Up on the roof. near the edge (Before it starts to drop off. lay a inverted "V" of Dicor non-self leveling caulk.. Just lay a bead the peak of the inverted V is above the center of the door and the ends a few inches either side
Make it fairly flat (You only need about 15 Degrees off inline)
Hopefully the water will hit it and run off the ends of the V on either side of the door.
I do not currently have THAT problem.. YEt..
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times