"John" wrote in message
...
I had a new roof put on in 1998, with a 10 year unconditional warranty.
Water is coming in though a window casing. Apparently snow on the roof is
melting, coming in though the roof, coming down the Cathedral ceiling into
the wall, and then leaking through the window casing.

Sounds like what they call "Ice Dam".
There is some special rubber stuff to avoid this condition.
New roof shouldn't do it.
Google "Ice Dam damage"