RNW;

I say that because just about every Amazon owner (or anyone visiting here and reading along) is familiar with incontinent windshield gasket due to hardened rubber or poor seating against the body (or comb of both) which causes this...I suggest you remove the black metal inner trim around the windshield and watch the miniature Niagara Falls as a helper hoses down the windshield outside (you'd be surprised how much can find its way in!)...then dry everything off...wait a couple of weeks (this maybe tough given your alias)...or park the car in a garage for a couple of weeks, then clean, reseal glass to gasket, and gasket to body ALL THE WAY AROUND THE WINDSHIELD...I like black RTV for this...and a fresh windshield gasket (alone) wont even fix this...

The heating/defrost syst air intake has its own (2) drains (tubes on either side of heat exchanger box in egine compartment)...they do sometimes get clogged (especially if rodents have found that spot to be a good winter home)...gently pop out grate (tape covered putty knife under spring clips to assist), then lift out and clear biomass out of plastic tub and heater core under tub...inspect/clear drain hoses...I expect the windshield is the cause though...

Cheers