THE SUN, DUE WEST.
THIS EVENT HAPPENED IN BROAD DAYLIGHT.  I DID NOT NOTICE LIGHTS OF ANY KIND COMING FROM THE CRAFT.