Play through the day can impact what is seen on certain lanes through the house. The centers in this area do not always run the lanes prior to the early shift, so you may be bowling on carrydown from open play during the day.
Weather can be a factor (as others mentioned) as can the construction of the center. I bowled in a small (6-lane center) that weather conditions created a situation where you knew that lanes 1 and 6 played the same, 2 and 5 played the same and 3-4 were pretty close to each other but still significantly different from the outside pairs. When bowling the 3-game sweepers in there, knowing the house gave locals the advantage of those from out of town.
Following on the comment of 'bones about the oiling habits, even the location of the machine can be a factor. Left against a cool wall, it can take a few lanes for the viscosity to become a little more consistent. Also, some machines take a few passes to really get going (moreso I believe with the older Century type machines than with the Phoenix and other newer equipment).
And, lets not forget that it could be a mental thing...
