If your Jeep is commonly parked in an area where there are a lot of trees/leaves, it could be that your cowl drain is plugged. Here's directions on how to clean it out:
Open the hood, and there is a screw along the edge on each side behind the weather stripping, pull those out. Close the hood and pull off the wiper arms, then remove the 4 screws along the top and the one in the louver.
After that you can remove the cowl cover. In the very center underneath is a sheet metal tunnel that runs straight down...that is the cowl drain. There is a rubber flapper on the bottom that you cannot see, but they get plugged up with leaves and debris and cause the area to fill up with rain/car wash water, then spill over and come through your fresh air vents. Take something long and flat, like a yard stick, and stick it down through the flapper on the bottom (you have to feel for it) then turn it sideways to open it up. Use a hose with a sprayer on it and flush it out real good...you should see all kinds of junk coming out from under your Jeep.