One morning after torrential rains the night before, got in the driver's side and noticed a puddle of water on the floor (fortunately it was contained by the WeatherTech floor mats we'd gotten). Cleaned it out and got on the road, and just as I was backing up and turning out of the driveway I heard a disconcerting sloshing sound coming from the sunroof area above, and then moments thereafter water drizzled down from the little sunglasses storage compartment above the door.

Did some research, apparently the sunroof although surrounded by a rubber gasket can over time develop leaks, and there are at least 2 maybe 4 drain holes in each corner to catch and channel water down the A-pillar and down some tubing which ends up draining just behind each of the front tires. I used a stiff but pliable piece of wire to run down into the sunroof drain holes, then poured some bleach water down and was relieved to see it happily dripping out from both the driver's and passenger's side drains.

Proof that this worked came just today after another heavy rain; no sloshing, no dripping. Problem appears to be solved.