Roof leaks only during driving rain from one direction

What we told them

Directional leaks are wind-driven ingress, not a hole. Water is being pushed horizontally under laps or around a flashing that sheds fine under gravity alone. Inspect the windward side: mortar fillets at the abutment, flashing laps and any penetration facing west. Roofers who look for a hole in the field of the roof will find nothing, which is why this one gets misdiagnosed repeatedly.