In general, it does not matter what your reasons are. Driving faster than the posted speed limit is illegal in all states.
The posted speed limit is always the maximum speed permitted on that particular road. Sometimes you must drive slower than the posted speed limit. You may never drive faster than what is reasonable and prudent under current conditions. Reduce speed when weather is bad, or when there are potential hazards on the road.
In Minnesota, the speed limit on two-lane highways with a posted speed limit of 55 mph or higher is increased by 10 mph when the driver is lawfully passing another vehicle in the same direction.