Drain holes on the window plugged?

"Don Phillipson" wrote in message
...
Problem occurs only in north wind and
rain, in only one north-facing window, a
non-opening half-moon over a large sash
window. There is a substantial windowsill
below the half-moon and above the sash
window, and water enters where this horizontal
sill meets the vertical part of the window.

This leak first appeared last fall, when I tried to
fix it by silicone caulk outside, finger-smoothed
into two small visible cracks in exterior finish
(oil-based stain) in the vertical/horizontal corner.
This seemed to work OK but the problem recurred
recently (2 inches of rain in a day in north wind.)

But I now see outside no visible cracks down in
the corner -- only cracks along the edge of the
putty (20 years old) that holds the window glass,
extending about half the width (3 ft. overall.)
Could rainwater enter at this point and travel down
the wood (under the finish) at least one inch, and
then another two inches horizontally to enter the
house?

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)