How to stop water leaks windshield, front floor?

I'm fighting with my own battles with water leaks on my 99 Blazer. They are hard to track down sometimes. Dissemble the cowl vent panel. Check in there and make sure it is free of debris. Sometimes the water drains get clogged up and the water backs up inside the vehicle. Also check the corner drains where the fenders meet the doors. Same thing happens here, especially if you park it under a pine tree. Those darn pine needles.

Also check all of your door seals. I found my leak and it turned out to be poor contact where the upper window frame on the door was not making good contact with the rubber seal.