Nova Scotians are being asked to avoid unnecessary travel during Fiona's visit.
RCMP expects the extreme weather to cause hazardous driving conditions, decreased visibility and possible hydroplaning on roads and highways.
"Drivers may also encounter wind-blown debris on the road and sudden flooding which can be dangerous for motorists and detrimental to highway conditions," Mounties said in a news release.
They say if you have to go out, give yourself plenty of extra time, slow down and watch for pooling water.
Let someone know where you're going and if you have to stop, use your hazard signals.
And remember, if you encounter traffic lights that aren't working, you're required to treat those intersections as all-way stops.
Mounties are also asking people to stay a safe distance away from the shoreline.
"Well away from the water's edge and stay completely off rocks, breakwaters, and piers where waves are breaking," police explained.
"Storm-driven waves and tides can cause unpredictable and deadly conditions, as anyone close to the coast could be swept into the ocean."