If the water is coming in from between the rubber and the glass it can be fixed by back-filling with urethane. The rubber doesn't actually make a seal, there is a band of adhesive (urethane) that "glues" the w/s to the metal frame. That inside piece of rubber is cosmetic only. You may have a w/s that was replaced poorly and the torrential rain just exposed its weak points.
Get a good caulk gun (21:1 compression or better if you can), and buy a tube of w/s urethane. Cut the tip about 1/8 in down from the top at a 45 angle. Pump the urethane between the rubber and glass from the inside. Start and finish about 6" on either side of problem area and use a popsicle stick to paddle the extra down in there. Don't try to clean up excess until it dries or you will just make a big mess. Any squeeze through can be trimmed off with a razor blade in about 12 hours.